Resumo

GARCIA-FRANCO, José Luis et al. Morphological characterization of resistant and susceptible Phalaris minor biotypes to ACCase inhibitors. Bot. sci [online]. 2014, vol.92, n.2, pp.169-176. ISSN 2007-4476.

Phalaris minor Retz. (Little-seed Canary Grass) is considered an important weed of the wheat crop in the Mexican Bajio region, which has developed resistance to herbicides inhibitors of acetyl coenzyme A carboxylase. In some cases, it has been observed that weeds mimic the crop, as Echinochloa spp. with the rice. The aim of this study were: (1) to determine whether there are morphological differences between resistant and susceptible little-seed canary grass biotypes, and (2) to compare the morphology in vegetative stage of P. minor biotypes with the wheat. Experiments were performed in Montecillo, Estado de México, under a greenhouse and in a non-competition condition. The resistant biotypes used were: C4, C7, Guanajuato, Jalisco, and one susceptible. Wheat cultivars used were: Cortazar and Nana. Twenty morphological variables were recorded in the vegetative phase for comparison with wheat and twenty-three variables throughout the little-seed canary grass life cycle for the comparison between biotypes. Data was analyzed using discriminant analysis, which showed a statistical separation between little-seed canary grass biotypes. Thus, it is possible that the resistance had been developed independently in the biotypes and not that resistance had been developed solely from an initial population. If they were originated from a single resistant population, biotypes are expected to be similar morphologically due to its genetic closeness. The discriminant analysis also showed a statistical separation between little seed canary grass biotypes and wheat cultivars, making it practical to distinguish them visually.

Palavras-chave : graminicides; morphological characterization; resistance to herbicide.

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