Comparative mutagenicity of four organophosphorous insecticides in meiotic system of red pepper.

Abstract

A study has been made of the effects of four organophosphorous insecticides: TARA 909, DDVP, phosphomidon (PMN) and monocrotophos (MCP) on ger-mination, survival and meiotic behaviour in Capsicum annuum. Soaked (24 h) seeds were treated with 0.1, 0.5 and 1.0% of the insecticides for 24h. There was a sig-nificant decline in germination and seedling survival percentage in all insecticidal treatments. All the insecticides were capable of inducing various types of meiotic alterations. Abnormalities consisted of univalents, multivalents, bridges, lagging chromosomes, non-synchronization, multipolar formation, micronuclei, unoriented and unequal disjunction of chromosomes at various divisional stages of PMCs. Stickiness and clumping of chromosomes was a common effect. As a result of these abnormalities, the tetrad formation were highly irregular and caused a high pollen sterility. Chromosomal aberrations and pollen sterility were dose-dependent and there was an apparent relationship between frequency of chromosomal damage and pollen sterility. Among the four insecticides, DDVP and TARA produced greater damage on chromosomes, which also caused significant reduction in ger-mination, survival and pollen viability followed by PMN and MCP.The present study has shown that the insecticides were effective mutagenic agents with radiomimetic action, and point out the need of adequate information concerning plant responses to agricultural chemicals to ensure their safe use.