Barley FASCIATED EAR genes determine inflorescence meristem size and yield traits

In flowering plants,the inflorescence meristem(IM)provides founder cells to form successive floral meristems,which are precursors of fruits and seeds.The activity and developmental progression of IM are thus critical for yield production in seed crops.In some cereals,such as rice(Oryza sativa)and maize(Zea mays),the size of undifferentiated IM,which is located at the inflorescence apex,is positively associated with yield traits such as spikelet number.However,the relationship between IM size and yieldrelated spike traits remains unknown in the Triticeae tribe.Here we report that IM size has a negative correlation with yield traits in barley(Hordeum vulgare).Three FASCIATED EAR(FEA)orthologs,HvFEA2,HvFEA3,and HvFEA4,regulate IM size and spike morphogenesis and ultimately affect yield traits.Three HvFEAs genes are highly expressed in developing spikes,and all three loss-of-function mutants exhibit enlarged IM size,shortened spikes,and reduced spikelet number,which may lead to reduced grain yield.Natural variations identified in HvFEAs indicate selection events during barley domestication.We further reveal that HvFEA4,as a transcription factor,potentially targets multiple pathways during reproductive development,including transcriptional control,phytohormone signaling,and redox status.The roles of barley FEA genes in limiting IM size and promoting spikelet formation suggest the potential of increasing yield by manipulating IM activity.

Heritability of Main Yield Traits in Red-seed Watermelon and Their Correlation Analysis

[Objectives]This study was conducted to provide a reliable theoretical basis for the correct formulation of breeding programs for red-seed watermelon and the effective breeding of hybrid offspring.[Methods]With local varieties and inbred lines of red-seed watermelon as test materials,the generalized heritability of fruit number per plant,single-fruit weight,single-fruit seed number,single-fruit seed weight,seed kernel weight,1000-seed weight,kernel-producing ratio,seed production ratio and seed volume were estimated by variance analysis;and the heritability,genetic variation coefficients,and correlation of the nine yield traits in 43 red-seed watermelon varieties were studied.[Results]The generalized heritability of fruit number per plant,single-fruit weight,single-fruit seed number,single-fruit seed weight,seed kernel weight,1000-seed weight,kernel-producing ratio,seed production ratio and seed volume were 12.86%,80.14%,75.96%,74.39%,48.01%,17.12%,24.97%,18.60%,and 37.07%,respectively.The heritability of single-fruit weight,single-fruit seed number and single-fruit seed weight was higher,and early-generation individual selection could achieve a better effect on them;and 1000-seed weight and kernel-producing ratio had a higher coefficient of genetic variation,indicating a high selection potential.[Conclusions]Indirect selection could be achieved for traits such as the single-fruit seed number,single-fruit seed weight,seed kernel weight,and seed volume by selecting the single-fruit weight.In the process of red-seed watermelon breeding,traits with high heritability can be selected in early generations of hybrids,thus playing the role of early-generation orientation.

Dissection of QTLs for Yield Traits on the Short Arm of Rice Chromosome 6

This study was undertaken to dissect quantitative trait loci （QTLs） controlling yield traits on the short arm of rice chromosome 6. A residual heterozygous line that carries a heterozygous segment extending from RM587 to RM19784 on the short arm of rice chromosome 6 was selected from an F7 population of the indica rice cross Zhenshan 97B/Milyang 46. An F2：3 population consisting of 221 lines was derived and grown in two trial sites. Six yield traits including number of panicles per plant, number of filled grains per panicle, total number of spikelets per panicle, spikelet fertility, 1 000-grain weight, and grain yield per plant were measured. An SSR marker linkage map was constructed and employed to determine QTLs for yield traits with Windows QTL Cartographer 2.5. QTLs were detected in the target interval for all the traits analyzed except NP, with phenotypic variance explained by a single QTL ranging between 6.3% and 35.2%. Most of the QTLs for yield components acted as additive QTLs, while the three QTLs for grain yield had dominance degrees of 1.65, 0.84, and -0.42, respectively. It was indicated that three or more QTLs for yield traits were located in the target region. The genetic action mode, the direction of the QTL effect, and the magnitude of the QTL effect varied among different QTLs for a given trait, and among QTLs for different traits that were located in the same interval.

Quantitative Trait Loci for Heading Date and Their Relationship with Genetic Control of Yield Traits in Rice (Oryza sativa)

Grain yield and heading date are key factors determining the commercial potential of a rice variety. Mapping of quantitative trait loci （QTLs） in rice has been advanced from primary mapping to gene cloning, and heading date and yield traits have always attracted the greatest attention. In this review, genomic distribution of QTLs for heading date detected in populations derived from intra-specific crosses of Asian cultivated rice （Oryza sativa） was summarized, and their relationship with the genetic control of yield traits was analyzed. The information could be useful in the identification of QTLs for heading date and yield traits that are promising for the improvement of rice varieties.

Genetic architecture of maize yield traits dissected by QTL mapping and GWAS in maize

The study of yield traits can reveal the genetic architecture of grain yield for improving maize production.In this study, an association panel comprising 362 inbred lines and a recombinant inbred line population derived from X178 × 9782 were used to identify candidate genes for nine yield traits. High-priority overlap(HPO) genes, which are genes prioritized in a genome-wide association study(GWAS), were investigated using coexpression networks. The GWAS identified 51 environmentally stable SNPs in two environments and 36 pleiotropic SNPs, including three SNPs with both attributes. Seven hotspots containing 41 trait-associated SNPs were identified on six chromosomes by permutation. Pyramiding of superior alleles showed a highly positive effect on all traits, and the phenotypic values of ear diameter and ear weight consistently corresponded with the number of superior alleles in tropical and temperate germplasm. A total of 61 HPO genes were detected after trait-associated SNPs were combined with the coexpression networks. Linkage mapping identified 16 environmentally stable and 16 pleiotropic QTL.Seven SNPs that were located in QTL intervals were assigned as consensus SNPs for the yield traits.Among the candidate genes predicted by our study, some genes were confirmed to function in seed development. The gene Zm00001 d016656 encoding a serine/threonine protein kinase was associated with five different traits across multiple environments. Some genes were uniquely expressed in specific tissues and at certain stages of seed development. These findings will provide genetic information and resources for molecular breeding of maize grain yield.

Dissection of QTLs for Yield Traits Using Near Isogenic Lines Derived from Residual Heterozygous Lines in Rice

Three residual heterozygous lines (RHLs) carrying heterozygous segments in the intervals RM587–RM225, RM204–RM6119 and RM6119–RM402 on the short arm of rice chromosome 6, respectively, were selected from a rice population derived from an RHL for the interval RM587–RM402. Ten maternal homozygotes, 10 paternal homozygotes and 20 heterozygotes were selected from each of the F2 populations derived from the three RHLs. The three sets of near isogenic lines (NILs) were grown to detect the grain yield per plant, number of panicles per plant, number of filled grains per panicle and 1000-grain weight. With analysis on the phenotypic differences among the three genotype groups in each NIL set and those among overlapping chromosome segment substitution lines, three QTLs for number of filled grains per panicle and two QTLs for grain yield per plant were resolved. They were located in the intervals ranging from 0.66 Mb to 2.49 Mb. The additive effect was higher than the dominance effect at each locus. The allele for increasing the trait value was derived from the paternal parent at qNFGP6-1, and from the maternal alleles at other QTLs. Based on the present study, an approach for constructing new genetic resource to facilitate fine mapping of QTLs in rice was proposed.

Quantitative Trait Locus Analysis for Rice Yield Traits under Two Nitrogen Levels

A recombinant inbred line population derived from a super hybrid rice Xieyou 9308（Xieqingzao B/Zhonghui 9308） and its genetic linkage map were used to detect quantitative trait loci（QTLs） for rice yield traits under the low and normal nitrogen（N） levels. A total of 52 QTLs for yield traits distributed in 27 regions on 9 chromosomes were detected, with each QTL explaining 4.93%–26.73% of the phenotypic variation. Eleven QTLs were simultaneously detected under the two levels, and 30 different QTLs were detected under the two N levels, thereby suggesting that the genetic bases controlling rice growth under the low and normal N levels were different. QTLs for number of panicles per plant, number of spikelets per panicle, number of filled grains per panicle, and grain density per panicle under the two N levels were detected in the RM135–RM168 interval on chromosome 3. QTLs for number of spikelets per panicle and number of filled grains per panicle under the two N levels, as well as number of panicles per plant and grain density per panicle, under the low N level, were detected in the RM5556–RM310 interval on chromosome 8. The above described QTLs shared similar regions with previously reported QTLs for rice N recycling.

Relationships of Panicle Type Index with Subspecies Characteristics and Yield Traits in Filial Generation of Crosses between Indica and Japonica Rice

Two recombinant inbred line （RIL） populations, one derived from a cross between Zhongyouzao 8 （indica） and Toyonishiki （japonica） and the other from a cross between Qishanzhan （indica） and Akihikari （japonica）, were grown in Liaoning and Sichuan Provinces, China, to study the panicle type index （PTI, the ratio of a number of node position on panicle axis where the secondary branch with the most numerous secondary branch grains is located to the number of primary branches） and its relationships with subspecies characteristics and yield traits. With continuous distribution of PTI and numerous of lines with different PTIs in the progenies, indica-japonica hybridization could be a method for breeding cultivars with ideal panicle type. PTI was significantly influenced by environments, with a significant decrease from Liaoning to Sichuan A significantly negative correlation was found between PTI and most of subspecies characteristics. PTI varied remarkably with different subspecies types. As a whole, it showed a trend of indica （H）〉indicalinous （H＇）〉japonicalinous （K＇）〉japonica （K） However, it is not appropriate to regard PTI as a parameter for subspecies classification in rice because it was recombined in the filial generations of cross between indica and japonica rice. The negative correlations were found between PTI and most of panicle characteristics, as well as yield-related traits. Based on PTI, most of lines from the two populations were middle dominant panicle type （the number of grains on the secondary branch is numerous in middle position of the panicle） and lower dominant panicle type （the number of grains on the secondary branch is numerous in lower position of the panicle and becomes less towards the top of panicle） with significant yield advantages.

QTL Mapping and Epistasis Analysis for Yield Traits in an RIL Population of Rice(Oryza sativa L.)

A genetic linkage map consisting of 168 DNA markers was constructed based on a recombinant inbred line(RID population derived from a cross between a high yielding indica variety, Zhong156, and a low yielding indica variety, Gumeil. The markers on the linkage map were distributed on all 12 chromosomes and covered 1 447. 9 cM of the genome. The parents and 304 RILs were grown in China National Rice Research Institute(CNRRI), Hangzhou, China, in 2001, over two seasons in a randomized block design. The statistic software of QTL Mapper 1.01 was applied to detect quantitative trait loci(QTLs)and additive by environment(AE)interactions for yield traits, including panicle length, number of panicles per plant, number of spikelets per panicle, number of filled grains per panicle, fertility and kilo-grain weight. A total of 30 QTLs with significant additive effects located on all chromosomes, except chromosomes 5 and 9, and two QTLs with significant AE interactions, were detected. Thirty-one interactions of QTLs showing significant additive by additive epistatic effects for yield traits were also detected. Genetic contributions were generally lower for QTLs showing epistatic effects compared with QTLs showing additive effects. No significant interactions between epistasis and environment were detected.

Relationship Between Heterosis and Parental Genetic Distance Based on Molecular Markers for Functional Genes Related to Yield Traits in Rice

The genetic distances among 18 cytoplasmic male sterile lines and 11 restorer lines were analyzed with molecular markers derived from yield-related functional genes. The correlation between parental genetic distance and heterosis was investigated by analyzing the performance of 47 combinations. The results showed that the genetic distance was significantly correlated with yield heterosis （r=0.29^＊）, but not significantly correlated with heterosis for other traits, such as number of effective panicles per plant, seed setting rate, 1000-grain weight, number of grains per panicle and theoretical yield. However, the correlation coefficient was so small that the parental genetic distance could not to be used to predict heterosis.

Characterization and mapping of QTLs on chromosome 2D for grain size and yield traits using a mutant line induced by EMS in wheat

Production of mutants with altered phenotypes is a powerful approach for determining the biological functions of genes in an organism. In this study, a high-grain-weight mutant line M8008 was identified from a library of mutants of the common wheat cultivar YN15 treated with ethylmethane sulfonate(EMS). F2 and F2:3generations produced from crosses of M8008 × YN15(MY) and M8008 × SJZ54(MS) were used for genetic analysis. There were significant differences between M8008 and YN15 in plant height(PH), spike length(SL),fertile spikelet number per spike(FSS), grain width(GW), grain length(GL), GL/GW ratio(GLW), and thousand-grain weight(TGW). Most simple correlation coefficients were significant for the investigated traits, suggesting that the correlative mutations occurred in M8008. Approximately 21% of simple sequence repeat(SSR) markers showed polymorphisms between M8008 and YN15, indicating that EMS can induce a large number of mutated loci. Twelve quantitative trait loci(QTLs) forming QTL clusters(one in MY and two in MS) were detected. The QTL clusters coinciding with(MY population) or near(MS population) the marker wmc41 were associated mainly with grain-size traits, among which the M8008 locus led to decreases in GW, factor form density(FFD), and TGW and to increases in GLW. The cluster in the wmc25–barc168 interval in the MS population was associated with yield traits, for which the M8008 locus led to decreased PH, spike number per plant(SN), and SL.

Auxin signaling module OsSK41-OsIAA10-OsARF regulates grain yield traits in rice

Auxin is an important phytohormone in plants, and auxin signaling pathways in rice play key roles in regulating its growth, development, and productivity. To investigate how rice grain yield traits are regulated by auxin signaling pathways and to facilitate their application in rice improvement, we validated the functional relationships among regulatory genes such as OsIAA10, OsSK41, and OsARF21 that are involved in one of the auxin(OsIAA10) signaling pathways. We assessed the phenotypic effects of these genes on several grain yield traits across two environments using knockout and/or overexpression transgenic lines.Based on the results, we constructed a model that showed how grain yield traits were regulated by OsIAA10 and OsTIR1, OsAFB2, and OsSK41 and OsmiR393 in the OsSK41-OsIAA10-OsARF module and by OsARF21 in the transcriptional regulation of downstream auxin response genes in the OsSK41-OsIAA10-OsARF module. The population genomic analyses revealed rich genetic diversity and the presence of major functional alleles at most of these loci in rice populations. The strong differentiation of many major alleles between Xian/indica and Geng/japonica subspecies and/or among modern varieties and landraces suggested that they contributed to improved productivity during evolution and breeding. We identified several important aspects associated with the genetic and molecular bases of rice grain and yield traits that were regulated by auxin signaling pathways.We also suggested rice auxin response factor(OsARF) activators as candidate target genes for improving specific target traits by overexpression and/or editing subspecies-specific alleles and by searching and pyramiding the ‘best' gene allelic combinations at multiple regulatory genes in auxin signaling pathways in rice breeding programs.

Correlation and variability analysis of yield and quality related traits in different peanut varieties across various ecological zones of China

Peanut cultivation in China spans various ecological zones, each with unique environmental conditions. Identifying suitable peanut varieties for these regions has been challenging due to significant phenotypic variations observed across environments. This study, based on a comprehensive analysis of 256 peanut varieties, selected nine representative varieties(Huayu23, Yuanza9102, Silihong, Wanhua2, Zhonghua6, Zhonghua16, Zhonghua21,Zhonghua215, Zhonghua24) for cultivation in five distinct ecological zones including Chengdu, Hefei, Nanjing,Shijiazhuang, and Wuhan. The yield and quality related phenotypic traits of these varieties were thoroughly assessed, revealing a complex interplay between genetic and environmental factors. Principal component analysis(PCA) effectively distinguished varieties based on yield and quality traits. Strong correlations were observed between specific traits, such as seed size and quality components. The G × E interaction was evident, as some varieties consistently performed better in certain environments. Varieties with lower coefficient of variation(CV)values exhibited stable trait expression, making them reliable choices for broad cultivation. In contrast, varieties with higher CV values displayed greater sensitivity to environmental fluctuations, potentially due to specific genetic factors. Two high oleic acid varieties, Zhonghua24 and Zhonghua215, demonstrated remarkable stability in oleic acid content across diverse environments, suggesting the presence of genetic mechanisms that buffer against environmental variations. Overall, this study underscores the importance of selecting peanut varieties based on their adaptability and performance in specific ecological zones. These findings provide valuable insights for peanut breeders and farmers, facilitating informed decisions for improved crop production and quality.

Effect of Different Mulch Materials on Yield and Nutrition Profile of Common Capsicum (Capsicum annuum) Cultivars in Bangladesh

Capsicum is a nutritious vegetable and its cultivation in farms is getting popular in Bangladesh. Although many efforts have lain to explore better yielding and nutritionally rich cultivars with suitable modern cultivation techniques but still have to find the desired outcome. Thus, it’s necessary to conduct further research to identify the high-yielding and nutritious capsicum cultivars in Bangladesh. An experiment was conducted from July 2021 to June 2022 at the Bangladesh Institute of Research and Training on Applied Nutrition (BIRTAN) research field with three cultivars of capsicum: B0 = California Wonder, B1 = BARI Misti Morich-1 and B2 = BARI Misti Morich-2 and three mulching: T0 = No mulching, T1 = Water hyacinth, T2 = Poly Mulching in randomized complete block design with three replications to identify better quality capsicum cultivar and suitable mulching material. Among cultivars the BARI Misti Morich-2 (B2) showed increased agronomic parameters like number of branches and effective branches per plant, leaves length and width, consequently yield and yield contributing traits were also enhanced like fruits per plant, fruit length, fruit diameter and yield per plant (25.97%, 4.54%, 3.64% and 21.43%, respectively). Poly Mulching (T2) increased agronomic traits, yield traits and yield (0.61 kg) than BARI Misti Morich-1 (T1). The combined effect of B2T2 increased the number of branches per plant, effective branches per plant, leaves length and breadth by 40%, 90%, 15.57% and 26.22%, respectively, hence resulting in an increased yield of 20%. BARI Misti Morich-2 cultivar showed an increase in Fe, Zn and Vitamin-C content of 26.24% and 23.10%, 8.82% and 5.14%, and 6.03% and 5.74% than B0 and B1 cultivars, respectively. Therefore, BARI Misti Morich-2 exhibited the improved agronomic, yield and nutritional traits of capsicum under poly mulching among other cultivars in Bangladesh.

Identification of Rice Ethylene-Response Mutants and Characterization of MHZ71OsEIN2 in Distinct Ethylene Response and Yield Trait Regulation

Ethylene plays essential roles in adaptive growth of rice plants in water-saturating environment; how- ever, ethylene signaling pathway in rice is largely unclear. In this study, we report identification and characterization of ethylene-response mutants based on the specific ethylene-response phenotypes of etiolated rice seedlings, includ- ing ethylene-inhibited root growth and ethylene-promoted coleoptile elongation, which is different from the ethylene triple-response phenotype in Arabidopsis. We establish an efficient system for screening and a set of rice mutants have been identified. Genetic analysis reveals that these mutants form eight complementation groups. All the mutants show insensitivity or reduced sensitivity to ethylene in root growth but exhibit differential responses in cole0ptile growth. One mutant group mhz7 has insensitivity to ethylene in both root and coleoptile growth. We identified the corresponding gene by a map-based cloning method. MHZ7 encodes a membrane protein homologous to EIN2, a central component of ethylene signaling in Arabidopsis. Upon ethylene treatment, etiolated MHZ7-overexpressing seedlings exhibit enhanced coleoptiie elongation, increased mesocotyl growth and extremely twisted short roots, featuring enhanced ethylene- response phenotypes in rice. Grain length was promoted in MHZ7-transgenic plants and 1000-grain weight was reduced in mhz7 mutants. Leaf senescent process was also affected by MHZ7 expression. Manipulation of ethylene signaling may improve adaptive growth and yield-related traits in rice.

Genome-wide association and linkage mapping strategies reveal the genetic loci and candidate genes of important agronomic traits in Sichuan wheat

Increasing wheat yield is a long-term goal for wheat breeders around the world.Exploiting elite genetic resources and dissecting the genetic basis of important agronomic traits in wheat are the necessary methods for high-yield wheat breeding.This study evaluated nine crucial agronomic traits found in a natural population of 156 wheat varieties and77 landraces from Sichuan,China in seven environments over two years.The results of this investigation of agronomic traits showed that the landraces had more tillers and higher kernel numbers per spike (KNS),while the breeding varieties had higher thousand-kernel weight (TKW) and kernel weight per spike (KWS).The generalized heritability (H2) values of the nine agronomic traits varied from 0.74 to 0.95.Structure analysis suggested that the natural population could be divided into three groups using 43 198 single nucleotide polymorphism (SNP) markers from the wheat 55K SNP chip.A total of 67 quantitative trait loci (QTLs) were identified by the genome-wide association study (GWAS) analysis based on the Q+K method of a mixed linear model.Three important QTLs were analyzed in this study.Four haplotypes of QFTN.sicau-7BL.1 for fertile tillers number (FTN),three haplotypes of QKNS.sicau-1AL.2 for KNS,and four haplotypes of QTKW.sicau-3BS.1 for TKW were detected.FTN-Hap2,KNS-Hap1,and TKW-Hap2 were excellent haplotypes for each QTL based on the yield performance of 42 varieties in regional trials from 2002 to 2013.The varieties with all three haplotypes showed the highest yield compared to those with either two haplotypes or one haplotype.In addition,the KASP-AX-108866053 marker of QTL QKNS.sicau-1AL.2 was successfully distinguished between three haplotypes(or alleles) in 63 varieties based on the number of kernels per spike in regional trials between 2018 and 2021.These genetic loci and reliable makers can be applied in marker-assisted selection or map-based gene cloning for the genetic improvement of wheat yield.

Genetic architecture of quantitative trait loci(QTL)for FHB resistance and agronomic traits in a hard winter wheat population

Wheat resistance to Fusarium head blight(FHB)has often been associated with some undesirable agronomic traits.To study the relationship between wheat FHB resistance and agronomic traits,we constructed a linkage map of single nucleotide polymorphisms(SNPs)using an F6:8 population from G97252WG97380A.The two hard winter wheat parents showed contrasts in FHB resistance,plant height(HT),heading date(HD),spike length(SL),spike compactness(SC),kernel number per spike(KNS),spikelet number per spike(SNS),thousand-grain weight(TGW)and grain size(length and width).Quantitative trait locus(QTL)mapping identified one major QTL(QFhb.hwwg-2DS)on chromosome arm 2DS for the percentage of symptomatic spikelets(PSS)in the spike,deoxynivalenol(DON)content and Fusarium damaged kernel(FDK).This QTL explained up to 71.8%of the phenotypic variation for the three FHB-related traits and overlapped with the major QTL for HT,HD,SL,KNS,SNS,TGW,and grain size.QTL on chromosome arms 2AL,2DS,3AL and 4BS were significant for the spike and grain traits measured.G97252W contributed FHB resistance and high SNS alleles at QFhb.hwwg-2DS,high KNS alleles at the QTL on 2AL and 2DS,and high TGW and grain size alleles at QTL on 3AL;whereas G97380A contributed high TGW and grain size alleles at the QTL on 2AL and 2DS,respectively,and the high KNS allele at the 4BS QTL.Combining QFhb.hwwg-2DS with positive alleles for spike and grain traits from other chromosomes may simultaneously improve FHB resistance and grain yield in new cultivars.

Dissection of heterosis for yield and related traits using populations derived from introgression lines in rice

Despite the great success achieved by the exploitation of heterosis in rice,the genetic basis of heterosis is still not well understood.We adopted an advanced-backcross breeding strategy to dissect the genetic basis of heterosis for yield and eight related traits.Four testcross(TC) populations with 228 testcross F1 combinations were developed by crossing57 introgression lines with four types of widely used male sterile lines using a North Carolina II mating design.Analysis of variance indicated that the effects of testcross F1 combinations and their parents were significant or highly significant for most of the traits in both years,and all interaction effects with year were significant for most of the traits.Positive midparent heterosis(HMP) was observed for most traits in the four TC populations in the two years.The relative HMPlevels for most traits varied from highly negative to highly positive.Sixty-two dominant-effect QTL were identified for HMPof the nine traits in the four TC populations in the two years.Of these,22 QTL were also identified for the performance of testcross F1.Most dominant-effect QTL could individually explain more than 10% of the phenotypic variation.Four QTL clusters were observed including the region surrounding the RM9–RM297 region on chromosome 1,the RM110–RM279–RM8–RM5699–RM452 region on chromosome 2,the RM5463 locus on chromosome 6 and the RM1146–RM147 region on chromosome 10.The identified QTL for heterosis provide valuable information for dissecting the genetic basis of heterosis.

Major Gene Identification and Quantitative Trait Locus Mapping for YieldRelated Traits in Upland Cotton(Gossypium hirsutum L.)

Segregation analysis of the mixed genetic model of major gene plus polygene was used to identify the major genes for cotton yield-related traits using six generations P1, P2, F1, B1, B2, and F2 generated from the cross of Baimian 1 x TM-1. In addition to boll size and seed index, the major genes for the other five traits were detected： one each for seed yield, lint percentage, boll number, lint index; and two for lint yield. Quantitative trait locus/loci （QTL） mapping was performed in the F2 and F2：3 populations of above cross through molecular marker technology, and a total of 50 QTL （26 suggestive and 24 significant） for yield-related traits were detected. Four common QTL were discovered： qLP-3b（F2）/qLP-3（F2：3） and qLP-19b （F2）/qLP-19（F2：3） for lint percentage, qBN-17（F2）/qBN-17（F2：3） for boll number, and qBS-26b（F2）/qBS-26（F2：3） for boll size. Especially, qLP- 3b（Fz）/qLP-3（F2：3）, not only had LOD scores 〉3 but also exceeded the permutation threshold （5.13 and 5.29, respectively）, correspondingly explaining 23.47 and 29.55% of phenotypic variation. This QTL should be considered preferentially in marker assisted selection （MAS）. Segregation analysis and QTL mapping could mutually complement and verify, which provides a theoretical basis for genetic improvement of cotton yield-related traits by using major genes （QTL）.