Perspectives on the application of biotechnology to assist the genetic enhancement of plantain and banana (Musa spp.)

Abstract

Bananas and plantains (Musa spp.) are the most important tropical fruit crops. They form an integral component of the farming systems in the humid agroecological zones of the tropics. A broad array of applied cell and molecular techniques are increasingly being used worldwide to facilitate and enhance the handling and improvement of plantain and banana germplasm. Tissue culture is used for germplasm exchange, conservation and rapid multiplication, while in vitro seed germination (based on embryo culture or rescue) plays a critical role in generating hybrid plants. DNA marker systems have been developed in Musa to assist germplasm management, selection within the breeding pool or gene introgression from wild species, and for disease diagnosis. Likewise, genetic transformation using the particle gun method or through Agrobacterium co-cultivation shows potential for the genetic betterment of the crop. This article discusses the applications of biotechnology for the genetic enhancement of banana and plantain. It highlights current advances by research teams across the world and reviews progress in molecular breeding of Musa by the International Institute of Tropical Agriculture and its collaborators. Plantains and bananas (Musa spp.) are staple foods for rural and urban consumers in the humid tropics and an important source of rural income, particularly in some locations where smallholders produce them in compound or home gardens. World Musa production is around 85.5 million tonnes annually (FAO 1998), of which bananas cultivated for the export trade account for only 10%. Hence, fruit harvested from bananas and plantains are important components of food security in the tropical world, and provide income to the farming community through local and international trade. Most banana cultivars and all plantain landraces have 33 chromosomes (2n = 3x). These triploid genotypes are virtually or completely sterile and develop their fruit by vegetative parthenocarpy. Diploid landraces and tetraploid cultivars (mostly artificial hybrids) are also cultivated. The