A novel procedure for identifying a hybrid QTL-allele system for hybrid-vigor improvement, with a case study in soybean(Glycine max)yield

“Breeding by design” for pure lines may be achieved by construction of an additive QTL-allele matrix in a germplasm panel or breeding population, but this option is not available for hybrids, where both additive and dominance QTL-allele matrices must be constructed. In this study, a hybrid-QTL identification approach, designated PLSRGA, using partial least squares regression(PLSR) for model fitting integrated with a genetic algorithm(GA) for variable selection based on a multi-locus, multi-allele model is described for additive and dominance QTL-allele detection in a diallel hybrid population(DHP). The PLSRGA was shown by simulation experiments to be superior to single-marker analysis and was then used for QTL-allele identification in a soybean DPH yield experiment with eight parents. Twenty-eight main-effect QTL with 138 alleles and nine QTL × environment QTL with 46 alleles were identified, with respective contributions of 61.8% and 23.5% of phenotypic variation. Main-effect additive and dominance QTL-allele matrices were established as a compact form of the DHP genetic structure. The mechanism of heterosis superior-to-parents(or superior-to-parents heterosis, SPH) was explored and might be explained by a complementary locus-set composed of OD+(showing positive over-dominance, most often), PD+(showing positive partial-to-complete dominance, less often) and HA+(showing positive homozygous additivity, occasionally) loci, depending on the parental materials. Any locus-type, whether OD+, PD + and HA+, could be the best genotype of a locus. All hybrids showed various numbers of better or best genotypes at many but not necessarily all loci, indicating further SPH improvement. Based on the additive/dominance QTL-allele matrices, the best hybrid genotype was predicted, and a hybrid improvement approach is suggested. PLSRGA is powerful for hybrid QTL-allele detection and cross-SPH improvement.

Analysis of QTLs for the Trichome Density on the Upper and Downer Surface of Leaf Blade in Soybean [Glycine max (L.) Merr.]

Trichomes （plant hairs） are present on nearly all land plants and are known to play important roles in plant protection, specifically against insect herbivory, drought, and UV radiation. The identification of quantitative trait loci （QTL） associated with trichome density should help to interpret the molecular genetic mechanism of soybean trichome density. 184 recombinant inbred lines （RILs）, derived from a cross between soybean cultivars Kefeng 1 and Nannong 1138-2 were used as segregating population for evaluation of TDU （trichome density on the upper surface of leaf blade） and TDD （trichome density on the downer surface of leaf blade）. A total of 15 QTL were detected on molecular linkage groups （MLG） A2, Dla, Dlb, E and H by composite interval mapping （CIM） and among all the QTL, qtuA2-1, qtuD 1 a-1, qtuD lb-2, qtuH-2 qtuE-1, qtdDlb-2, and qtdH- 2 were affirmed by multiple interval mapping （MIM）. The contribution ofphenotypic variance of qtuH-2 was 31.81 and 29.4% by CIM and MIM, respectively, suggesting it might be major gene Ps loci. Only 10 pairs of main QTL interactions for TDU were detected, explained a range of 0.2-5.1% of phenotypic variations for each pair for a total of 22.8%. The QTL on MLG Dlb affecting trichome density were mapped near to Rsc-7 conditioning resistance to SMV （soybean mosaic virus）. This study showed that the genetic mechanism of trichome density was the mixed major gene and polygene inheritance, and also suggested that the causal nature between trichome density and other agronomic traits.

Genetic Analysis of Combining Abilities and Heterosis for the Contents of Soybean Isoflavone and Its Components Among the Soybean Varieties [Glycine max (L.) Merr.]

The genetic analysis of soybean isoflavone content and its components were carried out based on the NC Ⅱ matingdesign in eight soybean varieties. The results showed that the isoflavone contents and its components of soybean seedare quite differences among the tested materials, the contents of isoflavone and daidzein are controlled not only byadditive effects and but also by non-additive effects, while the content of genistin is dominated by non-additive effects,and genistein, glycitin and daidzin are mainly controlled by additive effects. There are significant differences in thecontents of isoflavone and its components among the combinations derived from different parents. Results also indicatedthat the tested traits are negatively heterosis except for the contens of daidzein and daidzin are positively heterosis basedon the data of the GCA and SCA in average heterosis values. In this research we have a suggestion that soybean varietywith high isoflavone should be used as one of the parents in the breeding program, and it is the best choice that thecombinations crossed between two high isoflavone varieties or a high variety and a low one.

Genetic Analysis of Embryo, Cytoplasm and Maternal Effects and Their Environment Interactions for Isoflavone Content in Soybean [Glycine max (L.) Merr.]

Soybean seed products contain isoflavones （genistein, daidzein, and glycitein） that display biological effects when ingested by humans and animals. These effects are species, dose and age dependent. Therefore, the content and quality of isoflavones in soybeans is a key factor to the biological effect. Our objective was to identify the genetic effects that underlie the isoflavone content in soybean seeds. A genetic model for quantitative traits of seeds in diploid plants was applied to estimate the genetic main effects and genotype x environment （GE） interaction effects for the isoflavone content （IC） of soybean seeds by using two years experimental data with an incomplete diallel mating design of six parents. Results showed that the IC of soybean seeds was simultaneously controlled by the genetic effects of maternal, embryo, and cytoplasm, of which maternal genetic effects were most important, followed by embryo and cytoplasmic genetic effects. The main effects of different genetic systems on IC trait were more important than environment interaction effects. The strong dominance effects on isoflavone from residual was made easily by environment conditions. Therefore, the improvement of the IC of soybean seeds would be more efficient when selection is based on maternal plants than that on the single seed. Maternal heritability （65.73%） was most important for IC, followed by embryo heritability （25.87%） and cytoplasmic heritability （8.39%）. Based on predicated genetic effects, Yudou 29 and Zheng 90007 were better than other parents for increasing IC in the progeny and improving the quality of soybean, The significant effects of maternal and embryo dominance effects in variance show that the embryo heterosis and maternal heterosis are existent and uninfluenced by environment interaction effects.

Genome-wide association with transcriptomics reveals a shade-tolerance gene network in soybean

Shade tolerance is essential for soybeans in inter/relay cropping systems.A genome-wide association study(GWAS)integrated with transcriptome sequencing was performed to identify genes and construct a genetic network governing the trait in a set of recombinant inbred lines derived from two soybean parents with contrasting shade tolerance.An improved GWAS procedure,restricted two-stage multi-locus genome-wide association study based on gene/allele sequence markers(GASM-RTM-GWAS),identified 140 genes and their alleles associated with shade-tolerance index(STI),146 with relative pith cell length(RCL),and nine with both.Annotation of these genes by biological categories allowed the construction of a protein–protein interaction network by 187 genes,of which half were differentially expressed under shading and non-shading conditions as well as at different growth stages.From the identified genes,three ones jointly identified for both traits by both GWAS and transcriptome and two genes with maximum links were chosen as beginners for entrance into the network.Altogether,both STI and RCL gene systems worked for shade-tolerance with genes interacted each other,this confirmed that shadetolerance is regulated by more than single group of interacted genes,involving multiple biological functions as a gene network.

Sampling Survey and Identification of Races of Soybean Cyst Nematode (Heterodera glycines Ichinohe) in Huang-Huai Valleys

Soybean cyst nematode （SCN Heterodera glycines Ichinohe） is one of the most important nationwide soybean diseases in China. A total of 38 soil specimens or locations in the area was sampled and tested for SCN races during 2001-2003 for the inspection of race distribution in Huang-Huai Valleys. A map of race distribution was constructed according to the data from both the present study and the published reports cited. Three areas, namely, the area of southeast to Jinan in Shangdong Province; the area of northern Henan Province and its border region to south of Hebei Province; and the area of Luohe, Zhoukou of Henan Province and Fuyang of Anhui Province mainly infested with Race 1 were identified. Race 4 was predominant in Shanxi Province, Beijing and the adjacent area of Henan, Shandong, and Anhui provinces, and the delta of Huanghe River in Shandong Province. Race 2 was mainly found in Liaocheng, Dezhou of Shangdong Province and Shijiazhuang of Hebei Province, and Jiaozuo and Huojia of Henan Province. Race 7 was distributed in the west part of Jiaodong Peninsula of Shandong Province and Kaifeng, Huaxian, Wenxian of Henan Province. Race 5 was found and scattered in Hebei and Henan Province. Race 9 was found in Shangqiu of Henan Province, which was reported for the first time in China. It can be seen that Race 1 and Race 4 were the two predominant races in Huang-Huai Valleys, and that research should focus on developing resistant cultivars of these races. There might exist other races in an area with some predominant races. The race substitution in the past decade was not obviously found, therefore, the results should be meaningful to future breeding for resistance to SCN in Huang-Huai Valleys.

垄作和覆膜下盐碱地水盐运移和大豆产量的变化

选择河北省黄骅市中度盐碱土区布置夏播大豆[Glycine max(L.)Merr.]田间试验,共设平播(对照)、平播覆膜、垄作及垄作覆膜4个处理,研究垄作和覆膜对土壤水盐运移和大豆产量的影响。结果表明,与传统平播方式相比,平播覆膜处理对土壤水盐运移和大豆产量的影响不显著;垄作处理能显著改变土壤水盐分布,特别是大豆生长中后期降雨量开始减少后,垄作定植沟会产生叠加集雨效果,显著提高大豆生长中期0~20 cm和20~40 cm土壤含水量,减缓作物生长后期向表层返盐进程,有效降低土壤表层盐分含量,对保障大豆植株生长和产量均有一定的促进效果,可增产27.2%;垄作覆膜处理效果与垄作处理类似,覆膜措施影响不显著。垄作技术可以作为滨海盐碱地夏播大豆种植的农耕措施。

汉川市带状复合种植模式下不同品种大豆玉米产量及效益分析

为了探索汉川市带状复合种植模式下不同品种大豆[Glycine max(L.)Merr.]、玉米(Zea mays L.)的产量及效益表现,分析了多个品种大豆、玉米在该模式下的产量、经济效益、社会效益。结果表明,大豆品种中豆63和玉米品种汉玉919在经济效益上表现优异。

Effect of Phosphorus Fertilization to P Uptake and Dry Matter Accumulation in Soybean with Different P Efficiencies

Phosphorus （P） is an essential element for plant growth and yield. Improving phosphorus use efficiency of crops could potentially reduce the application of chemical fertilizer and alleviate environmental damage. Soybean （Glycine max （L.） Merr.） is sensitive to phosphorus （P） in the whole life history. Soybean cultivars with different P efficiencies were used to study P uptake and dry matter accumulation under different P levels. Under low P conditions, the P contents of leaf in high P efficiency cultivars were greater than those in low P efficiency cultivars at the branching stage. The P accumulation in stems of high P efficiency cultivars and in leaves of low P efficiency cultivars increased with increasing P concentration at the branching stage. At the late podding stage, the P accumulation of seeds in high and low P efficiency cultivars were 22.5 and 26.0%, respectively; and at the mature stage were 69.8 and 74.2%, respectively. In average, the P accumulation in whole plants and each organ was improved by 24.4% in high P efficiency cultivars compared to low P efficiency cultivars. The biomass between high and low P efficiency cultivars were the same under extended P condition, while a significant difference was observed at late pod filling stage. At the pod setting stage, the biomass of high P efficiency cultivars were significant greater （17.4%） than those of low P efficiency cultivars under high P condition. Meanwhile, under optimum growth conditions, there was little difference ofbiomass between the two types of cultivars, however, the P agronomic efficiency and P harvest index were significant higher in high P efficiency cultivars than those in low P efficiency cultivars.

Synergistic interaction of NaCl and Cd on growth and photosynthetic parameters in soybean genotypes differing in salinity tolerance

The effects of salinity （50 mmol/L NaCI） and Cd （1 μmol/L CdCl2） as sole and combined on growth and photosynthetic parameters were studied using two soybean genotypes, Huachun 18 and NGB. The concentrations of Cd^2＋, Zn^2＋, Ca^2＋, Mg^2＋, K^＋ and Na^＋were also determined in seeds and pods. Huachun 18 suffered a more serious decrease than NGB in net photosynthetic rate （P,） in the treatments of salinity stress alone and combined stress （NaCl＋Cd）, showing that it is relatively sensitive to salinity. The decrease in P, caused by salt stress in Huachun 18 was mainly due to the reduced total chlorophyll content and photosynthetic efficiency （the ratio of variable fluorescence to maximal fluorescence, Fv/Fm）, whereas the decease in NGB was mainly related to reduced stomatal conductance （Gs）, The combined stress of both Na and Cd did not induce further decrease in photosynthesis and fluorescence in the two genotypes relative to salt or Cd stress alone. Greater change in the pod concentrations of Zn^2＋, Ca^2＋, Mg^2＋, K^＋ and Na^＋was detected under salt stress for Huachun 18 than for NGB. The results suggested that the interactive effect of NaCl-Cd on growth and nutrient uptake differs between the two soybean genotypes.

Constitutive expression of feedback-insensitive cystathionine γ-synthase increases methionine levels in soybean leaves and seeds

Soybean （Glycine max （L.） Merr.） is a major crop that provides plant-origin protein and oil for humans and livestock. Al- though the soybean vegetative tissues and seeds provide a major source of high-quality protein, they suffer from low con- centration of an essential sulfur-containing amino acid, methionine, which significantly limits their nutritional quality. The level of methionine is mainly controlled by the first unique enzyme of methionine synthesis, cystathione y-synthase （CGS）. Aiming to elevate methionine level in vegetative tissues and seeds, we constitutively over-expressed a feedback-insensitive Arabidopsis CGS （AtD-CGS） in soybean cultivars, Zigongdongdou （ZD） and Jilinxiaoli 1 （JX）. The levels of soluble methionine increased remarkably in leaves of transgenic soybeans compared to wild-type plants （6.6- and 7.3-fold in two transgenic ZD lines, and 3.7-fold in one transgenic JX line）. Furthermore, the total methionine contents were significantly increased in seeds of the transgenic ZD lines （1.5- to 4.8-fold increase） and the transgenic JX lines （1.3- to 2.3-fold increase） than in the wild type. The protein contents of the transgenic soybean seeds were significantly elevated compared to the wild type, suggesting that the scarcity of methionine in soybeans may limit protein accumulation in soybean seeds. The increased protein content did not alter the profile of major storage proteins in the seeds. Generally, this study provides a promising strategy to increase the levels of methionine and protein in soybean through the breeding programs.

A novel TIR-NBS-LRR gene regulates immune response to Phytophthora root rot in soybean

Phytophthora root rot(PRR),caused by Phytophthora sojae,is a devastating disease of soybean.The NBSLRR gene family is a class of plant genes involved in disease resistance.miRNA mediates plant response to biotic stresses by regulating the expression of target genes at the transcriptional or post-translational level.Glyma.16G135500,encoding an NBS-LRR-type protein,is a target of gma-miR1510 that responds to pathogen infections.We cloned and overexpressed Glyma.16G135500(naming it GmTNL16)and knocked down mi R1510 using short tandem target mimic technology to identify the roles of the GmTNL16/gma-mi R1510 pair in the interaction of soybean and the oomycete.By overexpressing GmTNL16 in transgenic hairy roots of soybean,we showed that biomass of P.sojae was lower in overexpressing hairy roots than in control roots.Thus,miR1510 expression was reduced upon P.sojae infection,reflecting the induced expression of GmTNL16 conferring resistance to P.sojae in soybean.Differentially expressed genes were enriched in plant-pathogen interaction,plant hormone signal transduction,and secondary metabolism by RNA sequencing analyze.In particular,jasmonate and salicylic acid pathway-associated genes,including JAZ,COI1,TGA,and PR,responded to P.sojae infection.All of these results indicate that the GmTNL16/gma-miR1510 pair participates in soybean defense response via the JA and SA pathways.

Effect of Plant Density on Modern Soybean Cultivars Released from Ohio and Liaoning

Seeding rate is an important management practice for soybean production.Chinese and U.S.soybean growers use different seeding rates,and breeders in the two countries have developed cultivars adapted to respective plant densities.The objective of this study was to compare the effect of plant density on cultivars recently released in different breeding programs,using four cultivars developed in Liaoning,China and four in Ohio,USA.We used 3 plant density treatments(7.5,15.0,22.5 x 104 plants/hm2) and assessed yield and agronomic traits from 2004 to 2006 in Liaoning.There was no significant effect of plant density on yield for either group of the cultivars.The average yield of Ohio cultivars was higher than that of Liaoning cultivars,and there was no significant interaction between plant density and cultivar for all the assessed traits.The plant height of Liaoning cultivars was significantly higher than that of Ohio cultivars,and there was a significant effect of plant density on plant height.The average branch number of Ohio cultivars was larger than that of Liaoning cultivars;higher plant density reduced the branch number per plant greatly.Plant density had a signifi-cant effect on the node number and internode length,Liaoning cultivars generally had longer internode length.Plant density had a significant effect on seed yield:stem ratio,as the plant density increased the seed yield:stem ratio decreased for both groups of cultivars.However,100-seed weight was not affected by plant density.

Research Progress of Maternal Environmental Effects in Resource-based Regions

Heavy metal pollution is common in resource-based regions.However,the morphological,physiological and biochemical mechanisms of plants transmitting environmental information to their offspring in environments polluted by heavy metals have not been studied yet.Taking soybean,an annual self-pollinated plant in Huang-Huai-Hai region,as the research object,the morphological,physiological and biochemical indexes and heavy metal enrichment and distribution characteristics of plants under heavy metal stress were monitored continuously for about three generations,and the trans-generational differences of soybean reproduction,vegetative growth,stress resistance and life cycle in heavy metal stress environment were elucidated.The results will be helpful to better understand the long-term adaptive strategy of plants to heavy metal stress and provide the theory basis for ecological security of soybean and other crops under heavy metal stress.

转基因技术提高大豆对非生物胁迫耐受性的研究进展

大豆(Glycine max(L.)Merr.)起源于中国,可以为人类提供主要的植物蛋白和油脂。随着环境条件的日渐恶劣,中国干旱与半干旱的地区发生干旱、高温、盐渍等非生物胁迫的频率日渐增高,严重影响了中国大豆的生产。转基因技术的出现使培育植物新品种的效率大大提高。利用转基因技术提高大豆对非生物胁迫耐受性的报道已经日渐增多。因此,对利用转基因技术来提高大豆对非生物胁迫耐受性的研究进行综述对于大豆生物工程育种具有十分重要的意义。

世界大豆生育阶段光温综合反应的地理分化和演化

【目的】大豆是短日喜温植物,对光温(日长、温度)条件敏感。大豆对光温反应的敏感性是大豆重要的驯化性状和适应性性状。在自然条件下,地理位置和/或播种季节是决定野生和栽培大豆分化的重要生态因素,这两个因素均是通过日长和温度等环境因素来调控大豆的生长发育。因而研究和比较野生和栽培大豆生长发育阶段光温综合反应特性的地理和季节分化,可以为大豆引种和适应性育种提供理论依据。【方法】选取1519份世界代表性野生和栽培大豆,在安徽当涂进行2年春播和夏播田间试验,使用播季间生育期差异作为品种光温综合反应敏感性(photo-thermal comprehensive response sensitivity,PTCRS)评价指标,研究各地理生态型大豆生长发育阶段的光温反应特性。【结果】(1)大豆的光温反应特性存在于生长发育的全过程。(2)野生大豆由南向北迁移时,生育前期和全生育期PTCRS减小,生育后期PTCRS增大,光温反应类型由前敏后钝变为前钝后敏,全生育期光温反应敏感。(3)野生大豆驯化为栽培大豆后,生育前期和全生育期PTCRS分别减小20%和16%,生育后期PTCRS变化较小,主要光温反应类型由前敏后钝变为前钝后敏和前钝后钝。(4)夏秋大豆和春大豆的全生育期PTCRS均表现由南向北逐渐减小;生育前期和生育后期PTCRS的地理分化则存在差异,其中,由南向北迁移时,夏秋大豆生育前期PTCRS减小、生育后期PTCRS先增后减,春大豆生育前期PTCRS无明显变化、生育后期PTCRS减小。(5)以中国黄淮和南方作为栽培大豆的起源中心,向北传播至中国东北、俄罗斯远东和瑞典南部,生育前期、后期和全生育期PTCRS均大幅减小;向东传播至朝鲜半岛和日本岛以及向西传播至北美北部、北美南部和中南美,生育前期和全生育期PTCRS减小,生育后期PTCRS无明显变化;向南传播至东南亚、南亚和非洲,生育前期和全生育期PTCRS增大、生育后期PTCRS无明显变化。(6)同一生态区不同生态型间PTCRS比较,春大豆生育前期、后期和全生育期PTCRS均最小,野生大豆生育前期PTCRS强于夏秋大豆,生育后期则表现相反,全生育期与夏秋大豆无显著差异。不同地理-播季生态型间PTCRS比较,生育前期PTCRS:南方野生大豆最敏感,其次是长江中下游野生大豆和南方夏秋大豆,然后是黄淮野生大豆和长江中下游夏秋大豆,余下地理生态型间无显著差异,均表现较钝感;生育后期PTCRS:长江中下游夏秋大豆最敏感,其次是东北和黄淮野生大豆及南方和黄淮夏秋大豆,余下地理生态型间差异较小,光温反应均较钝感;全生育期PTCRS:南方和长江中下游的野生及夏秋大豆间无显著差异,均表现敏感,其次是黄淮野生大豆,然后是东北野生大豆和黄淮夏秋大豆,春大豆PTCRS最小,且随纬度升高而显著减小。【结论】由地理和播季决定的光温综合条件是影响大豆生长发育的关键因素,不同地理-播季生态类型的野生和栽培大豆生育阶段对光温综合反应存在差异。中国黄淮及南方的栽培大豆向世界不同纬度的地理区域传播时,生育阶段光温综合反应的变化不同。全生育期光温反应敏感是大豆的原始性状,长江中下游的夏秋大豆可能为最具这种野生原始性状的栽培类型。

钾肥用量对夏大豆干物质、养分累积和产量的影响

为探讨大豆[Glycine max(L.)Merr.]适宜的钾肥施用量,于2017年和2018年在河南省临颍县开展2年田间试验,设K2O用量分别为0、60、120、180 kg/hm^24个钾肥梯度,分析了不同钾肥用量对大豆干物质、养分累积、产量、肥料利用率及经济效益的影响。结果表明,大豆干物质累积量及钾素累积量随着生育期的推进不断增加,开花结荚期至鼓粒期干物质累积速度较快。2017年,成熟期大豆干物质累积量随着施钾量增加呈先增加后降低的趋势,钾素累积量则随施钾量的增加先降低后增加;2018年成熟期干物质累积量和钾素累积量均随着施钾量增加而增加。2017年所有处理间大豆产量差异均不显著,2018年各施钾处理比对照增产34.3%~52.7%,差异均达显著水平,且2018年以K2O用量为120 kg/hm^2时产量最高,且该施肥处理的增产效益也最高。因此,豫中地区推荐施钾肥量为K2O 120 kg/hm^2。

黄淮海大豆新品种（系）在江汉平原的引种表现

为了便于从黄淮海大豆[Glycine max (L.) Merr.]新品种(系)中筛选出适应在江汉平原种植的高产大豆品种(系),以新引进的13个新育成的黄淮海大豆品种(系)为研究对象,利用灰色关联分析结合相关分析法解析大豆产量相关主要农艺性状的主次关系及农艺性状间的相互关系。结果表明,单株粒重和有效分枝数与大豆产量呈极显著正相关,单株粒数与产量呈显著正相关;在灰色关联分析中,各农艺性状与产量的关联度排序为单株粒重(0.805)>有效分枝数(0.763)>生育期(0.746)>单株粒数(0.745)>开花期(0.727)>百粒重(0.715)>主茎节数(0.702)>株高(0.698)>单株有效荚数(0.691)。相关性分析与灰色关联度分析的研究结果一致说明,对大豆产量影响最大的农艺性状是单株粒重和有效分枝数,对新引进品种的选择和评价上注重单株粒重和有效分枝数更容易获得高产的品种(系)。同时,明确主要农艺性状对大豆产量影响的主次关系,也可为长江流域鄂中地区新品种选育、鉴定及推广提供参考。

播种期与种植密度对中豆46产量及主要农艺性状的影响

以大豆(Glycine max(L.)Merr.)品种中豆46为试验材料,采用双因素完全随机区组试验设计,设置3个播种期(5月21日、5月30日、6月8日)和4个种植密度(25.05、37.95、50.10、66.75万株/hm^(2)),研究播种期和种植密度对中豆46主要农艺性状、产量及产量构成因子和品质性状的影响。结果表明,播种期和种植密度显著影响该大豆产量和生育期,对主茎节数、有效分枝数无显著影响;播种期、种植密度及播种期和种植密度互作对大豆单株有效荚数、单株粒数和单株粒重均产生极显著影响,对蛋白质含量和脂肪含量无显著影响。中豆46在江汉平原的适宜播种期为5月30日,在此播种期下,中豆46在种植密度37.95万株/hm^(2)时产量最高,为3963.36 kg/hm^(2)。

Detection of Quantitative Trait Loci for Yield and Drought Tolerance Traits in Soybean Using a Recombinant Inbred Line Population

To investigate the genetic basis of drought tolerance in soybean （Glycine max L. Merr.） a recombinant inbred population with 184 F2：7：11 lines developed from a cross between Kefengl （drought tolerant） and Nannong1138-2 （drought sensitive） were tested under water-stressed and well-watered conditions in field and greenhouse trials. Traits measured included leaf wilting coefficient, excised leaf water loss and relative water content as indicators of plant water status and seed yield. A total of 40 quantitative trait loci （QTLs） were identified： 17 for leaf water status traits under drought stress and 23 for seed yield under well-watered and drought-stressed conditions in both field and greenhouse trials. Two seed yield QTLs were detected under both well-watered and drought-stressed conditions in the field on molecular linkage group H and Dlb, while two seed yield QTLs on molecular linkage group C2 were found under greenhouse conditions. Several QTLs for traits associated with plant water status were identified in both field and greenhouse trials, including two leaf wilting coefficient QTLs on molecular linkage group A2 and one excised leaf water loss QTL on molecular linkage group H. Phenotypic correlations of traits suggested several QTLs had pleiotropic or location-linked associations. These results will help to elucidate the genetic basis of drought tolerance in soybean, and could be incorporated into a marker-assisted selection breeding program to develop high-yielding soybean cultivars with improved tolerance to drought stress.