Alternaria blight severity as influenced by meteorological parameters in mustard cultivars

A field experiment was conducted to study the effect of meteorological parameters on Alternaria blight severity at Punjab Agricultural University, Ludhiana. Mustard was cultivated with three dates of sowing (10^th October, 5^th November, 1^st December) and two mustard cultivars (RLC-3 and PBR-357) replicated thrice under split plot design during rabi 2017–18. Alternaria blight severity was observed at weekly intervals randomly from ten plants per plot under different treatments. The late sown crop showed higher disease severity (44.2 & 51.5%) followed by normal (39.7 & 45.5%) and late sown crop (31.5 & 40.0%) in mustard cultivars RLC-3 and PBR-357, respectively. Area under disease progress curve (AUDPC) was highest in late sowing (162) followed by normal (148) and early (126) sowing. Among cultivars, PBR-357 showed more AUDPC (162) as compared to RLC-3 (135). It was observed that the maximum, minimum temperature and sunshine hours showed a significant positive correlation with disease severity. While morning relative humidity had a significant negative correlation with disease severity. The R² value explained the percent variability in disease severity due to different meteorological parameters. The R² value was observed in the range of 0.84 to 0.96 indicating that most of the meteorological parameters contributed significantly in Alternaria blight severity.