Differential response of chickpea genotypes to isoxaflutole

A polyhouse experiment was conducted to determine the tolerance of twenty chickpea genotypes, ten from desi and ten from kabuli types, to isoxaflutole applied preemergence at 0, 25, 50, 100 (recommended rate), 200, 400 and 800 g ha(-1). There was a strong dose response, and injury ratings, plant height, shoot and root dry weight reduction were greater at the higher doses than at the lower doses for all genotypes. Shoot dry matter was significantly reduced for desi chickpea genotypes Jimbour, Amethyst, ICLL 87322 and 91025-3021. But the reductions were not significant for most of the kabuli types except for Kaniva and S 95425. The genotypexherbicide rate interactions were weakly significant (P = 0.07) for root dry matter but the effects of single factor were highly significant. Root dry weight reductions were significant for the desi genotypes Jimbour, Amethyst, Yorker, ICLL 87322 and 91025-3021. FLIP 94-90C, Kaniva and S 95425 only showed significant reductions in root dry matter among the kabuli types. There was less herbicide injury to the kabuli genotypes than to the desi types at both of the assessment days. The desi chickpea genotypes Yorker, Howzat, Amethyst, Gully and 91025-3021 exhibited overall mean injury ratings greater than 4.1 and can be regarded as susceptible. Among these genotypes significant shoot dry weight reductions occurred in Amethyst and 91025-3021. Amethyst, Yorker and 91025-3021 also experienced significant root dry matter reductions. Furthermore, all of the five above mentioned desi genotypes exhibited significant plant height reductions. Hence, chickpea genotypes differed in their response to isoxaflutole and desi genotypes are more susceptible than to the kabuli types.