Botany Section, College of Agriculture, Poona-5
*Present address: Andhra Pradesh Agricultural University, Regional Oilseeds Research Station, Kadiri (P.O.), Anantapur Dt., A.P.
The facultative apomictic tetraploid D. annulatum (2n=40) was crossed with the diploid sexual biotypes of D. aristatum (2n=20) and D. caricosum (2n=20). The species D. aristatum and D. caricosum mere also crossed among themselves. Sixteen hybrids were obtained, seven from D. annulatum × D. aristatum, four from D. annulatumD. caricosum, and five from the reciproal crosses between D. aristatum and D. caricosum. Besides the above hybrids, there were two androgenetic plants one in each progeny of D. annulatum × D. aristatum and D. annulatum × D.caricosum. In the hybrids, to the erosses in which D. annulatum was the female parent, there were six pentaploids (2n=50), one tetraploid (2n=40), one triploid (2n=30), and three aneuploids (2n=31, 42 and 46). There were two tetraploids (2n=40) and three diploids (2n=20) in the progeny of the crosses of D. aristatum and D. caricosum. The two androgenetic plants were tetraploids. Embryological studies indicated that the diploids were sexual tetraploids were apomictic triploids and aneuploids were sterile and pentaploids were partly sterile and partly apomictic. Studies of the F progenies supported the findings as observed in these plants and indicated that sexuality and apomixis were independent phenomena associated with the ploidy and depended upon complex genetic balance for their expression
