Cucurbitaceae and Polyploidy

Abstract

The role of polyploidy in family Cucurbitaceae has been debated by many scientists. Bhaduri and Bose (1947), while discussing the cytogenetics of some cultivated cucurbitaceous taxa pointed out that chromosomal alterations are mainly responsible for the speciation in different genera of this family. Stebbins (1950) and Ayyangar (1967) have further developed this argument and denied the role of polyploidy in speciation of the family Cucurbitaceae. But these generalised statements require to be justified through intensive cytological survey of the wild and cultivated taxa. Whitaker (1950) while describing a case of natural polyploidy in Echinocystis macrocarpa, rightly pointed out that polyploidy might have played an important role in the evolutionary progress of a few genera, if not the whole family. The author also realised the same while reviewing the cytological data in the family Cucurbitaceae (Singh 1977). In genera like Trichosanthes (Singh and Roy 1977) and Melothria (Singh 1974) good number of polyploid forms are present indicating the role of polyploidy in evolving new populations or species. Similar controversial situations exist in relation to polyploid breeding where artificial polyploids have yet to prove their worth over their diploid counterparts from commercial point of view excepting Citrullus vulgaris (water melon) (Kihara 1951, Andrus et al. 1971). On the basis of these facts success of polyploid breeding in family Cucurbitaceae was almost denied. © 1979, Japan Mendel Society, International Society of Cytology. All rights reserved.