Screening of Rapeseed and mustard genotypes against Alternaria blight disease and its development of in the field condition in Assam

D Talukdar; B.C. Das

Volume : IV, Issue : V, May - 2015

Screening of Rapeseed and mustard genotypes against Alternaria blight disease and its development of in the field condition in Assam

D Talukdar, B. C. Das

Abstract :

The study was conducted with the objective to assess the resistance source against Alternaria blight in rapeseedmustard at Instructional cum research farm, AAU, Jorhat , Assam, during Rabi 20012–13 and 2013–14. None of the genotypes was found to be highly resistant against Alternaria blight of rapeseed and mustard. Four genotypes were rated as moderately resistant (MR). Sixteen genotypes were marked as moderately susceptible (MS). The susceptible (S) group comprised of nine genotypes. Control (TS 38) was found highly susceptible (HS) towards blight disease exhibiting the highest disease incidence of 80.56 per cent on leaves and 76.66 per cent on pods. Significant differences on disease development among 30 genotypes of rapeseed and mustard against Alternaria blight were observed for the components (number of spots and spots size on leaves and pods) and time interval. In case of number of spots per leaf, at 80 DAS, lowest number of spots was found in Pusa Mustard 25 (13.40) while at 60 DAS, lowest numbers of spots was found in Pusa Mustard 28 (12.11). Highest number of spots/leaf was 54.56 at 80DAS in TS 38, a highly susceptible variety. In case of number of spots/pod, lowest number of spots was found in NRCDR 601(11.00) at 100 DAS. Again TS 38 got the highest number of spots/pods (39.35) at 100 DAS. Smallest size of spots (mm) on leaves was found at 80 DAS in Pusa Mustard 28 (14.81). Largest size of spots was found in TS 38 with 52.30mm at 80 DAS. In case of pods, smallest spot size was 12.65mm at 100 DAS in Pusa Mustard 27. TS 38 got the largest spot i.e., 41.07mm at 100 DAS.