Studies on pre-fertilization crossability barriers between cultivated and wild species of pigeonpea [Cajanus cajan (L.) Millspaugh]

Abstract The present day commercially grown cultivars of pigeonpea are susceptible to pod borer, pod fly insect pest and a number of diseases those causes huge economic loss every year to the farmers. On the other hand wild relative of cultivated pigeonpea possess genes for insect pest/ diseases resistance besides having some other useful genes. Transfer of desirable gene from wild to cultivated pigeonpea is hindered by several pre fertilization barriers. The identification of pre fertilization barriers will help in the introgression of desirable genes for insect pest and diseases resistance into cultivated types for enhancing and stabilizing pigeonpea production. In present investigation crossability barriers between the cultivated Cajanus cajan (PADT-16 and Pusa-992) and wild species Cajanus scarabaeoides (ICP-15683, ICP-15703) and Cajanus platycarpus (ICP-15663) were examined by pre-fertilization parameters like pollen germination, pollen tube growth, and pollen tube abnormalities. In hand-selfing and intervarietal crosses mean pollen germination and pollen tube growth was higher than interspecific crosses. Strong pre-fertilization barriers were observed in C. cajan x C. platycarpus crosses. However in interspecific crosses involving C. platycarpus as female, low level of reproductive barriers were observed when crossed with C. scarabeoides compared to cross with C. cajan, though pollen tube reached ovule in both crosses. More pollen tube abnormalities were observed in interspecific crosses involving cultivated and species from tertiary gene pool. Molecular diversity among experimental material through SSR markers exhibited maximum diversity between cultivated C. cajan and wild C. platycarpus whereas closest relationship was observed between C.scarabeoides ICP-15683 and ICP-15703.