Singh, DhirendraPamei, Chungong2018-09-052018-09-052015-06http://krishikosh.egranth.ac.in/handle/1/5810071971The present investigation was undertaken at Vegetable Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand), to evaluate the effect of photoperiod on potato during rabi season of 2013-2014. The experiment material consisted of 17 genotypes, 3 checks and two photoperiods (P1- Normal Photoperiod and P2- Extended Photoperiod) grown in Two Factorial Randomized Block Design to determine the best genotypes, suitable photoperiod and their interaction. Between the two photoperiod conditions, extended photoperiod found better for seedling, plant height, leaves per shoot, shoot per plant, tuber width, tuber length, tubers number per plant, average tuber weight, average tuber weight per plant, dry matter content at 0 days after storage (0 DAS), dry matter content at 90 DAS, specific gravity at 0 DAS, specific gravity at 90 DAS, TSS at 0 DAS, TSS at 90 DAS, protein content at 0 DAS, protein content at 90 DAS, ascorbic acid content at 0 DAS, ascorbic acid content at 90 DAS and tuber yield per m2 whereas the physiological weight loss and total weight loss was less for extended photo period condition. Among all genotypes C-17 produced significantly higher tuber weight per plant and Kufri Pukhraj produced significantly more number of tubers per plant. Genotype MM-7 performed better for tuber weight per plant. Tuber yield per m2 was recorded maximum in PNT-1 followed by B-420 and Kufri Pukhraj. Among all the forty interactions, PNT-1 (Extended Photoperiod) produce higher tuber yield per m2. Correlation studies indicated that tuber length viz., 0.451 and tuber weight viz., 0.765 showed highly significant and positive correlation with tuber weight per plant in P1 and P2 respectively. It also showed negative and significant correlation with physiological weight loss (-0.288) in P2. In normal photoperiod, Path Coefficient Analysis revealed that tuber length exerted high order of positive direct effect (0.473) toward tuber weight per plant followed by TSS at 90 DAS (0.375). However, specific gravity at 90 DAS (-0.566) and total weight loss (- 0.270) exerted negative direct effect towards tuber weight per plant, whereas under extended photoperiod, average tuber weight (0.357) exerted high order of positive direct effect towards tuber weight per plant followed by total weight loss (0.355) and plant height (-0.271), exerted negative direct effect towards tuber weight per plant.ennullThesis