Induction of Parthenocarpy in Pointed Gourd (Trichosanthes dioica Roxb.) by Application of Plant Growth Regulators

Abstract

Pointed gourd (TrichosanthesdioicaRoxb.) is a dioecious, cucurbit summer vegetable, and green fruit is the main edible part at 15-18 days after pollination. However, consumer preference goes to fruit without seed since seeds are unpalatable to have after cooking due to their hard seed coat. To overcome this problem by parthenocarpy induction, six types of plant growth regulators [2,4-dichlorophenoxyacetic acid (2,4-D); naphthaleneacetic acid (NAA); N-(2-chloro-4 pyridyl)-N-phenylurea (CPPU); forchlorophenuron (Fulmet); gibberellic acid (GA3) and 2,3,5-triiodobenzoic acid (TIBA) with four concentrations (25, 50, 100 and 200ppm) were sprayed to the unpollinated ovaries of three different female accessions of pointed gourd at anthesis. Results revealed successful parthenocarpy induction by plant growth regulators in all the studied accessions while progressive variation observed in fruit length, diameter and weight according to the differences of plant growth regulators concentrations. The length, diameter and weight of parthenocarpic fruit induced by GA3at 200ppm, CPPU and TIBA at 100ppm in three studied accessions of pointed gourd were comparable with those of their respective hand-pollinated fruits. In most of the parthenocarpic fruits, seeds were found as empty at ripening stage apart from NAA and GA3at 200ppm treated fruits had few abnormal seeds. The results confirmed the useful technique of producing seedless fruits in pointed gourd through the application of GA3at 200ppm, CPPU and TIBA at 100ppm regardless of accessions.