The effect of salicylic acid on winter crop production of new potato cultivars (Solanum tuberosum L.) in different planting dates in Ahvaz

Autumn cultivation of potato plant is very important because of meeting domestic needs of the country in winter and reducing the price of this product in the market. Cold stress in the early stages of potato growth is the most important factor that limits potato production in these areas.The yield and chemical composition of potato tubers under winter planting date and salicylic acid foliar application in Khuzestan region are very importance because one of the problems in cultivation of potato under Khuzestan conditions is insufficient growth due to dealing with high temperature at the end of the growing season in the autumn cultivation. Because few studies have been done in this regard on new cultivars of potato plant. Therefore, this experiment was performed to investigate of the tuber yield and attributes of tuber yield in potato plant.

The current study was conducted in a split-split plot based on randomized complete block design with three replication in the experimental farm of the Department of Plant Genetics and Production Engineering, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran, during the crop year 2020-21. The experimental factors in this research include the date of cultivation as the main plot in three levels (25 November, 9 December, 26 December), salicylic acid foliar application as a sub-plot in two levels (0.5 mM and non-foliar application) and cultivars as sub-sub plot at three levels (including early and new cultivars Sifra, Challenger and Columba).

According to the results of this experiment, the three-way interaction effects of investigated factors on tuber yield and attributes of tuber yield, the number of tubers more than 100 g, number of tubers between 50-100 g and number of tubers less than 50 g was significant. The interaction effects of planting date × salicylic acid foliar application and planting date × cultivar on plant height trait was significant, also the interaction effect of salicylic acid foliar application × cultivar was significant for the starch percentage trait and the simple effect of planting date and cultivar on the SPAD value trait was significant. In the following, the results of three-way interaction effects of the studied factors showed that the highest number of tubers more than 100 g in Sifra cultivar under 0.5 mM salicylic acid foliar application in 9 December planting date (with an average of 4.33 tubers per 1 kg), the highest number of tubers between 50-100 g related to the Challenger cultivar with 0.5 mM salicylic acid foliar spraying under 9 December planting date (with an average of 8.33 tubers per 1 kg), the highest number of tubers less than 50 g related to the Challenger cultivar under 26 December planting date and non-foliar application of salicylic acid (with an average of 33.33 tubers per 1 kg) and the highest tuber yield (with an average of 2.368 kg /m2) was related to the Sifra cultivar with 0.5 mM salicylic acid foliar application in the 9 December planting date. In addition, the highest amount of SPAD value belonged to the 25 November planting date (with an average of 42.61) and the Challenger cultivar (with an average of 42.41). Sifra cultivar also showed the highest starch percentage of tubers under 0.5 mM salicylic acid foliar application (with an average of 46.16%).

Now, due to the lack of potato product in late winter, especially in the southern regions in the Iran, cultivation of early cultivars compatible with the region, such as Sifra on 9 December, in order to achieve optimal yield, and the use of salicylic acid foliar application is suggested in conditions similar to this study.