EFFECTS OF PLANTING DENSITY AND DEPTH ON GROWTH AND TUBER YIELD OF POTATO CULTIVAR DIAMANT IN MIANEH

In order to evaluate effects of planting density and depth on growth and yield of potato cultivar Diamant, an experiment was carried out in 1998 in Mianeh located in East Azarbaijan. A factorial experiment with randomized complete block design and three replications was used. Three planting densities 45000, 55000 and 65000 plant ha^ -1 (30, 24 and 20 cm between plants on 75 cm rows, respectively) with four planting depths 5, 10, 15 and 20 cm were used as experimental factors. Tuber yield, plant development and other traits were significantly influenced by planting density. Density of 55000 plant ha^-1, caused longer period of emergence and tuber set, higher stand percentage, higher number of tubers per unit area and tuber yield, compared to the other densities. All of the measured traits were affected by planting depth. Stand percentage, number of stems per plant and per unit area, main stem length and percentage of tuber lost were decreased as planting depth increased. Number of days to emergence, tuber set and flowring increased with increasing planting depth from 5 to 10 cm and from 10 to 15 cm, then decreased from 15 to 20 cm. Planting density and planting depth intraction significantly affected the number of days from planting to flowering. The earliest date of flowering was occurred with density of 65000 plant ha^ -1 planting depth of 15 cm and the latest with 45000 plant ha -1 at depth of 5 cm.