Manipulation of agronomic practices for tuber-size distribution in potato (Solanum tuberosum) seed crop

Abstract

To improve the production of seed-size tubers in potato (Solanum tuberosum L), 31 experiments were con- ducted during 1999-2003 at nine centres, situated in different agro-climatic regions of the country. Two levels each of planting spacing (60 x 15 and 60 x 10 cm), fertilizer doses (1 00+35+66 and 150+52+66 kg of N+P+Wha respec- tively) and dates of haulm cutting (70 and 80 days after planting) were imposed on popular potato cultivars of the regions. Mean results over the locations indicated that although the yield of seed-size tuber at closer spacing (13.9 t/ha) increased by a 15.7% compared with that at wider spacing, it could not compensate for the improved seed rate of 2.22 to 2.67 t/ha. An increase in fertiliser level gave 1.6 t/ha more total tuber yield (25.3 t/ha), out of which 0.7 t/ha was in seed-size grade. Delay in haulm cutting from 70 to 80 days after planting potato improved the total tuber yield by 4.8 t/ha (21.6%), out of which 1.1 t/ha was in seed-size. Economics of potato cultivation for produci tion of seed size tubers also favoured planting at wider spacing (60 x 15 cm), with higher fertiliser rate (150+52+66 kg of N+P+Wha) and dehaulming at 80 days after planting.