Genetic Evaluation and Screening of Diverse Wheat Genotypes for Spot Blotch Resistance

Abstract Production of wheat (Triticum aestivum L.) the main food source of South Asian countries including India faces several constraints including spot blotch caused by Bipolaris sorokiniana resulting in yield loss of 25–43 % depending upon the stage of infection. Fifty genotypes were evaluated for nine quantitative characters and area under disease progress curve (AUDPC) to identify superior genotype with spot blotch resistance. High heritability coupled with moderate to high genetic advance as percent of mean was registered for grains per spike, tillers per square meter, days to 50% heading and days to 50% flowering indicating the characters to be governed by additive genes. Correlation and path coefficient analysis favored days to 50% heading, days to 50% flowering and grains per spike since they had significant positive correlation with yield and simultaneous negative correlation with AUDPC and also conferring highest positive direct effect towards yield. Multiple linear regression (MLR) analysis indicated days to 50% heading to be most sensitive with negative influence on AUDPC. D2 analysis grouped the 50 genotypes into 10 clusters suggesting presence of diversity among the genotypes. Frequency distribution of AUDPC among the genotypes showed more or less normal distribution of the character. Low AUDPC score with acceptable level of yield performance were recorded for the genotypes 29882, 29610, 29473, 29940, 29477, 29748 and 30081. Identification of high yielding and less susceptible genotypes for spot blotch disease in the present investigation offered an opportunity for wheat improvement through selective breeding.