MORPHOLOGICAL RESPONSES OF Vigna mungo L. HEPPER GENOTYPES TO HERBICIDES GLYPHOSATE AND METRIBUZIN

Herbicides are a group of chemical substances which are widely used to improve agricultural production by eliminating weeds and enhancing crop yields. However, their excessive use can generate several toxic impacts on non-target crop plants. The present study was carried out to assess the morpho-toxic effect of herbicides on non-target plant. Black gram is one such non-target crop and therefore it becomes necessary to select ideal Black gram genotypes, which may be tolerant to herbicide stress and produce substantial yield under herbicidal stress conditions. Six genotypes of Vigna mungo were treated with different concentrations of glyphosate (1, 2, 4, 6, 8 and 10 mM) and metribuzin (100, 200, 400, 600, 800 and 1000 ppm) to evaluate their effect on various morphological parameters viz. germination percentage, survival percentage, root length, shoot length, vigour index, tolerance index and phytotoxicity percentage. Our findings showed that increasing concentrations of both herbicides caused significant reduction in all the studied parameters of seedlings except phytotoxicity in all the genotypes but response was different among genotypes. Percent phytotoxicity of roots was increased with increasing doses of herbicides. The dose-dependent reduction in morphological parameters indicates the toxicity of herbicides and showed an adverse effect on Vigna genotypes. Among the two herbicides glyphosate shows more toxic impact on all genotypes of V. mungo in comparison to metribuzin. Based on result obtained, it was concluded that V. mungo genotypes tolerant to the herbicide stress can be of considerable practical importance for studying the mechanism of herbicide tolerance and for providing genetic resources for the development of herbicide-tolerant cultivars.