Division of Genetics, Indian Agricultural Research Institute, New Delhi-12
Online published on 25 January, 2012.
Cytogenetic behaviour of crosses involving a typical indica variety viz. TKM-6 and fourteen different types of rice collected from North East India was studied to determine the relative sexual affinity of the former to the latter.
It was evident from the wide range of sterility found in the hybrids that the rice types of N.E. India, which is considered to be on the periphery of the centre of origin of O. sativa, differ in their sexual affinity with typical indica type from the plains. It also appears that the degree of sterility is in no way related to subspecific differentiation.
Cytological anomalies observed in the crosses were too low in frequency to account for the high percentage of pollen and seed sterility. Thus it seems that the intervarietal hybrid sterility might be largely as a result of disharmonious gene combinations rather than detectable structural differences.
