Effect of whole seed tubers, cut seed and within row spacing on potato (cv. Sebago) tuber yield

Abstract

Whole seed potato tubers in the size ranges 35-100 g, 101-150 g and 35-150 g were compared with cut seed and a mixed run grade of both whole 35-100 g tubers and cut seed, at within row spacings of 25 and 33.3 cm in rows 81.3 cm wide, at Healesville, Ballarat and Warragul districts in 1986-87 and 1987-88. Whole 35-250 g tubers and 40 cm within row spacing were also included in experiments at Healesville during the 2 seasons. The mean total tuber yield from planting whole 35-150 g tubers (47.9 t/ha) was significantly higher than from planting Run grade seed [44.9 t/ha, 1.s.d. (P=0.05)=2.0]. Yields of 35-100 g and 101-150 g tubers were also significantly higher with plantings of whole seed compared with Cut or Run seed. The mean yield of tubers >250 g was significantly higher from planting Run grade seed (12.0 t/ha) than whole 35-150 g tubers [9.7 t/ha, 1.s.d. (P=0.05)=1.8]. Increasing the within row spacing from 25 to 33.3 or 40 cm significantly increased the yield of tubers >250 g and significantly reduced the yield of 101-150 g tubers. The effect on yield of 35-100 g, 151-250 g tubers and total tuber yield was variable. The mean multiplication rate (total yield/seed planting rate) from plantings of 101-150 g whole seed was significantly lower than from plantings of Cut and Run seed but was increased significantly with plantings of whole 35-100 g seed. Increasing the within row spacing significantly increased the multiplication rate and values from 1 environment were 17.2 at 25 cm, 22.2 at 33.3 cm and 24.6 at 40 cm [l.s.d. (P=0.05)=1.5]. The mean number of tubers per plant was significantly higher from plantings of whole seed (8.0-9.1) than from Cut or Run grade seed [6.8-7.1, 1.s.d. (P=0.05)=0.4] and was increased significantly by increasing the within row spacings from 25 to 33.3 or 40 cm.