Effect of Age of Seedlings and Irrigation on Mortality, Bolting, Bulb Weight and Yield of Onion (Allium cepa L.)

An on-farm study was carried out at six farmers’ field in Roopnagar (Punjab) district during rabi 2010–11 to determine the effect of age of seedlings and lag period to first irrigation on yield, seedling mortality rate, bolting and bulb weight of onion (Allium cepa L.) var. Punjab-Naroya. The trial was conducted in randomized block design. The treatments consisted of transplanting 45 and 60 days old seedlings and application of first irrigation; immediately after transplanting, 2 days after transplanting and 4 days after transplanting. The results showed that seedling mortality rate increased significantly with delay in first irrigation after transplanting and the highest seedling mortality rate was recorded in plots irrigated at 4 days after transplanting irrespective of age of seedlings. Bolting was more in the treatments having 60 days old seedlings as compared to the 45 days old seedlings. However, the effect of different time lags of first irrigation on onion bolting was non-significant. No significant effect of age of seedlings and different lags of first irrigation on bulb weight was observed among all the treatments. The highest yield (326.0 q/ha.) was recorded in fields with 45 days old seedlings irrigated immediately after transplanting while it was the lowest (227.3 q/ha) in the plots having 60 days old seedling irrigated after four days of transplanting. Thus, it was concluded that transplanting of 45 days old seedling of onion crop and applying irrigation immediately after transplanting helps in reducing bolting, seedling mortality and results in significantly higher economic yield.