Evidence confirms the occurrence of stenospermocarpic seedless fruit development in pointed gourd (Trichosanthes dioica Roxb.)

Abstract

Pointed gourd (Trichosanthes dioica) is a perennial and vegetatively propagated cucurbitaceous vegetable grown for its tender fruits, and the occurrence of harder seeds reduces consumers’ preference. The present study was undertaken to understand the mechanism of seedless fruit development in pointed gourd. The period of rapid fruit growth and development in pointed gourd took place generally 3-7 days after pollination due to faster cell division and cell enlargement. Significantly higher fruit growth recorded in seeded clone as compare to seedless clones (49.1% for fruit length, 16.7% for fruit diameter and 55.2% for fruit weight) at harvestable fruit maturity but at the same time no significant differences found at initial stage of fruit development. The occurrence of various mechanisms of seedless fruit development such as vegetative parthenocarpy, stimulative parthenocarpy and stenospermocarpy have been studied in details through different pollination treatments in both seeded and seedless clones. In seedless clone, the growth/development of seed was normal for first 3-4 days after pollination and become abnormal (aborted and degenerated embryo, shriveled and disintegrated cotyledons, traces of aborted seeds yellowishwhite in colour and zero per cent seed germination) indicate the existence of fertilization and subsequent abortion of fertilized embryo which confirms the occurrence of stenospermocarpic seedlessness and absence of stimulative parthenocarpy in pointed gourd.