Effect of Planting Date on Total and Marketable Yield of Potato Cultivars in Khuzestan Province in Iran

A field experiment was carried out to determine the interactions of cultivar planting date on total and marketable yields of potato. cvs. Cosima، Sante، Savalan، Santana and Almera، were planted in four planting dates، 22 December)mean daily air temperature was 16 and 14. 1 ºC in the first and second year of experiment، respectively)، 01 January)mean daily air temperature was 16. 5 ºC in both year of experiment)، 11 January)mean daily air temperatures were 10 and 17. 3 ºC in the first and second year of experiment، respectively) and 21 January)mean daily air temperature was 11. 5 and 4. 4 ºC in the first and second year of experiment، respectively) in two years (2009-2010 and 2010-2011) in Behbahan Agriculture Research Station، Khuzestan، Iran. A split-plot arrangement with four planting dates as main plots and five cultivars as sub plots in randomized block design with three replications was used. One week before harvesting haulms were defoliated. Tubers were harvestd in mid May. The longest duration period between planting date and 50% emergence (51. 83 days) belonged to planting date of 22 December. By delaying planting date، days to 50% emergence decreased at 1% probability level. Effect of planting date on total and marketable yield، yield components and tuber dry matter (%) was not significant. Cosima produced the highest stem number plant-1 (3. 34) and tuber number plant-1 (7. 15). The highest tuber weight (64. 04 g) and tuber dry matter (22. 26%) belonged to Santana and Savalan، respectively. Planting date × cultivar interaction effect on total and marketable yield was significant. The marketable yield of Savalan was higher than the other cultivars in most of planting dates. Results of this experiment showed that planting of Savalan on 22 January is recommended for winter season potato planting in Khouzestan Province.