Indian Society of Genetics & Plant Breeding


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DURING the course of an investigation on the genetic differences between the japonica
and indica sub-species of rice, a significant feature was noted in the F, hybrids of these
two sub-species with regard to photoperiodic response. The F, hybrids in general
proved capable of flowering and setting seed throughout the year when propagated by
stubbles or ratoons.
It was well established that the indica parental varieties included
in the present investigations were those which normally do not flower under the long
day conditions at Cuttack from April to October and might be considered short-day
plants. Since the
japonica parents were not sensitive to photoperiod, it seemed that the
character of
japonica parents was dominant over that of the indica parents. Such
a dominance of insensitivity (period-fixed) over sensitivity (season-bound) had been
recorded by Srinivasan (Quoted by Ramiah and Rao, 1953) in
inter-indica hybrids.
But this is seemingly contradictory to the findings of Chandraratna (1955) who had
conducted critical experiments on the genetics ofphotoperiod response in rice and therefore, a series of experiments were started at the Central Rice Research Institute
and the first two years' results are presented below.


Year: 1961
Volume: 21
Issue: 1
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906



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