Effect of Planting Date and Application of Anti-Freeze on Tuber Yield and Some Physiological Traits of Potato Cultivars in Autumn Planting in Jiroft Region of Iran

Cold stress is the important factor that reduces yield of fall planting potatoes in sub-tropical regions of southern Iran. Therefore، to assess the possibility of reducing damage of cold stress a field experiment was conducted in 2010-2011 in Agricultural Research Center of Jiroft in southern part of Iran. Experimental design was strip factorial arrangement in randomized complete block design with three replications. Experimental treatments included planting dates (11 September، 21 September، 01 October and 11 October)، and potato cultivars (Santé، Ramose، Oceania and Arinda)، and anti-freeze (application and no application). During growing season physiological traits including leaf area index، tuber dry matter، proline accumulation and tuber yield were measured and recorded. Results showed that the effects of planting date، genotypes and anti-freeze and their interactions were significant (p < 0. 01) on physiological traits. Maximum tuber dry matter (18%) was observed in third planting date in Santé with anti-freeze application. Anti-freeze increased dry matter by 1. 2%. The highest accumulation of proline was observed in third planting date in Ramose and application of anti-freeze which increased proline accumulation by 19. 5%. Maximum LAI (4. 47) was also observed in first planting date in Arinda and anti-freeze application which was 16. 7% greater than non-anti-freeze treatment. The highest tuber yield (26. 7 t ha-1) was obtained for Sante with application of anti-freeze in the second planting date، and the lowest tuber yield (6. 2 t ha-1) for Ramose in first planting date and no application of anti-freeze. In conclusion the risk of chilling and freezing stress damages can be reduced with second planting date، Santé cultivar and anti-freeze application.