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Rice grain number is a crucial agronomic trait impacting yield. In this study, we characterized a quantitative trait locus (QTL), GRAIN NUMBER 1.1 (GN1.1), which encodes a Flowering Locus T‐like1 (FT‐L1) protein and acts as a negative regulator of grain number in rice. The elite allele GN1.1B, derived from the Oryza indica variety, BF3‐104, exhibits a 14.6% increase in grain yield compared with the O. japonica variety, Nipponbare, based on plot yield tests. We demonstrated that GN1.1 interacted with and enhanced the stability of ADP‐ribosylation factor (Arf)‐GTPase‐activating protein (Gap), OsZAC. Loss of function of OsZAC results in increased grain number. Based on our data, we propose that GN1.1B facilitates the elevation of auxin content in young rice panicles by affecting polar auxin transport (PAT) through interaction with OsZAC. Our study unveils the pivotal role of the GN1.1 locus in rice panicle development and presents a novel, promising allele for enhancing rice grain yield through genetic improvement. [ABSTRACT FROM AUTHOR]

Rising CO2 concentration in the atmosphere is a matter of global concern and poses apprehension about how plants will adapt to the changing environment. Various studies have proved that under high CO2 levels, plant physiology alters and affects plant functioning. However, under elevated CO2, the stomatal characters and their relation with physiological responses are still not yet clear. To find out these changes in the stomatal parameters at ambient and two elevated CO2 (550 ppm and 700 ppm) levels, four genotypes of maize (Zea mays L.) viz. DHM-117, Harsha, Varun and M-24 were grown in open-top chambers. In the study, it was observed that the stomatal density increased, stomatal size altered, stomatal conductance (gs) and transpiration rate (Tr) decreased under elevated CO2 (eCO2) while photosynthetic rate (Pn), water use efficiency (WUE), yield and biomass, of which especially the reproductive biomass increased. Under eCO2, stomatal and physiological changes were genotypic and CO2 concentration specific. Increased stomatal density at eCO2 was mainly due to increased abaxial stomatal density. The improved Pn and reduced Tr at 550 ppm improved the WUE in the plants, while this response was not observed at 700 ppm. These results elucidate that this C4 crop responded positively to up to 550 ppm of CO2 concentrations, and beyond this, the impact was minimal. [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]

Rising CO2 concentration in the atmosphere is a matter of global concern and poses apprehension about how plants will adapt to the changing environment. Various studies have proved that under high CO2 levels, plant physiology alters and affects plant functioning. However, under elevated CO2, the stomatal characters and their relation with physiological responses are still not yet clear. To find out these changes in the stomatal parameters at ambient and two elevated CO2 (550 ppm and 700 ppm) levels, four genotypes of maize (Zea mays L.) viz. DHM-117, Harsha, Varun and M-24 were grown in open-top chambers. In the study, it was observed that the stomatal density increased, stomatal size altered, stomatal conductance (gs) and transpiration rate (Tr) decreased under elevated CO2 (eCO2) while photosynthetic rate (Pn), water use efficiency (WUE), yield and biomass, of which especially the reproductive biomass increased. Under eCO2, stomatal and physiological changes were genotypic and CO2 concentration specific. Increased stomatal density at eCO2 was mainly due to increased abaxial stomatal density. The improved Pn and reduced Tr at 550 ppm improved the WUE in the plants, while this response was not observed at 700 ppm. These results elucidate that this C4 crop responded positively to up to 550 ppm of CO2 concentrations, and beyond this, the impact was minimal.

SUMMARY: Gibberellins (GAs) play crucial roles in regulating plant architecture and grain yield of crops. In rice, the inactivation of endogenous bioactive GAs and their precursors by GA 2‐oxidases (GA2oxs) regulates stem elongation and reproductive development. However, the regulatory mechanisms of GA2ox gene expression, especially in rice reproductive organs, are unknown. The BEL1‐like homeodomain protein OsBLH4, a negative regulatory factor for the rice OsGA2ox1 gene, was identified in this study. Loss of OsBLH4 function results in decreased bioactive GA levels and pleiotropic phenotypes, including reduced plant height, decreased grain number per panicle, and delayed heading date, as also observed in OsGA2ox1‐overexpressing plants. Consistent with the mutant phenotype, OsBLH4 was predominantly expressed in shoots and young spikelets; its encoded protein was exclusively localized in the nucleus. Molecular analysis demonstrated that OsBLH4 directly bound to the promoter region of OsGA2ox1 to repress its expression. Genetic assays revealed that OsBLH4 acts upstream of OsGA2ox1 to control rice plant height, grain number, and heading date. Taken together, these results indicate a crucial role for OsBLH4 in regulating rice plant architecture and yield potential via regulation of bioactive GA levels, and provide a potential strategy for genetic improvements of rice. Significance Statement: GA 2‐oxidases (GA2oxs) play crucial roles in regulating plant architecture and yield by inactivating endogenous bioactive GAs and their precursors, but the regulatory mechanisms of GA2ox gene expression remain unclear. This study identifies that OsBLH4, a member of the BEL1‐like homeodomain proteins, acts upstream of OsGA2ox1, modulates endogenous bioactive GA levels, and regulates stem elongation and reproductive development in rice. [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]

The number of grains per sea rice panicle is an important parameter directly related to rice yield, and it is also a very important agronomic trait in research related to sea rice breeding. However, the grain number per sea rice panicle still mainly relies on manual calculation, which has the disadvantages of being time-consuming, error-prone, and labor-intensive. In this study, a novel method was developed for the automatic calculation of the grain number per rice panicle based on a deep convolutional neural network. Firstly, some sea rice panicle images were collected in complex field environment and annotated to establish the sea rice panicle image data set. Then, a sea grain detection model was developed using the Faster R-CNN embedded with a feature pyramid network (FPN) for grain identification and location. Also, ROI Align was used to replace ROI pooling to solve the problem of relatively large deviations in the prediction frame when the model detected small grains. Finally, the mAP (mean Average Precision) and accuracy of the sea grain detection model were 90.1% and 94.9%, demonstrating that the proposed method had high accuracy in identifying and locating sea grains. The sea rice grain detection model can quickly and accurately predict the number of grains per panicle, providing an effective, convenient, and low-cost tool for yield evaluation, crop breeding, and genetic research. It also has great potential in assisting phenotypic research. [ABSTRACT FROM AUTHOR]

Inflorescence structure affects final grain yield (GY) in wheat (Triticum aestivum L.). Recent breeding efforts have focused on improving grain number per spike, which is positively correlated with GY. Grain Number Increase 1 (GNI-A1) encodes a homeodomain leucine zipper class I (HD-Zip I) transcription factor that controls the number of grains per spike and GY. However, how this increase in grain number affects grain quality, especially grain protein content (GPC) in wheat, remains elusive. Here we investigated within-spikelet variation in GPC using GNI-A1 near-isogenic lines. Yield trials in two seasons and at two sites demonstrated that lines harboring a reduced-function allele, GNI-A1 (105Y), consistently showed improved GY due to a 27% increase in grain number per spike, along with a 1.7% reduction in GPC compared with lines containing a functional allele, GNI-A1 (105N). We confirmed the positive correlation between GY and grain number and the negative correlation between GY and GPC, but we observed no correlation between GY and thousand-grain weight. The increased grain number conferred by the 105Y allele was due to better floret fertility around the central part of the spike and whole florets. In-depth phenotypic analysis using dissected grain samples revealed that GPC was nearly uniform among spikelets and florets. These results suggest that in plants carrying a mutation in GNI-A1, the increase in the total number of grains is accompanied by a reduction in GPC. [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]

Nitrogen (N) fertilization is critical for spike and floret development, which affects the number of fertile florets per spike (NFFs). However, the physiological regulation of the floret development process by N fertilization is largely unknown. A high temporal-resolution investigation of floret primordia number and morphology, dry matter, and N availability was conducted under three N fertilization levels: 0 (N0), 120 (N1) and 240 (N2) kg ha−1. Interestingly, fertile florets at anthesis stage were determined by those floret primordia with meiotic ability at booting stage: meiotic ability was a threshold that predicted whether a floret primordium became fertile or abortive florets. Because the developmental rate of the 4th floret primordium in the central spikelet was accelerated and then they acquired meiotic ability, the NFFs increased gradually as N application increased, but the increase range decreased under N2. There were no differences in spike N concentration among treatments, but leaf N concentration was increased in the N1 and N2 treatments. Correspondingly, dry matter accumulation and N content of the leaf and spike in the N1 and N2 treatments was increased as compared to N0. Clearly, optimal N fertilization increased leaf N availability and transport of assimilates to spikes, and allowed more floret primordia to acquire meiotic ability and become fertile florets, finally increasing NFFs. There was no difference in leaf N concentration between N1 and N2 treatment, whereas soil N concentration at 0–60 cm soil layers was higher in N2 than in N1 treatment, implying that there was still some N fertilization that remained unused. Therefore, improving the leaf’s ability to further use N fertilizer is vital for greater NFFs.

Abstract Background The number of grains per panicle is an important factor in determining rice yield. The DST-OsCKX2 module has been demonstrated to regulate panicle development in rice by controlling cytokinin content. However, to date, how the function of DST-OsCKX2 module is regulated during panicle development remains obscure. Result In this study, the ABNORMAL PANICLE 1 (ABP1), a severely allele of FRIZZY PANICLE (FZP), exhibits abnormal spikelets morphology. We show that FZP can repress the expression of DST via directly binding to its promotor. Consistently, the expression level of OsCKX2 increased and the cytokinin content decreased in the fzp mutant, suggesting that the FZP acts upstream of the DST-OsCKX2 to maintain cytokinin homeostasis in the inflorescence meristem. Conclusions Our results indicate that FZP plays an important role in regulating spikelet development and grain number through mediating cytokinin metabolism.

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.

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]

Background: The number of grains per panicle is an important factor in determining rice yield. The DST-OsCKX2 module has been demonstrated to regulate panicle development in rice by controlling cytokinin content. However, to date, how the function of DST-OsCKX2 module is regulated during panicle development remains obscure. Result: In this study, the ABNORMAL PANICLE 1 (ABP1), a severely allele of FRIZZY PANICLE (FZP), exhibits abnormal spikelets morphology. We show that FZP can repress the expression of DST via directly binding to its promotor. Consistently, the expression level of OsCKX2 increased and the cytokinin content decreased in the fzp mutant, suggesting that the FZP acts upstream of the DST-OsCKX2 to maintain cytokinin homeostasis in the inflorescence meristem. Conclusions: Our results indicate that FZP plays an important role in regulating spikelet development and grain number through mediating cytokinin metabolism. [ABSTRACT FROM AUTHOR]

Drought and soil salinization are threatening maize production in Northwest China, and climate change is exacerbating water shortages. The objective of this study is to explore the mechanisms underlying spring maize yield and water use efficiency under water deficit and salt stress, to coordinate water conservation and maize production. A three-year field trial was conducted with two water levels (full irrigation and deficit irrigation) and two salt levels (0.65‰ and 2‰) using two maize genotypes (ZD958 and XY335). Leaf area, leaf photosynthesis, dry matter accumulation, floret number, grain abortion, ear characteristics and water use efficiency were evaluated. Water, salt and their combined stress significantly decreased the grain yield by 7.3%, 20.5%, and 38.7%, respectively, 93.6% of which was explained by grain number depending on spikelet differentiation. Grain abortion was identified as the primary reason for maize yield reduction under water and salt stress. The reduction in total biomass, rather than biomass allocation suppressed spikelet differentiation under water and salt stress. Water or salt single stress improved water use efficiency (3.7%–17.5%) by reducing evaporation compared with no stress. Furthermore, water and salt combined stress significantly decreased maize productivity leading to reduction in water use efficiency. Taken together, reducing grain abortion to maintain grain number is the key to alleviate maize yield loss and improve water use efficiency under water and salt stress.

The number of grains per sea rice panicle is an important parameter directly related to rice yield, and it is also a very important agronomic trait in research related to sea rice breeding. However, the grain number per sea rice panicle still mainly relies on manual calculation, which has the disadvantages of being time-consuming, error-prone, and labor-intensive. In this study, a novel method was developed for the automatic calculation of the grain number per rice panicle based on a deep convolutional neural network. Firstly, some sea rice panicle images were collected in complex field environment and annotated to establish the sea rice panicle image data set. Then, a sea grain detection model was developed using the Faster R-CNN embedded with a feature pyramid network (FPN) for grain identification and location. Also, ROI Align was used to replace ROI pooling to solve the problem of relatively large deviations in the prediction frame when the model detected small grains. Finally, the mAP (mean Average Precision) and accuracy of the sea grain detection model were 90.1% and 94.9%, demonstrating that the proposed method had high accuracy in identifying and locating sea grains. The sea rice grain detection model can quickly and accurately predict the number of grains per panicle, providing an effective, convenient, and low-cost tool for yield evaluation, crop breeding, and genetic research. It also has great potential in assisting phenotypic research.

Late spring cold (LSC) occurred in the reproductive period of wheat impairs spike and floret differentiation during the reproductive period, when young spikelets are very cold-sensitive. However, under LSC, the responses of wheat spikelets at various positions, leaves, and stems and the interactions between them at physiological levels remain unclear. In the present study, two-year treatments at terminal spikelet stage under two temperatures (2 °C, −2 °C) and durations (1, 2, and 3 days) were imposed in an artificial climate chamber to compare the effects of LSC on grain number and yield in the wheat cultivars Yannong 19 (YN19, cold-tolerant) and Xinmai 26 (XM26, cold-sensitive). The night temperature regimes were designed to reproduce natural temperature variation. LSC delayed plant growth and inhibited spike and floret differentiation, leading to high yield losses in both cultivars. LSC reduced dry matter accumulation (DMA, g) in spikes, stems, and leaves, reducing the DMA ratios of the spike to leaf and spike to stem. Plant cell wall invertase (CWINV) activity increased in upper and basal spikelets in YN19, whereas CWINV increased in middle spikelets in XM26. Under LSC, soluble sugar and glucose were transported and distributed mainly in upper and basal spikelets for glume and rachis development, so that spike development was relatively complete in YN19, whereas the upper and basal spikelets were severely damaged and most of the glumes in middle spikelets were relatively completely developed in XM26, resulting in pollen abortion mainly in upper and basal spikelets. The development of glumes and rachides was influenced and grain number per spike was decreased after LSC, with kernels present mainly in middle spikelets. Overall, reduced total DMA and dry matter partitioning to spikes under LSC results in poor spikelet development, leading to high losses of grain yield.

Abstract Background Large-scale genotype–phenotype association studies of crop germplasm are important for identifying alleles associated with favorable traits. The limited number of single-nucleotide polymorphisms (SNPs) in most wheat genome-wide association studies (GWASs) restricts their power to detect marker-trait associations. Additionally, only a few genes regulating grain number per spikelet have been reported due to sensitivity of this trait to variable environments. Results We perform a large-scale GWAS using approximately 40 million filtered SNPs for 27 spike morphology traits. We detect 132,086 significant marker-trait associations and the associated SNP markers are located within 590 associated peaks. We detect additional and stronger peaks by dividing spike morphology into sub-traits relative to GWAS results of spike morphology traits. We propose that the genetic dissection of spike morphology is a powerful strategy to detect signals for grain yield traits in wheat. The GWAS results reveal that TaSPL17 positively controls grain size and number by regulating spikelet and floret meristem development, which in turn leads to enhanced grain yield per plant. The haplotypes at TaSPL17 indicate geographical differentiation, domestication effects, and breeding selection. Conclusion Our study provides valuable resources for genetic improvement of spike morphology and a fast-forward genetic solution for candidate gene detection and cloning in wheat.

Delays in sowing have significant effects on the grain yield, yield components, and grain protein concentrations of winter wheat. However, little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes. In this study, the effects of sowing date were investigated in a winter wheat cultivar, Shannong 30, which was sown in 2019 and 2020 on October 8 (normal sowing) and October 22 (late sowing) under field conditions. Delayed sowing increased the partitioning of 13C-assimilates to spikes, particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet. Consequently, the increase in grain number was the greatest for the apical sections, followed by the basal and central sections. No significant differences were observed between sowing dates in the superior grain number in the basal and central sections, while the number in apical sections was significantly different. The number of inferior grains in each section also increased substantially in response to delayed sowing. The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and 13C-assimilate partitioning to grains at specific positions in the spikes. Increases in grain number m–2 resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains. Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections, followed by the central and apical sections. No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing. In conclusion, a 2-week delay in sowing improved grain yield through increased grain number per spike, which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet. However, grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.

Abstract Background Grain count is crucial to wheat yield composition and estimating yield parameters. However, traditional manual counting methods are time-consuming and labor-intensive. This study developed an advanced deep learning technique for the segmentation counting model of wheat grains. This model has been rigorously tested on three distinct wheat varieties: ‘Bainong 307’, ‘Xinmai 26’, and ‘Jimai 336’, and it has achieved unprecedented predictive counting accuracy. Method The images of wheat ears were taken with a smartphone at the late stage of wheat grain filling. We used image processing technology to preprocess and normalize the images to 480*480 pixels. A CBAM-HRNet wheat grain segmentation counting deep learning model based on the Convolutional Block Attention Module (CBAM) was constructed by combining deep learning, migration learning, and attention mechanism. Image processing algorithms and wheat grain texture features were used to build a grain counting and predictive counting model for wheat grains. Results The CBAM-HRNet model using the CBAM was the best for wheat grain segmentation. Its segmentation accuracy of 92.04%, the mean Intersection over Union (mIoU) of 85.21%, the category mean pixel accuracy (mPA) of 91.16%, and the recall rate of 91.16% demonstrate superior robustness compared to other models such as HRNet, PSPNet, DeeplabV3+ , and U-Net. Method I for spike count, which calculates twice the number of grains on one side of the spike to determine the total number of grains, demonstrates a coefficient of determination R2 of 0.85, a mean absolute error (MAE) of 1.53, and a mean relative error (MRE) of 2.91. In contrast, Method II for spike count involves summing the number of grains on both sides to determine the total number of grains, demonstrating a coefficient of determination R2 of 0.92, an MAE) of 1.15, and an MRE) of 2.09%. Conclusions Image segmentation algorithm of the CBAM-HRNet wheat spike grain is a powerful solution that uses the CBAM to segment wheat spike grains and obtain richer semantic information. This model can effectively address the challenges of small target image segmentation and under-fitting problems in training. Additionally, the spike grain counting model can quickly and accurately predict the grain count of wheat, providing algorithmic support for efficient and intelligent wheat yield estimation.

ABSTRACTIn Kenya and many other African countries, improving rice productivity is vital for future food security. To improve rice productivity in Kenya, near-isogenic lines (NIL) were developed by introducing Gn1a and WFP, genes that function to increase grain number per panicle by increasing secondary and primary rachis-branches, into NERICA 1, a registered variety in Kenya. The aim of this study was to determine whether the introduction of these genes has the potential to improve rice productivity under tropical highland conditions in central Kenya. Field experiments were conducted in 2016 and 2017 at a lowland rice field in Mwea, Kenya, under different nitrogen fertilization conditions using three lines of NERICA 1 introgressed with Gn1a and/or WFP (NIL-Gn1a, NIL-WFP, and NIL-Gn1a+WFP) and their recurrent parents, NERICA 1. Two years of field experiments revealed that the introgression lines enhanced grain yield by increasing the number of primary and secondary rachis-branches and the number of grains per panicle. Gn1a and WFP showed additive effects and the introgression of both genes alleviated the negative effects on yield components observed in the introgressed lines, resulting in higher grain yield. Sufficient nitrogen fertilization was required to increase yield in the single-gene introgression lines. However, the line with both Gn1a and WFP achieved reasonable yields even under low fertilizer conditions in Mwea, Kenya. As these introgression lines have similar growing characteristics to their parent variety, they are expected to contribute to increased rice production in Kenya and similar environments in sub-Saharan Africa.

The yield of wheat in wheat–rice rotation cropping systems in the Yangtze River Plain, China, is adversely impacted by waterlogging. A raised bed planting (RBP) pattern may reduce waterlogging and increase the wheat yield after rice cultivation by improving the grain number per spike. However, the physiological basis for grain formation under RBP conditions remains poorly understood. The present study was performed over two growing seasons (2018/2019 and 2019/2020) to examine the effects of the planting pattern (i.e., RBP and flat planting (FP)) on the floret and grain formation features and leaf photosynthetic source characteristics of wheat. The results indicated that implementation of the RBP pattern improved the soil–plant nitrogen (N) supply during floret development, which facilitated balanced floret development, resulting in a 9.5% increase in the number of fertile florets per spike. Moreover, the RBP pattern delayed wheat leaf senescence and increased the photosynthetic source capacity by 13.9%, which produced more assimilates for grain filling. Delayed leaf senescence was attributed to the resultant high leaf N content and enhanced antioxidant metabolism. Correspondingly, under RBP conditions, 7.6–8.6% more grains per spike were recorded, and the grain yield was ultimately enhanced by 10.4–12.7%. These results demonstrate that the improvement of the spike differentiation process and the enhancement of the leaf photosynthetic capacity were the main reasons for the increased grain number per spike of wheat under the RBP pattern, and additional improvements in this technique should be achievable through further investigation.

The developmental process of spike is critical for spike fertility through affecting floret primordia fate in wheat; however, the genetic regulation of this dynamic and complex developmental process remains unclear. Here, we conducted a high temporal‐resolution analysis of spike transcriptomes and monitored the number and morphology of floret primordia within spike. The development of all floret primordia in a spike was clearly separated into three distinct phases: differentiation, pre‐dimorphism and dimorphism. Notably, we identified that floret primordia with meiosis ability at the pre‐dimorphism phase usually develop into fertile floret primordia in the next dimorphism phase. Compared to control, increasing plant space treatment achieved the maximum increasement range (i.e., 50%) in number of fertile florets by accelerating spike development. The process of spike fertility improvement was directed by a continuous and dynamic regulatory network involved in transcription factor and genes interaction. This was based on the coordination of genes related to heat shock protein and jasmonic acid biosynthesis during differentiation phase, and genes related to lignin, anthocyanin and chlorophyll biosynthesis during dimorphism phase. The multi‐dimensional association with high temporal‐resolution approach reported here allows rapid identification of genetic resource for future breeding studies to realise the maximum spike fertility potential in more cereal crops. Summary statement: Floret primordia fates are determined by meiotic ability at the pre‐dimorphism phase: floret primordia with meiotic ability always develop into fertile florets, whereas meiotically incapable floret primordia usually abort. [ABSTRACT FROM AUTHOR]

Spike traits play an important role in improving wheat yield. However, the application of reported spike-related loci remains unclear. Here, we assessed six spike-related traits across seven different environments using 406 wheat accessions. A negative correlation was observed between two components of wheat yield: thousand kernel weight (TKW) and grain number per spike (GN). Nonetheless, TKW and GN were significantly higher in modern cultivars compared to landraces. Two reliable quantitative trait loci (QTLs) related to GN, QGN.nwafu-4A and QGN.nwafu-7A, were identified through genome-wide associate analysis. QGN.nwafu-4A showed pleiotropy on GN, kernel number per spikelet and spike length. Both elite haplotypes of QGN.nwafu-7A were prominently present in Chinese modern cultivars, particularly those released after the year 2000. Elite haplotype A of QGN.nwafu-7A was significantly prevalent in Chinese Yellow and Huai wheat zone, while elite haplotype D of QGN.nwafu-7A was concentrated in other wheat-growing regions of China. This observation suggests distinct preferences in wheat cultivation across various agro-ecological regions. Conversely, elite haplotype A of QGN.nwafu-4A was more common in introduced cultivars from abroad. This divergence may be attributed to the reduced TKW of haplotype A. Overall, these findings provide valuable insights into the application of these two QTLs in high-yield wheat breeding. [ABSTRACT FROM AUTHOR]

The genetic heritage of wheat (Triticum spp.) crops has been shaped by millions of years of predomestication natural selection, often driven by competition among individuals. However, genetic improvements in yield potential are thought to involve selection towards reduced competitiveness, thus enhancing adaptation to the crop environment. We investigated potential trade‐offs between individual plant fitness and community performance using a population of introgression lines carrying chromosome segments of wild emmer (nondomesticated) in the background of an elite durum cultivar. We focused on light as a primary factor affecting plant–plant interactions and assessed morphological and biomass phenotypes of single plants grown in mixtures under sunlight and a simulated canopy shade, and the relevance of these phenotypes for the monoculture community in the field. We found that responses to canopy shade resemble responses to high density and contribute to both the individual and the community. Stepwise regressions suggested that grain number per spike and its persistence under shade are essential attributes of productive communities, advocating their use as a breeding target during early‐generation selection. Overall, multiple phenotypes attained under shade could better explain community performance. Our novel, applicable, high‐throughput set‐up provides new prospects for studying and selecting single‐plant phenotypes in a canopy‐like environment. Summary statement: Individual fitness and the performance of the monoculture community are associated with distinct and conflicting plant behaviours, some related to response to shade. Simulation of canopy shade on single plants can improve our predictions of the genotype performance as a community. [ABSTRACT FROM AUTHOR]

Lack of soil moisture and phosphorus deficiency limits wheat grain yield in dryland areas. However, the moisture-conserving effect of straw mulching combined with phosphor fertilization on fertile florets per spike (FFS) and grain yield remains unclear. During the 2020–2021 and 2021–2022 growing seasons, we investigated the combined effects of straw mulching (0 and 8000 kg ha−1) and phosphorus fertilization (0, 75, and 120 kg P2O5 ha−1) on spike development, assimilates' availability, and the photosynthetic properties of flag leaves by conducting a field experiment. Compared with no straw mulch control, straw mulching increased fertile spike, grain number per spike (15.6%), and grain yield (22.6%), and grain number per spike was the most important contribution to increasing wheat grain yield (46%). An increase in grain number per spike is associated with FFS. Compared with no straw mulch control, straw mulching increased FFS by 19.5%, and it increased with increasing phosphorus fertilization levels. Moreover, straw mulching combined with phosphorus fertilization promoted the light compensation point (LCP), light saturation point (LSP), net photosynthetic rate (Pn), Chl b, and the maximal photochemical efficiency of photosystem II (Fv/Fm) of flag leaves to produce carbohydrates. Our study has shown that the primary factor for the divergence in FFS under straw mulching and phosphorus application was the efficiency of assimilate utilization in the spike, which ultimately led to increased grain number per spike and grain yield. [ABSTRACT FROM AUTHOR]

Water deficit is one of the main abiotic stresses that affect wheat production worldwide. Plants exhibit phenotypic variations to mitigate the negative effects of water stress on grain yield. The objective of the work was to evaluate whether wheat (Triticum aestivum L.) plants showed transgenerational inheritance of environmental adaptation when exposed to water deficit around flowering (i.e. the critical phenological stage for the definition of grain yield). During the first experimental year, plants from three genotypes PIF: commercial cultivar; TR1 and TR4: transgenic genotypes derived from PIF containing the transcription unit PSARK::IPT (associated with the cytokinin-induced enhanced drought tolerance) were cultivated under well-watered (WWm) or water deficit from Z3.2 to Z6.9 + 5 days (WDm). Offspring of this first year were then grown under well-watered (WWo) or water deficit from Z3.2 to Z6.9 + 5 days (WDo) during the next two years, following a crop arrangement. Plants from seeds exposed to WDm tended to have a poor grain yield for both water regimes of the progeny (i.e. WWo and WDo) in both years. The number of grains per unit area was the numerical component that best explained grain yield (r2 = 0.98; p < 0.05), due to variations in the number of grains per ear. Grain weight was a highly conservative trait. Aboveground biomass and harvest index reduced in response to WDo compared to WWo and followed similar responses to grain yield. In conclusion, a restrictive maternal water environment worsened yield response in the following generation, independent of the water condition to which the offspring were exposed, due to reductions in the number of grains per spike, in total aboveground biomass at maturity, and in its partitioning to the grain. [ABSTRACT FROM AUTHOR]

The cytochrome P450 (CYP450) gene family plays a critical role in plant growth and developmental processes, nutrition, and detoxification of xenobiotics in plants. In the present research, a comprehensive set of 105 OsCYP71 family genes was pinpointed within the genome of indica rice. These genes were categorized into twelve distinct subfamilies, where members within the same subgroup exhibited comparable gene structures and conserved motifs. In addition, 105 OsCYP71 genes were distributed across 11 chromosomes, and 36 pairs of OsCYP71 involved in gene duplication events. Within the promoter region of OsCYP71, there exists an extensive array of cis-elements that are associated with light responsiveness, hormonal regulation, and stress-related signaling. Further, transcriptome profiling revealed that a majority of the genes exhibited responsiveness to hormones and were activated across diverse tissues and developmental stages in rice. The OsCYP71P6 gene is involved in insect resistance, senescence, and yield-related traits in rice. Hence, understanding the association between OsCYP71P6 genetic variants and yield-related traits in rice varieties could provide novel insights for rice improvement. Through the utilization of linear regression models, a total of eight promoters were identified, and a specific gene variant (Ser33Leu) within OsCYP71P6 was found to be linked to spikelet fertility. Additionally, different alleles of the OsCYP71P6 gene identified through in/dels polymorphism in 131 rice varieties were validated for their allelic effects on yield-related traits. Furthermore, the single-plant yield, spikelet number, panicle length, panicle weight, and unfilled grain per panicle for the OsCYP71P6-1 promoter insertion variant were found to contribute 20.19%, 13.65%, 5.637%, 8.79%, and 36.86% more than the deletion variant, respectively. These findings establish a robust groundwork for delving deeper into the functions of OsCYP71-family genes across a range of biological processes. Moreover, these findings provide evidence that allelic variation in the promoter and amino acid substitution of Ser33Leu in the OsCYP71P6 gene could potentially impact traits related to rice yield. Therefore, the identified promoter variants in the OsCYP71P6 gene could be harnessed to amplify rice yields. [ABSTRACT FROM AUTHOR]

This study was carried out to determine the critical period in oats, which is relevant for locating that period under the best climatic conditions. Trials were conducted in the Argentinian Pampas during 2015–2016, using four oat genotypes with different growing cycle. The experimental design was a split-split-plot, with three replications; being genotypes the main plot and the subplots six shading treatments [unshaded control and five shaded treatments during 25 days, from different growth stages [GS31 (first-visible-node), GS32, GS33, GS40 (boot), and GS60 (flowering)]. GY and its components [(number of panicles (NP), grains number per panicles (GNP), grains number per square meter (GN), and thousand kernel weight (TKW)] were determined at harvest. GY was sensitive to radiation limitations, showing falls of 20 to 70%, varying according to shading and genotypes. The shading mainly affected GY between GS32 and a few days after flowering in the short-intermediate cycle genotypes, and from GS33 in those with the longest cycles. Regression analysis showed that GN was the most affected yield component, being GNP more sensitive to stress and closely related to GN than NP. TKW showed less magnitude reductions (4.6 to 17.4%), being the shading at GS40, the one that caused the greatest decreases. [ABSTRACT FROM AUTHOR]

Background: Grain count is crucial to wheat yield composition and estimating yield parameters. However, traditional manual counting methods are time-consuming and labor-intensive. This study developed an advanced deep learning technique for the segmentation counting model of wheat grains. This model has been rigorously tested on three distinct wheat varieties: 'Bainong 307', 'Xinmai 26', and 'Jimai 336', and it has achieved unprecedented predictive counting accuracy. Method: The images of wheat ears were taken with a smartphone at the late stage of wheat grain filling. We used image processing technology to preprocess and normalize the images to 480*480 pixels. A CBAM-HRNet wheat grain segmentation counting deep learning model based on the Convolutional Block Attention Module (CBAM) was constructed by combining deep learning, migration learning, and attention mechanism. Image processing algorithms and wheat grain texture features were used to build a grain counting and predictive counting model for wheat grains. Results: The CBAM-HRNet model using the CBAM was the best for wheat grain segmentation. Its segmentation accuracy of 92.04%, the mean Intersection over Union (mIoU) of 85.21%, the category mean pixel accuracy (mPA) of 91.16%, and the recall rate of 91.16% demonstrate superior robustness compared to other models such as HRNet, PSPNet, DeeplabV3+ , and U-Net. Method I for spike count, which calculates twice the number of grains on one side of the spike to determine the total number of grains, demonstrates a coefficient of determination R2 of 0.85, a mean absolute error (MAE) of 1.53, and a mean relative error (MRE) of 2.91. In contrast, Method II for spike count involves summing the number of grains on both sides to determine the total number of grains, demonstrating a coefficient of determination R2 of 0.92, an MAE) of 1.15, and an MRE) of 2.09%. Conclusions: Image segmentation algorithm of the CBAM-HRNet wheat spike grain is a powerful solution that uses the CBAM to segment wheat spike grains and obtain richer semantic information. This model can effectively address the challenges of small target image segmentation and under-fitting problems in training. Additionally, the spike grain counting model can quickly and accurately predict the grain count of wheat, providing algorithmic support for efficient and intelligent wheat yield estimation. [ABSTRACT FROM AUTHOR]

In Kenya and many other African countries, improving rice productivity is vital for future food security. To improve rice productivity in Kenya, near-isogenic lines (NIL) were developed by introducing Gn1a and WFP, genes that function to increase grain number per panicle by increasing secondary and primary rachis-branches, into NERICA 1, a registered variety in Kenya. The aim of this study was to determine whether the introduction of these genes has the potential to improve rice productivity under tropical highland conditions in central Kenya. Field experiments were conducted in 2016 and 2017 at a lowland rice field in Mwea, Kenya, under different nitrogen fertilization conditions using three lines of NERICA 1 introgressed with Gn1a and/or WFP (NIL-Gn1a, NIL-WFP, and NIL-Gn1a+WFP) and their recurrent parents, NERICA 1. Two years of field experiments revealed that the introgression lines enhanced grain yield by increasing the number of primary and secondary rachis-branches and the number of grains per panicle. Gn1a and WFP showed additive effects and the introgression of both genes alleviated the negative effects on yield components observed in the introgressed lines, resulting in higher grain yield. Sufficient nitrogen fertilization was required to increase yield in the single-gene introgression lines. However, the line with both Gn1a and WFP achieved reasonable yields even under low fertilizer conditions in Mwea, Kenya. As these introgression lines have similar growing characteristics to their parent variety, they are expected to contribute to increased rice production in Kenya and similar environments in sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

SUMMARY: In plants, variations in seed size and number are outcomes of different reproductive strategies. Both traits are often environmentally influenced, suggesting that a mechanism exists to coordinate these phenotypes in response to available maternal resources. Yet, how maternal resources are sensed and influence seed size and number is largely unknown. Here, we report a mechanism that senses maternal resources and coordinates grain size and number in the wild rice Oryza rufipogon, a wild progenitor of Asian cultivated rice. We showed that FT‐like 9 (FTL9) regulates both grain size and number and that maternal photosynthetic assimilates induce FTL9 expression in leaves to act as a long‐range signal that increases grain number and reduces size. Our findings highlight a strategy that benefits wild plants to survive in a fluctuating environment. In this strategy, when maternal resources are sufficient, wild plants increase their offspring number while preventing an increase in offspring size by the action of FTL9, which helps expand their habitats. In addition, we found that a loss‐of‐function allele (ftl9) is prevalent among wild and cultivated populations, offering a new scenario in the history of rice domestication. Significance Statement: Offspring number and size are the cornerstones of the life history of wild plants and are essential in crop yield. By using the phenotypic variation of grain traits among Oryza rufipogon, a wild progenitor of Asian cultivated rice, we found that FT‐like 9 (FTL9) mediates maternal‐offspring signaling that senses maternal resource availability and coordinates grain size and number. [ABSTRACT FROM AUTHOR]

Introduction Cultivating forage plants is an important way to address the problem of a lack of forage and its consequences, which can be beneficial to the economy and improving food security. Millet is an excellent source of forage for livestock because of its high dry matter production, low water footprint and adaptability to different environments. However, there is not available well documented experimental results on the crop planting date for Rasht, Guilan province, Iran. Therefore, this study was performed to evaluate the impact of various planting dates on the crop grain and biomass yield in Rasht, which could be extended to similar regions. Materials and methods The study was conducted to evaluate the impact of various planting dates on the grain and biomass yield of proso millet (Pishahang cultivar) in Rasht, Guilan province. The study was conducted at the Faculty of Agricultural Sciences, University of Guilan in two cropping years, 2017-18 and 2018-19. A RCBD based experiment with four replications and four planting dates was used. The planting dates were May 29, June 27, July 29 and August 29 in the first year, and June 4, July 7, August 5 and September 6 in the second year. The central rows of each plot were used to measure grain yield and biomass yield, respecting the margin effect. We tracked the growth of the leaf area over time by measuring leaf area and maximum leaf area index from tillering stage to final harvest. The SAS software was used to analyze variance and compare data values. Research findings The results of the study showed that the interaction between planting date and year had a significant effect on biomass yield, grain yield, harvest index, leaf area index, panicle weight, panicle number, grain number, and 1000- grain weight. In the first year, planting millet on June 27 resulted in the highest biomass yield (9927 kg ha-1), grain yield (2182 kg ha-1), panicle dry weight (25.53 g.plant-1 ), panicle number (15.08 per plant), grain number (2121 per plant), 1000 -grain weight (5.23 g), and leaf area index (5.14). This was likely due to the favorable temperature conditions at that time of year. In the second year, planting millet on July 7 resulted in the highest biomass yield (6537 kg ha-1), grain yield (1283 kg ha-1), panicle dry weight (11.77 g. plant-1), panicle number (6.75 per plant), grain number (1345per plant), 1000-grain weight (4.7 g), and leaf area index (3.69). This was likely due to the favorable meteorological parameters at that time of year, such as maximum and minimum temperature (30.24 and 21.46 0 C, respectively), solar radiation (17.7 MJ.m-2.day-1), and sunshine hours Conclusion Overall, the results of the study suggest that planting millet in the period from June 4 to June 27 will result in the highest dry matter and grain yield in the Rasht region. [ABSTRACT FROM AUTHOR]

The photosynthetic capacity of flag leaf plays a key role in grain yield in rice. Nevertheless, there are few studies on the heterosis of the rice flag leaf. Therefore, this study focuses on investigating the genetic basis of heterosis for flag leaf in the indica super hybrid rice combination WFYT025 in China using a high-throughput next-generation RNA-seq strategy. We analyzed the gene expression of flag leaf in different environments and different time periods between WFYT025 and its female parent. After obtaining the gene expression profile of the flag leaf, we further investigated the gene regulatory network. Weighted gene expression network analysis (WGCNA) was used to identify the co-expressed gene sets, and a total of 5000 highly expressed genes were divided into 24 co-expression groups. In CHT025, we found 13 WRKY family transcription factors in SDGhps under the environment of early rice and 16 WRKY family genes in SDGhps of under the environment of middle rice. We found nine identical transcription factors in the two stages. Except for five reported TFs, the other four TFs might play an important role in heterosis for grain number and photosynthesis. Transcription factors such as WRKY3, WRKY68, and WRKY77 were found in both environments. To eliminate the influence of the environment, we examined the metabolic pathway with the same SDGhp (SSDGhp) in two environments. There were 312 SSDGhps in total. These SSDGhps mainly focused on the phosphorus metallic process, phosphorylation, plasma membrane, etc. These results provide resources for studying heterosis during super hybrid rice flag leaf development. [ABSTRACT FROM AUTHOR]

The varieties and lines that have reached a constant state at the Research Institute of Cereals and Leguminous Crops have been tested in the 3-year competitive variety test nursery in the experimental hybrid lines AC2012-D3, AC-2010-D23, AC-2014-D7, AC-2013-D30, AC-2010-D21, AC2012-D41-8, the IDK indicator of the lines was 70-80%, it was determined that they belonged to the I-group, and the productivity of the studied lines was a positive indicator for 3 years AC-2010-D33, AC-2010-D45, in lines AC-2010-D21, AC-2012-D31, AC-2012-D14, AC-2013-D30, AC-2013-D33 was 70.0 to 81.7 ts/ha. Most of the lines achieved higher yields than the model varieties. [ABSTRACT FROM AUTHOR]

France suffered, in 2016, the most extreme wheat yield decline in recent history, with some districts losing 55% yield. To attribute causes, we combined the largest coherent detailed wheat field experimental dataset with statistical and crop model techniques, climate information, and yield physiology. The 2016 yield was composed of up to 40% fewer grains that were up to 30% lighter than expected across eight research stations in France. The flowering stage was affected by prolonged cloud cover and heavy rainfall when 31% of the loss in grain yield was incurred from reduced solar radiation and 19% from floret damage. Grain filling was also affected as 26% of grain yield loss was caused by soil anoxia, 11% by fungal foliar diseases, and 10% by ear blight. Compounding climate effects caused the extreme yield decline. The likelihood of these compound factors recurring under future climate change is estimated to change with a higher frequency of extremely low wheat yields. [ABSTRACT FROM AUTHOR]

Boron is an essential micronutrient for plant growth. The BOR gene encodes an efflux-type B transporter, and the grain number of BOR1 mutants decreased. To determine the relationship between TaBOR1 and grain number in common wheat, polymorphic sites within genomic and promoter sequences and haplotypes of TaBOR1.2 were identified. Association analysis was carried out between haplotypes and grain number in a natural population. The results indicated that the exon–intron structures of TaBOR1.1, TaBOR1.2 and TaBOR1.3 were conserved, with sequence homologies ranging from 96 to 97%. Two polymorphic sites were identified, one at − 1085 bp upstream from the start codon of TaBOR1.2 and another at 1102 bp downstream, in ten modern varieties and ten landraces. Two cleaved amplified polymorphic sequence markers were developed, and four haplotypes in 348 modern varieties were detected. Hap-G-A was the favored haplotype and increased grain numbers by 5.22, 3.47, and 4.91 in 2002, 2005, and 2010, respectively. This haplotype has been selected during Chinese wheat improvement; its frequency has increased from 16.21% in the 1960s to 26% in the 2020s. Overall, cleaved amplified polymorphic sequence markers of TaBOR1.2 could be used for marker-assisted selection for increasing the grain number of common wheat. [ABSTRACT FROM AUTHOR]

The grain number is one of the highly complex and crucial traits determining the grain yield in rice. To identify grain number QTLs in rice, we employed the QTL-seq approach in the 297 F2 population derived from the cross between BPT5204 and NLR33892. In this investigation, five regions viz., qGN1, qGN3, qGN7, qGN9, and qGN12 on chromosomes 1,3,7,9, and 12, respectively, were identified as QTLs governing grain number per panicle in rice. To verify the QTLs identified in the present study, traditional QTL mapping was carried out using InDel markers and previously reported SSRs in the QTL region. From qGN12 QTL, RM6953 showed a significant association with the number of grains per panicle with a phenotypic variance of 24.58, 22.10, and 17.20% in F2, F2:3, and BC1F2 populations, respectively, at < 0.0001 P value, indicating major QTL. From genome resequencing data, a missense variance was observed in the exonic region of LOC_Os12g39330 gene controlling AP2 domain-containing protein which plays an important role in seed development in rice. Hence, this QTL can be a potential target for map-based cloning and marker-assisted transfer to enhance the grain number in rice. [ABSTRACT FROM AUTHOR]

Winter wheat production is threatened by drought stress under rainfed conditions; thus, screening high- and stable-yielding wheat varieties to ensure the sustainable development of wheat production and food security in the Huang-Huai-Hai Plain (HHHP) is vital. In this research, four-year field experiments with twelve winter wheat varieties were conducted during the winter wheat-growing seasons between 2016 and 2020 in order to: (1) screen high- and stable-yielding winter wheat varieties under rainfed conditions, (2) investigate the mechanism of high-yielding wheat yield formation and the relationships among grain-yield formation traits, and (3) investigate the nitrogen utilization efficiency (NUtE) of high-yielding wheat. The results showed that high-yield level wheat varieties (HL; Yannong999, Taimai1918 and Yannong173) obtained a higher average grain yield than medium-yield level wheat varieties (ML) and low-yield level wheat varieties (LL) by 10.1% and 29.0%, respectively. Compared with ML and LL, HL had a higher biomass at anthesis, higher spike dry matter at anthesis, higher spike partitioning index and fruiting efficiency (grain set per unit of spike dry weight at anthesis), and the highest grain number per square meter (24.2 × 103 m−2). Simultaneously, HL maintained a higher leaf area index (LAI) at anthesis and a higher net photosynthesis rate (Pn) of flag leaves after anthesis, which contributed to a higher post-anthesis biomass; HL also had higher maturity biomass, harvest index (HI), and biomass remobilization in comparison to ML and LL. The above results demonstrated that HL improved grain yield by increasing grain number per square meter, post-anthesis biomass, biomass remobilization, maturity biomass, and HI. Additionally, HL also obtained higher NUtE by improving grain yield. Therefore, screening winter wheat varieties with traits such as HL can help achieve high and stable yields and high NUtE under rainfed conditions. [ABSTRACT FROM AUTHOR]

Rice is one of the leading cereal crops that consumed over half of the world’s population. The number of grains per panicle is the main trait to decide grain yield potential of rice. Rice germplasm have rich diversity for panicle related trait. Hence, a study was undertaken to screen 77 diverse rice germplasm for grain number per panicle and its contributing traits. Mahalanobis’ D2 analysis was performed to study genetic diversity among the germplasm. Eight clusters were formed and cluster IV was found to be the largest cluster with 37 genotypes. Cluster V had 20 genotypes with the highest cluster mean value of 298 for the number of grains per panicle. Grain yield per plant and the number of spikelets per panicle were found to be the biggest contributor for total divergence. QTL linked markers were screened in diverse rice germplasm. Among the six QTLs screened, five QTLs were significantly associated with grain number per panicle and its relevant traits. For grain number per panicle the QTLs, Gn1a (0.1058), qGN 4.1 (0.117) and NGP 4 (0.062) recorded high R2 values. Among the markers, Gn1a indel 3 (GN1a), NKSSR 04-19 (q GN 4.1), RM 6314 (NGP 4) and RM1183 (NOG 1) were identified as the most informative markers for utilization in marker assisted breeding programme. From this study, genotypes viz., Kallukar, CO52, IET 29504, IET 29506, RP-5594-97-5-1, MTU1360, ADT 54 possess high mean value for grain number per panicle and grain yield, linked with functional markers could be used as a donor in marker assisted breeding programme.

Identifying traits for improving sink strength is a bottleneck to increasing wheat yield. The interacting processes determining sink strength and yield potential are reviewed and visualized in a set of 'wiring diagrams', covering critical phases of development (and summarizing known underlying genetics). Using this framework, we reviewed and assembled the main traits determining sink strength and identified research gaps and potential hypotheses to be tested for achieving gains in sink strength. In pre-anthesis, grain number could be increased through: (i) enhanced spike growth associated with optimized floret development and/or a reduction in specific stem–internode lengths and (ii) improved fruiting efficiency through an accelerated rate of floret development, improved partitioning between spikes, or optimized spike cytokinin levels. In post-anthesis, grain, sink strength could be augmented through manipulation of grain size potential via ovary size and/or endosperm cell division and expansion. Prospects for improving spike vascular architecture to support all rapidly growing florets, enabling the improved flow of assimilate, are also discussed. Finally, we considered the prospects for enhancing grain weight realization in relation to genetic variation in stay-green traits as well as stem carbohydrate remobilization. The wiring diagrams provide a potential workspace for breeders and crop scientists to achieve yield gains in wheat and other field crops. [ABSTRACT FROM AUTHOR]

Spike traits play an important role in improving wheat yield. However, the application of reported spike-related loci remains unclear. Here, we assessed six spike-related traits across seven different environments using 406 wheat accessions. A negative correlation was observed between two components of wheat yield: thousand kernel weight (TKW) and grain number per spike (GN). Nonetheless, TKW and GN were significantly higher in modern cultivars compared to landraces. Two reliable quantitative trait loci (QTLs) related to GN, QGN.nwafu-4A and QGN.nwafu-7A, were identified through genome-wide associate analysis. QGN.nwafu-4A showed pleiotropy on GN, kernel number per spikelet and spike length. Both elite haplotypes of QGN.nwafu-7A were prominently present in Chinese modern cultivars, particularly those released after the year 2000. Elite haplotype A of QGN.nwafu-7A was significantly prevalent in Chinese Yellow and Huai wheat zone, while elite haplotype D of QGN.nwafu-7A was concentrated in other wheat-growing regions of China. This observation suggests distinct preferences in wheat cultivation across various agro-ecological regions. Conversely, elite haplotype A of QGN.nwafu-4A was more common in introduced cultivars from abroad. This divergence may be attributed to the reduced TKW of haplotype A. Overall, these findings provide valuable insights into the application of these two QTLs in high-yield wheat breeding.

Lack of soil moisture and phosphorus deficiency limits wheat grain yield in dryland areas. However, the moisture-conserving effect of straw mulching combined with phosphor fertilization on fertile florets per spike (FFS) and grain yield remains unclear. During the 2020–2021 and 2021–2022 growing seasons, we investigated the combined effects of straw mulching (0 and 8000 kg ha−1) and phosphorus fertilization (0, 75, and 120 kg P2O5 ha−1) on spike development, assimilates’ availability, and the photosynthetic properties of flag leaves by conducting a field experiment. Compared with no straw mulch control, straw mulching increased fertile spike, grain number per spike (15.6%), and grain yield (22.6%), and grain number per spike was the most important contribution to increasing wheat grain yield (46%). An increase in grain number per spike is associated with FFS. Compared with no straw mulch control, straw mulching increased FFS by 19.5%, and it increased with increasing phosphorus fertilization levels. Moreover, straw mulching combined with phosphorus fertilization promoted the light compensation point (LCP), light saturation point (LSP), net photosynthetic rate (Pn), Chl b, and the maximal photochemical efficiency of photosystem II (Fv/Fm) of flag leaves to produce carbohydrates. Our study has shown that the primary factor for the divergence in FFS under straw mulching and phosphorus application was the efficiency of assimilate utilization in the spike, which ultimately led to increased grain number per spike and grain yield.

This study aimed to quantify the changes in grain yield and main agronomic traits in winter wheat cultivars registered during the past 90 years . A field trial with 18 winter wheat cultivars registered from 1930 to 2016 was conducted at the experimental field Rimiski šančevi during two growing seasons . The following agronomic traits were measured: grain yield, stem height, spike length, heading date, hectolitre mass, 1000 grain weight, and grain number per unit area . The results of this study showed that there was a significant genotypic effect on the studied traits . Du-ring the past 90 years, grain yield increased at rate of 50 kg ha -1 per year of cultivar release . Grain yield improvement was followed by stem height decrease (0 .4 cm per year of cultivar release) and earlier heading date in modern cultivars, which were 7 -8 days earlier than the older ones . Modern wheat cultivars were characterized by a higher grain number per unit area than the ol-der ones while during the past 90 years, the 1000 grain weight was not significantly related to the year of cultivar release . Further grain yield improvement should be related to a further increase of grain number per unit area while maintaining a higher 1000 grain weight.

The aim of the study was to examine the impact of microbiological and organic fertilizers on morphological and productive characteristics of triticale during a three-year period (2009/10-2011/12). A two-factorial field experiment was arranged using a randomized block design with four replications. The object of the study was the triticale winter cultivar Odisej, and the following treatments were applied: a control variant without fertilization, microbiological fertilizer "Slavol" (Agrounik Serbia) 5.0 l ha-1 , organic fertilizer "Biohumus Royal offert" (Altamed RS) 3.0 t ha-1 + microbiological fertilizer "Slavol" (Agrounik Serbia) 5.0 l ha-1 . The results showed that the expression of the characteristics was significantly affected by the environment. The lowest values were obtained in the first year when the most unfavourable meteorological conditions were observed. The application of microbiological fertilizer had no impact on the stem length and grain weight per spike, but it significantly increased the number of fertile spikelets (3.7%), spike length (7.7%) and grain yield (18.6%). The combined application of fertilizers provided better results for all the examined characteristics, while in comparison with the control, the differences ranged from 4.3% for the number of fertile spikelets to 46.5% for grain yield. The strongest correlation was determined between the spike length and the number of fertile spikelets (r = 0.939**). The obtained results lead to the conclusion that under variable environmental conditions, the application of fertilizers has a significant impact on morphological and productive characteristics of triticale, and consequently on the stability of this crop production in the organic farming system.

Background. The breeding value of accessions from the VIR collection can be estimated only under specific climate and soil conditions. Studying such accessions helps to include them in the breeding process.Materials and methods. Forty-two accessions of naked oats of various origin were studied at the FARC of the North-East. Biochemical analysis of grain and statistical data processing using descriptive statistics and correlation analysis techniques were carried out.Results. The accessions were divided into groups according to their ripening schedule: early (up to 80 days), medium (81–84 days), and mid-late (85–89 days). High yielding genotypes were identified in each ripeness group. The plant height depended on the hydrothermal conditions of the growing season (r = 0.25). The studied accessions were all classified as undersized (64.0–99.1 cm), including the reference cv. ‘Vyatsky’ (88.1 cm). A significant contribution of some panicle productivity components to an increase in yield was observed. The protein and fat content in grain determines its nutritional and energy value. The results showed a positive relationship between yield and protein content (r = 0.44). A significant negative correlation between fat content and protein content (r = –0.61) was registered. The study of naked oat accessions showed different fat content in grain across the ripeness groups.Conclusion. According to the results of the study, some accessions were identified as sources of traits useful for breeding. The following accessions were selected as the best according to a set of characters (yield, plant height, number of grains per panicle, panicle weight, protein and fat content in grain): early ‘Litovsij nagij’ (k-15234, Lithuania), ‘Gkzalon’ (k-15299, Mongolia) and ‘MF9224-164’ (k-15090, USA); medium k-15248 (local, Poland) and MF9521-281 (k-15095, USA); and mid-late ‘Bai Yan 2’ (k-15525, China), ‘Progress’ (k-15339, Russia), ‘Visit’ (k-15501, Ukraine) and ‘Mina’ (k-15192, Bulgaria).