Insect-aided natural out-crossing in four wild relatives of pigeonpea

Abstract

Insect-aided natural out-crossing in pigeonpea [Cajanus cajan (L.) Millsp.] is a common event. It is considered to be a prime constraint in maintaining genetic purity of cultivars and genetic stocks. On the contrary, the out-crossing has also been exploited to select high-yielding varieties from landraces. This paper, for the first time, reports natural out-crossing in four wild relatives of pigeonpea. The highest (17.1%) natural out-crossing was recorded in C. lineatus and it was comparable to the control cultivar Asha (22.2%). C. albicans and C. scarabaeoides exhibited 10.0 and 8.3% out-crossing, respectively. C. sericeus was found to have lowest (2.3%) natural out-crossing. A process of breeding a new cytoplasmic-nuclear male-sterility (CMS) system arising from a natural hybrid of C. lineatus has also been described. Once stabilized, this CMS will be used in breeding programs aimed to develop high-yielding pigeonpea hybrids.