Single plant selection for improving root rot disease (Phytophthora medicaginis) resistance in Chickpeas (Cicer arietinum L.)

The root rot caused by Phytophthora medicaginis is a major disease of chickpea in Australia. Grain yield loss of 50 to 70% due to the disease was noted in the farmers’ fields and in the experimental plots, respectively. To overcome the problem, resistant single plants were selected from the National Chickpea Multi Environment Trials (NCMET)—Stage 3 (S3) of NCMET-S1 to S3, which were conducted in an artificially infected phytophthora screening field nursery in the Hermitage Research Station, Queensland. The inheritance of resistance of these selected resistant single plants were tested in the next generation in three different trials, (1) at seedling stage in a shade house during the off-season, (2) as bulked single plants and (3) as individual single plants in the disease screening filed nursery during the next season. The results of the tests showed that many of the selected single plants had higher level of resistance and seed yield (P < 0.05) than the best resistant cultivars used as checks. The single plants with bidirectional expression of anthocyanin pigment, both at the shoot apex and at the base of stem, showed higher level of resistance than plants without it. The results also indicated certain level of heterozygosity-induced heterogeneity, which could cause higher levels of susceptibility, if the selected single plants were not screened further for the disease resistance in advanced generation/s. The genetics of resistance to PRR disease was confirmed as quantitative in nature