Abstract
Weed control in chickpea (Cicer arietinum L.) is challenging due to narrow genetic base of available germplasm and limited herbicide options. In this view, present research was focused on induced mutagenesis in chickpea for development of herbicide (glyphosate) tolerant mutants and subsequent screening under field conditions. Further, objective was to analyze the defence response and biochemical adjustments in selected glyphosate tolerant chickpea mutants. Initially, 376 chickpea mutants (M(6) populations developed through EMS and gamma rays) were screened for glyphosate tolerance under filed conditions and scored on a 1 to 5 scale based on plant injury related traits. Among tested mutants, 40 were found highly tolerant (score = 5), 32 as tolerant (score = 4) and 20 as highly sensitive (score = 1) to glyphosate. Chickpea mutants with variable glyphosate tolerance also differed significantly (Tukey test, p < 0.05) in leaf biochemical profiles. For instant, lowest total oxidant status (4175.µM/g f. wt.) was detected in glyphosate tolerant mutant developed from desi chickpea genotype "D3009" using 0.3% EMS and in highly tolerant mutant (1775. µM/g f. wt.) developed from kabuli genotype "K709" using 0.2% EMS. In general, highly tolerant chickpea mutants exhibited highest antioxidant potential (SOD, POD, CAT, TAC) that contributed in glyphosate tolerance. Desi i.e. D1M1HT-2 and Kabuli i.e. KM3HT-2 type mutants with highest seed yield had maximum catalase activity (4200 Units/g f. wt and 540 Units/g f. wt.). Mutants developed from desi type genotypes were comparably superior to mutants derive from Kabuli in terms of herbicide tolerance.