Phenotypic and genotypic responses of chili (Capsicum annuum L.) progressive lines with different resistant genes against anthracnose pathogen (Colletotrichum spp.)

摘要

Anthracnose disease caused by Colletotrichum spp. is a serious disease of chili (Capsicum annuum), particularly in tropical countries. Host plant resistance breeding is one of the most effective disease management strategies. It requires identification of parents with genes resistant to Colletotrichum species predominant in a given region. For phenotypic evaluation, 35 chili lines consisting of progressive lines of C. annuum derived from C. baccatum PBC80 (34 lines) and from C. chinense PBC932 (one line) were inoculated with two aggressive isolates of Colletotrichum acutatum (Ca) and C. capsici (Cc) by injection into the pericarp of green and red-ripe fruit. Lesion diameters were scored at seven days after inoculation. Two simple sequence repeat (SSR) and one sequence characterized amplified region (SCAR) markers were used for validation in four progressive lines and three each of susceptible and resistant checks for genotypic response. The progressive lines were classified into 10 groups based on their responses to two pathogens and at the two fruit stages. Four progressive lines (101, 205, 210 and 215) were selected and used for developing crosses to combine resistance genes from two sources resistant to Ca and Cc at both fruit stages. Progressive lines derived from PBC80 showed DNA fragment 231 bp amplified by primer HpmsE032 associated with Cc at green fruit stages. Hence the HpmsE032 marker could be considered useful in the selection of resistant genotypes derived from PBC80.