Effect of planting depth and hilling practices on total, U.S. No. 1, and field greening tuber yields

Previous research suggests that field greening of potato tubers can be minimized by planting seedpieces at an appropriate depth along with sufficient hilling to minimize exposure to sunlight. The appropriate planting depth and hilling practices to minimize field tuber greening have not been determined for newer cultivars. Two separate studies, each conducted for three years, are reported here. The first measured the effect of seedpiece planting depth on the yield, quality, and field greening tuber yield of ‘Russet Burbank’, ‘Frontier Russet’, and ‘Shepody’ potatoes. Seedpieces were handplanted in pre-formed hills at 8, 15, or 23 cm measured from the top of the seedpiece to the top of the hill. Planting at 23 cm resulted in significantly lower total yield compared with the 8- and 15-cm depths for Russet Burbank and Frontier Russet, but planting depth did not affect total yield of Shepody. U.S. No. 1 yield of Russet Burbank was not affected by planting depth, but U.S. No. 1 yield of Frontier Russet was significantly less at the 23-cm depth. For Shepody, the 8-cm depth caused a significant reduction in U.S. No. 1 yield compared with the 15-cm depth. Field greening tuber yield of Russet Burbank was significantly less at the 23-cm planting depth compared to 8 cm. For Frontier Russet and Shepody, planting at 15 or 23 cm resulted in significantly less field tuber greening compared to the 8-cm depth. The second experiment examined the effects of planting depth and hilling practices on yield, quality, and field tuber greening of Russet Burbank and Gem Russet potatoes. Six planting depth and hilling treatment combinations were used. Seedpieces were planted at a depth of either 8 or 15 cm, then hilled to either 15 or 23 cm at emergence or after plants had formed a rosette of leaves approximately 10 cm in diameter (post-emergence hilling). At-emergence hilling treatments had no effect on total or U.S. No. 1 yields of Russet Burbank compared with the 15-cm planting depth, non-hilled control. However, all post-emergence hilling treatments significantly reduced Russet Burbank total and U.S. No. 1 yields. Planting Russet Burbank at 8 cm and hilling to 23 cm at emergence, or planting at 8 or 15 cm and hilling to 23 cm post-emergence reduced field tuber greening of Russet Burbank. The effects of planting depth and hilling on Gem Russet total and U.S. No. 1 yields were less definitive than for Russet Burbank, and no treatments significantly reduced field tuber greening yield compared with the control.