Studies on the resistance of some Australasian chickpeas (Cicer arietinum L.) to Phytophthora root rot disease.
Australian Journal of Crop Science ; 2013 [Vol.6] Pages:-
Abstract
Phytophthora root rot (PRR) is a disease of chickpea (Cicer arietinum L.) caused by the Phytophthora megasperma Drechs. f. sp. medicaginis (Pmm). It is the most serious disease for this crop in Australia because there is no strong resistance exists in current cultivars. Therefore, it is vitally important to identify the new source of resistance for the improvement of chickpea cultivars. A range of chickpea genotypes were evaluated in this study to identify sources of resistance to this disease. Three Australian chickpea varieties (Jimbour, Flipper, and Yorker) were used to assess the pathogenicity of 4 Pmm isolates (4019, 4021, 4027, and 4046). The most aggressive pathogenic isolate 4027 and a mixture of two other isolates were selected to assess the resistance of 16 international and Australian chickpea genotypes to PRR. The general score (GS) (0.5 × plant infection rate+0.5 × plant death rate) was used in this study to indicate the severity of the disease. According to the GS value derived from the most aggressive isolate 4027, 4 genotypes (FLIP97-114C, ICCV 05111, ICCV 98818, and ICCV 96852) were considered resistant with a GS of 3.9-4.4, 3 genotypes (Bumper, ICCV 98801, and Yorker) were classified as moderately to resistant with a GS of 4.7-4.9, and the rest of them were susceptible with GS scores above 5.8. The large variation in pathogenicity observed for these isolates suggested that the 4 Pmm isolates represented different pathogen strains. Significant differences in plant infection rate, plant death rate, and disease development were observed among the chickpea genotypes. These findings indicated that the basis of resistance differed among the chickpea genotypes evaluated. The PRR resistance in chickpea is a multi-gene controlled trait. These resistant genotypes provided different sources of resistance and could be combined in breeding program to produce durable and high level of resistant cultivars.
Full Text