Inter- and Intra-Plant Variations in Cytomictic Behavior of Chromosomes in Corchorus fascicularis Lamk. (Tiliaceae)

抄録

Cytomictic behavior (assessed from meiotic studies performed during July to August—period A and August to September—period B; out of 7 plants—designated as P₁ to P₇, cytomixis is recorded in P₁ and P₇ in both the periods, while P₄ 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°11′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 (P₁ showed high degree of cytomictic behavior; while it was incipient in P₄ and P₇) and between the periods. Cytomixis was evidenced at early prophase including diplotene-diakinesis and metaphase I 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 gene(s) involved in the process, and that it may be differentially expressed or repressed under a given set of condition(s).