Effect of sowing depth on qualitative characteristics tuber yield and water use efficiency of potato cultivars in autumn and spring cultivations of moderate and cold regions

The scientifically named potato (Solanum tuberosum L.) is one of the most important agricultural products in the world that belongs to the Solanaceae family, an autotetraploid plant (2n=4x=48), with complex inheritance patterns and in terms of nutritional importance, it ranks fourth after wheat, rice and maize and plays an important role in the nutrition and food basket of the global population. This research aims of this study was to investigate the effect of planting date and planting depth on some quality traits, glandular function and water use efficiency of potato cultivars in autumn and spring cultivation of temperate cold region in Araloo Agricultural Research and Natural Resources Station farm in Ardabil region for 2 years (2017-2018).

Split-factorial experiment based on complete randomized block design in three replications of planting date at three levels (10 Novomber, 10 December and 10 May)  as the main factor and factor combination of four potato cultivars (Sprite, Marfona, Savalan and Agria) And four planting planting depths (10, 15, 20 and 25 cm) were considered as a secondary factor. After performing the normality of the data and the experimental error uniformity of the compound analysis based on the statistical factor design and comparing the mean based on the LSD test at 5% probability level by SAS9.1 software and correlation between traits using Minitab.16 software. And the graphs were drawn with Excel software.

The results of analysis of variance of the evaluated traits showed that the simple effect of planting date (gland function and water use efficiency) and simple effect of planting depth (nitrogen content, fiber percentage and soluble sugars) had a statistically significant difference between 5 and 1% probability. In terms of the quadrilateral effect A×B×C×D, the traits (percentage of dry matter and soluble sugars) had a significant difference. Water Use efficiency was higher in November and December planting at depths of 10, 15 and 25 with the number of sprays with water efficiency of 6 (kg/m3).The average yield of the tuber in Marfona cultivar was 30 tons per hectare in May and 24 tons per hectare in November cultivation and 20 tons per hectare in December cultivation.The difference in glandular function between spring and autumn planting was on average 8 tons per hectare. Meanwhile, in the autumn cultivation, about 4551 cubic meters per hectare (4 irrigations) and in the spring, about 14214 cubic meters per hectare (12 irrigations) were done. In this study, the number of irrigation times in autumn and spring planting was reduced from 12 irrigations to 4 irrigations and the difference in water consumption was 9663 cubic meters per hectare.The gland with the traits of the percentage of glandular starch and the percentage of fiber of the gland was negative and significant and with the percentage of dry matter of the gland was positive and significant.
 

Finally, it can be concluded that autumn cultivation of potato is suitable, especially in areas with water shortages. The highest water use efficiency in autumn cultivation at depths of 10, 15 and 25 cm was related to the Esprit cultivar.