Identification of QTLs controlling somatic embryogenesis using RI population of cultivar x weedy soybean

Quantitative trait loci (QTLs) controlling ability of somatic embryogenesis were identified in soybean. A frame map with 204-point markers was developed using an RI population consisting of 117 F(11) lines derived from a cross between cultivar 'Keburi' and a weedy soybean 'Masshokutou Kou 502'. The parents differed greatly in their abilities of somatic embryogenesis using immature cotyledons as explants. The ability of somatic embryogenesis was evaluated in five different experiments: the F(11) (evaluated in 1998) and F(15) (2002) generations cultured on basal media supplemented with 40 mg l(-1) 2,4-D (2,4-D1998 and 2,4-D2002), F(14) (2001) generation on medium with 40 mg l(-1) 2,4-D and high sucrose concentration [2,4-D2001 (30 g l(-1) sucrose)], and the F(11) (1998) and F(12) (1999) generations on medium with 10 mg l(-1) NAA (NAA1998 and NAA1999). The RILs showed wide and continuous variations in each of the five experiments. In the composite interval mapping analysis, 2 QTLs were found in group 8 (D1b + W, LOD = 5.42, r (2) = 37.5) in the experiment of 2,4-D1998 and in group 6 (C2, LOD = 6.03, r (2) = 26.0) in the experiment of 2,4-D2001 (high concentration sucrose). In both QTLs, alleles of 'Masshokutou Kou 502' with high ability of somatic embryogenesis contributed to the QTLs. For the other three experiments, no QTL was detected in the criteria of LOD > 3.0, suggesting the presence of minor genes.