The Behaviour of Meiotic Chromosomes as Revealed through the Use of Bavistin on Pea

Abstract

Meiotic studies in Bavistin (a systemic fungicide) sprayed plants of Pisum sativum L. cv. BR/12 and P. sativum L. cv T/169 were made with a view to assess the effects of fungicide on chiasma frequencies upto M₂ generations. The recom-mended dose i.e. 0.2% aqueous solution of Bavistin and higher dose i.e. 0.4 aqueous solution were sprayed on two cultivars of pea. 0.2% aqueous solution of Bavistin has caused a decrease in number of ring bivalents as well as number of chiasmata per nucleus formed in P. sativum cv. BR/12. Average chiasmata per bivalent were also lower in comparison to control.
An increase in number of ring bivalent formation in M₂ generation of 0.4% Bavistin treated P. sativum cv. T/169 was recorded. Average chiasmata per bivalent and total number of chiasmata per nucleus formed were also higher. Lower/ higher number of ring bivalent/chiasmata formed have been shown to be significant by ‘t’ test value. The increase/decrease in the total number of chiasmata per nucleus formed may be due to i) change in general metabolism of cellular system or ii) failure of parts of chromosome pairing or iii) change in chromatin length due to spiralisation induced by Bavistin. Thus, Bavistin may be termed as recombinogenic and its meiotic effects are specific as have been recorded in two cultivars of pea in the present investigation.