Gynoecy in Cucumber and Muskmelon

T.A. More

Department of Horticulture, Mahatma Phule Krishi Vidyapeeth, Rahuri-413 722. Dist.
Ahmednagar, Maharashtra, India

V.S. Seshadri

Indo-American Hybrid Seeds, 214, Palika Bhavan, R.K. Puram, Sector XIII, New Delhi-110 066, India

Additional index words. hybrid, gibberellic acid, AVG, silver nitrate, silver thiosulfate, sex expression, gynoecious, hermaphrodite, monoecious, Cucumis sativus, Cucumis melo

Abstract. In India, at the Indian Agricultural Research Institute, New Delhi, several true breeding gynoecious lines were developed in cucumber (Cucumis sativus L.) and muskmelon (C. melo L.). Detailed investigations were undertaken on their genetics and maintenance, and their potential to exploit heterosis under open-field and greenhouse cultivation. In cucumber, gynoecious sex expression was found to be governed by a single dominant gene possibly with some modifiers; all the F1 hybrid plants were gynoecious. In muskmelon, gynoecy was recessive and governed by two genes with some modifiers. Induction of staminate flowers on gynoecious cucumber can be achieved by the application of gibberellic acid and silver nitrate, which makes it easy to maintain gynoecious parents. In contrast, silver nitrate, silver thiosulfate or AVG-induced hermaphrodite flowers instead of staminate flowers on muskmelon. The number of fruit harvested from gynoecious parents and hybrids of cucumber was greater than from monoecious types because each node bears a fruit that is harvested when immature. In muskmelon, the number of fruit harvested from gynoecious parents did not increase as dramatically because the fruit are harvested at full maturity. F1 hybrids are advantageous in cucumber because of high productivity and uniform size and shape of the fruit. In muskmelon, earlier maturity and uniform fruit quality, especially sweetness, of F1 hybrids are more preferred than an increase in the number of fruit. Thus, gynoecy in cucumber and muskmelon presents contrasting prospects of use.

Cucurbitaceae '98