Problems and Prospects of Banana Breeding in India

Abstract

Banana breeding programme in India involves maintenance of various genetic resources of banana, of which triploids constitute the maximum share over diploids or tetraploids. RAPD studies conducted in these clones exhibit many distinct genotypes. During a hybridization programme, although many crosses were made, seed set and seed germination were relatively poor in many crosses. Male fertility in banana hybrids could be assessed by pollen output per anther; pollen viability and pollen size, which vary from cross to cross, and also from ploidy to ploidy. Ploidy levels in hybrids are estimated by phenotypic appearance (scoring technique) and confirmed either by stomatal density, size and number of chloroplast per guard cell pair or root tip mitosis. However, flow cytometry appears to be the most reliable method in many disputed cases. Generation of parthenocarpic hybrids depends largely upon selection and utilization of parents with parthenocarpic pedigree in a breeding programme. Evaluation of hybrids and parents indicated the nature of inheritance with respect to plant height and suckering habit but no definite trend could be ascribed to the traits of bunch orientation. Diploid x Diploid breeding approach has led to identification of a superior triploid hybrid, NPH 02-01, while Triploid (with AB)xDiploid approach has led to the development of a promising diploid hybrid H.212 and a triploid hybrid H.96/7 (ABB). Similarly, the Triploid x Diploid breeding programme resulted in development of many potential tetraploids that need further improvement. Innovative breeding approaches through in vitro mutation breeding and in vitro polyploidazation resulted in the development of many potentially useful variants. Breeding for resistance against biotic stresses such as Fusarium wilt and nematodes holds promise in banana, and, biochemical mechanisms for resistance in resistant genotypes/hybrids have been elucidated.