Somaclonal Variation: A Tool for the Improvement of Cavendish Banana Cultivars

Abstract

An improvement program for disease resistance and horticultural traits in Cavendish banana cultivars was established using somaclonal variants as a source of variation. The improvement procedure included single plant selection, clonal evaluation and experimental variety trials. Resistance to Fusarium wilt (race 4) is the most important breeding objective of the program. Resistant clones were selected by the pot screening technique using the fungal pathogen as the innoculum. A large quantity of young plants derived from tissue culture were subjected to the challenge of the disease. Putative resistant plants were identified and were multiplied by tissue culture for further evaluation. Through this procedure, several promising clones showing a high level of resistance to Fusarium wilt were selected and subjected to further evaluation. Somaclonal variation is also an effective tool in the improvement of horticultural traits of banana. A semi-dwarf resistant clone, TC1-229, which is about 70 cm shorter, was identified. It was derived from 'Tai-Chiao No. 1' which is tall and susceptible to wind damage. This clone was registered as ' Tai-Chiao No. 3' in 2000 and released for commercial planting in 2001. Further selection from TC1-229 resulted in the identification of clones with improved bunch size and shape, and these are now undergoing further evaluation. Triploid Cavendish bananas are highly sterile and hence very difficult to improve by conventional hybridization method. Selection among somaclonal variants has proved to be an effective alternative in the improvement of Cavendish bananas.

Morphological and RAPD-marker characterization of Melia volkensii (Grke) in vitro plants regenerated via direct and indirect somatic embryogenesis

“…Tissue culture-induced somaclonal variation can produce off-types which are undesirable when the expected outcome is mass production of uniform genotypes (Bairu and Kane, 2011). However, it can also be a source of useful novel variations (Larkin and Scowcroft, 1981;Tang, 2005).…”

FusariumWilt in Banana: Epidemics and Management Strategies

“…It is commonly known that by gaining a desired trait, the plant might be losing some others. This was also demonstrated in banana [112]. Hwang and Tang [111] observed some poorer traits in resistant somaclone that included longer maturation period, lower fruit production, as well as reduced fruit quality.…”

“…1, however, was inferior to the parental Giant Cavendish in certain areas. The variety had weaker defense against wind/typhoon due to its taller and slender stature besides lower fruit bunch production and longer maturation period [110,112]. Another study concerning somaclonal variation was carried out in Malaysia using micropropagated plantlets of "Rastali" cultivar.…”

Identification of SSR & ISSR Markers Associated to Off-Type Somaclonal Variants in Micro-Propagated Banana

“…Variations may decline in productivity of a particular plant in the field, ultimately resulting in heavy loss in terms of economics to the end user. Somaclonal variation being random and non-directional, is unpredictable, not controllable and poses the disadvantage of giving rise to very low number of useful variants [11]. A total of 150 SSR and ISSR markers were screened, all one hundred fifty SSR markers showed monomorphic band.…”