GENETIC-CONTROL OF THE FUNGUS COLLETOTRICHUM-LINDEMUTHIANUM (SACC. AND MAGN.) SCRIB. REACTION AND CORONA COLOR IN THE COMMON BEAN (PHASEOLUS-VULGARIS L.)

An important trait for common bean (Phaseolus vulgaris L.) cultivars w ith Carioca type grain is resistance to Colletotrichum lindemuthianum, which causes anthracnose and a pale corona. The present study was con ducted to understand the genetic control of common bean reaction to th e fungus and of the corona color, to provide guides to future breeding studies. Genotypes P-45, with brown corona, and EMGOPA 201-Ouro, with yellow corona, are resistant to C. lindemuthianum. Cultivar Carioca i s susceptible to anthracnose, but it has desirable grain and corona co lor. Anthracnose resistance and corona color were studied in the F-1 a nd F-2 generations of three populations resulting from crosses of P-45 , EMGOPA 201-Ouro, and Carioca. The Carioca x P-45 cross indicated tha t the Mex.2 allele, which conditions resistance to the pathogen, is li nked with a recombination frequency of 0.0604 +/- 0.0232 to one of the alleles which determines the dark brown corona color. The EMGOPA 201- Ouro x Carioca cross revealed that the resistance allele of EMGOPA 201 -Ouro was independent from the alleles which determine the yellow coro na. These resistance alleles were also determined to be independent ac cording to EMGOPA 201-Ouro x P-45 cross results.