Genetics of semi-determinacy and identification of molecular marker linked to Dt1 locus in chickpea (Cicer arietinum L.)

Abstract

Chickpea is predominantly an indeterminate (IDT) plant due to which high fertility and irrigation have adverse effect on seed yield. The semi-determinate (SDT) types are relatively early, lodging resistant and found to be similar in their yield potential to that of IDT genotypes. However, the inheritance of SDT stem type is not well understood in chickpea. The present investigation was aimed at studying the genetics of SDT stem type and identifying molecular marker linked to Dt1 locus through Bulked Segregant Analysis (BSA). The genetics of semi-determinacy was studied in BGD 72 (IDT) x BG 3078-1(SDT) cross in which the genetic constitution of BGD 72 was already known as Dt1Dt1Dt2Dt2 based on the previous study. The F1 was IDT indicating the dominance of indeterminacy over semideterminacy. The segregation in F2 and F3 revealed that SDT stem growth in the new-found genotype BG3078-1 was governed by a single dominant gene Dt2 and its genotype designated as dt1dt1Dt2Dt2. The study of polymorphic survey between BGD-72(IDT) and BG 3078- 1(SDT) using 581 SSR markers found 50 markers polymorphic. The BSA using 50 polymorphic markers has identified TA42 and TR29 as polymorphic between IDT and SDT parents as well as IDT and SDT bulks and hence considered putatively linked to Dt1 locus governing IDT stem growth in chickpea. The two linked markers were validated in 15 IDT and 15 SDT F2 plants individually. These two markers were also validated in 3 IDT, 8SDT and 3 DT genotypes. This is the first report on the identification of a molecular marker associated with stem growth habit in chickpea.