Inter- And intra-plant variations in cytomictic behavior of chromosomes in corchorus fascicularis Lamk. (Tiliaceae)

Abstract

Cytomictic behavior (assessed from meiotic studies performed during July to Augustperiod A and August to September-period B; out of 7 plants-designated as P 1 to P 7, cytomixis is recorded in P 1 and P 7 in both the periods, while P 4 only in period B) was noted in a wild species of Corchorus (C. fascicularis Lamk.; Family: Tiliaceae, important genetic resource for Jute) under acclimatization /cultivation (3rd generation raised from bulk seeds of previous generation plants) in the experimental field plots of University of Kalyani, West Bengal, India (latitude 22°50' to 24° 1 l'N, longitude 88°09' to 88°48'E, altitude 9.75 m, sandy loamy soil, pH-6.89). The intensity of cytomixis varied among the plants (P 1 showed high degree of cytomictic behavior; while it was incipient in P 4 and P 7) and between the periods. Cytomixis was evidenced at early prophase including diplotenediakinesis and metaphase 1 and rare, often in anaphase I cells resulting in aneuploid (hypo-: n= 1-6, hyperploid: n=8 to 14 and 18) variations in chromosome number at meiosis I. These results may suggest that the phenomenon of cytomixis is a natural cellular process controlled genetically and to an extent influenced by environmental factor(s) and the gcne(s) involved in the process, and that it may be differentially expressed or repressed under a given set of condition(s). © 2012 The Japan Mendel Society.