Reproductive biology of Coccinia grandis (L.) Voigt, a dioecious vegetatively propagated cucurbit: evidence for facultative apomixis

Reproductive biology of Coccinia grandis (L.) Voigt, a dioecious vegetatively propagated cucurbit: evidence for facultative apomixis

2015

E10735

Coccinia grandis, a dioecious cucurbit, is characterized by the presence of a pair of sex chromosomes. It exhibits both sexual and asexual modes of reproduction. Phenological observations revealed that production of flowers and fruits occur throughout the year, although the highest rate of production was noticed during the summer. Flowering pattern showed a staminate biased ratio typical of dioecious plants. Pollen characterization of male accessions revealed numerous viable pollen grains while anthers of morphologically perfect flowers possessed malformed pollen grains clumped together in the sporangium. The presence of rudimentary stamens at various stages of development was also observed during morphological characterization of the accessions. These characteristics may reflect an intermediate stage in the evolution from hermaphroditism to dioecy, suggesting that sexual dimorphism may be a relatively recent phenomenon in C. grandis. The study of breeding systems revealed that open pollination was the most effective method in terms of fruit set and seed set both in the cultivated and wild accessions. Fruit set observed in the unpollinated flowers indicate the apomictic nature of the species. Occurrence of apomixis along with sexual reproduction suggests the operation of facultative apomixis in C. grandis.

7(1):67-77, THE INTERNATIONAL JOURNAL OF PLANT REPRODUCTIVE BIOLOGY

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