Identifying QTL for seed weight in a cross between vegetable and grain type soybeans

The variation for 100 seed weight in F2 population derived from a cross, AGS456 (an exotic vegetable type from Taiwan)/SL958 of soybean followed a normal curve with a range of 8.00-27.22g indicating quantitative nature of genetic control for seed size. Parental lines were screened with 207 SSR markers to identify polymorphism and 90 primer pairs detected polymorphism between the parents. These ninety markers were used for detecting polymorphism between two extreme bulks for seed weight. Out of these, 18 primer pairs were polymorphic for the bulks and were used for bulk segregant analysis in 200 F2 plants. One major QTL for seed weight was identified on LG M with Sat_244 and Satt175 as flanking markers, explaining 19.0 per cent phenotypic variation. Two minor QTLs were also identified on LG D1b, one in interval Satt041-Sat_069 with an estimated phenotypic variation (R2) of 6.0 per cent and the other in interval Sat_069-Sat_0183 estimating 7.0 per cent phenotypic variance. The markers flanking TLs may help in marker-assisted selection (MAS) for improvement of seed weight in soybean after fine mapping and validation.