qGW11a/OsCAT8,encoding an amino acid permease,negatively regulates grain size and weight in rice

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

Transcriptomic and metabolomic analysis of changes in grain weight potential induced by water stress in wheat

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

GSW3.1,a novel gene controlling grain size and weight in rice

Grain size and weight are closely related traits determining yield in rice(Oryza sativa L.).Since indica and japonica rice varieties differ significantly in multiple traits,a high-generation recombinant inbred line(RIL)population derived from the crossing LH9(indica)and RPY(japonica)was used to map grainrelated traits in six environments.Pyramiding of the quantitative trait loci(QTL)for thousand-grain weight showed that combinations of multiple QTL significantly increased the phenotypic effect.A novel gene named GSW3.1 controlling grain size and weight was discovered using the major QTL for the colocalization of grain width and thousand-grain weight on chromosome 3.Gene editing revealed that GSW3.1(LOC_Os03g16850)was pleiotropic,positively regulating grain size and weight while affecting several other agronomic traits.Haplotype analysis indicated that some traits,including grain width and weight,were highly correlated with indica-japonica differentiation.

Effects of Spraying Nitrogen and Zinc Fertilizers after Flowering on Grain Weight and Nutritional Quality of Winter Wheat

In order to explore the effect of spraying fertilizers after flowering on grain weight and nutritional quality of different winter wheat cultivars, twenty wheat culti- vars in wheat zones along Yellow River and Huai River, were used to investigate the change of thousand kernel weight （TKW）, phytic acid content （PAC）, contents of Fe, Zn and Mg and bioavailability by spraying zinc and nitrogen fertilizers after flowering. The results showed that both of TKW and protein content in grains in- creased by spraying Zn and N fertilizers, and the effect of N fertilizer proved more significant. The PAC decreased significantly after Zn treatment, for example, PAC of ＂955159＂, a wheat cultivar, decreased by 27.95%. However, PAC was in- significantly influenced by N fertilizer. On the other hand, Zn content in wheat grains were improved after spraying Zn fertilizer and the increase aveaged 54.38%. Furthermore, Fe and Zn contents grew significantly after spraying N fertilizer, and the increase averaged 36.88% and 11.25% respectively. However, Mg content in grains declined by N fertilizer. Still, the bioavailability of zinc in grains was enhanced after spraying Zn fertilizer, and of Fe was also increased greatly after spraying N fertilizer. In conclusion, grain weight, and content and effectiveness of mineral ele-ments can be improved simultaneously by rational spraying of N and Zn fertilizers to improve quality of grains.

Effect of Enhanced UV-B Radiation on Seed Setting Rate and 1 000-grain Weight of Indica Hybrid Rice Restorer Lines

[Objective] This study was to investigate the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight of hybrid rice combinations. [Method] The seed setting rate and 1 000-grain weight of 10 new sterile indica restorer lines planted in pots under enhanced UV-B radiation and fluorescent lamps （control） were respectively measured, and the differences were compared. [Result] The enhanced UV-B radiation significantly reduced the seed setting rate of indica restorer lines, and the differences between that UV-B radiation treatment and control all reached extremely significant level. In addition, the enhanced UV-B radiation reduced the 1 000-grain weight of most indica restorer lines, and compared with that of control the difference achieved significant or very significant level. However, the effect of enhanced UV-B radiation on seed setting rate and 1 000-grain weight differed to different indica restorer lines, and the differences among restorer lines tested were significant or very significant, which indicated the possibility to screen antiUV-B radiation rice materials and combinations. Finally, the indica restorer lines 09R-14, Luhui 37 and 10R-7703 which were strongly resistant to UV-B radiation were screened out. [Conclusion] This study laid foundation for breeding hybrid rice varieties resistance to UV-B radiation.

Isolation and initial characterization of GW5, a major QTL associated with rice grain width and weight

Grain weight is a major determinant of crop grain yield and is controlled by naturally occurring quantitative trait loci （QTLs）. We earlier identified a major QTL that controls rice grain width and weight, GW5, which was mapped to a recombination hotspot on rice chromosome 5. To gain a better understanding of how GW5 controls rice grain width, we conducted fine mapping of this locus and uncovered a 1 212-bp deletion associated with the increased grain width in the rice cultivar Asominori, in comparison with the slender grain rice IR24. In addition, genotyping analyses of 46 rice cultivars revealed that this deletion is highly correlated with the grain-width phenotype, suggesting that the GW5 deletion might have been selected during rice domestication. GW5 encodes a novel nuclear protein of 144 amino acids that is localized to the nucleus. Furthermore, we show that GW5 physically interacts with polyubiquitin in a yeast two-hybrid assay. Together, our results suggest that GW5 represents a major QTL underlying rice width and weight, and that it likely acts in the ubiquitin-proteasome pathway to regulate cell division during seed development. This study provides novel insights into the molecular mechanisms controlling rice grain development and suggests that GW5 could serve as a potential tool for high-yield breeding of crops.

Effect of Grain Position within a Panicle and Variety on As,Cd,Cr,Ni,Pb Concentrations in japonica Rice

Two japonica rice varieties, a compact panicle (CP) Xiushui 63 and a loose panicle (LP) Xiushui 11 were grown in a slightly contaminated paddy field, to determine the effect of grain positions within a panicle and variety on grain As, Cd, Cr, Ni and Pb concentrations. There was a significant difference in grain As, Cd, Cr, Ni and Pb concentrations among grain positions, and the extent of the difference was variety- and metal-specific; Xiushui 63 showed greater difference than Xiushui 11, and As, Cd, Cr and Pb being greater than Ni. The top grains (TG) of a panicle had higher As, Cd and Ni concentrations than the middle ones (MG), and the bottom ones (BG) contained the lowest. With regard to Cr and Pb, the case was opposite. Significantly positive correlations were found between grain weight and As, Cd, Ni concentrations, but there was a negative correlation between grain weight and Cr, and Pb concentrations. There was a remarkable variation in grain filling pattern among grains within a panicle, and between Xiushui 63 and Xiushui 11. In comparison with MG and TG, BG had the lowest grain filling rate and grain weight, leading to obvious difference in grain weight among grains within a panicle, and a greater difference for Xiushui 63 than for Xiushui 11. The regression analysis showed that grain As and Cd concentrations were positively correlated with the maximum grain filling rate (GRm),while negatively correlated with the required time for reaching the maximum grain filling rate (Tpol). Concerning Cr and Pb, the case was just reverse. It is suggested that As and Cd accumulation in grains might be accompanied by the carbohydrate accumulations, while Cr and Pb accumulation displayed a different pattern.

Effect of delayed sowing on grain number, grain weight, and protein concentration of wheat grains at specific positions within spikes

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 ^(13)C-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 ^(13)C-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.

Poaceae Orthologs of Rice OsSGL,DUF1645 Domain-Containing Genes,Positively Regulate Drought Tolerance,Grain Length and Weight in Rice

Grain yield is a polygenic trait that can be influenced by environmental factors and genetic compositions at all plant growth stages.Currently,the molecular mechanisms behind the coordination of the interaction between grain yield-related traits remain unknown.In this study,we characterized the function of four STRESS_tolerance and GRAIN_LENGTH(Os SGL)Poaceae ortholog genes that are transcribed into DUF1645 domain-containing proteins in relation to the grain length,grain weight,and drought stress-tolerance of rice.The transgenic plants with overexpressing or heterologous high levels of Poaceae OsSGL ortholog genes exhibited longer grain size than the wild type plants.Larger cells were seen in panicles of the four transgenic lines with paraffin sectioning and scanning electron microscopy analyses.In addition,four Poaceae OsSGL ortholog genes positively affected the drought tolerance of rice.Four transgenic plants displayed higher resistance to drought stress at the seedling and vegetative stages.RNA-sequencing and qRT-PCR results indicated that over-or heterologous-expression of four Poaceae OsSGL ortholog genes also affected the transcriptome of rice plants.These genes may play a role in auxin and cytokinin biosynthesis and their transduction pathways.Taken together,these results suggested that the four OsSGL orthologs have a conserved function in the regulation of stress-tolerance and cell growth by modulating hormonal biosynthesis and signaling.

Source-sink relations and responses to sink-source manipulations during grain filling in wheat

The source-sink ratio during grain filling is a critical factor that affects crop yield in wheat,and the main objective of this study was to determine the source-sink relations at both the canopy scale and the individual culm level under two nitrogen(N)levels at the post-jointing stage.Nine widely-used cultivars were chosen for analyzing source-sink relations in southwestern China;and three typical cultivars of different plant types were subjected to artificial manipulation of the grain-filling source-sink ratio to supplement crop growth measurements.A field experiment was conducted over two consecutive seasons under two N rates(N+,150 kg ha^(-1);N-,60 kg ha^(-1)),and three manipulations were imposed after anthesis:control(Ct),removal of flag and penultimate leaves(Lr)and removal of spikelets on one side of each spike(Sr).The results showed that the single grain weights in the three cultivars were significantly decreased by Lr and increased by Sr,which demonstrated that wheat grain yield potential seems more source-limited than sink-limited during grain filling,but the source-sink balance was obviously changed by climatic variations and N deficient environments.Grain yield was highly associated with sink capacity(SICA),grain number,biomass,SPAD values,and leaf area index during grain filling,indicating a higher degree of source limitation with an increase in sink capacity.Therefore,source limitation should be taken into account by breeders when SICA is increased,especially under non-limiting conditions.Chuanmai 104,a half-compact type with a mid-sized spike and a long narrow upper leaf,showed relatively better performance in source-sink relations.Since this cultivar showed the characteristics of a lower reduction in grain weight after Lr,a larger increase after Sr,and a lower reduction in post-anthesis dry matter accumulation,then the greater current photosynthesis during grain filling contributed to the grain after source and sink manipulation.

TaABI19 positively regulates grain development in wheat

Starch is the most important component in the endosperm, and its synthesis is regulated by multiple transcription factors(TFs) in cereals. However, whether the functions of these TFs are conserved among cereals remains unclear. In this study,we cloned a B3 family TF in wheat, named TaABI19, based on its orthologous sequence in maize(Zea mays L.). Alignment of the DNA and protein sequences showed that ABI19 is conserved in maize and wheat(Triticum aestivum L.). We found that TaABI19 is highly expressed in young spikes and developing grains, and encodes a nucleus-localized transcriptional activator in wheat. The taabi19-b1 null mutants obtained by EMS exhibited a down-regulation of starch synthesis, shorter grain length and lower thousand-grain weight(TGW). Furthermore, we proved that TaABI19 could bind to the promoters of TaPBF homologous genes and enhance their expression. Haplotype association showed that TaABI19-B1 is significantly associated with TGW. We found that Hap2 and Hap3 were favored and had undergone positive selection in China’s wheat breeding programs. Less than 50% of the modern cultivars convey the favored haplotypes, indicating that TaABI19 still can be considered as a target locus for marker-assisted selection breeding to increase TGW in China.

The 218th amino acid change of Ser to Ala in TaAGPS-7A increases enzyme activity and grain weight in bread wheat

ADP-glucose pyrophosphorylase(AGPase)influences cereal productivity.There are few reports on the function of cytosolic AGPase small subunit in bread wheat(TaAGPS).In the present study,TaAGPS was preferentially expressed in developing endosperm during grain-filling stages in bread wheat.TaAGPS allelic variations were characterized in 143 wheat accessions by PacBio RS II sequencing.Two haplotypes(TaAGPS-7A-TG and TaAGPS-7A-CT)of TaAGPS-7A were identified and corresponding functional markers were developed,whereas no variants of TaAGPS-7B and TaAGPS-7D were detected.TaAGPS-7A was associated with thousand-kernel weight(TKW)by haplotype–trait association analysis in two populations.Near-isogenic lines(NILs)with TaAGPS-7A-TG showed higher TKW and total kernel starch content than those with TaAGPS-7A-CT,owing to the higher AGPase activity of TaAGPS-7A-TG than TaAGPS-7A-CT both in vitro and in vivo.Overexpression of TaAGPS-7A-TG in bread wheat doubled the transcription levels of TaAGPS and increased AGPase activity by 55.7%,resulting in a 3.0-g higher TKW than in the wild type(WT).Knockdown of TaAGPS led to reduced expression of TaAGPS,AGPase activity,and TKW than in the WT.Thus,owing to the 218th amino acid change of Ser to Ala in TaAGPS-7A,the favorable haplotype TaAGPS-7A-TG showed higher AGPase activity,resulting in higher kernel starch content and grain weight.This finding could be applied to increasing starch content and grain weight in bread wheat.

Symptom of the Shrunk-Grain Panicle and the Change Characteristics in Its Grain

Over the past two years, an abnormal growth phenomenon Jiangsu Province of China. The phenomenon is described in called shrunk-grain panicle has occurred in a large area in details by figures and characters in this article. The method with a japonica rice Wuyujing 3 as the experimental material, the characteristics of grain morphology distribution and the grain weight were studied. Normal and shrunk-grain panicles were sampled from several representative areas. The length, width, and weight of the normal grains were distributed as regular, continuous, and single peaks. Plant growth typically had a right-leaning tendency. On the contrary, the distribution of the grain morphology and weight were irregular and nearly double that of the shrunk-grain panicle. The proportion of the cumulative distribution in the two kinds of peaks was closely related to the degree of shrunk-grain panicle. The article discusses the phenomenon＇s symptoms, problems, and diagnosis.

Effect of Nitrogen on Hull Traits and Its Causes in Yangdao6

The experiments were carried out under solution and pot cultural conditions with rice Yang-dao6. Effect of nitrogen on hull size, weight and plumpness and its relationship with plant nutrition were analysed. On comparison with no fertilization, low N application concentration from transplanting to heading, or employing basal fertilizer or tiller promoting one would result in increment of hull size and weight, while raising N application concentration from transplanting to heading or employing excessive spike fertilizer would result in smaller, lighter hull and poorer hull plumpness. The more amount of nitrogen applied, the more hull development would be inhibited. Top dressing at heading would facilitate hull substance accumulation, but its effect on hull size was small. The variation of hull traits differed in the following order: hull weight>hull weight per unit area>hull area>hull length>hull width. Hull traits were highly significantly correlated to the nitrogen content of plant at heading, with correlation coefficient from - 0. 8684* * to - 0.9336 * * , and positively correlated to the contents of soluble sugar and starch at heading, with correlation coefficient of 0.6660NS - 0.9501 * * . Improving hull characters would be beneficial to substance accumulation of grain, thus improving grain weight considerably(r = 0.6388* - 0.9574* * ).

Characterization of transgenic wheat lines expressing maize ABP7 involved in kernel development

Wheat is one of the major food crops in the world.Functional validation of the genes in increasing the grain yield of wheat by genetic engineering is essential for feeding the ever-growing global population.This study investigated the role of ABP7,a bHLH transcription factor from maize involved in kernel development,in regulating grain yield-related traits in transgenic wheat.Molecular characterization showed that transgenic lines HB123 and HB287 contained multicopy integration of ABP7 in the genome with higher transgene expression.At the same time,QB205 was a transgenic event of single copy insertion with no significant difference in ABP7 expression compared to wild-type(WT) plants.Phenotyping under field conditions showed that ABP7 over-expressing transgenic lines HB123 and HB287 exhibited improved grain yield-related traits(e.g.,grain number per spike,grain weight per spike,thousand-grain weight,grain length,and grain width) and increased grain yield per plot,compared to WT plants,whereas line QB205 did not.In addition,total chlorophyll,chlorophyll a,chlorophyll b,and total soluble sugars were largely increased in the flag leaves of both HB123and HB287 transgenic lines compared to the WT.These results strongly suggest that ABP7 positively regulates yieldrelated traits and plot grain yield in transgenic wheat.Consequently,ABP7 can be utilized in wheat breeding for grain yield improvement.

QTL analysis for some quantitative traits in bread wheat

Quantitative trait loci (QTL) analysis was conducted in bread wheat for 14 important traits utilizing data from four different mapping populations involving different approaches of QTL analysis. Analysis for grain protein content (GPC) sug- gested that the major part of genetic variation for this trait is due to environmental interactions. In contrast, pre-harvest sprouting tolerance (PHST) was controlled mainly by main effect QTL (M-QTL) with very little genetic variation due to environmental interactions; a major QTL for PHST was detected on chromosome arm 3AL. For grain weight, one QTL each was detected on chromosome arms 1AS, 2BS and 7AS. QTL for 4 growth related traits taken together detected by different methods ranged from 37 to 40; nine QTL that were detected by single-locus as well as two-locus analyses were all M-QTL. Similarly, single-locus and two-locus QTL analyses for seven yield and yield contributing traits in two populations respectively allowed detection of 25 and 50 QTL by composite interval mapping (CIM), 16 and 25 QTL by multiple-trait composite interval mapping (MCIM) and 38 and 37 QTL by two-locus analyses. These studies should prove useful in QTL cloning and wheat improvement through marker aided selection.

Identification and validation of stable quantitative trait loci for yield component traits in wheat

Grain weight and grain number are important yield component traits in wheat and identification of underlying genetic loci is helpful for improving yield.Here,we identified eight stable quantitative trait loci(QTL)for yield component traits,including five loci for thousand grain weight(TGW)and three for grain number per spike(GNS)in a recombinant inbred line population derived from cross Yangxiaomai/Zhongyou 9507 across four environments.Since grain size is a major determinant of grain weight,we also mapped QTL for grain length(GL)and grain width(GW).QTGW.caas-2D,QTGW.caas-3B,QTGW.caas-5A and QTGW.caas-7A.2 for TGW co-located with those for grain size.QTGW.caas-2D also had a consistent genetic position with QGNS.caas-2D,suggesting that the pleiotropic locus is a modulator of trade-off effect between TGW and GNS.Sequencing and linkage mapping showed that TaGL3-5A and WAPO-A1 were candidate genes of QTGW.caas-5A and QTGW.caas-7A.2,respectively.We developed Kompetitive allele specific PCR(KASP)markers linked with the stable QTL for yield component traits and validated their genetic effects in a diverse panel of wheat cultivars from the Huang-Huai River Valley region.KASP-based genotyping analysis further revealed that the superior alleles of all stable QTL for TGW but not GNS were subject to positive selection,indicating that yield improvement in the region largely depends on increased TGW.Comparative analyses with previous studies showed that most of the QTL could be detected in different genetic backgrounds,and QTGW.caas-7A.1 is likely a new QTL.These findings provide not only valuable genetic information for yield improvement but also useful tools for marker-assisted selection.

Activity of Corn Silk at Different Days after Silk Emergence

This study was carried out to evaluate the changes in silk activity of two corn cultivars Xundan 518 and Yongyou 618 after silk emergence. Artificial pollination was conducted at different days after silk emergence, and the ear length, ear diameter,barren tip length, 100-grain weight, grain number per ear and grain weight per ear were measured at harvest. The results showed that with the delay of pollination, the number and weight of grains per ear increased at first, peaked at D2 to D4, and decreased subsequently; ear diameter and 100-grain weight showed a downward trend. Correlation analysis revealed that grain number per ear and grain weight per ear were most closely correlated. Rapid silk extrusion and long-lasting silk activity proved that the two corn cultivars Xundan 518 and Yongyou 618 are tolerant to high temperature.

Effect of the degree of milling on the microstructure and composition of japonica rice

The effect of the degree of milling(DM)on the distribution of the residual bran layer on the surface of rice grains and subsequent rice quality is essential for rice milling technology.This study used scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)to examine the microstructure of japonica rice grains,the microstructural changes in different bran portions after milling,and the content and distribution changes of the elements and nutrients in rice after milling to identify the components that can quantify bran residue according to DM.The SEM results revealed that the thickness of the bran layer and the depth of the grooves in different parts of a rice grain varied,while the depth of the grooves differed between varieties.When DM was 12%,aleurone layer(Al)cells embedded in endosperm(En)remained in the dorsal area.It was speculated that this was the reason why there was no significant difference in bran degree when the DM estimated via grain weight loss increased from 10%to 14%(P>0.05).The EDS elemental mapping image showed the qualitative distribution of the elements,which was condensed in the bran and uniform in the En.The compositional changes revealed that milling caused the loss of rice nutrients,and the loss rate of DM at 0–10%was more serious than that of DM at 10%–14%.Higher DM(>10%)could remove marginal bran from the dorsal groove.Therefore,the crude protein,ash,crude fat,dietary fiber,vitamin B1(VB1),and vitamin B2(VB2)content did not change significantly(P>0.05),while the magnesium(Mg),kalium(K),and phosphorus(P)levels decreased substantially(P<0.05).The microstructural and compositional changes indicated that the DM estimated via the grain weight loss increased from 2%to 10%,with the bran decreasing progressively.The DM estimated via the grain weight loss increased from 10%to 14%,with minimal changes in the residual bran in the dorsal grooves of the rice grains,while the Mg,P,and K levels presented precise DM indices during the rice milling process.This result will provide a theoretical reference for the accurate evaluations of DM.

Natural variation in MORE GRAINS 1 regulates grain number and grain weight in rice

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.