بررسی اثر تاریخ کاشت بر عملکرد و اجزای عملکرد ارقام سیب‌زمینی تحت تاثیر یخ‌بندان در شرایط مزرعه

Frost occurrence during plant growth created special conditions to evaluate the effects of planting date . on yield and yield components of potato cultivars as influenced by frost in field conditions in this reasearch. A split-plot experiment with three replications was used to compare three planting dates, as main plot, from 1 to 21 December with 10 day intervals and four cultivars (Sante, Savalan, Santana and Elmera) as sub plot for one year ( 2011-2012) at Behbahan Agriculture Research Station. The treatments were arranged in a randomized complete block design. When frost occurred, the phonological stages of plants in planting dates of 1 and 11 Dec. were vegetative growth and tuber initiation stages respectively, so that all haulms were killed. However plants in planting date of 21 Dec. didn’t emerge. One week before harvesting haulms were defoliated. Tubers were harvested at mid-May. The comparison characteristics of . treatments showed that frost caused total and marketable yield, mean tuber weight of 1 and 11 Dec. planting dates were lower than 21 Dec. planting date at 1% statistical probability level, However the effect of frost on mean tuber number and tuber dry matter content was not significant. In regard to results, Planting of winter potato should be avoided before late December in Khuzestan province to minimize the risk of yield damaged by frost and Savalan cultivar is recommended for winter potato planting in this province.