Screening of Selected Canola Cultivars for Yield and Tolerance against Mustard Aphid, Lipaphis erysimi Kalt. (Hemiptera: Aphididae).

Canola (Brassica napus L.) is one of the economically important crops of Pakistan and mustard aphid, Lipaphis erysimi Kalt. (Hemiptera: Aphididae), is a serious threat to this crop. This experiment was conducted with an aim to screen out selected canola cultivars for their tolerance against L. erysimi infestation under glasshouse conditions. Experiment was carried out using completely randomized design with ten replications for each treatment during growing seasons of 2018 and 2019. Data were documented based on the tolerance indices (TI) and proportional plant dry weight change (DWT) to identify tolerance of canola crop. Results revealed that commercial cultivar 'Zahoor' comparatively performed well despite higher number of aphids found on itas compared its other counterparts "Abaseen, Omega and KS-75" and hence, was identified as tolerant to mustard aphid. This cultivar also exhibited strong vigor against mustard aphid and minimal symptoms of damages were observed. The yield losses based on DWT and TI in susceptible cultivar "Abaseen" was 40.79%, whereas it was 23.56% in Zahoor which confirmed the reduced percent yield losses in the later genotype. This study identified "Zahoor" as the most tolerant cultivar to mustard aphid followed by KS-75 and Omega hence, other susceptible cultivars should be replaced by Zahoor to attain higher and sustainable yield production in canola. [ABSTRACT FROM AUTHOR]