CHARACTERIZATION OF RESISTANCE RESPONSE OF GARDEN PEA (Pisum sativum L.) AGAINST POWDERY MILDEW (Erysiphe pisi DC) IN SUB-TROPICAL PLAINS OF INDIA

In field conditions, the level of plant responsiveness to powdery mildew under severe disease incidence was assessed during reproductive phase of the crop and expressed as Percentage Disease Index (PDI) and Disease Incidence (DI). For PDI severity index, 26.7% genotypes were observed to be resistant (21 highly resistant and 6 resistant) whereas, 9.9% were tolerant to powdery mildew pathogen. The results of PDI were highly correlated with obtained DI values (r = 0.95; P < 0.01). The genotypes VRPMR-9, VRPMR-11, Punjab-89, PMR-62 along with 17 other genotypes were found to be immune while maximum disease incidence was observed in genotype IC-36 (PDI = 87.3%). In the detached leaf assay, plants were evaluated for days to pustule formation. Detached leaf and field results were comparable except for genotypes JP-15, JP-501A/2, JP-825, Arka Ajit, VP-233 and Vasundhra. There was a highly significant and positive correlation between laboratory (detached leaf assay) and field condition results for powdery mildew resistance in garden pea (r = 0.83; P < 0.05) on the basis of PDI values. The overall results show the utility of detached leaf assay for screening garden pea for powdery mildew resistance. No disease reaction or slow disease development of powdery mildew in number of garden pea genotypes proved their potential for resistance breeding.