Exploitation of Sexual Polymorphism in Cucurbits for Hybrid Development

Abstract

Cucurbitaceae, a family comprising over 900 species, exhibits remarkable sexual polymorphism, a trait that has been effectively harnessed in hybrid development. This review explores the evolutionary progression of sex forms in cucurbits, from primitive hermaphroditism to specialised forms such as monoecy, gynoecy, and andromonoecy. It emphasises the pivotal role of genetic and environmental factors in regulating sex expression and how these factors are exploited through cultural practices, growth regulators, and nutrient management to manipulate floral biology. Particular attention is given to the utilisation of gynoecious and male sterile lines, and the application of growth regulators such as gibberellins and silver compounds in inducing desired sex forms. The review also details various hybrid seed production techniques, including hand emasculation, manual defloration, and the use of genetic male sterility and highlights the significance of these methods in achieving hybrid vigor, disease resistance, and yield uniformity. By integrating classical breeding techniques with modern physiological and chemical approaches, this synthesis underscores the strategic value of sexual polymorphism in advancing cucurbit hybrid technology.