Maximization of Seed Size Tubers in Potato through Manipulation of Intra Row Spacing, Nitrogen Levels and Crop Duration under Irrigated Condition in Indo –Gangetic Plains of Bihar

Afield experiment was conducted during winter season (Oct-Feb) of 2013-14 and 2014-15 with four replications and eight treatments to produce maximum yield of seed size tubers of potato cultivar, “Kufri Pukhraj” by interaction of two nitrogen levels (120 and 150 kg N/ha), two intra row spacing (15 and 20cm), and two crop duration(haulm cutting at 70 and 80 days after planting). The narrow intra row spacing i.e. 15 cm, produced significantly higher yield of seed size grade tubers while wide spacing i.e. 20 cm produced higher yield of large grade tubers. The total tuber yield and tuber number was significantly more in closer spacing. Percent production of seed size tubers to total tubers (both on weight as well as number basis) was higher at narrow spacing. Haulm cutting at 80 days after planting produced significantly higher yield of large grade tuber, while haulm cutting at 70 days after planting, produced significantly higher yield of seed size grades tubers. The total tuber number and tuber yield was significantly higher in haulm cutting at 80 days after planting. Lowest total tuber yield and number was observed in wider spacing with lower nitrogen level and shorter duration. Per cent production (both on weight as well as number basis) of seed size tubers to the total tuber was significantly higher at 60 x 15 cm with 120 kg N /ha and longer crop duration. Plant spacing of 60 x 15 cm with higher fertility levels and shorter crop duration (70 day) was found to be second best treatment in terms of production of seed size tuber.