Development of tetra-null soybean genotype lacking antinutrients using marker-assisted selection

초록

In the development of soybean varieties through crossbreeding, marker-assisted selection (MAS) is a very effective approach for selecting individuals with desirable alleles in the early stages of plant growth. The purpose of this study was to develop a tetra-null soybean genotype lacking four antinutritional factors: lectin, Kunitz trypsin inhibitor (KTI), P34, and the 7S α′ subunit protein using MAS. Two parental lines were used. The P1 parent possessed the Cgy1 Cgy1LeLetitip34p34 genotype, in which the 7S α' subunit and lectin proteins were present in mature seeds, whereas the KTI and P34 proteins were absent. The P2 parent possessed the cgy1cgy1leleTiTiP34P34 genotype, in which the 7S α′ subunit and lectin proteins were absent from mature seeds, whereas the KTI and P34 proteins were present. Among the 462 F2 seeds obtained by crossing the P1 × P2 parental lines, we selected 132 F2 seeds lacking the 7S α′ subunit protein and grew them into F2 plants. Genotyping of these F2 plants with the DNA markers for the Ti, Le, and P34 genes identified the following genotype classes: 51 Ti_Le_P34_: 15 Ti_Le_p34p34: 21 Ti_leleP34_: 5 Ti_lelep34p34: 23 titiLe_ P34_: 4 titiLe_p34p34: 10 titileleP34_: 3 titilelep34p34. We selected a single F2 plant with the tetra-null genotype that exhibited the best agronomic traits. This plant matured around October 18, had an approximate height of 50 cm, exhibited a determinate stem habit, and had a 100-seed weight of 22.4 g. These results demonstrate that MAS is a highly effective strategy for screening soybean lines with multiple antinutritional factor deficiencies in early breeding generations.

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