Department of Genetics and Plant Breeding, Kalyani University, West Bengal
1,2 Present address: JARI, Barrackpore, W. Bengal.
*Part of the Ph.D. thesis submitted by the senior author to the University of Kalyani.
Cytological and breeding behaviour of seven possible primary trisomics of jute (Corchorus olitorius L.) was analysed. It was observed that the frequency of trivalent formation was not dependent on the length of the extra chromosome. Trivalents in the form of chain were most frequent in most of the trisomics. In the majority of PMC’s the extra chromosome was found to move to either of the poles during anaphase-I. The univalents lagging during anaphase-I were found to divide equationally and the resulting half chromosomes were found to move to opposite poles. Though a marked reduction in pollen fertility was not observed, a definite reduction in ovule fertility and seed set per pod was observed in all the trisomies. The average frequencies of trisomies in selfed, (2n + 1) × 2n, and 2n × (2n + 1) progenies were 8⋅60, 14⋅26 and 2⋅21 percent respectively. The frequency of individual trisomies was found to vary between 0⋅83 to 22⋅48 percent in different progenies. There was no apparent relationship between the length of extra chromosome and the rate of its transmission in different progenies.
