FIELD PERFORMANCE OF TRUE POTATO SEED TUBERLETS AS INFLUENCED BY SIZE AND HARVESTING PERIOD

A field experiment was conducted in the research field of Sher-e-Bangla Agricultural University, Dhaka, during the period from November 2012 to April 2013 to investigate the effect of seed tuber size and harvesting time on morpho-physiological characters, yield attributes and yield of potato. The experiment comprised of four different size of seed tubers, viz., 28-<45 mm, 20-<28 mm,    10-<20 mm and <10 mm and four harvesting time, viz., 70 days after planting (DAP), 80 DAP, 90 DAP and 100 DAP. The experiment was laid out in randomized complete block design factorial with three replications. The growth parameters such as stems hill^-1, leaves hill^-1, tuber yield plot^-1, marketable yield plot^-1 and tuber yield ha^-1 were significantly influenced by the seed tuber size and harvesting time. Results revealed that in general, plant height, stems hill^-1 increased with increasing seed tuber size but yield attributes and yield increased with 28-<45 mm  tuber size. The highest tuber yield hectare was recorded on the tuber size of 28-<45 mm due to increase of tubers hill^-1 and tuber yield plot^-1. In contrast, the lowest tuber yield ha^-1 was recorded in the smaller seed tuber of <10 mm. Results showed that stems and leaves hill^-1 and tubers hill^-1, single tuber weight and tuber weight plot^-1 increased with increasing time of harvest upto 90 DAP. The highest number of stems and leaves hill^-1, tubers hill^-1, single tuber weight and tuber weight plot^-1 were observed in the harvesting time 90 DAP and the lowest in harvesting time 70 DAP. However, the highest gross tuber yield ha^-1 was observed in the harvesting time 90 DAP and the lowest was recorded in 70 DAP. For combined effect of seed tuber size and harvesting time, the highest gross tuber yield was observed in the treatment combination of 20-<28 mm seed tuber with the harvesting time of 90 DAP which was economically adventitious.