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The rice albumin (RAG) gene family belongs to the Tryp_alpha_amyl family. RAG2, specifically expressed in 14–21 DAP (days after pollination) seeds, regulates grain yield and quality. In this study, we identified another RAG family gene, RAL6, which exhibits specific expression in developing seeds, particularly in 7, 10, and 15 DAP seeds. Employing the CRISPR/Cas9 system, we analyzed functions of RAL6 and found that the ral6 lines (ral6-1, ral6-2, ral6-3, and ral6-4) displayed thinner seeds with significantly decreased 1000-grain weight and grain thickness compared to ZH11. Additionally, the cell width of spikelet cells, total protein and glutelin contents were significantly reduced in ral6. The germination assay and 1% TTC staining revealed a significant decrease in seed vigor among the ral6 lines. The alpha-amylase activity in ral6 mutant seeds was also markedly lower than in ZH11 seeds after 2 days of imbibition. Furthermore, co-expression analysis and GO annotation showed that co-expressed genes were involved in immune response, oligopeptide transport, and the glucan biosynthetic process. Collectively, our findings suggest that RAL6 plays a coordinating role in regulating grain weight and seed germination in rice. [ABSTRACT FROM AUTHOR]

Introduction Wheat (Triticum aestivum L.) is one of the oldest and most widely used crops in the world and is the most important source of human food that grows in a wide range of climatic conditions in the world. In arid and semi-arid regions, water is the main limitation. Iran is a dry and semi-arid country with limited precipitations. Therefore, the mean annual rainfall in Iran is even less than one third of the global average. There are many solutions for sustainability in agriculture, one of which is the use of biological fertilizers. Among these biofertilizers are mycorrhizal fungi. The symbiotic relationship between the arbuscular mycorrhizal fungus and the roots of the host plant significantly increases the growth and absorption of plant nutrients. In this research, the aim is to investigate the effect of arbuscular mycorrhizal fungus on improving the yield, yield components, and chlorophyll index of wheat by applying water deficit stress through increasing the interval of irrigation cycles. Materials and Methods This factorial experiment was conducted based on a randomized complete block design in four replications in the research farm of the Azad Islamic University of Miandoab, northwestern Iran in 2021. The experimental factors included the application of arbuscular mycorrhiza fungus species in three levels, control (without inoculation), inoculation with Glomus mosseae and inoculation with Glomus intraradices and three levels of irrigation regimes (i.e. irrigation after every 6, 13 and 20 days). Seeds of Elvand wheat cultivar were inoculated with mycorrhizal fungus, then the inoculated seeds were immediately planted into a depth of 3. Before planting, 15 tons/ha of manure and 25 kig of nitrogen fertilizer in the form of urea were uniformly applied to the soil. During the growing season, 50 kg of nitrogen fertilizer in the form of urea was used during the two stages of stem growth and spike formation. To measure wheat grain yield components, 10 plants were harvested and to determine grain yield and plant above- ground dry mass, 0.25 m-2 was taken from each plot. In this way, after removing two rows from each side and half a meter from the beginning and end of all rows as a margin, sampling of experimental units was done. The evaluated traits included the spikes/plant, grains/spike, the thousand-grain weight, plant aboveground dry mass, grain yield, harvest index, and greenness index Results and Discussion Results indicated that the effect of irrigation intervals and mycorrhiza fungus were significant for grains/spike, thousand-grain weight, grain yield, above-ground dry mass, harvest index, chlorophyll index, photosynthetic pigments and proline concentrations. G. mosseae species increased the grains/spike, thousand-grain weight, above-ground dry mass, harvest index, and chlorophyll concentration compared to G. intraradices species by 5.21, 9.73, 8.86, 6.96 and 4.08% and increased the above-mentioned attributes compared to the control by 29.94, 30.28, 39.68, 27.90 and 21.43%, respectively. The highest spikes/plant, grain yield, chlorophyll index and concentration of chlorophyll a belonged to irrigation interval of 6 days and inoculation with G. mosseae species with 6.34, 612.45 g m-2, 62.89 SPAD unit, and 0.306 mg g-1 FW, respectively. Prolongation of irrigation interval by creating water deficit stress caused the sterility of the spikes and significantly reduced the grains/spikes. The irrigation regime had a significant effect on the grain yield and by reducing the irrigation intervals, the grain yield was increased. The drought-induced decrease in grain yield stemmed from the decrease in green index, chlorophyll concentration, spikes/plant and grains/spike, leading to decrease in the harvest index. With increase in the irrigation interval, the concentration of chlorophyll a and b decreased, but the mycorrhizal inoculation led to significant increase in the concentration of chlorophyll a and b under water deficit stress. The plants inoculated with mycorrhizal fungus suffered less from water deficit stress than the non-colonized plants, and as a result, the concentration of proline increased less compared to the plants deprived from mycorrhizal fungus. According to these results, irrigation of wheat plants every 13 days and application of G. mosseae can produce the desirable grain yield, while decreasing water consumption for wheat production. Conclusions Mycorrhizal fungus increased the plant's resistance to drought stress by improving the absorption of water and nutrients under water stress deficit. G. mosseae was more effective in increasing the resistance of wheat against water deficit stress and as a result, it increased the grain yield, yield components, chlorophyll index and chlorophyll concentration of wheat to a greater extent compared to G. intraradices. In order to make the best use of water resources and soil nutrients, irrigation of wheat should be done every 13 days and must be accompanied by inoculation with G. mosseae to achieve an acceptable grain yield. [ABSTRACT FROM AUTHOR]

Durum wheat (DW) is one of the major crops grown in the Mediterranean area, a climate-vulnerable region where the increase in day/night (d/n) temperature is severely threatening DW yield stability. In order to improve DW heat tolerance, the introgression of chromosomal segments derived from the wild gene pool is a promising strategy. Here, four DW-Thinopyrum spp. near-isogenic recombinant lines (NIRLs) were assessed for their physiological response and productive performance after intense heat stress (IH, 37/27 °C d/n) had been applied for 3 days at anthesis. The NIRLs included two primary types (R5, R112), carriers (+) of a differently sized Th. ponticum 7el1L segment on the DW 7AL arm, and two corresponding secondary types (R69-9/R5, R69-9/R112), possessing a Th. elongatum 7EL segment distally inserted into the 7el1L ones. Their response to the IH stress was compared to that of corresponding non-carrier sib lines (−) and the heat-tolerant cv. Margherita. Overall, the R112+, R69-9/R5+ and R69-9/R112+ NIRLs exhibited a tolerant behaviour towards the applied stress, standing out for the maintenance of leaf relative water content but also for the accumulation of proline and soluble sugars in the flag leaf and the preservation of photosynthetic efficiency. As a result, all the above three NIRLs (R112+ > R69-9/R5+ > R69-9/R112+) displayed good yield stability under the IH, also in comparison with cv. Margherita. R112+ particularly relied on the strength of spike fertility/grain number traits, while R69-9/R5+ benefited from efficient compensation by the grain weight increase. This work largely confirmed and further substantiated the value of exploiting the wild germplasm of Thinopyrum species as a useful source for the improvement of DW tolerance to even extreme abiotic stress conditions, such as the severe heat treatment throughout day- and night-time applied here. [ABSTRACT FROM AUTHOR]

IDEAL PLANT ARCHITECTURE1 (IPA1) is a pivotal gene controlling plant architecture and grain yield. However, little is known about the effects of Triticum aestivum SQUAMOSA PROMOTER‐BINDING‐LIKE 14 (TaSPL14), an IPA1 ortholog in wheat, on balancing yield traits and its regulatory mechanism in wheat (T. aestivum L.). Here, we determined that the T. aestivum GRAIN WIDTH2 (TaGW2)‐TaSPL14 module influences the balance between tiller number and grain weight in wheat. Overexpression of TaSPL14 resulted in a reduced tiller number and increased grain weight, whereas its knockout had the opposite effect, indicating that TaSPL14 negatively regulates tillering while positively regulating grain weight. We further identified TaGW2 as a novel interacting protein of TaSPL14 and confirmed its ability to mediate the ubiquitination and degradation of TaSPL14. Based on our genetic evidence, TaGW2 acts as a positive regulator of tiller number, in addition to its known role as a negative regulator of grain weight, which is opposite to TaSPL14. Moreover, combinations of TaSPL14‐7A and TaGW2‐6A haplotypes exhibit significantly additive effects on tiller number and grain weight in wheat breeding. Our findings provide insight into how the TaGW2‐TaSPL14 module regulates the trade‐off between tiller number and grain weight and its potential application in improving wheat yield. [ABSTRACT FROM AUTHOR]

Grain weight and grain shape are important traits that determine rice grain yield and quality. Mining more quantitative trait loci (QTLs) that control grain weight and shape will help to further improve the molecular regulatory network of rice grain development and provide gene resources for high-yield and high-quality rice varieties. In the present study, a QTL for grain length (GL) and grain width (GW), qGL5.2, was firstly fine-mapped into a 21.4 kb region using two sets of near-isogenic lines (NILs) derived from the indica rice cross Teqing (TQ) and IRBB52. In the NIL populations, the GL and ratio of grain length to grain width (RLW) of the IRBB52 homozygous lines increased by 0.16–0.20% and 0.27–0.39% compared with the TQ homozygous lines, but GW decreased by 0.19–0.75%. Then, by analyzing the grain weight and grain shape of the knock-out mutant, it was determined that the annotation gene Os05g0551000 encoded a RING-type E3 ubiquitin ligase, which was the cause gene of qGL5.2. The results show that GL and RLW increased by 2.44–5.48% and 4.19–10.70%, but GW decreased by 1.69–4.70% compared with the recipient. Based on the parental sequence analysis and haplotype analysis, one InDel variation located at −1489 in the promoter region was likely to be the functional site of qGL5.2. In addition, we also found that the Hap 5 (IRBB52-type) increased significantly in grain length and grain weight compared with other haplotypes, indicating that the Hap 5 can potentially be used in rice breeding to improve grain yield and quality. [ABSTRACT FROM AUTHOR]

The sink strength of developing ovaries in wheat determines the grain weight potential. The period from booting to the grain setting stage is critical for ovary growth and development and potential sink capacity determination. However, the underlying regulatory mechanism during this period by which the wheat plant balances and coordinates the floret number and ovary/grain weight under water stress has not been clarified. Therefore, we designed two irrigation treatments of W0 (no seasonal irrigation) and W1 (additional 75 mm of irrigation at the jointing stage) and analyzed the responses of the ovary/grain weight to water stress at the phenotypic, metabolomic, and transcriptomic levels. The results showed that the W0 irrigation treatment reduced the soil water content, plant height, and green area of the flag leaf, thus reducing grain number, especially for the inferior grains. However, it improved the grain weight of the superior and inferior grains as well as average grain weight at maturity, while the average ovary/grain weight and volume during –3 to 10 days after anthesis (DAA) also increased. Transcriptomic analysis indicated that the genes involved in both sucrose metabolism and phytohormone signal transduction were prominently accelerated by the W0 treatment, accompanied by greater enzymatic activities of soluble acid invertase (SAI) and sucrose synthase (Sus) and elevated abscisic acid (ABA) and indole-3-acetic acid (IAA) levels. Thus, the sucrose content decreased, while the glucose and fructose contents increased. In addition, several TaTPP genes (especially TaTPP-6) were down-regulated and the IAA biosynthesis genes TaTAR1 and TaTAR2 were up-regulated under the W0 treatment before anthesis, which further increased the IAA level. Collectively, water stress reduced the growth of vegetative organs and eliminated most of the inferior grains, but increased the ABA and IAA levels of the surviving ovaries/grains, promoting the enzymatic activity of Sus and degrading sucrose into glucose and fructose. As a result, the strong sucrose utilization ability, the enhanced enzymatic activity of SAI and the ABA- and IAA-mediated signaling jointly increased the weight and volume of the surviving ovaries/grains, and ultimately achieved the trade-off between ovary/grain weight and number in wheat under water stress.

The main sown areas in the Republic of Crimea are occupied by winter grain crops. The study conducted by Crimean scientists over many years and confirmed in production has shown that productivity of winter grain crops is unstable and varies significantly in years with different weather conditions. The difference in productivity is also found to depend on a variety. The purpose of the current study was to estimate the main elements of productivity and yield of new winter common wheat varieties developed by the FSBSI “ARC “Donskoy” in the contrasting weather conditions of the steppe Crimea. The current paper has summed up the results of the long-term study of winter common wheat cultivation and identified the varieties most adapted to dry conditions. The trials were carried out on the fields of the FSBSI “Research Institute of Agriculture in Crimea” after black fallow in the years of different weather conditions (2018–2023). The objects of research were 12 winter common wheat varieties from the Agricultural Research Center “Donskoy”, the standard variety being ‘Ermak’. The registration area of the experimental plots was 25 m2 . The placement of plots was systematic and repeated four times. The wheat sowing rate was 5 million pcs. of germin. grains per hectare. The trials and statistical processing were performed according to the methods of B. A. Dospekhov and the State Variety Testing. The study of winter wheat varieties bred by the ARC “Donskoy” has shown their different responses to the contrasting weather conditions of Crimea from the early periods of plant growth and development up to the formation of basic productivity indicators. Under unfavorable conditions of 2020, the mean productivity of varieties was 3.90 t/ha; in 2019, 2022 and 2023 it exceeded 5.0 t/ha. The study has made it possible to identify varieties with maximum productivity, such as ‘Donskaya Step’ (5.38 t/ha) and ‘Razdolie’ (5.33 t/ha). The main component of the productivity of the variety ‘Donskaya Step’ was grain weight per ear, and that of variety ‘Razdolie’ was a productive stem.

Grain size is a key factor influencing grain weight in rice. In this study, a chromosome segment substitution line (CSSL9-17) was identified, that exhibits a significant reduction in both grain size and weight compared to its donor parent 93-11. Further investigation identified two quantitative trait loci (QTL) on chromosome 11, designated qGW11a and qGW11b, which contribute to 1000-grain weight with an additive effect. LOC_Os11g05690, encoding the amino acid permease OsCAT8, is the target gene of qGW11a. Overexpression of OsCAT8 resulted in decreased grain weight, while OsCAT8 knockout mutants exhibited increased grain weight. The 287-bp located within the OsCAT8 promoter region of 93-11 negatively regulates its activity, which is subsequently correlated with an increase in grain size and weight. These results suggest that OsCAT8 functions as a negative regulator of grain size and grain weight in rice. [ABSTRACT FROM AUTHOR]

Grain size is a primary determinant of grain weight, which is one of the three essential components of rice grain yield. Mining the genes that control grain size plays an important role in analyzing the regulation mechanism of grain size and improving grain appearance quality. In this study, two closely linked quantitative trait loci (QTL) controlling grain size, were dissected and fine-mapped in a 515.6-kb region on the long arm of chromosome 10 by using six near isogenic line populations. One of them, qGS10.2, which controlled 1000 grain weight (TGW) and grain width (GW), was delimited into a 68.1-kb region containing 14 annotated genes. The Teqing allele increased TGW and GW by 0.17 g and 0.011 mm with the R2 of 12.7% and 11.8%, respectively. The other one, qGL10.2, which controlled grain length (GL), was delimited into a 137.3-kb region containing 22 annotated genes. The IRBB52 allele increased GL by 0.018 mm with the R2 of 6.8%. Identification of these two QTL provides candidate regions for cloning of grain size genes. [ABSTRACT FROM AUTHOR]

SUMMARY: Heat stress poses a significant threat to maize, especially when combined with drought. Recent research highlights the potential of water replenishment to ameliorate grain weight loss. However, the mitigating mechanisms of heat in drought stress, especially during the crucial early grain‐filling stage, remain poorly understood. We investigated the mechanism for mitigating heat in drought stress by water replenishment from the 12th to the 32nd days after silking in a controlled greenhouse experiment (Exp. I) and field trial (Exp. II). A significant reduction in grain weight was observed in heat stress compared to normal conditions. When water replenishment was applied to increase soil water content (SWC) under heat stress, the grain yield exhibited a notable increase ranging from 28.4 to 76.9%. XY335 variety was used for transcriptome sequencing to analyze starch biosynthesis and amino acid metabolisms in Exp. I. With water replenishment, the transcripts of genes responsible for trehalose 6‐phosphate phosphates (TPP), alpha‐trehalase (TRE), ADP‐glcpyrophosphorylase, and starch synthase activity were stimulated. Additionally, the expression of genes encoding TPP and TRE contributed to an enhanced conversion of trehalose to glucose. This led to the conversion of sucrose from glucose‐1‐phosphate to ADP‐glucose and ADP‐glucose to amylopectin, ultimately increasing starch production by 45.1%. Water replenishment to boost SWC during heat stress also elevated the levels of essential amino acids in maize, including arginine, serine, tyrosine, leucine, glutamic acid, and methionine, providing valuable support to maize plants in adversity. Field trials further validated the positive impact of water replenishment on SWC, resulting in a notable increase in grain yield ranging from 7.1 to 9.2%. This study highlights the vital importance of adapting to abiotic stress and underscores the necessity of developing strategies to counteract its adverse effects on crop yield. [ABSTRACT FROM AUTHOR]

Introduction: To address issues related to shallow soil tillage, low soil nutrient content, and single tillage method in maize production in the Western Inner Mongolia Region, this study implemented various tillage and straw return techniques, including strip cultivation, subsoiling, deep tillage, no-tillage, straw incorporation with strip cultivation, straw incorporation with subsoiling, straw incorporation with deep tillage, and straw incorporation with no tillage, while using conventional shallow spinning by farmers as the control. Methods: We employed Xianyu 696 (XY696) and Ximeng 6 (XM6) as experimental materials to assess maize 100-grains weight, grain filling rate parameters, and grain nutrient quality. This investigation aimed to elucidate how tillage and straw return influence the accumulation of grain material in different maize varieties. Results and discussion: The results indicated that proper implementation of tillage and straw return had a significant impact on the 100-grains weight of both varieties. In comparison to CK (farmer's rotary rotation), the most notable rise in 100-grains weight was observed under the DPR treatment (straw incorporation with deep tillage), with a maximum increase of 4.84% for XY696 and 6.28% for XM6. The proper implementation of tillage and straw return in the field resulted in discernible differences in the stages of improving the grain filling rates of different maize varieties. Specifically, XY696 showed a predominant increase in the filling rate during the early stage (V1), while XM6 exhibited an increase in the filling rates during the middle and late stages (V2 and V3). In comparison to CK, V1 increased by 1.54% to 27.56% in XY696, and V2 and V3 increased by 0.41% to 10.42% in XM6 under various tillage and straw return practices. The proper implementation of tillage and straw return had a significant impact on the nutritional quality of the grains in each variety. In comparison to CK, the DPR treatment resulted in the most pronounced decrease in the soluble sugar content of grains by 25.43% and the greatest increase in the crude fat content of grains by 9.67%. Conclusion: Ultimately, the proper implementation of soil tillage and straw return facilitated an increase in grain crude fat content and significantly boosted grain weight by improving the grouting rate parameters at all stages for various maize varieties. Additionally, the utilization of DPR treatment proved to be more effective. Overall, DPR is the most promising strategy to improve maize yield and the nutritional quality of grain in the long term in the Western Inner Mongolia Region. [ABSTRACT FROM AUTHOR]

Grain yield is determined mainly by grain number and grain weight. In this study, we identified and characterized MORE GRAINS1 (MOG1), a gene associated with grain number and grain weight in rice (Oryza sativa L.), through map‐based cloning. Overexpression of MOG1 increased grain yield by 18.6%–22.3% under field conditions. We determined that MOG1, a bHLH transcription factor, interacts with OsbHLH107 and directly activates the expression of LONELY GUY (LOG), which encodes a cytokinin‐activating enzyme and the cell expansion gene EXPANSIN‐LIKE1 (EXPLA1), positively regulating grain number per panicle and grain weight. Natural variations in the promoter and coding regions of MOG1 between Hap‐LNW and Hap‐HNW alleles resulted in changes in MOG1 expression level and transcriptional activation, leading to functional differences. Haplotype analysis revealed that Hap‐HNW, which results in a greater number and heavier grains, has undergone strong selection but has been poorly utilized in modern lowland rice breeding. In summary, the MOG1–OsbHLH107 complex activates LOG and EXPLA1 expression to promote cell expansion and division of young panicles through the cytokinin pathway, thereby increasing grain number and grain weight. These findings suggest that Hap‐HNW could be used in strategies to breed high‐yielding temperate japonica lowland rice. [ABSTRACT FROM AUTHOR]

Grain weight (GW) is the most important stable trait that directly contributes to crop yield in case of cereals. A total of 105 backcross introgression lines (BC2F10 BILs) derived from Swarna/O. nivara IRGC81848 (NPS) and 90 BILs from Swarna/O. nivara IRGC81832 (NPK) were evaluated for thousand-grain weight (TGW) across four years (wet seasons 2014, 2015, 2016 and 2018) and chromosome segment substitution lines (CSSLs) were selected. From significant pair- wise mean comparison with Swarna, a total of 77 positively and 29 negatively significant NPS lines and 62 positively and 29 negatively significant NPK lines were identified. In all 4 years, 14 NPS lines and 9 NPK lines were positively significant and one-line NPS69 (IET22161) was negatively significant for TGW over Swarna consistently. NPS lines and NPK lines were genotyped using 111 and 140 polymorphic SSRs respectively. Quantitative trait locus (QTL) mapping using ICIM v4.2 software showed 13 QTLs for TGW in NPS. Three major effect QTLs qTGW2.1, qTGW8.1 and qTGW11.1 were identified in NPS for two or more years with PVE ranging from 8 to 14%. Likewise, 10 QTLs were identified in NPK and including two major effect QTL qTGW3.1 and qTGW12.1 with 6 to 32% PVE. In all QTLs, O. nivara alleles increased TGW. These consistent QTLs are very suitable for fine mapping and functional analysis of grain weight. Further in this study, CSSLs NPS1 (10-2S) and NPK61 (158 K) with significantly higher grain weight than the recurrent parent, Swarna cv. Oryza sativa were selected from each population and secondary F2 mapping populations were developed. Using Bulked Segregant QTL sequencing, a grain weight QTL, designated as qTGW3.1 was fine mapped from the cross between NPK61 and Swarna. This QTL explained 48% (logarithm of odds = 32.2) of the phenotypic variations and was fine mapped to a 31 kb interval using recombinant analysis. GRAS transcription factor gene (OS03go103400) involved in plant growth and development located at this genomic locus might be the candidate gene for qTGW3.1. The results of this study will help in further functional studies and improving the knowledge related to the molecular mechanism of grain weight in Oryza and lays a solid foundation for the breeding for high yield. [ABSTRACT FROM AUTHOR]

Introduction: Autotetraploid rice holds high resistance to abiotic stress and substantial promise for yield increase, but it could not be commercially used because of low fertility. Thus, our team developed neo-tetraploid rice with high fertility and hybrid vigor when crossed with indica autotetraploid rice. Despite these advances, the molecular mechanisms underlying this heterosis remain poorly understood. Methods: An elite indica autotetraploid rice line (HD11) was used to cross with neo-tetraploid rice, and 34 hybrids were obtained to evaluate agronomic traits related to yield. WE-CLSM, RNA-seq, and CRISPR/Cas9 were employed to observe endosperm structure and identify candidate genes from two represent hybrids. Results and discussion: These hybrids showed high seed setting and an approximately 55% increase in 1000-grain weight, some of which achieved grain yields comparable to those of the diploid rice variety. The endosperm observations indicated that the starch grains in the hybrids were more compact than those in paternal lines. A total of 119 seed heterosis related genes (SHRGs) with different expressions were identified, which might contribute to high 1000-grain weight heterosis in neo-tetraploid hybrids. Among them, 12 genes had been found to regulate grain weight formation, including OsFl3, ONAC023, OsNAC024, ONAC025, ONAC026, RAG2, FLO4, FLO11, OsISA1, OsNF-YB1, NF-YC12, and OsYUC9. Haplotype analyses of these 12 genes revealed the various effects on grain weight among different haplotypes. The hybrids could polymerize more dominant haplotypes of above grain weight regulators than any homozygous cultivar. Moreover, two SHRGs (OsFl3 and SHRG2) mutants displayed a significant reduction in 1000-grain weight and an increase in grain chalkiness, indicating that OsFl3 and SHRG2 positively regulate grain weight. Our research has identified a valuable indica autotetraploid germplasm for generating strong yield heterosis in combination with neo-tetraploid lines and gaining molecular insights into the regulatory processes of heterosis in tetraploid rice. [ABSTRACT FROM AUTHOR]

Enlarging the lateral space of drip tubes saves irrigation equipment costs (drip tubes and bypass), but it will lead to an increased risk of grain yield heterogeneity between wheat rows. Adjusting wheat row spacing is an effective cultivation measure to regulate a row's yield heterogeneity. During a 2-year field experiment, we investigated the variations in yield traits and photosynthetic physiology by utilizing two different water- and fertilizer-demanding spring wheat cultivars (NS22 and NS44) under four kinds of drip irrigation patterns with different drip tube lateral spacing and wheat row spacing [① TR4, drip tube spacing (DTS) was 60 cm, wheat row horizontal spacing (WRHS) was 15 cm; ② TR6, DTS was 90 cm, WRHS was 15 cm; ③ TR6L, DTS was 90 cm, WRHS was 10 cm, inter-block spacing (IBS) was 35 cm; and ④ TR6S, DTS was 80 cm, WRHS was 10 cm, IBS was 25 cm]. The results showed that under 15-cm equal row spacing condition, after the number of wheat rows served by a single tube increased from four (TR4, control) to six (TR6), NS22 and NS44 exhibited a marked decline in yield. The decline of NS22 (9.93%) was higher than that of NS44 (9.04%), and both cultivars also showed a greater decrease in grain weight and average grain-filling rate (AGFR) of inferior grains (NS22: 23.19%, 13.97%; NS44: 7.78%, 5.86%) than the superior grains (NS22: 10.60%, 8.33%; NS44: 4.89%, 4.62%). After the TR6 was processed to narrow WRHS (from 15 to 10 cm) and add IBS (TR6L: 35 cm; TR6S: 25 cm), the grain weight per panicle (GWP) and AGFR of superior and inferior grains in the third wheat row (RW3) of NS22 and NS44 under TR6L increased significantly by 26.05%, 8.22%, 14.05%, 10.50%, 5.09%, and 5.01%, respectively, and under TR6S, they significantly increased by 20.78%, 9.91%, 16.19%, 9.28%, 5.01%, and 4.14%, respectively. The increase in GWP and AGFR was related to the increase in flag leaf area, net photosynthetic rate, chlorophyll content, relative water content, actual photochemical efficiency of PSII, and photochemical quenching coefficient. Among TR4, TR6, TR6L, and TR6S, for both NS22 and NS44, the yield of TR6S was significantly higher than that of TR6 and TR6L. Furthermore, TR6S showed the highest economic benefit. [ABSTRACT FROM AUTHOR]

Objective: This experiment was conducted to investigate the effects of nanoparticles (Zn and Si) and putrescine on grain-filling components of wheat under salinity stress. Methods: An experimental factorial based on a randomized complete block design with three replications was conducted at the research greenhouse of the University of Mohaghegh Ardabili in 2022. The experimental factors included salinity at four levels (without salinity application as control, application of 40, 80, and 120 mM salinity with NaCl) and nanoparticle and putrescine foliar application at eight levels (foliar application with water as control, foliar application of 50 mg.L-1 of Si, foliar application of 1 g.L-1 of Zn, foliar application of 1 mM putrescine, foliar application of Si-Zn, foliar application of Si and putrescine, foliar application of Zn and putrescine, foliar application of Si-Zn and putrescine). Results: The results showed that the highest grain-filling period and effective grain-filling period were obtained under nanoparticles and putrescine foliar application. This treatment combination under non-saline condition increased the root weight and volume (48.1 and 53.03% respectively), chlorophyll index (45.75%), and grain-filling rate (20%). There was an increase of 45.34, 62.72, 40.5, 36.21 and 37.37% in plant height, spike length, number of grains per spike, 100 grains weight and grain yield, respectively, under non-saline condition and foliar application with nanoparticle and putrescine in compared with no foliar application under 120 mM salinity. Conclusion: It seems that the foliar application of nanoparticles and putrescine under salinity can increase the yield of wheat by improving root characteristics and grain-filling components. [ABSTRACT FROM AUTHOR]

The application rate of potassium fertilizer is closely related to the yield of crops. Thin-shelled Tartary buckwheat is a new variety of Tartary buckwheat with the advantages of thin shell and easy shelling. However, little is known about application rate of potassium fertilizer on the yield formation of thin-shelled Tartary buckwheat. This study aimed to clarify the effect of potassium fertilizer on the growth and yield of thin-shelled Tartary buckwheat. A field experiment to investigate the characteristics was conducted across two years using thinshelled Tartary buckwheat (Miku 18) with four potassium fertilizer applications including 0 (no potassium fertilizer, CK), 15 (low-concentration potassium fertilizer, LK), 30 (medium-concentration potassium fertilizer, MK), and 45 kg·ha-1 (high-concentration potassium fertilizer, HK). The maximum and average grain filling rates; starch synthase activity; superoxide dismutase and peroxidase activities in leaves; root morphological indices and activities; available nitrogen, phosphorus, and organic matter content in rhizosphere soil; urease and alkaline phosphatase activities in rhizosphere soil; plant height, main stem node number, main stem branch number, leaf number; grain number per plant, grain weight per plant, and 100-grain weight increased first and then decreased with the increase in potassium fertilizer application rate and reached the maximum at MK treatment. The content of malondialdehyde was significantly lower in MK treatment than in other three treatments. The yields of thin-shelled Tartary buckwheat treated with LK, MK, and HK were 1.22, 1.37, and 1.07 times that of CK, respectively. In summary, an appropriate potassium fertilizer treatment (30kg·ha-1) can delay the senescence, promote the grain filling, and increase the grain weight and final yield of thin-shelled Tartary buckwheat. This treatment is recommended to be used in production to achieve high-yield cultivation of thin-shelled Tartary buckwheat. [ABSTRACT FROM AUTHOR]

Main conclusion: The up-regulation of OsmiR5519 results in the decrease of grain size, weight and seed setting rate. OsmiR5519 plays important roles in the process of grain filling and down-regulates sucrose synthase gene RSUS2. MicroRNAs (miRNAs) are one class of small non-coding RNAs that act as crucial regulators of plant growth and development. In rice, the conserved miRNAs were revealed to regulate the yield components, but the function of rice-specific miRNAs has been rarely studied. The rice-specific OsmiR5519 was found to be abundantly expressed during reproductive development, but its biological roles remain unknown. In this study, the function of rice-specific OsmiR5519 was characterized with the miR5519-overexpressing line (miR5519-OE) and miR5519-silenced line (STTM5519). At seedling stage, the content of sucrose, glucose and fructose was obviously lower in the leaves of miR5519-OE lines than those of wild-type (WT) line. The grain size and weight were decreased significantly in miR5519-OE lines, compared to those of WT rice. The cell width of hull in miR5519-OE was smaller than that in WT. The seed setting rate was notably reduced in miR5519-OE lines, but not in STTM5519 lines. Cytological observation demonstrated that the inadequate grain filling was the main reason for the decline of seed setting rate in miR5519-OE lines. The percentage of the defects of grain amounted to 40% in miR5519-OE lines, which almost equaled to the decreased value of seed setting rate. Furthermore, the sucrose synthase gene RSUS2 was identified as a target of OsmiR5519 via RNA ligase-mediated 3'-amplification of cDNA ends (3'-RLM-RACE), dual luciferase assays and transient expression assays. In summary, our results suggest that OsmiR5519 regulates grain size and weight and down-regulates RSUS2 in rice. [ABSTRACT FROM AUTHOR]

Echinochloa crus-galli (L.) Beauv. is a stronger competitor of rice for resources than other weeds. An adequate knowledge of the biology, ecology and critical period of competition of E. crus-galli with dry-seeded rice (DSR) is fundamental in designing effective, sustainable and integrated weed management programs. Experiments were conducted in the 2013 dry and wet seasons to determine the effect of two E. crus-galli densities (40 and 80 plants m−2) emerging at four intervals (2, 15, 30 and 45 d after rice emergence, DARE) with and without rice interference on the growth and biomass accumulation of both rice and weed, and the productivity of rice. The E. crus-galli plant height decreased with the interference of rice plants. The maximum height of 115–130 cm and number of tillers of 477–508 m−2 in rice plants were recorded when grown alone, and these growth parameters declined to 105–109 cm and 315–352 m−2, respectively, when rice emerged simultaneously with E. crus-galli. Other rice growth parameters (stem, leaf, panicle and shoot biomass, and leaf area) and grain yield attributes (panicle density, per panicle filled spikelets and grain weight) decreased significantly with increases in E. crus-galli density at the early emergence time. A delay in E. crus-galli emergence from 0 to 45 DARE caused a significant reduction in E. crus-galli biomass, which resulted in less reduction in rice biomass and leaf area index. Rice grain yield, grain weight, and harvest index improved significantly with a delay in weed emergence up to 45 DARE. The highest grain yield was recorded when rice was grown alone (6.8–7.3 t ha−1), which was similar to the yield produced in the plots wherein E. crus-galli sown at 40 plants m−2 (6.9–7.0 t ha−1) and 80 plants m−2 (6.4–6.7 t ha−1) emerged at 45 DARE. The lowest grain yield (4.3–4.9 t ha−1) was recorded in the plots wherein E. crus-galli emerged simultaneously with rice. This study established that E. crus-galli emergence at 45 DARE could not cause an economic yield loss because of less biomass accumulation and lower survival rate. [ABSTRACT FROM AUTHOR]

Grain yield in rice is a complex trait and it is controlled by a number of quantitative trait loci (QTL). To dissect the genetic basis of rice yield, QTL analysis for nine yield traits was performed using an F2 population containing 190 plants, which was developed from a cross between Youyidao (YYD) and Sanfenhe (SFH), and each plant in the population evaluated with respect to nine yield traits. In this study, the correlations among the nine yield traits were analyzed. The grain yield per plant positively correlated with six yield traits, except for grain length and grain width, and showed the highest correlation coefficient of 0.98 with the number of filled grains per plant. A genetic map containing 133 DNA markers was constructed and it spanned 1831.7 cM throughout 12 chromosomes. A total of 36 QTLs for the yield traits were detected on nine chromosomes, except for the remaining chromosomes 5, 8, and 9. The phenotypic variation was explained by a single QTL that ranged from 6.19% to 36.01%. Furthermore, a major QTL for grain width and weight, qGW2-1, was confirmed to be newly identified and was narrowed down to a relatively smaller interval of about ~2.94-Mb. Collectively, we detected a total of 36 QTLs for yield traits and a major QTL, qGW2-1, was confirmed to control grain weight and width, which laid the foundation for further map-based cloning and molecular design breeding in rice. [ABSTRACT FROM AUTHOR]

Common bean is an important crop due to its high nutritional value. However, its production in Ecuador has decreased due to biotic and abiotic factors. Understanding the mechanisms that determine the yield components of this crop is essential to establish strategies that allow increasing the yield. In this study, the plant density was modified to evaluate its impact on yield and its two main components, the grain number and grain weight under field conditions in an Andean region of Ecuador. Two experiments planted on different dates were performed, where two planting densities 4 and 11 plants m􀀀2 were evaluated. The effect of the treatments was studied on the length of the period, from emergence to anthesis, the number of full and empty pods, grain number, 100 grain weight and grain yield. The results indicate that the plant density has a significant effect (p<0.05) on the yield, reaching an average of 257.15 g m􀀀2 in high density, and 151.45 g m􀀀2 in low density. The yield main components showed a different response to plant density modification; the grain number exhibited a strong variability and was positively associated with final grain yield (p<0.05) while the grain weight was not affected. [ABSTRACT FROM AUTHOR]

Grain size and grain weight contribute greatly to the final grain yield in rice. In order to identify QTLs conferring grain size and grain weight, an F2 population derived from a cross between two indica rice accessions, Guangzhan 63-4S (GZ63-4S) and Dodda, and its derived F2:3 population were developed, and were exploited for QTL analysis of the five related traits, namely grain length (GL), grain width (GW), length-to-width ratio (LWR), grain thickness (GT) and thousand-grain weight (TGW). A total of 36 QTLs were detected, and the number of beneficial alleles was contributed roughly equally by the two parents. Among those, 7 QTL regions were repeatedly detected in the two populations. In order to further validate effects of QTLs detected, a BC1F2 population derived from a backcross of a mixture of F2 plants with GZ63-4S was developed and was exploited for QTL selection. Heterozygous regions of 3 QTLs, qGS3, qTGW6.2 and qGT7 were identified respectively, and corresponding near-isogenic lines (NILs) of each QTL were constructed with three rounds of self-crosses. In the background of NILs, qGS3 was responsible for GL, LWR, GT and TGW, qTGW6.2 was for GL and TGW, and qGT7 was for GT and TGW. These results have laid the foundation of further fine mapping work, and could be of great use in breeding and improvement of rice lines with desirable size and yield. [ABSTRACT FROM AUTHOR]

This article, published in the Plant Biotechnology Journal, discusses the discovery of a gene in wheat called GRAIN WIDTH2 (TaGW2) that has a dual effect on enhancing leaf rust resistance and increasing grain weight. Leaf rust, caused by the fungal pathogen Puccinia triticina Eriksson, is a major threat to global wheat production. The limited number of cloned resistance genes often have undesirable agronomic traits, so finding new resistance genes while balancing yield is important for breeding strategies. The researchers used CRISPR/Cas9 technology to edit TaGW2 and found that knockout plants had increased resistance to leaf rust and increased grain weight, offering a novel approach to enhancing wheat's resistance without sacrificing yield. [Extracted from the article]

Grain weight and grain shape are important traits that determine rice grain yield and quality. Mining more quantitative trait loci (QTLs) that control grain weight and shape will help to further improve the molecular regulatory network of rice grain development and provide gene resources for high-yield and high-quality rice varieties. In the present study, a QTL for grain length (GL) and grain width (GW), qGL5.2, was firstly fine-mapped into a 21.4 kb region using two sets of near-isogenic lines (NILs) derived from the indica rice cross Teqing (TQ) and IRBB52. In the NIL populations, the GL and ratio of grain length to grain width (RLW) of the IRBB52 homozygous lines increased by 0.16–0.20% and 0.27–0.39% compared with the TQ homozygous lines, but GW decreased by 0.19–0.75%. Then, by analyzing the grain weight and grain shape of the knock-out mutant, it was determined that the annotation gene Os05g0551000 encoded a RING-type E3 ubiquitin ligase, which was the cause gene of qGL5.2. The results show that GL and RLW increased by 2.44–5.48% and 4.19–10.70%, but GW decreased by 1.69–4.70% compared with the recipient. Based on the parental sequence analysis and haplotype analysis, one InDel variation located at −1489 in the promoter region was likely to be the functional site of qGL5.2. In addition, we also found that the Hap 5 (IRBB52-type) increased significantly in grain length and grain weight compared with other haplotypes, indicating that the Hap 5 can potentially be used in rice breeding to improve grain yield and quality.

Postharvest management is critical to attaining household food, nutrition, and income security. Hermetic grain storage bags offer an effective pesticide‐free way to protect stored grain against fungal and insect infestation. We evaluated articles indexed in the Web of Science that included experiments comparing the storage efficacy of conventional and hermetic storage bags based on grain germination rate, insect infestation, physical damage, mycotoxin contamination, and changes in weight and moisture content. Compared with grain stored in hermetic bags, grain stored in conventional bags lost 3.6‐fold more seed viability, contained 42‐fold more insects, had 11‐fold more physical damage, and lost 23‐fold more grain weight, while grain moisture levels were similar for both hermetic and conventional storage bags. Mycotoxin contamination levels were not as frequently assessed. Levels could be low in grain stored in both types of bags, or levels could be low in hermetic bags and significantly higher in conventional bags. The improved properties of grain stored in hermetic bags can increase food security and household income by providing safe storage options for maintaining seed germinability, and for consumption and/or sale when food supplies are high, or when prices are low. Hermetic bags are economically feasible for use by subsistence farmers in Sub‐Saharan Africa for grain for household consumption and for carrying‐over seed for planting in the next season. Additional studies are needed to verify the mycotoxin contamination results and to determine if there are differences in functional food characteristics, e.g. flavor and cooking properties, that have not been as comprehensively studied. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Introducing variations in inflorescence architecture, such as the 'Miracle-Wheat' (Triticum turgidum convar. compositum (L.f.) Filat.) with a branching spike, has relevance for enhancing wheat grain yield. However, in the spike-branching genotypes, the increase in spikelet number is generally not translated into grain yield advantage because of reduced grains per spikelet and grain weight. Here, we investigated if such trade-offs might be a function of source–sink strength by using 385 recombinant inbred lines developed by intercrossing the spike-branching landrace TRI 984 and CIRNO C2008, an elite durum (T. durum L.) cultivar; they were genotyped using the 25K array. Various plant and spike architectural traits, including flag leaf, peduncle, and spike senescence rate, were phenotyped under field conditions for 2 consecutive years. On chromosome 5AL, we found a new modifier QTL for spike branching, branched head t 3 (bh t -A3), which was epistatic to the previously known bh t -A1 locus. Besides, bh t -A3 was associated with more grains per spikelet and a delay in flag leaf senescence rate. Importantly, favourable alleles, viz. bh t -A3 and grain protein content (gpc-B1) that delayed senescence, are required to improve grain number and grain weight in the spike-branching genotypes. In summary, achieving a balanced source–sink relationship might minimize grain yield trade-offs in Miracle-Wheat. [ABSTRACT FROM AUTHOR]

Changes in yield components and spike traits are associated with wheat grain yield genetic progress. The aim of this study was to determine variation in yield components, spike and individual grain traits, and their role in winter wheat grain yield genetic improvement under conditions of the Pannonian Plain. Therefore, two-year field trials were conducted in a southern Pannonian location (Novi Sad, Serbia) with ten winter wheat cultivars released between 1931 and 2015. The grain yield had a significant positive linear relationship with the year of cultivar release, showing the improvement rate of 46.4 kg ha−1 yr−1. Grain yield increase has been positively related to the improvement of spike grain weight. Spike grain weight improvement with a rate of 0.25 g yr−1 was followed by simultaneous rise of the individual grain number and grain weight at different positions within a spikelet. Compared to other grains at different positions within a spikelet, G3 grains showed the highest rate of grain weight and the grain number improvement with the year of cultivar release. On the other hand, there was a significant decrease trend of grain protein content in individual grains at different positions. Therefore, wheat breeders should be more focused on grain number and weight improvement of distal grains in order to regain higher grain yield genetic gain under conditions of the Pannonian Plain. [ABSTRACT FROM AUTHOR]

Grain size is a primary determinant of grain weight, which is one of the three essential components of rice grain yield. Mining the genes that control grain size plays an important role in analyzing the regulation mechanism of grain size and improving grain appearance quality. In this study, two closely linked quantitative trait loci (QTL) controlling grain size, were dissected and fine-mapped in a 515.6-kb region on the long arm of chromosome 10 by using six near isogenic line populations. One of them, qGS10.2, which controlled 1000 grain weight (TGW) and grain width (GW), was delimited into a 68.1-kb region containing 14 annotated genes. The Teqing allele increased TGW and GW by 0.17 g and 0.011 mm with the R2 of 12.7% and 11.8%, respectively. The other one, qGL10.2, which controlled grain length (GL), was delimited into a 137.3-kb region containing 22 annotated genes. The IRBB52 allele increased GL by 0.018 mm with the R2 of 6.8%. Identification of these two QTL provides candidate regions for cloning of grain size genes.

CRISPR/Cas9 system has emerged as an efficient tool for sustainable crop improvement. Roots are the “principal hidden organ” that has a crucial function in vascular plants. Receptor-like protein kinase 1 (RPK1) has been reported to regulate root architecture system (RAS), abiotic stress, and yield both in Arabidopsis and rice. We employed a CRISPR/Cas9-based system, namely LR-1 and LR-2 constructs having double guided RNAs transformed via agrobacterium for targeted mutagenesis of TaRPK1 genes to alter the root architecture and hence yield in Triticum aestivum. Sequencing confirmed seven CRISPR/Cas9-based mutated T0 lines of LR-1 constructs and six T0 lines of LR-2 constructs, with an overall mutation efficiency of 41.93%. The T0 plants displayed higher monoallelic mutation compared to the diallelic mutation. 37.5% monoallelic mutation at target site 1 within the D genome by gRNA1 was observed by the LR-1 construct. The LR-2 constructs showed a higher monoallelic mutation frequency of 26.67% at target sites 1 and 2 within A, B, and D genomes. The deletions were mainly short, however longer deletions such as 12d, 17d, 19d, and 20d were detected by gRNA2 of LR-1 construct. Transgenic lines revealed significant alteration in morphology and RSA with a significant increase in number of effective tillers, grain weight, root length, root depth, root volume, and root surface area while reduced root diameter, root angle, and spike length, compared to the wild plants. Tillers and total grain weight increased significantly, suggesting edited lines increased grain production by decreasing spike length. The study validates that CRISPR/Cas9 mediated targeted editing of TaRPK1 is a practical approach for modifying RAS and hence yield enhancement in wheat.

Grain yield in rice is a complex trait and it is controlled by a number of quantitative trait loci (QTL). To dissect the genetic basis of rice yield, QTL analysis for nine yield traits was performed using an F2 population containing 190 plants, which was developed from a cross between Youyidao (YYD) and Sanfenhe (SFH), and each plant in the population evaluated with respect to nine yield traits. In this study, the correlations among the nine yield traits were analyzed. The grain yield per plant positively correlated with six yield traits, except for grain length and grain width, and showed the highest correlation coefficient of 0.98 with the number of filled grains per plant. A genetic map containing 133 DNA markers was constructed and it spanned 1831.7 cM throughout 12 chromosomes. A total of 36 QTLs for the yield traits were detected on nine chromosomes, except for the remaining chromosomes 5, 8, and 9. The phenotypic variation was explained by a single QTL that ranged from 6.19% to 36.01%. Furthermore, a major QTL for grain width and weight, qGW2-1, was confirmed to be newly identified and was narrowed down to a relatively smaller interval of about ~2.94-Mb. Collectively, we detected a total of 36 QTLs for yield traits and a major QTL, qGW2-1, was confirmed to control grain weight and width, which laid the foundation for further map-based cloning and molecular design breeding in rice.

Drought is one of the important factors affecting wheat yield. However, the effect of split application of phosphorus fertilizer on the programmed cell death (PCD) of wheat endosperm cells under different post-anthesis water treatments is still unclear. In this study, three phosphorus fertilization methods (P1, all phosphorus fertilizer was applied at the spring green-up stage; P2, 50 % and 50 % of phosphorus fertilizer were applied at the spring green-up stage and jointing stage, respectively; P3, 40 %, 30 %, and 30 % of phosphorus fertilizer were applied at the spring green-up, jointing, and grain filling stages, respectively) were designed. Besides, two post-anthesis water treatments were designed: WT, full irrigation treatment; DT, drought stress treatment. Then, the effects of P1, P2, and P3 treatments on the endosperm cell development, nuclear number, nuclease activity, DNA fragmentation, DNA content, grain weight, and phosphorus content of winter wheat variety "Xindong 23" under WT and DT conditions were determined at different stages after anthesis. The results showed that under WT and DT conditions, the degree of nuclear deformation and nuclear membrane depression in P3 treatment was milder than that in P1 and P2 treatments. The ACPase amount in P3 treatment was more than that in P1 and P2 treatments. The number of endosperm nuclei in P3 treatment was higher than that in P1 and P2 treatments. Under DT condition, the endosperm DNA content of wheat grains collected 14–35 days post anthesis (DPA) in P3 treatment increased, and the peak time of genomic DNA fragmentation in P3 treatment was later, compared with those in P1 treatment. Under DT condition, the grain weight and grouting rate in P3 treatment were higher than those of P1 treatment at 7–28 DPA, and the 1000-grain weight of P3 was the highest under both WT and DT conditions, reaching 47.03 and 40.57 g, respectively. Under WT and DT conditions, compared with P1 treatment, the protein content change rate (3.16 % and 5.59 %, respectively) and the total phosphorus content change rate (34.36 % and 35.08 %, respectively) of wheat grains in P3 treatment were the highest. In summary, under the DT condition, split application of phosphorus fertilizer (P3, spring green-up stage stage: jointing stage: filling stage = 4: 3: 3) could increase the phosphorus uptake and utilization of wheat plants and grains, suppress the DNA fragmentation of endosperm cells, and delay the deformation and disintegration of nuclei, which ultimately delayed the PCD in endosperm and realized high grain weight and protein content. • Phosphorus management significantly affected the wheat grain filling under drought. • Postponed application of some phosphorus delayed the wheat endosperm PCD under drought. • Postponed application of some phosphorus increase grain weight and phosphorus content. [ABSTRACT FROM AUTHOR]

Maize, one of the most important crops in the food chain, is facing severe threats from the escalating incidence of drought stress worldwide. Maize grain development requires assimilate uptake from the attached cob, however, the spatial distribution of sugars (the main carbon assimilate) within ear and its relationship with grain development under drought stress remain unclear. Here, we systematically investigated the dynamics of sugars and starch in different sub-tissues of cob (pith, woody ring, pedicel, and glume) and grain at different regions (the apical, middle and basal) of the developing ear under drought stress during grain filling. Results showed that the major sugar within cob was sucrose, followed by hexoses (fructose and glucose) and starch. Spatially, sucrose was highest in the woody ring and decreased toward the pedicel and then grain, whilst the hexoses were higher in the grain and then the cob center (pith) but gradually decreased towards the pedicel. Under drought, sucrose and hexoses were significantly accumulated in the pedicel but reduced in the grain, revealing that sugar uptake from the pedicel by grain was blocked. Moreover, sugars were reduced in the apical and middle regions of cob but were promoted in the basal region by drought, suggesting a drought-suppressed sugar translocation within cob. Accordingly, grain weight in the apical, middle, and basal regions were reduced by 18.9 %, 11.3 %, and 10.8 %, with starch weight decreased by 25.2 %, 21.4 %, and 2.0 %, respectively, at maturity. Collectively, these results support that sugar uptake from the pedicel by the grain and upward translocation along the cob are associated with grain weight in response to drought. These findings firstly uncover the spatial patterns for sugars within ear to respond to drought stress and highlight the importance of sugar availability within cob in grain yield formation. • Spatial-temporal distributions of sugars in maize ear in response to drought. • Drought hinders assimilate uptake by grain from pedicel. • Drought hinders upward translocation of assimilate along the cob. • Grain weight loss is associated with stuck sugar translocation under drought. [ABSTRACT FROM AUTHOR]

Estimating grain filling rate (GFR) and thousand-grain weight (TGW) plays an important role in evaluating yield and guiding the selection of varieties and cultivation strategies of winter wheat (Triticum aestivum L.). However, the current GFR and TGW monitoring methods mainly rely on destructive sampling, which can not achieve rapid estimation in a large area of farmland. This study aims to establish a method for estimating GFR and TGW of winter wheat using multispectral UAV images. Initially, grey correlation analysis method was used to evaluate the contributions of Leaf Area Index (LAI), Chlorophyll Content (SPAD), Aboveground Biomass (AGB) to GFR. A new comprehensive indicator, called LAI-SPAD-AGB index (LSA), was proposed to characterize GFR by establishing a linear regression model between LSA and GFR. Subsequently, UAV-based multispectral images were used to estimate LAI, SPAD, AGB, employing the methods such as Partial Least Squares Regression (PLSR), Random Forest (RF), and eXtreme Gradient Boosting (XGBoost). Using the linear regression equation between LSA and GFR along with estimated LSA values, GFR was estimated and mapped. TGW was estimated based on GFR and grain-filling duration (GFD). Results showed the high GFR estimation accuracy (R2: 0.89, RMSE: 0.29 g/d, NRMSE: 10.0 %) and remarkable TGW estimation precision (R2: 0.92, RMSE: 4.20 g, NRMSE: 8.1 %). The parcel-scale distribution maps of estimated GFR and TGW were generated. The novel and non-destructive method of estimating GFR and TGW of winter wheat using UAV-based images can offer strong support for water and fertilizer management in the field. • The grain filling rate of winter wheat had good correlation with LAI or SPAD or AGB. • An estimation model of grain filling rate was proposed based on LAI, SPAD and AGB. • The dynamic changes of LAI, SPAD and AGB were monitored using UAV images. • The grain filling rate of wheat at filling stage was mapped at the field scale. [ABSTRACT FROM AUTHOR]

The ovary-to-grain transition process is crucial for individual grain weight potential, but the but the physiological regulation of this highly dynamic and complex developmental process remains largely unknown unknown. Here, we performed a high temporal-resolution analysis of the proximal (large) and distal (small) ovaries/grains collected at an interval of 3 days from the booting stage to maturity stage. During grain-filling process, proximal grains always maintained a greater dry matter (0–36 days after anthesis, DAA), water (0–33 DAA), sugar (3–33 DAA), protein (6–36 DAA), and starch (amylose and amylopectin, 18–36 DAA) content, and larger volume (-15–36 DAA) than distal grains, but their partition or concentration did not differ between the proximal and distal grains. This result suggested that the capability of proximal and distal grains to produce water, sugar, protein, and starch within the same volume was similar; thus, grain sink (i.e. volume) was the cause in determinant of grain weight potential. In fact, the proximal ovary had a larger volume and related parameters (length, width and thickness) than the distal ovary before anthesis stage. in addition, the correlation coefficients of length and width with volume are higher than the correlation coefficients of thickness with volume. Clearly, we discovered a dynamic physiological mechanism for high proximal grain weight: the rapid elongation and widening of the proximal ovary improved its size, which passed to the proximal grain a volume advantage in the following ovary-grain transition, which allowed it to took up more sucrose and then converted into more starch and protein, improving dry matter accumulation and increasing proximal grain weight. Our findings provide a precise strategy for breeding and cultivation to increase individual grain weight potential by improving ovary volume. • Ovary morphology and volume are closely linked to grain volume potential. • Ovary length and width determines ovary volume potential. • Grain-filling rate and duration is limited by grain volume. • Increasing the proportion of fast-growing duration improves grain-filling potential. [ABSTRACT FROM AUTHOR]

Fatty acids play a putative role as second messengers of phytohormones and regulate the rice grain weight. However, the inner mechanism is still unclear and needs to be further studied. In this study, we identified that oleic acid (C18:1) negatively correlates while linoleic acid (C18:2) positively correlates with rice grain weight. Field trials showed that 1000-grain weight was significantly reduced when treated with the fatty acid synthesis inhibitor, Firsocostat S enantiomer (FSE), at the heading and flowering stages. RNA-seq analysis revealed that FSE affects grain weight by modulating processes, such as glycolysis, sucrose metabolism, and hormone signaling. Notably, FSE inhibited the expression of OsLIN6 , which is responsible for transporting C18:1 to the phosphatidylcholine pool for C18:2 synthesis. Compared with the wild type (WT), the OsLIN6 knockout mutant exhibited a lower grain weight, an increased C18:1 content, and a decreased C18:2 content. Importantly, OsARF12 was shown to bind to the OsLIN6 promoter and activate its expression. In summary, this study highlights the crucial role of the fatty acid synthesis gene, OsLIN6 , which was regulated by OsARF12, in rice grain weight determination, thus establishing the molecular link between fatty acid synthesis and auxin signaling.

Grain size and grain weight are important determinants for grain yield. In this study, we identify a novel OsMAPK5-OsWRKY72 module that negatively regulates grain length and grain weight in rice. We found that loss-of-function of OsMAPK5 leads to larger cell size of the rice spikelet hulls and a significant increase in both grain length and grain weight in an indica variety Minghui 86 (MH86). OsMAPK5 interacts with OsMAPKK3/4/5 and OsWRKY72 and phosphorylates OsWRKY72 at T86 and S88. Similar to the osmapk5 MH86 mutants, the oswrky72 knockout MH86 mutants exhibited larger size of spikelet hull cells and increased grain length and grain weight, whereas the OsWRKY72-overexpression MH86 plants showed opposite phenotypes. OsWRKY72 targets the W-box motifs in the promoter of OsARF6, an auxin response factor involved in auxin signaling. Dual-luciferase reporter assays demonstrated that OsWRKY72 activates OsARF6 expression. The activation effect of the phosphorylation-mimicking OsWRKY72 T86D/S88D on OsARF6 expression was significantly enhanced, whereas the effects of the OsWRKY72 phosphorylation-null mutants were significantly reduced. In addition, auxin levels in young panicles of the osmapk5 and oswrky72 mutants were significantly higher than that in the wild-type MH86. Collectively, our study uncovered novel connections of the OsMAPKK3/4/5-OsMAPK5-mediated MAPK signaling, OsWRKY72-mediated transcription regulation, and OsARF6-mediated auxin signaling pathways in regulating grain length and grain weight in an indica-type rice, providing promising targets for molecular breeding of rice varieties with high yield and quality., (© 2024 The Author(s). Journal of Integrative Plant Biology published by John Wiley & Sons Australia, Ltd on behalf of Institute of Botany, Chinese Academy of Sciences.)

Grain weight, a key determinant of yield in rice (Oryza sativa L.), is governed primarily by genetic factors, whereas grain chalkiness, a detriment to grain quality, is intertwined with environmental factors such as mineral nutrients. Nitrogen (N) is recognized for its effect on grain chalkiness, but the underlying molecular mechanisms remain to be clarified. This study revealed the pivotal role of rice NODULE INCEPTION-LIKE PROTEIN 3 (OsNLP3) in simultaneously regulating grain weight and grain chalkiness. Our investigation showed that loss of OsNLP3 leads to a reduction in both grain weight and dimension, in contrast to the enhancement observed with OsNLP3 overexpression. OsNLP3 directly suppresses the expression of OsCEP6.1 and OsNF-YA8, which were identified as negative regulators associated with grain weight. Consequently, two novel regulatory modules, OsNLP3-OsCEP6.1 and OsNLP3-OsNF-YA8, were identified as key players in grain weight regulation. Notably, the OsNLP3-OsNF-YA8 module not only increases grain weight but also mitigates grain chalkiness in response to N. This research clarifies the molecular mechanisms that orchestrate grain weight through the OsNLP3-OsCEP6.1 and OsNLP3-OsNF-YA8 modules, highlighting the pivotal role of the OsNLP3-OsNF-YA8 module in alleviating grain chalkiness. These findings reveal potential targets for simultaneous enhancement of rice yield and quality., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The utilization of crop nitrogen (N) status as an in-season diagnosis tool for predicting N needs to maximize grain yield (GY) is a well-established concept in agronomy. However, a cross-species comparison including the characterization of yield components, grain number (GN) and grain weight (GW), to understand the physiological basis behind the GY-crop N status relationship is still missing. The main goal of this study was to perform a cross-species comparison for maize (Zea mays L.), rice (Oryza sativa L.), and wheat (Triticum aestivum L.) of the relationship between crop N status around anthesis as a GY and GY components prediction diagnosis method. A systematic literature search was carried out for these major field crops, the final dataset (comprising 629 observations) consisted of 15 publications including information on i) shoot biomass and plant N concentration or N nutrition index (NNI) values at anthesis, ii) GY, and iii) GN and/or GW. An analysis was conducted to assess the sensitivity (slope of the linear models) of GY, GN, and GW to changes in crop NNI status at anthesis. Notably, the crop N status at anthesis demonstrated a strong relationship between both GY (R2 between 0.66 and 0.93) and GN (R2 between 0.58 and 0.94) across all crops, with a slightly weaker relationship with GW (R2 between 0.30 and 0.83). Considerable uncertainty was observed on the GY and GN sensitivity (S) to N deficiency across all crops. Maize showed the greatest sensitivity of GY to NNI (S = 964 g m−2), with lowest sensitivity for wheat crop (S = 496 g m−2). Regarding GN, rice showed the greatest sensitivity to NNI (S = 23859 GN m−2), whereas maize was less sensitive (S = 2673 GN m−2). While maize exhibited a positive association between NNI and GW (although with considerable uncertainty), this relationship was less evident for rice and wheat crops. Our findings demonstrated that crop N status at anthesis is a better predictor of GY and GN than GW in maize, rice, and wheat. Maize showed the greatest range in observed values for relative GW relative to NNI, highlighting the impact of crop N status on GW determination. These findings contribute to improving the understanding of the importance of achieving adequate crop N status at anthesis as key aspect for yield formation, with implications for both breeding programs and the optimization of on-farm crop N management. • Crop N status at anthesis showed a strong relationship with grain number. • Maize showed the greatest sensitivity of grain yield to NNI at anthesis. • Rice showed the greatest sensitivity of grain number to NNI at anthesis. • Maize showed the greatest responses of grain weight to crop N status at anthesis. [ABSTRACT FROM AUTHOR]

Introduction: To address issues related to shallow soil tillage, low soil nutrient content, and single tillage method in maize production in the Western Inner Mongolia Region, this study implemented various tillage and straw return techniques, including strip cultivation, subsoiling, deep tillage, no-tillage, straw incorporation with strip cultivation, straw incorporation with subsoiling, straw incorporation with deep tillage, and straw incorporation with no tillage, while using conventional shallow spinning by farmers as the control., Methods: We employed Xianyu 696 (XY696) and Ximeng 6 (XM6) as experimental materials to assess maize 100-grains weight, grain filling rate parameters, and grain nutrient quality. This investigation aimed to elucidate how tillage and straw return influence the accumulation of grain material in different maize varieties., Results and Discussion: The results indicated that proper implementation of tillage and straw return had a significant impact on the 100-grains weight of both varieties. In comparison to CK (farmer's rotary rotation), the most notable rise in 100-grains weight was observed under the DPR treatment (straw incorporation with deep tillage), with a maximum increase of 4.84% for XY696 and 6.28% for XM6. The proper implementation of tillage and straw return in the field resulted in discernible differences in the stages of improving the grain filling rates of different maize varieties. Specifically, XY696 showed a predominant increase in the filling rate during the early stage (V1), while XM6 exhibited an increase in the filling rates during the middle and late stages (V2 and V3). In comparison to CK, V1 increased by 1.54% to 27.56% in XY696, and V2 and V3 increased by 0.41% to 10.42% in XM6 under various tillage and straw return practices. The proper implementation of tillage and straw return had a significant impact on the nutritional quality of the grains in each variety. In comparison to CK, the DPR treatment resulted in the most pronounced decrease in the soluble sugar content of grains by 25.43% and the greatest increase in the crude fat content of grains by 9.67%., Conclusion: Ultimately, the proper implementation of soil tillage and straw return facilitated an increase in grain crude fat content and significantly boosted grain weight by improving the grouting rate parameters at all stages for various maize varieties. Additionally, the utilization of DPR treatment proved to be more effective. Overall, DPR is the most promising strategy to improve maize yield and the nutritional quality of grain in the long term in the Western Inner Mongolia Region., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Yu, Gao, Ma, Liu and Hu.)

Introduction: Autotetraploid rice holds high resistance to abiotic stress and substantial promise for yield increase, but it could not be commercially used because of low fertility. Thus, our team developed neo-tetraploid rice with high fertility and hybrid vigor when crossed with indica autotetraploid rice. Despite these advances, the molecular mechanisms underlying this heterosis remain poorly understood., Methods: An elite indica autotetraploid rice line (HD11) was used to cross with neo-tetraploid rice, and 34 hybrids were obtained to evaluate agronomic traits related to yield. WE-CLSM, RNA-seq, and CRISPR/Cas9 were employed to observe endosperm structure and identify candidate genes from two represent hybrids., Results and Discussion: These hybrids showed high seed setting and an approximately 55% increase in 1000-grain weight, some of which achieved grain yields comparable to those of the diploid rice variety. The endosperm observations indicated that the starch grains in the hybrids were more compact than those in paternal lines. A total of 119 seed heterosis related genes (SHRGs) with different expressions were identified, which might contribute to high 1000-grain weight heterosis in neo-tetraploid hybrids. Among them, 12 genes had been found to regulate grain weight formation, including OsFl3, ONAC023, OsNAC024, ONAC025, ONAC026, RAG2, FLO4, FLO11, OsISA1, OsNF-YB1, NF-YC12 , and OsYUC9 . Haplotype analyses of these 12 genes revealed the various effects on grain weight among different haplotypes. The hybrids could polymerize more dominant haplotypes of above grain weight regulators than any homozygous cultivar. Moreover, two SHRGs ( OsFl3 and SHRG2 ) mutants displayed a significant reduction in 1000-grain weight and an increase in grain chalkiness, indicating that OsFl3 and SHRG2 positively regulate grain weight. Our research has identified a valuable indica autotetraploid germplasm for generating strong yield heterosis in combination with neo-tetraploid lines and gaining molecular insights into the regulatory processes of heterosis in tetraploid rice., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Lu, Huang, Ge, Liang, Sun, Wu, Ghouri, Shahid and Liu.)

Enlarging the lateral space of drip tubes saves irrigation equipment costs (drip tubes and bypass), but it will lead to an increased risk of grain yield heterogeneity between wheat rows. Adjusting wheat row spacing is an effective cultivation measure to regulate a row's yield heterogeneity. During a 2-year field experiment, we investigated the variations in yield traits and photosynthetic physiology by utilizing two different water- and fertilizer-demanding spring wheat cultivars (NS22 and NS44) under four kinds of drip irrigation patterns with different drip tube lateral spacing and wheat row spacing [① TR4, drip tube spacing (DTS) was 60 cm, wheat row horizontal spacing (WRHS) was 15 cm; ② TR6, DTS was 90 cm, WRHS was 15 cm; ③ TR6L, DTS was 90 cm, WRHS was 10 cm, inter-block spacing (IBS) was 35 cm; and ④ TR6S, DTS was 80 cm, WRHS was 10 cm, IBS was 25 cm]. The results showed that under 15-cm equal row spacing condition, after the number of wheat rows served by a single tube increased from four (TR4, control) to six (TR6), NS22 and NS44 exhibited a marked decline in yield. The decline of NS22 (9.93%) was higher than that of NS44 (9.04%), and both cultivars also showed a greater decrease in grain weight and average grain-filling rate (AGFR) of inferior grains (NS22: 23.19%, 13.97%; NS44: 7.78%, 5.86%) than the superior grains (NS22: 10.60%, 8.33%; NS44: 4.89%, 4.62%). After the TR6 was processed to narrow WRHS (from 15 to 10 cm) and add IBS (TR6L: 35 cm; TR6S: 25 cm), the grain weight per panicle (GWP) and AGFR of superior and inferior grains in the third wheat row (RW3) of NS22 and NS44 under TR6L increased significantly by 26.05%, 8.22%, 14.05%, 10.50%, 5.09%, and 5.01%, respectively, and under TR6S, they significantly increased by 20.78%, 9.91%, 16.19%, 9.28%, 5.01%, and 4.14%, respectively. The increase in GWP and AGFR was related to the increase in flag leaf area, net photosynthetic rate, chlorophyll content, relative water content, actual photochemical efficiency of PSII, and photochemical quenching coefficient. Among TR4, TR6, TR6L, and TR6S, for both NS22 and NS44, the yield of TR6S was significantly higher than that of TR6 and TR6L. Furthermore, TR6S showed the highest economic benefit., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Jing, Qian, Chang, Li and Li.)

The application rate of potassium fertilizer is closely related to the yield of crops. Thin-shelled Tartary buckwheat is a new variety of Tartary buckwheat with the advantages of thin shell and easy shelling. However, little is known about application rate of potassium fertilizer on the yield formation of thin-shelled Tartary buckwheat. This study aimed to clarify the effect of potassium fertilizer on the growth and yield of thin-shelled Tartary buckwheat. A field experiment to investigate the characteristics was conducted across two years using thin-shelled Tartary buckwheat (Miku 18) with four potassium fertilizer applications including 0 (no potassium fertilizer, CK), 15 (low-concentration potassium fertilizer, LK), 30 (medium-concentration potassium fertilizer, MK), and 45 kg·ha -1 (high-concentration potassium fertilizer, HK). The maximum and average grain filling rates; starch synthase activity; superoxide dismutase and peroxidase activities in leaves; root morphological indices and activities; available nitrogen, phosphorus, and organic matter content in rhizosphere soil; urease and alkaline phosphatase activities in rhizosphere soil; plant height, main stem node number, main stem branch number, leaf number; grain number per plant, grain weight per plant, and 100-grain weight increased first and then decreased with the increase in potassium fertilizer application rate and reached the maximum at MK treatment. The content of malondialdehyde was significantly lower in MK treatment than in other three treatments. The yields of thin-shelled Tartary buckwheat treated with LK, MK, and HK were 1.22, 1.37, and 1.07 times that of CK, respectively. In summary, an appropriate potassium fertilizer treatment (30kg·ha -1 ) can delay the senescence, promote the grain filling, and increase the grain weight and final yield of thin-shelled Tartary buckwheat. This treatment is recommended to be used in production to achieve high-yield cultivation of thin-shelled Tartary buckwheat., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Tang, Tang, Huang and Huang.)

Despite its global significance as a highly nutritious food, the critical period for grain yield and grain protein determination of quinoa has not yet been identified. This study aimed to determine the critical period of grain number, yield, and grain protein of quinoa in contrasting environments of South America. Five experiments were conducted in contrasting South American environments, including Argentina, Chile, Ecuador, and Peru, from latitudes 4°S to 39°S, and between 19 and 2165 m.a.s.l. Treatments consisted of the factorial combination of two quinoa cultivars (except in Peru, where only one genotype was used) and 4–9 shading treatments (50–85% shade) applied over 10–20 days throughout the crop cycle, depending on the site and the length of the crop cycle. We evaluated how GY, its components, and grain protein responded to the reduction of the source-sink ratio at different phenological stages. Yield of unstressed controls varied from 2.2 t ha−1 in Lima to 9.8 t ha−1 recorded in Valdivia. The grain protein concentration ranged between 12.6% in Lima and 16.8% in Loja. The most sensitive yield-determining period was between –26 and 445 °Cd from flowering across genotypes and environments. Grain protein concentration increased by up to 19% when the source of assimilates was reduced after anthesis; however, this was insufficient to compensate for the protein yield that was affected by the reduction in grain yield due to shading. The critical period for quinoa grain yield was determined throughout the flowering and grain-filling stages across genotypes and environments, mainly due to a decrease in both grain number and above-ground biomass. Identifying the critical period provides a useful target for breeding and management strategies to increase the quinoa crop yield. • Shading negatively affects grain setting and yield of quinoa, decreasing biomass and harvest index. • The critical period of grain yield is between –26 and 445 °Cd from flowering in quinoa. • Inter-Andean valley and see level genotypes have differences around the common critical period. • Grain weight is less sensitive to sequential shading than grain number. • Grain protein concentration of quinoa has variable sensitivity to shading. [ABSTRACT FROM AUTHOR]

CRISPR/Cas9 system has emerged as an efficient tool for sustainable crop improvement. Roots are the "principal hidden organ" that has a crucial function in vascular plants. Receptor-like protein kinase 1 (RPK1) has been reported to regulate root architecture system (RAS), abiotic stress, and yield both in Arabidopsis and rice. We employed a CRISPR/Cas9-based system, namely LR-1 and LR-2 constructs having double guided RNAs transformed via agrobacterium for targeted mutagenesis of TaRPK1 genes to alter the root architecture and hence yield in Triticum aestivum. Sequencing confirmed seven CRISPR/Cas9-based mutated T0 lines of LR-1 constructs and six T0 lines of LR-2 constructs, with an overall mutation efficiency of 41.93%. The T0 plants displayed higher monoallelic mutation compared to the diallelic mutation. 37.5% monoallelic mutation at target site 1 within the D genome by gRNA1 was observed by the LR-1 construct. The LR-2 constructs showed a higher monoallelic mutation frequency of 26.67% at target sites 1 and 2 within A, B, and D genomes. The deletions were mainly short, however longer deletions such as 12d, 17d, 19d, and 20d were detected by gRNA2 of LR-1 construct. Transgenic lines revealed significant alteration in morphology and RSA with a significant increase in number of effective tillers, grain weight, root length, root depth, root volume, and root surface area while reduced root diameter, root angle, and spike length, compared to the wild plants. Tillers and total grain weight increased significantly, suggesting edited lines increased grain production by decreasing spike length. The study validates that CRISPR/Cas9 mediated targeted editing of TaRPK1 is a practical approach for modifying RAS and hence yield enhancement in wheat. [ABSTRACT FROM AUTHOR]

Population density exerts a decisive influence on the production of most grain crops, so it is essential to identify suitable populations in experimental genotypes, before delivering them to producers. Therefore, in this work we evaluated the effect of population density on the yield components of the cowpea bean in the department of Córdoba. An experimental design was implemented in divided plots of 2 x 5 and 4 replicates, where the main factor was two cowpea bean cultivars (Missouri and IT-86) and the secondary factor was five (5) population densities, with five (5) additional population treatments, for the commercial variety Caupicor 50. Aspects evaluated included dry mass distribution, biometrics and performance components. The results indicated that the genotype has a significant effect on most of the variables studied, highlighting the IT86 genotype for its superior dry mass accumulation and yield compared to the other cultivars evaluated (51% and 197.5 kg ha-1), respectively. In addition, higher values of the leaf area index were observed in 43% and 51%, in high densities for all cultivars. Finally, it was found that the variety Caupicor 50 obtained the highest weight of one thousand grains (215 g) compared to the other genotypes, due to its greater longitudinal dimensions and grain width and also recorded the highest grain yield values (197.5 kg ha-1) when it was set at high densities. [ABSTRACT FROM AUTHOR]