ABSTRACT


Mario Alvarez A.1
 
Detached F1, F2 and RC1, primary leaves of bean plants obtained from crosses between the Chilean susceptible varieties Cristal Bayo, Cristal Blanco, Coscorrom and Tortola with foreing resistant varieties as U.S. 5 Refugee, Topcrop, Idaho Refugee and Wisconsin Refugee were mechanically inoculated with bean common mosaic virus (BCMV) and placed in a moist chamber under constant light and a temperature of 29-32ºC. As control, detached leaves of the eight parental varieties were inoculated. Symptoms were recorded three and seven days after the inoculation. Resistant controls reacted with veinal necrosis. Hybrid plants with leaves reacting with veinal necrosis upon inoculations were considered genetically similar to these varieties in relation to their resistance to BCMV. Inoculated leaves of the Chilean varieties remained normal. Thus, those plants that did not react with veinal necrosis were considered susceptible.
All F1 plants reacted with necrosis, demostrating that hypersensibility is dominantover susceptibility. A proportion of 3 : 1 and 1 : 1 hypersensitive and susceptibleplants was established in the F2 and RC1 generations respectively, indicating thepresence of one pair of genes, which differentiates the varieties derived of CorbettRefugee from the Chilean susceptible varieties. The efficiency of inoculating detachedcotyledonary leaves of bean plants when screening for resistant material tothe virus was also demonstrated.
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1Ing. Agr., Ph. D., Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias (INIA), Casilla 5427, Santiago, Chile.