Marker assisted gene introgression in to common bean (Phaseolus vulgaris l) against angular leaf spot (Pseudosercospora griseola) and anthracnose (Colletotrichum lindemuthianum)

Angular leaf spot (ALS) and Anthracnose (ANT) are important diseases of common bean in Ethiopia. This study was conducted to pyramid resistant genes for ALS and ANT diseases into advanced line and to evaluate isolines against ALS and ANT using marker assisted selection in combination with phenotypic selection. The parent AND277 donor of Phg-1 and Co-14 genes for ALS and ANT respectively and the recipient KT-ABC001 line was used for this experiment. In genotypic selection, SSR and SCAR marker were used. Marker assisted backcrossing procedure was adopted and inheritances for resistant genes were characterized by using F2 and backcrosses. The Chi-square values showed no significant differences for ALS and ANT, 0.05 (p<0.78) and 0.03 (p<0.9) in genotypic and phenotypic selection respectively. The narrow sense heritability for ALS and ANT were 0.97 and 0.95 implying that selection for ALS and ANT can be done at early stage in a segregating population. Correlation values for ALS (r = -0.65) and for ANT (r = -0.73) were obtained between phenotypic and molecular data respectively. Eight gene pyramid groups were developed and evaluated against ALS and ANT. The gene pyramid group means were significantly different from each other (p<0.01) of which, Phg1+phg2+co14+cbb qtl and Phg-1+co-14+cbb QTL exhibited the lowest mean disease score to the three pathogens indicating both a high degree and a broad spectrum of resistance. The study identified three isolines with all four desirable genes. In general, pyramiding multiple genes for durable resistance using MAS in combination with phenotypic selection is invaluable for breeding program.