Development of male sterile lines of tomato and assessment of their utility in hybrid development

Abstract

High cost of hybrid tomato seeds is attributed to labour involved for emasculation and pollination processes. Emasculation can be avoided and labour saved if male sterile line is used as the female parent. Efforts were made to incorporate functional male sterility conditioned by ps2 gene and sporogenic male sterility conditioned by ms2 and ms33 genes into locally adapted and horticulturally superior genotypes. The lines viz. ‘ps2 L 3841’, `ps2 NS 101’ `ps2 San Pedro’ and `ps2 UC 82-B’ (all functional male sterile); and ‘ms2 IPA’ and `ms33 IPA’ (both sporogenic male sterile) were stabilized after six cycles of alternate selfing and backcrossing. It is suggested that the utility of functional male sterile lines can be enhanced if it is combined with exserted stigma conditioned by the gene ex. The stigma position of ‘ms33 IPA’ is exserted and is, therefore, accessible for hand-pollination for F1 hybrid seed production without disturbing the anther cone. It was estimated that while using ‘ms33 IPA’ as a female parent, 54.4 per cent time was saved over its fertile counterpart for F1 hybrid seed production. This indicated the potential of exploiting male sterility for heterosis breeding in tomato.