REACTION OF Phaseolus sp. GERMPLASM TO Macrophomina phaseolina

Abstract

During 1996 and 1997, the reaction of 166 common bean genotypes, most of them cultivated, and 237 Phaseolus sp. genotypes, mainly landraces and wild populations from different origins to a highly aggressive isolate of Macrophomina phaseolina was determined under greenhouse conditions at Montecillo, México. Landraces, bred genotypes and wild populations of Phaseolus sp. were identified as resistant to M. phaseolina. Among the resistant genotypes stood out Amarillo de Calpan, Manzano, Negro Perla, G 4523, BAT 477, Bayo Zacatecas, Pastilla de Teocaltiche, "Ballacote" (P. coccineus) from San Francisco, Querétaro, Bayo Baranda, PT 91084, MUS 133, Michoacán 9-1-A, one accession from Villa Las Rosas, Chiapas, two from Teopisca, Chiapas, one from Pabellón, Aguascalientes, and G 12201. A negative correlation between disease severity caused by M. phaseolina and above-ground biomass was found. Associations between reaction to the pathogen and geographical adaptation, race or genetic status of germplasm were not clear. However, most resistant genotypes to M. phaseolina belong to the Mesoamérica race, while most susceptible genotypes
were detected in germplasm from Jalisco and Durango races.