Deciphering genetics and mapping of early flowering and maturity in Indian soybean [Glycine max (L.) Merr.]

Abstract

Soybean (Glycine max L.), a major oilseed crop of India, is predominantly cultivated during the kharif season under rainfed conditions. The development of early-maturing varieties is crucial due to the short growing season and the risks posed by terminal stresses like drought and high temperatures. To determine the genetics of photoperiod sensitivity, two soybean genotypes namely, SKAF148 (photoperiod insensitive) and DS9712 (photoperiod sensitive) were crossed. The F1 hybrids of the cross SKAF148 × DS9712 indicated that early flowering is predominant under short-day conditions, while intermediate flowering occurred under long-day conditions. The F2 plants on the other hand exhibited a continuous variation in photoperiod sensitivity indicating the trait to be controlled by polygenes. For trait mapping, 519 SSR markers were used, of which 258 were polymorphic. Analysis of 250 F2 segregating population led to the identification of five QTLs for days to flowering; one QTL each on chromosome 10 (qDF10.1) and 11 (qDF11.1), and three QTLS on chromosome 19 (qDF19.1, qDF19.2, qDF19.3) explaining 44.34% of the phenotypic variance. Similarly, five QTLs were mapped for days-to-maturity; two QTLs on chromosomes 1 (qDM1.1 and qDM1.2) and one QTL each on chromosome 4 (qDM4.1), 5 (qDM5.1) and 11 (qDM11.1), accounting for 34.89% of the variance. Chromosome 19 was notably involved in flowering regulations these 3 QTLs have been validated. The proximity of some QTLs reflects their potential for yield improvement. The genetic insights and QTLs identified in the present study along with the linked SSR markers, offer valuable resources for breeding soybean varieties adapted to diverse agricultural conditions across India.