Cytogenetic Studies in the Genus Ocimum: Interspecific Hybrids and Induced Amphiploids of O. gratissimum L. (2n=40)×O. viride Willd. (2n=40)
1986 Volume 51 Issue 2 Pages 225-234
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1986 Volume 51 Issue 2 Pages 225-234
Interspecific hybrids were produced between O. gratissimum (2n=40) and O. viride (2n=40). F1 hybrids were highly sterile and fertility was induced by treating the young developing shoots with colchicine. The amphidiploids with 2n=80 chromosomes were fertile like the parents. The F1 hybrids were more vigorous in growth and showed heterosis for most of their vegetative characters. The amphidiploids showed gigantism for both vegetative as well as for their floral characters but their height is little shorter than the F1 hybrids. The leaves of the amphidiploids are dark green, thicker and larger than the leaves of F1 hybrids.
F1 hybrids showed irregular meiosis with 1.4% to 1.9% seed set whereas the meiosis is normal in the synthesized amphidiploids with 68% to 75% seed set. The present investigation also revealed that there is a homology between one of the two genomes present in each of the species of O. gratissimum and O. viride and the genomes are classified as A+B in O. giratissimum and A'+C in O. viride.
