大豆耐旱种质鉴定和相关根系性状的遗传与QTL定位

Identification of Drought Tolerant Germplasm and Inheritance and QTL Mapping of Related Root Traits in Soybean (Glycine max (L.) Merr.)

从301份黄淮海和长江中下游地区代表性大豆地方品种和育成品种(系)中按根系类型选取59份,在苗期干旱胁迫和非胁迫条件下对地上部和地下部性状进行2年重复鉴定,发现材料间性状隶属函数值具有丰富遗传变异,以株高、叶龄、根干重和茎叶干重隶属函数的算术平均数为抗旱综合指标从中筛选出汉中八月黄、晋豆14,科丰1号,圆黑豆等强耐旱型(1级)和临河大粉青、宁海晚黄豆等干旱敏感型(5级)材料。比根干重、比总根长、比根体积与耐旱隶属函数平均值均呈极显著正相关,可作为耐旱性的根系性状指标。利用“科丰1号×南农1138 2”(1级×4级)衍生的RIL群体为材料,对耐旱相关根系性状采用主基因+多基因混合遗传模型分离分析法进行遗传分析并进行QTL定位。结果表明,该两亲本间比根干重、比总根长、比根体积的遗传均为两对主基因加多基因模型,后两者主基因间有连锁(重组率分别为4.30%和1.93%);主基因遗传率为62.26%～91.81%,多基因遗传率为2.99%～24.75%;耐旱相关根系性状各主要由1对主基因控制,另1对效应较小。QTL分析检测到5、3、5个QTLs分别控制比根重、比根总长、比根体积,位于N6 C2、N8 D1b+W、N11 E、N18 K连锁群上。3性状各有1个贡献率大的QTL(Dw1,Rl1,Rv1),而且均位在N6 C2的STAS8_3T STAS8_6T相同距离的区段上,其他QTLs效应均较小。分离分析与QTL定位的结果相对一致。

Fifty nine accessions of soybean （Glycine max （L.） Merr. ） selected from 301 ones in Huang-HuaiHai and Middle-Lower Changjiang Valleys were tested in two years for their tolerance to drought by using the mean membership index value averaged over those of plant height,leave number,dry root weight and dry stem and leaf weight. Four most tolerant accessions （ Rank 1 ） and two most sensitive ones （ Rank 5 ） were identified.There existed very significant correlations between drought tolerance and relative values of dry root weight,total root length ,and root volume （per plant dry weight basis）, respectively,which could be used as root indicators of drought tolerance. The RIL population derived from Kefeng 1 × Nannong 1138-2 was used to analyze the inheritance of the three related root traits by using the segregation analysis of quantitative traits under the major gene plus polygene mixed inheritance model. The results showed that between the two parents （ Rank 1 × Rank 4 ）,the relative values of dry root weight,total root length and root volume were respectively controlled by two major genes （linked together for the latter two traits, recombination value being 4.30% and 1.93%, respectively） plus polygenes with their major gene heritability values of 62.26% -91.81% and polygene heritability values 2.99%-24.75% ,indicating that the major genes, especially the one with larger effect,accounted for a major part of the genetic variation between the two parents. It was identified that five,three,and five QTLs located on N6-C2,N8-D1 b ＋ W, N11 -E ,and N18-K linkage groups for relative dry root weight, total root length and root volume, respectively, Each of the traits appeared to have one locus （ Dwl, R/1 ,and Rv1 ） with relatively targe effect in comparison with their other loci,and those major ones were located near the same site of the same linkage group N6-C2. The results of segregation analysis and QTL mapping appeared pretty consistent with each other,which could be used as a demonstration of each other.