大豆苗期耐旱种质鉴定和相关根系性状QTL定位

Identification of drought tolerant germplasm at seeding stage and QTL mapping of related root traits in soybean

从301份大豆品种中按根系类型选取黄淮海和长江中下游地区代表性材料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、比根总长、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R IL群体为材料,对耐旱相关根系性状进行QTL定位。检测到5、3、5个QTL s分别控制比根重、比根总长、比根体积,位于N 6-C 2、N 8-D 1b+W、N 11-E、N 18-K连锁群上。3个性状各有1个贡献率大的QTL(Dw 1、R l1、R v1),而且均位在N 6-C 2的STA S8_3T-STA S8_6T相同距离的区段上,其他QTL s效应均较小。

Fifty nine accessions of soybean selected from 301 ones from Huang-Huai-Hai and middle-lower Changjiang valleys were tested at seeding stage in two years for their tolerance to drought by using the mean membership index value averaged over those of plant height, leaf 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 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 × Nan- nong 1138-2 was used to analyze the QTLs of the three relative root traits. The results showed that between the two parents （Rank 1XRank 4）, there identified five, three, and five QTLs located on N6-C2, N8-Dlb＋W, Nll-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 （D＇wl, Rll, and Rwl） with relatively large effect in comparison with their other loci, and those major ones were located at about a same site of a same linkage group N6-C2.