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Glutaredoxins (Grxs) are a ubiquitous group of oxidoreductase enzymes that are important in plant growth and development; however, the functions of rice Grxs have not been fully elucidated. In this paper, we showed that one of the Grxs, encoded by OsGrxC2.2 , exhibited Grx activity. Furthermore, we demonstrated that OsGrxC2.2 was able to regulate embryo development during embryogenesis. Transgenic rice lines overexpressing OsGrxC2.2 unexpectedly exhibited degenerate embryos as well as embryoless seeds. Our data indicated that the embryonic abnormalities occurred at an early stage during embryogenesis. We found that the expression of several endodermal layer marker genes for embryo development, such as OSH1 (apical region marker), OsSCR (L2 ground tissue marker), and OsPNH1 (L3 vascular tissue marker), were significantly decreased in the OsGrxC2.2- overexpressed transgenic rice lines. In contrast, the transcript levels of the majority of protodermal layer markers, including HAZ1 , ROC2 , ROC3 , and RAmy1A , and the shoot apical meristem marker HB , showed little change between the wild-type (WT) and OsGrxC2.2 -overexpressing embryos. Surprisingly, the seed weight of the overexpressed transgenic rice was remarkably increased in comparison to that of the WT. These results indicate that the overexpression of OsGrxC2.2 interferes with the normal embryogenesis of rice embryos and leads to increased grain weight. To the best of our knowledge, this is the first report that OsGrxC2.2 is a rice embryo development-associated gene. [ABSTRACT FROM AUTHOR]

• HNT induces the heat-response related TFs LOC_Os03g53340 and LOC_Os10g28340 greatly upregulation in HTS of rice. • Unique SNPs locate on the genes LOC_Os04g55740 , LOC_Os10g38489 , LOC_Os04g51460 , LOC_Os12g08760 and LOC_Os05g26250. • Unique SNPs suppress gene expression and contribute to heat-tolerant characteristics of rice. • Heat-stress enhances cellular respiration, consumes the energy-rich substances, ultimately leading to reduced grain yield. Global warming-associated increases in temperature, particularly at nighttime, are detrimental to rice grain filling, ultimately leading to losses in grain weight. However, the molecular mechanisms associated with grain weight loss in rice exposed to high nighttime temperature stress are poorly understood. To screen the genes and single nucleotide polymorphisms (SNPs) associated with high nighttime temperature stress in rice, a hybrid sequencing strategy was used to analyze the differentially expressed genes and SNPs between two rice coisogenic strains, a heat-tolerant strain (HTS) and heat-sensitive strain (HSS), following short-term extreme high nighttime temperature stress at the first stage of seed ripening. Ultimately, 56 genes were differentially expressed between HTS and HSS. After short-term extreme high nighttime temperature stress, genes involved in photosynthesis, oxidation, and detoxication by glutathione were upregulated in HSS in comparison to HTS, while that of the heat response-related transcription factor genes were significantly upregulated in HTS in comparison to HSS. Unique SNPs located on the genes peroxidase precursor , glutathione S-transferase GSTU6 , glycosyl hydrolases , carboxyvinyl-carboxyphosphonate phosphorylmutase, and prolamin precursor PROLM3 were present in HTS but absent from HSS and showed slight alterations in gene expression between HTS and HSS. The proposed model indicated that high nighttime temperature enhanced cellular respiration, disturbed the oxidant-antioxidant balance, and consumed energy-rich substances, ultimately leading to reduced grain yield in HSS in contrast to HTS. These genes and unique SNPs provide genetic resources for the breeding of heat-tolerant rice varieties, and the model provides insights into the molecular basis of the response of rice to high nighttime temperature stress. [ABSTRACT FROM AUTHOR]

Summary: Marker‐based prediction holds great promise for improving current plant and animal breeding efficiencies. However, the predictabilities of complex traits are always severely affected by negative factors, including distant relatedness, environmental discrepancies, unknown population structures, and indeterminate numbers of predictive variables. In this study, we utilised two independent F1 hybrid populations in the years 2012 and 2015 to predict rice thousand grain weight (TGW) using parental untargeted metabolite profiles with a partial least squares regression method. A stable predictive model for TGW was built based on hybrids from the population in 2012 (r = 0.75) but failed to properly predict TGW for hybrids from the population in 2015 (r = 0.27). After integrating hybrids from both populations into the training set, the TGW of hybrids could be predicted but was largely dependent on population structures. Then, core hybrids from each population were determined by principal component analysis and the TGW of hybrids in both environments were successfully predicted (r > 0.60). Moreover, adjusting the population structures and numbers of predictive analytes increased TGW predictability for hybrids in 2015 (r = 0.72). Our study demonstrates that the TGW of F1 hybrids across environments can be accurately predicted based on parental untargeted metabolite profiles with a core hybridisation strategy in rice. Metabolic biomarkers identified from early developmental stage tissues, which are grown under experimental conditions, may represent a workable approach towards the robust prediction of major agronomic traits for climate‐adaptive varieties. [ABSTRACT FROM AUTHOR]

The adequate combination of row spacing with the number of plants per meter in front of different edaphoclimatic conditions is fundamental to obtain greater common bean yields. This work aimed to identify the best spatial arrangement and dose of monoammonium phosphate (MAP) to maximize the productive potential of very early BRS FC104 common bean cultivar. The experiments were conducted in Formosa, Cristalina, Santa Helena de Goiás, and Santo Antônio de Goiás, Goiás, in a randomized block design with split plots and four replications. In the plots, five doses of MAP, 100, 150, 200, 250, and 300 kg ha-1, and, in the subplots, five plant populations, 6, 8, 10, 12, and 14 plants per meter were evaluated. Two experiments were carried out in each locality, one at 0.38 m spacing and another at 0.50 m spacing. Among the grain yield components, the number of pods per plant was the most affected by the spatial arrangement of plants, increasing its value with the increase in row spacing and the reduction in plant population. The response of common bean yield to row spacing was variable, depending on the local and the dose of MAP. The plasticity of the grain yield components kept the common bean yield stable in relation to changes in the plant population, except in Santa Helena de Goiás, where greater grain yield was obtained with about 14 plants per meter. Phosphate fertilization increased common bean yield in Santo Antônio de Goiás. [ABSTRACT FROM AUTHOR]

Carbon loss under high night‐time temperature (HNT) leads to significant reduction in wheat yield. Growth chamber studies were carried out using six winter wheat genotypes, to unravel postheading HNT (23°C)–induced alterations in carbon balance, source‐sink metabolic changes, yield, and yield‐related traits compared with control (15°C) conditions. Four of the six tested genotypes recorded a significant increase in night respiration after 4 days of HNT exposure, with all the cultivars regulating carbon loss and demonstrating different degree of acclimation to extended HNT exposure. Metabolite profiling indicated carbohydrate metabolism in spikes and activation of the TriCarboxylic Acid (TCA) cycle in leaves as important pathways operating under HNT exposure. A significant increase in sugars, sugar‐alcohols, and phosphate in spikes of the tolerant genotype (Tascosa) indicated osmolytes and membrane protective mechanisms acting against HNT damage. Enhanced night respiration under HNT resulted in higher accumulation of TCA cycle intermediates like isocitrate and fumarate in leaves of the susceptible genotype (TX86A5606). Lower grain number due to lesser productive spikes and reduced grain weight due to shorter grain‐filling duration determined HNT‐induced yield loss in winter wheat. Traits and mechanisms identified will help catalyze the development of physiological and metabolic markers for breeding HNT‐tolerant wheat. Carbon loss under high night‐time temperature (HNT) leads to significant yield decline in wheat. Winter wheat genotypes exhibited considerable variation for HNT‐induced enhanced night respiration in flag leaves and acclimation upon extended HNT exposure. Alterations in carbohydrate metabolism in spikes with increased sugars acting as osmoprotectants and activation of TCA cycle in leaves due to enhanced night respiration, provides novel insights into metabolites involved in HNT response in wheat. [ABSTRACT FROM AUTHOR]

Highlights • Effects of irrigation and fertilizer supply on grain filling characteristics were explored. • Temporal dynamics of grain weight was simulated using determinate-growth equation. • Fertilizer had significantly influence the appearance time of maximum filling rate and growth termination time. • Grain weight percentage of spike weight and spike moisture content had extremely significant relationship with grain weight. • Mild water deficit and appropriate fertilization improved grain filling and productivity. Abstract In the semi-arid regions of the world, irrigation and fertilization are essential for cereals growth and production because of water shortages and unfertile soils. However, inappropriate water and fertilizer management always causes unstable grain weight and yield. This study aims to explore the responses of grain filling characteristics, grain weight and productivity of winter wheat to varying water and fertilizer supplies. A three-year (2014–2017) experiment was conducted on winter wheat (Triticum aestivum L. 'Xinong 979') under drip fertigation, with three irrigation rates and three fertilization rates. The temporal dynamics of grain weight was simulated using determinate-growth equation. The appearance time of maximum filling rate (t m) and growth termination time (t e) increased as fertilization rate increased, whereas the maximum and average filling rate increased and then had a slight decrease. The t m and t e decreased with the increase of water deficit, the mild water deficit obtained higher grain filling rate. The grain weight percentage of spike weight (GPS) and spike moisture content (SMC) had extremely significant correlations with grain weight. GPS tended to decrease one week before maturity, and declined with the increase in water stress. SMC decreased in a parabolic form, and exhibited a dramatic decline about one week before maturity. With the increase of water or fertilizer supply, the grain weight firstly increased and then decreased, where the mild water deficit and appropriate fertilization improve grain filling and productivity of winter wheat. [ABSTRACT FROM AUTHOR]

Major effect of climate change can be seen in developing countries like Pakistan that make them food insecure. Grain yield of wheat (Triticum aestivum L.) is low as it is affected by erratic weather conditions. Latest development of wheat genotypes applicable for late planting is one of the prime objectives of wheat breeders. Keeping in view the climatic conditions of Pakistan, current investigations were conducted to figure out the inheritance pattern and extent of variations using generation mean analysis. For the aforementioned study the two genotypes Miraj 2008 and Punjab 2011 were evaluated along with following generations i.e. F1, F2, BC1 and BC2 in normal and late sowing trial in Faisalabad, Pakistan. The highest reduction percentage was observed in grain weight per spike (-33.6%). The inheritance of all traits revealed complex inheritance due to the involvement of non-allelic interactions. The traits like days to heading and days to maturity had both additive, additive × additive i.e. fixable and additive × dominant non fixable genetic effects. So, selection in later generation would be fruitful for these traits when combinations are fixed. Heritability estimates for narrow sense was also determined. Low to moderate heritability was depicted under late sowing conditions. [ABSTRACT FROM AUTHOR]

Background: Grain weight (GW) is a key component of sunflower yield and quality, but may be limited by maternal tissues. Cell growth is influenced by expansin proteins that loosen the plant cell wall. This study aimed to identify spatio-temporal expression of EXPN genes in sunflower reproductive organ tissues (ovary, pericarp, and embryo) and evaluate correlations between reproductive organ growth and expansin genes expression. Evaluations involved eight different developmental stages, two genotypes, two source-sink treatments and two experiments. The genotypes evaluated are contrasting in GW (Alybro and confection variety RHA280) under two source-sink treatments (control and shaded) to study the interactions between grain growth and expansin genes expression. Results: Ovaries and grains were sampled at pre- and post-anthesis, respectively. Final GW differed between genotypes and shading treatments. Shading treatment decreased final GW by 16.4 and 19.5% in RHA280 and Alybro, respectively. Relative expression of eight expansin genes were evaluated in grain tissues. EXPN4 was the most abundant expansin in the ovary tissue, while EXPN10 and EXPN7 act predominantly in ovary and pericarp tissues, and EXPN1 and EXPN15 in the embryo tissues. Conclusions: Specific expansin genes were expressed in ovary, pericarp and embryo in a tissue-specific manner. Differential expression among grain tissues was consistent between genotypes, source-sink treatments and experiments. The correlation analysis suggests that EXPN genes could be specifically involved in grain tissue extension, and their expression could be linked to grain size in sunflower. [ABSTRACT FROM AUTHOR]

Since starch is by far the major component of the mature wheat grain, it has been assumed that variation in the capacity for starch synthesis during grain filling can influence final grain weight. We investigated this assumption by studying a total of 54 wheat genotypes including elite varieties and landraces that were grown in two successive years in fields in the east of England. The weight, water content, sugars, starch, and maximum catalytic activities of two enzymes of starch biosynthesis, ADP-glucose pyrophosphorylase and soluble starch synthase, were measured during grain filling. The relationships between these variables and the weights and starch contents of mature grains were analysed. Final grain weight showed few or no significant correlations with enzyme activities, sugar levels, or starch content during grain filling, or with starch content at maturity. We conclude that neither sugar availability nor enzymatic capacity for starch synthesis during grain filling significantly influenced final grain weight in our field conditions. We suggest that final grain weight may be largely determined by developmental processes prior to grain filling. Starch accumulation then fills the grain to a physical limit set by developmental processes. This conclusion is in accord with those from previous studies in which source or sink strength has been artificially manipulated. [ABSTRACT FROM AUTHOR]

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Studies were undertaken for two consecutive years (kharif 2015 and 2016) at the CSK Himachal Pradesh Krishi Vishvidyalaya, Rice and Wheat Research Centre, Malan (Himachal Pradesh, India) under field conditions using paddy variety 'Kasturi Basmati'. Losses in paddy due to rice hispa, Dicladispa armigera (Oliver) were quantified in terms of release density (number of adults per tiller) and phenological stages of crop. Results revealed that both these aspects significantly influenced leaf damage as well as yield of paddy. Early stage release (20 DAT, days after transplanting) contributed to maximum leaf damage (69.9 PLDI (per cent leaf damage index)) and at the same time exerted a significant negative influence on various yield components, viz. number of tillers, panicles, grains and grain weight (g) for which the respective regression coefficients were 5.82, 5.73, 441.4 and 8.06, respectively (per 4 rice hills). [ABSTRACT FROM AUTHOR]

The application of exogenous plant growth regulator can improve plant resistance to drought stress. The effects of application of exogenous cytokinin (CTK), brassinolide (BR), or gibberellic acid (GA) at the silking time on the grain quality of two waxy maize hybrids under drought stress at grain formation stage were studied. Grain weight of both hybrids was unaffected by exogenous phytohormones under control conditions but increased under drought conditions with the application of BR. The grain starch content in response to drought varied with hybrid and phytohormone. Starch granule size and protein content in grains were increased by drought under all conditions, but various phytohormones exerted different forms of influence. The starch λmax in Yunuo7 was unaffected by single or interaction of phytohormones and water deficit, λmax in Jingkenuo2000 with BR was unaffected but with CTK or GA increased by drought. Relative crystallinity was reduced by drought without the application of phytohormone, but with phytohormones in response to drought it was different. Flour peak viscosity was reduced by drought. The value was increased with BR spraying under control and drought conditions. Retrogradation percentage under drought conditions was unaffected by exogenous phytohormones in Jingkenuo2000. In Yunuo7, retrogradation percentage was unaffected by BR but reduced by CTK and GA. In conclusion, spraying phytohormones at the silking stage can affect grain weight and starch quality, grains with a sticky taste can be improved by applying BR, and grains with low retrograde tendency can be produced by applying CTK.

This study analysed the effect of flowering time as influenced by photoperiod sensitivity genes on yield and yield stability in durum wheat. Twenty-three spring genotypes harbouring different allele combinations at Ppd-A1 and Ppd-B1 were grown in 15 field experiments at three sites at latitudes from 41° to 19° N (Spain, Mexico-North and Mexico-South). Low temperature and solar radiation before flowering and long day length during grain-filling characteristic for the Spanish site resulted in high grain number/m2 (GN) and yield (GY), while a moderate GN combined with high solar radiation during grain-filling at Mexico-North led to heavier grains. Allele combination GS100-Ppd-A1a/Ppd-B1a reduced the flowering time up to nine days when compared with Ppd-A1b/Ppd-B1a. Differences in flowering time caused by Ppd-A1/Ppd-B1 allele combinations did not affect yield. Combinations GS105-Ppd-A1a/Ppd-B1b and Ppd-A1b/Ppd-B1b resulted in the highest GN, linked to spikelets/spike, which was higher in GS105-Ppd-A1a/Ppd-B1b due to more grains/spikelet. Flowering time caused by Eps had a minor effect on GN, spikes/m2 and grains/spike, but late flowering resulted in reduced grain weight and GY. Allele combinations harbouring alleles conferring a similar photoperiod sensitivity response at Ppd-A1 and Ppd-B1 resulted in greater yield stability than combinations that carry alleles conferring a different response. Allele combination GS100-Ppd-A1a/Ppd-B1a was the most suitable in terms of yield and yield stability of durum wheat cultivated under irrigation within the studied latitudes.

In the current study, we used a linkage mapping–Genome-Wide Association Study (GWAS) joint strategy to investigate quantitative trait loci (QTLs) governing rice grain shape and weight in a doubled haploid (DH) population, using Kompetitive Allele-Specific PCR (KASP) markers. Results revealed the co-detection of the QTLs, qGLE-12-1 and qGLE-12-2 (Chromosome 12), qGTE-3-1 (Chromosome 3), and qGWL-5-1 and qLWRL-5-1 (Chromosome 5), associated with grain length, width, and length–width ratio, by both linkage mapping and GWAS. In addition, qGLL-7-1 (logarithm of the odds (LOD): 18.0, late-transplanted rice) and qGLE-3-1 (LOD: 8.1, early-transplanted rice), and qLWRL-7-1 (LOD: 34.5), detected only by linkage mapping, recorded a high phenotypic variation explained (PVE) of 32.5%, 19.3%, and 37.7% for grain length, and grain length–width ratio, respectively, contributed by the allele from 93-11. Meanwhile, qGWL-5-1 (LOD: 17.2) recorded a high PVE (31.7%) for grain width, and the allele from Milyang352 contributed to the observed phenotypic variation. Furthermore, qGTL-5-1 (LOD: 21.9) had a high PVE (23.3%) for grain thickness. Similarly, qTGWE-5-1 (LOD: 8.6) showed a high contribution to the PVE for grain weight (23.4%). Moreover, QTLs, qGW-5-1, qGT-5-1, qLWR-5-1, and qTGW-5-1 coincided on chromosome 5, flanked with KJ05_17 and KJ05_13 markers. Therefore, these QTLs are suggested to govern rice grain shape and weight. Additionally, the identified candidate genes could play active roles in the regulation of rice grain shape and weight, regarding their predicted functions, and similarity with previously reported genes. Downstream breeding and functional studies are required to elucidate the roles of these candidate genes in the regulation of grain shape and weight in rice.

• Higher than optimal temperature during reproductive stage affected maize production. • Elevating SWC mitigated the impacts of heat during reproductive stage. • Higher SWC improved grain weight by 2.0–14.8% and grain yield by 11.8–13.5%. • Higher SWC significantly improved G mean , G max , P f , DMA, grain weight, and final yield. The occurrence of heat often exacerbates drought stress by increasing atmospheric vapor pressure deficit and decreasing transpiration efficiency. Water replenishment to increase soil water content (SWC) could be an effective measure for improving crop resilience in heat. However, field observational evidence and the underlying mechanism for the mitigation were still limited. For this, two widely adopted maize hybrids (ZD958 and XY335) were planted in 2019 and 2020 in North China Plain with three growth environments during the reproductive stage: Normal field conditions (NC), High-temperature episodes (HT) and High-temperature together with elevating SWC (HT-W). Averagely, high temperature reduced grain yield by 21.6-65.1% in HT treatment compared with NC treatment. In HT-W treatment, grain yield was improved by 11.8-13.5% while SWC was elevated by 27.6–51.5% in 0–80 cm soil profile compared with HT treatment. In HT-W treatment, water replenishment to maize under heat stress improved canopy temperature and grain filling traits. The daily maximum canopy temperature was reduced by 1.0–3.1 °C. The effective grain-filling period (P f) was extended by 1.0–1.6 days and the mean grain-filling rate (G mean) was increased by 8.2%-10.5%. The improvement of G mean and P f for ZD958 was greater than XY335. Furthermore, the significant correlations between SWC in 0–20 cm soil profile and G mean , and between SWC in 40–80 cm soil profile and P f for both hybrids were observed. As a result, the fresh weight, volume, and water content of the grain were significantly improved in HT-W treatment compared with HT treatment. Overall, per unit increase in SWC (0–80 cm) decreased the daily maximum canopy temperature by 0.3 °C, increased dry matter accumulation by 1.5%, and grain yield by 2.1%. The information obtained from this study will be helpful to develop efficient management to protect against heat stress in the field. [Display omitted] [ABSTRACT FROM AUTHOR]

Chlormequat chloride (CCC) as one of the most important growth retardants has been used for manipulation of growth and yield of cereal crops; however, the effect of CCC has not yet been well understood under drought stress conditions. Therefore, one greenhouse and a field experiment were conducted to examine the effects of CCC on yield and yield components of wheat in drought conditions at College of Agriculture, Shiraz University during 2012-2014 growing seasons. The treatments in greenhouse were application and no-application of CCC, wheat cultivar (Marvdasht, Shiraz and Chamran) and irrigation regimes (100%, 75% and 50% of FC); while the treatments in filed were different CCC concentrations (0, 3 and 5 g L-1) and drought stress levels (no-, light-, moderate- and severe-drought). The results showed that under both greenhouse and field conditions, drought stress at different levels decreased yield and yield components of wheat cultivars. However, CCC improved drought tolerance in wheat with increasing yield and yield components; under field conditions, positive effects of CCC were enhanced with increasing its concentration up to 5 g L-1. The positive effect of CCC was greater under control and light stress compared to under severe stress conditions. In the greenhouse study where Marvdasht, Shiraz, and Chamran cultivars were evaluated, Chamran cultivar produced the highest grain yield under both normal and drought conditions; although Shiraz cultivar was found more responsive to CCC. Overall; drought stress reduced growth and grain yield of wheat crop; however, CCC could compensate, at least in part (i.e. 30% to 60%) for the latter reductions.

Interrogations of local germplasm and landraces can offer a foundation and genetic basis for drought tolerance in wheat. Potential of drought tolerance in a panel of 30 wheat genotypes including varieties, local landraces, and wild crosses were explored under drought stress (DS) and well-watered (WW) conditions. Considerable variation for an osmotic adjustment (OA) and yield components, coupled with genotype and environment interaction was observed, which indicates the differential potential of wheat genotypes under both conditions. Reduction in yield per plant (YP), thousand kernel weight (TKW), and induction of OA was detected. Correlation analysis revealed a strong positive association of YP with directly contributing yield components under both environments, indicating the impotence of these traits as a selection-criteria for the screening of drought-tolerant genotypes for drylands worldwide. Subsequently, the association of OA with TKW which contributes directly to YP, indicates that wheat attains OA to extract more water from the soil under low water-potential. Genotypes including WC-4, WC-8 and LLR-29 showed more TKW under both conditions, among them; LLR-29 also has maximum OA and batter yield comparatively. Result provides insight into the role of OA in plant yield sustainability under DS. In this study, we figure out the concept of OA and its incredible role in sustainable plant yield in wheat.

Grain size and weight are two important determinants of grain yield in rice. Although overexpression of sucrose synthase (SUS) genes has led to several improvements on cellulose and starch-based traits in transgenic crops, little is reported about SUS enhancement of hull size and grain weight in rice. In this study, we selected transgenic rice plants that overexpressed OsSUS1-6 genes driven with the maize Ubi promoter. Compared to the controls (wild type and empty vector line), all independent OsSUS homozygous transgenic lines exhibited considerably increased grain yield and grain weights. Using the representative OsSUS3 overexpressed transgenic plants, four independent homozygous lines showed much raised cell numbers for larger hull sizes, consistent with their enhanced primary cell wall cellulose biosynthesis and postponed secondary wall synthesis. Accordingly, the OsSUS3 transgenic lines contained much larger endosperm volume and higher starch levels than those of the controls in the mature grains, leading to increased brown grain weights by 15−19%. Hence, the results have demonstrated that OsSUS overexpression could significantly improve hull size and grain weight by dynamically regulating cell division and starch accumulation in the transgenic rice.

Genetic improvements have significantly contributed to wheat production. Five wheat cultivars—widely grown in north China in the 1950s, 1990s, or 2010s—were grown in field experiments conducted in the 2014–2015 and 2015–2016 growing seasons. This study evaluated the genetic progress in wheat grain yield and its related traits in north China and explored how breeding and selection have influenced grain numbers and weights within spikelets in the past 60 years. The results showed that the significant increases in grain yield in the past 60 years were mainly due to increases in grain number per spike and grain weight, while spike number per m2 has not changed significantly. Improvements in thousand grain weight (TGW) from the 1950s to 2010s have occurred at four grain positions (G1 to G4). The relative contribution of G4 to TGW increased over time, but was much less than the contributions of G1, G2, and G3. Indeed, the average grain weight at G4 was much less than that of 1000 grains. The increase in grain number per spike since the 1950s was mainly due to an increase in grain number at G1, G2 and G3, with the relative contribution of grain position to grain number being G1 > G2 > G3 > G4. Dwarfing genes increased grain number per spike and grain number at G3 and G4, but not TGW. In future, yields could be boosted by enhancing grain weight at G4 and grain number at G3 and G4, while maintaining those at G1 and G2.

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a staple crop for the people of arid and semi-arid regions of the world. It is fast gaining importance as a climate resilient nutricereal. Exploiting the bold seeded, semi-dwarf, and early flowering genotypes in pearl millet is a key breeding strategy to enhance yield, adaptability, and for adequate food in resource-poor zones. Genetic variation for agronomic traits of pearl millet inbreds can be used to dissect complex traits through quantitative trait locus (QTL) mapping. This study was undertaken to map a set of agronomically important traits like flowering time (FT), plant height (PH), panicle length (PL), and grain weight (self and open-pollinated seeds) in the recombinant inbred line (RIL) population of ICMB 841-P3 × 863B-P2 cross. Excluding grain weight (open pollinated), heritabilities for FT, PH, PL, grain weight (selfed) were in high to medium range. A total of six QTLs for FT were detected on five chromosomes, 13 QTLs for PH on six chromosomes, 11 QTLs for PL on five chromosomes, and 14 QTLs for 1,000-grain weight (TGW) spanning five chromosomes. One major QTL on LG3 was common for FT and PH. Three major QTLs for PL, one each on LG1, LG2, and LG6B were detected. The large effect QTL for TGW (self) on LG6B had a phenotypic variance (R2) of 62.1%. The R2 for FT, TGW (self), and PL ranged from 22.3 to 59.4%. A total of 21 digenic interactions were discovered for FT (R2 = 18–40%) and PL (R2 = 13–19%). The epistatic effects did not reveal any significant QTL × QTL × environment (QQE) interactions. The mapped QTLs for flowering time and other agronomic traits in present experiment can be used for marker-assisted selection (MAS) and genomic selection (GS) breeding programs.

Rice panicles are composed of many branches with two types of extreme grains, the superior and the inferior. Traditionally, it has been well accepted that earlier flowers result in superior grains and late flowers generate inferior grains. However, these correlations have never been strictly examined in practice. In order to determine the accurate relationship between superior and inferior grains and the flowering order, we localized all the seeds in a panicle in four distinct rice species and systematically documented the rice flowering order, flower locations and the final grain weight for their relationships. Our results demonstrated that the grain weight is more heavily determined by the position of the seeds than by the flowering order. Despite earlier flowering has a positive correlation with the grain weight in general, grains from flowers blooming on the second day after anthesis generally gained the highest weight. This suggests earlier flowers may not result in superior grains. Therefore, we concluded that superior and inferior grains, commonly determined by grain weight, are not fully correlated with the flowering order in rice. Following the order of the grain weight, the superior grains are generally localized at the middle parts of the primary branches, whereas inferior grains were mainly on the last two secondary branches of the lower half part of the panicle. In addition, the weight of inferior grains were affected by spikelet thinning and spraying with exogenous plant growth regulators, indicating that physiological incompetence might be the major reason for the occurrence of the inferior grains.

Variability of grain weight spike-1 was studied in 10 wheat genotypes: 'Ana Morava', 'Julija Mono', 'Gruža', 'Kuna', 'Lasta', 'Balkan', 'Rodna', 'NS Rana 2', 'Partizanka', 'Pobeda', grown over three experimental years under different environmental factors. The experiment was set up as a randomized block design in three replications. Differences in the average values of grain weight spike-1 among tested cultivars were determined in all three years. On average, for all genotypes, grain weight spike-1 was highest (2.32g) in the first experimental year (2005/06), and lowest (1.95g) in the second year (2006/07). For all investigated wheat cultivars, in the third experimental year, the average value of grain weight spike-1 was 2.24g, while the total average value for all cultivars and three experimental years was 2.17g. 'Ana Morava' had the highest average values for grain weight spike-1 in all three experimental years, while the lowest grain weight spike-1 was obtained in 'Balkan' (1.81g) in the second year 'Lasta' (1.40g) and in the third experimental year 'Partizanka' ( 1.91 g). On average, 'Ana Morava' had the highest value (2.67g) of grain weight spike-1, while the lowest average value (1.94g) was recorded in 'Balkan'.

Grain size is a key factor in determining rice (Oryza sativa) yield, and exploring new pathways to regulate grain size has immense potential to improve yield. In this study, we report that OsCBL5 encodes a calcineurin B subunit protein that significantly promotes grain size and weight. oscbl5 plants produced obviously smaller and lighter seeds. We further revealed that OsCBL5 promotes grain size by affecting cell expansion in the spikelet hull. Biochemical analyses demonstrated that CBL5 interacts with CIPK1 and PP23. Furthermore, double and triple mutations were induced using CRISPR/Cas9 (cr) to analyze the genetic relationship. It was found that the cr-cbl5/cipk1 phenotype was similar to that of cr-cipk1 and that the cr-cbl5/pp23, cr-cipk1/pp23, and cr-cbl5/cipk1/pp23 phenotype was similar to that of cr-pp23, indicating that OsCBL5, CIPK1, and PP23 act as a molecular module influencing seed size. In addition, the results show that both CBL5 and CIPK1 are involved in the gibberellic acid (GA) pathway and significantly affect the accumulation of endogenous active GA 4 . PP23 participates in GA signal transduction. In brief, this study identified a new module that affects rice grain size, OsCBL5-CIPK1-PP23, which could potentially be targeted to improve rice yield., (© 2023 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)

Grain weight is reported to be a relatively well conserved characteristic across spring barley ( Hordeum vulgare L.) crops that vary in grain number m −2 . Understanding the mechanisms that promote stability in grain weight is important to ensure that efforts to increase grain number beyond current high levels successfully increase yield without compromising grain quality. The aims of this study were to establish 1) whether post-anthesis grain abortion contributes to the stability of grain weight by helping match grain numbers to post-anthesis assimilate supply and 2) whether variations in post-anthesis assimilation per unit grain number affect the heterogeneity of grain weight. Field experiments were conducted in a high-yield potential environment for spring barley in 2011 and 2012. Crops were either shaded post anthesis (a 59% reduction in radiation incident on the crop) to reduce net carbon assimilation or grown unshaded. Grain growth was measured at different spikelet locations on the ear and on different shoots (main shoot and tillers) of the same plant. Shading crops from 14 days after anthesis until harvest maturity reduced yield by 19–20%, mean grain weight (MGW) by 12–16% and harvest index by 5–6%, but did not significantly affect grain number in either year. The magnitudes of these effects were considerably lower than the reduction in radiation imposed by shading suggesting some compensatory adjustment in radiation use efficiency or dry matter partitioning to grain after shading. The rate of grain filling was higher for grains in central spikelets than grains at distal or basal locations on the ear. Shading reduced the rate of grain filling to a similar extent (23–27%) at most locations evaluated on the ear, but had no effect on the duration of grain filling. In spite of the comparable effects of shading on grain growth across different spikelet positions and hierarchy of shoots, crops harvested after shading tended to have a more variable individual grain weight (larger interquartile range and coefficient of variation) than crops that were unshaded. The results show that post-anthesis grain abortion does not contribute to the stability of MGW in spring barley. Moreover, low levels of post-anthesis radiation in crops of large grain number m −2 (sink capacity) can increase heterogeneity of grain weight, which may have negative consequences for grain quality. [ABSTRACT FROM AUTHOR]

Sweet corn landraces are grown for local markets in Khyber Pakhtunkhwa, Pakistan. The present study aimed to document agronomic characteristics of landraces under different microclimatic regimes. Four landraces {Mingora (MNG), Mansehra (MNS), Swabi (SWB) and Parachinar (PRC)} with cv. Azam (check) were planted on five dates at almost one month interval at New Developmental Farm University of Agriculture Peshawar, Pakistan. Randomized complete block (RCB) design with split plots was employed. Planting dates and landraces alone or in combination significantly affected all parameters studied. Sweet corn attained maximum internode length under early plantations (April/March) in 2007 and 2008. Whereas, maximum number of leaves plant-1, ear length, kernels ear-1 and 1000-grain weight (TGW) were recorded from July plantations in both years. Landrace SWB produced maximum number of leaves plant-1. However, higher ear length, kernels ear-1 and TGW were recorded for Azam (check) in both years. Landrace SWB is therefore recommended for planting late in July to obtain higher yield attributes. [ABSTRACT FROM AUTHOR]

Availability of nitrogen and water are major constraints for crop yield, and their interactions are manyfold. Yield gap analysis in rainfed systems commonly uses water-limited yield potential (Y w ) as a benchmark; benchmarking against nitrogen-limited yield potential (Y N ) is less common. The aim of this study was to benchmark wheat yield against Y N in winter-rainfall regions of Australia. We established experiments, and sampled both farmers’ fields and National Variety Trials spanning wide ranges of soils, management practices, and water supply (seasonal rainfall + irrigation) from 153 to 759 mm in South Australia, and from 178 to 428 mm in Western Australia. We measured yield, quantified crop nitrogen nutrition index (NNI) at stem elongation, anthesis or both, derived boundary functions relating Y N and NNI, calculated yield gaps as the difference between Y N and actual yield, and explored the associations between yield gaps and environmental, crop and agronomic factors. In South Australia, NNI at anthesis ranged from 0.45 to 1.45 and yield from 0.9 to 8.9 t ha −1 ; in Western Australia NNI at stem elongation ranged from 0.27 to 1.16 and yield from 1.0 to 7.1 t ha −1 . Bi-linear boundary functions were fitted with a linear Y N – NNI phase up to a NNIx threshold (0.95 ± 0.134 in South Australia, 0.87 ± 0.145 in Western Australia), and a plateau reflecting yield potential (7.8 ± 0.38 t ha −1 in South Australia, 6.5 ± 0.52 t ha −1 in Western Australia). Similar bi-linear boundaries, with congruent NNIx (≈0.9), were found for grain number and shoot biomass at maturity. In South Australia, water supply explained 54% of the yield gap, which declined linearly from about 6 t ha −1 to zero with increasing water availability. Further, the yield gap correlated negatively with carbon isotope discrimination at anthesis, a direct measure of crop water status. In Western Australia, the direct association between yield gap and rainfall was weak, but there was an indirect agronomic link, where low seeding rate in low rainfall environments contributed to low biomass at stem elongation, which in turn explained a large part of the yield gap. In two out of five National Variety Trials, where the aim is comparing the yield of current and emerging varieties, crops were nitrogen deficient. This is a potential source of bias as some varieties were above and others below the NNIx threshold of nitrogen sufficiency. Supply of nitrogen in varietal comparisons needs attention. The approach advanced in this paper can be applied to benchmark yield against crop nitrogen status and identify causes of yield gaps, and for in-season quantification of crop nitrogen status to assist fertiliser decisions directly, or indirectly as a reference for spectral indices. [ABSTRACT FROM AUTHOR]

Summary: GW2 is emerging as a key genetic determinant of grain weight in cereal crops; it has three homoeologs (TaGW2‐A1, ‐B1 and ‐D1) in hexaploid common wheat (Triticum aestivum L.). Here, by analyzing the gene editing mutants that lack one (B1 or D1), two (B1 and D1) or all three (A1, B1 and D1) homoeologs of TaGW2, several insights are gained into the functions of TaGW2‐B1 and ‐D1 in common wheat grain traits. First, both TaGW2‐B1 and ‐D1 affect thousand‐grain weight (TGW) by influencing grain width and length, but the effect conferred by TaGW2‐B1 is stronger than that of TaGW2‐D1. Second, there exists functional interaction between TaGW2 homoeologs because the TGW increase shown by a double mutant (lacking B1 and D1) was substantially larger than that of their single mutants. Third, both TaGW2‐B1 and ‐D1 modulate cell number and length in the outer pericarp of developing grains, with TaGW2‐B1 being more potent. Finally, TaGW2 homoeologs also affect grain protein content as this parameter was generally increased in the mutants, especially in the lines lacking two or three homoeologs. Consistent with this finding, two wheat end‐use quality‐related parameters, flour protein content and gluten strength, were considerably elevated in the mutants. Collectively, our data shed light on functional difference between and additive interaction of TaGW2 homoeologs in the genetic control of grain weight and protein content traits in common wheat, which may accelerate further research on this important gene and its application in wheat improvement. [ABSTRACT FROM AUTHOR]

A field experiments were carried out at the Abu- Graib Research Station - Office of Agricultural Research Ministry of Agriculture , to investigate effect of moisture deletion for some traits of selected wheat genotypes , during 2014-2015, which depend to the long term of breeding program (2008-2014) . The 9th selected genotypes and the control variety IPA 99 were evaluated using split plot arrangement within RCBD and three replications. The main plots included four moisture depletion (20%, 40%, 60% and 80%) of available water while, genotypes occupied sub plots .The results revealed significant differences among depletion, genotypes and their interaction of all studied traits. Moisture depletion 20% , showed the superiority of number of spikes m-2 (385.7), number of grains spike-1 (57.23 grain), weight of 1000 grains (40.85 gm), higher grain yield (5.06 t ha-1), higher biological yield (16.51 t ha-1), and highest water use efficiency for grain yield (1.63 kg m-3). Significant differences were found among genotypes and interactions between genotypes and water stress in most studied characters , this shows of genotypes performance differences to water stress. So we can select one or more genotype which tolerance to water stress. [ABSTRACT FROM AUTHOR]