Inheritance pattern of photoperiod responsive flowering, growth habit and flower colour in Indian bean [Lablab purpureus (L.) Sweet.]

Abstract

Photoperiod responsive flowering and growth habit have played key role in evolution and domestication of Indian bean. Most of the land races of this crop exhibit photoperiod sensitive flowering and indeterminate growth habit. To deduce inheritance pattern of photoperiod responsive flowering, growth habit and flower colour, four crosses were made between genotypes having extreme phenotypes keeping determinate and photoperiod insensitive variety GNIB-21 as common female parent. Pure hybrids were selected on the basis of male dominant traits to raise true F2 generations. Segregation patterns of 3 : 1 in all F2 generations and χ2 estimates indicated that photoperiod insensitive flowering, determinate growth habit and white flower colour are monogenic recessive in nature, while photoperiod sensitivity, indeterminate growth habit and purple flowers are dominant in nature. Linkage analysis in the cross GNIB-21 x GP-189 revealed that loci governing photoperiod responsive flowering and growth habit are placed at the distance of 22.99 cM + 0.022. The analysis also revealed coupling phase of linkage between photoperiod insensitive flowering and determinate growth habit. The information obtained from present study will be helpful for molecular dissection of photoperiod responsive flowering and growth habit in Indian bean utilizing new genomics tools.

Keywords

• photoperiod insensitivity
• growth habit
• flower colour
• linkage mapping
• evolution