Inheritance of Stem and Leaf Morphological Traits in Pointed Gourd (Trichosanthes dioica Roxb.)

ABSTRACT

The inheritance of five stem and leaf morphological characters was studied in progeny of a perennial dioecious species, Trichosanthes dioica from the female clone IIVRPG-102 pollinated by the male clone IIVRPG-M. Because mature seeds failed to germinate even after scarification, embryos from almost fully developed seeds were excised and cultured in vitro. Fifty-two plants were raised in a glasshouse, and segregation was observed for sex expression, stem shape (angular > round), stem pubescence (pubescent > smooth), tendril coiling (coiled > uncoiled), tendril branching (branched > unbranched), and leaf pubescence (smooth > pubescent). There was a significant bias for female plants possibly due to lethal/sublethal gene(s) linked to the female determining locus. It is proposed that stem pubescence (sst), stem shape (rst), tendril coiling (stl), tendril branching (utl), and leaf pubescence (plf) are governed by a single gene each. We believe this to be the first such report in T. dioica.

KEYWORDS:

• Trichosanthes
• qualitative traits
• inheritance
• female-biased sex ratio

S. Kumar is thankful to the Director, Indian Institute of Vegetable Research, Varanasi, for granting study leave to carry out PhD research work and also for providing a part of the research facilities.