ANTHRACNOSE RESISTANCE IN STEM AND LEAVES OF COMMON BEAN IS CONFERRED BY ASSOCIATION OF DOMINANT AND RECESSIVE GENES

摘要

Anthracnose, caused by the ascomycete Colletotrichum lindemuthianum (Sacc. & Magn.) Lams-Scrib., is one of the most important diseases of the common bean (Phaseolus vulgaris L.) in Brazil and in other bean growing regions of the world. Typical symptoms of common bean anthracnose are observed in the leaf and in pods. However, if the environment favors the development of fungus, injuries in the stem can also be observed. This may weaken the stem and impair its capacity to support the plant. Differential symptoms in leaves and stem were observed in segregating populations derived from backcrosses involving common bean Brazilian cultivar AN 910408 (Carioca x [carioca (Rio Tibagi x Guanajuato 31)]), resistant to races 64, 67, 73 and 83 of C. lindemuthianum, with susceptible recurrent parent cultivar Ruda. This led to the hypothesis that different genes might be involved in resistance in leaves and stem. Thus, this work aimed to study the genetic mechanisms of the resistance in the leaf and stem in segregating populations from backcrosses involving resistant cultivar AN 910408 and susceptible cultivar Ruda.