Assessment of genetic variability in mustard against alternaria leaf spot disease through natural field conditions

The research was conducted for the source of resistance against Alternaria leaf spot disease of brassica. In the current research, ten varieties/ advanced lines were evaluated in 2016-17 and 2017-18 against this disease using Randomized Complete Block Design (RCBD) at the experimental research area of Oilseeds Research Institute, Ayub Agricultural Research Institute Faisalabad. During 2016, three advanced lines (RBN-13017, RBN-13022 and RBN-13029) exhibited moderately resistant response with 22.33%, 18.42% and 13.76% disease incidence respectively under rating 2 whereas two advanced lines namely KN-294 (34.56%) and 14CBN009 (42.99%) expressed a moderately susceptible response (rating 3). Similarly, four advanced lines/ varieties showed susceptible response with (66.54%), (54.28%), (64.77%) and (60.12) percent disease incidence while KJ-159 was used as spreader that expressed highly susceptible response with 92.14 % disease incidence. During 2017-18 four varieties/ advanced lines namely KN-279, 14CBN001, Faisal Canola and Rohi Sarson exhibited susceptible response with (68.84%), (56.38%), (66.97%) and (58.22) percent disease incidence (rating 4) whereas two advanced lines such as KN-294 (31.86%) and 14CBN009 (40.09%) showed moderately susceptible response (rating 3). Likewise, three advanced lines exhibited moderately resistant response with 24.63%, 19.82% and 12.06% disease incidence respectively under rating 2. It was concluded that source of resistance is the most economical management strategy for the farmers against Alternaria Leaf Spot Disease of brassica.