Resumo

MONTES-GARCIA, Noé et al. Disease Severity and Susceptibility of Sorghum [Sorghum bicolor (L.) Moench.] to Infection by Claviceps africana Frederickson, Mantle and de Milliano in Mexico and the United States of America. Rev. mex. fitopatol [online]. 2008, vol.26, n.2, pp.121-126. ISSN 2007-8080.

Experiments were carried out at College Station, USA, and Rio Bravo and Celaya, Mexico, under irrigated conditions during 2002 and 2003. Six sorghum hybrids and three male-sterile lines were planted at each location. Claviceps africana isolates were applied every other morning. Panicles were inoculated using a hand atomizer until runoff with a suspension of 1.6 x 10⁶ conidia mL^-1. Ergot severity was measured at milk stage. Bartlett's test was performed to determine homogeneity of variances among years. The results showed variability in susceptibility to ergot among genotypes at a single planting date, at planting dates within a year, locations and years. Ergot severity was statistically greater in 2002 in both hybrids and A-lines. Celaya had the greatest amount of ergot on hybrids, followed by College Station and Rio Bravo. In general, A-lines had the greatest severity. ATx2752 had the lowest ergot severity (22.8%), while ATx635 and ATx623, had 27.4% and 36.2%, respectively. Sorghum hybrid AP2233 was the most susceptible, and NC+8R18 showed the least amount of ergot severity.

Palavras-chave : Ergot, hybrids; male-sterile lines.

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