Abstract

Nature of gene action for three important fruit quality characters of tomato viz., total soluble solids (TSS), β-carotene and lycopene contents were determined by analyzing one 7 x 7 half diallel population and six genetic populations (P₁, P₂, F₁, F₂ , BC₁ and BC₂) of two cross combinations. The nature of gene action determined from two biometrical methods matched well and it appeared that the fruit quality characters were under the control of both fixable and non-fixable gene effects, with the non-fixable gene effects with gene interactions being more important. Diallel analysis revealed moderate narrow sense heritability estimates and 6-parameter model suggested duplicate epistasis as well as significant additive x additive type non-allelic interaction with negative sign for the characters, which will hinder the pace of progress through simple selection. Single seed descent method with progeny row testing and deferred selection will be the best breeding method to develop line bred varieties with good fruit quality character.

Key words: Gene action, diallel, generation mean, fruit quality, tomato.