تعيين بهترين تاريخ و عمق كاشت در غده بذري سيب زميني دو رقم دراگا و آگريا در شرايط خراسان شمالي

Determining the best planting date and depth for producing seeding tuber in varieties of potato, Draga and Agria, in northern Khorasan condition

To determine the best planting time and depth for producing seeding tuber in two varieties of potato: Draga and Agria, in northern khorasan conditions, a factorial experiment was done with three factors in three planting dates (10, 20, 30 April), three depths (10, 15, 20), and two varieties (Draga and Agria). The design of the study was Randomized Complete Block Design with three blocks in Marghzar village, suburb of Farooj, east of Northern Khorasan in the farming year of 2007-8, and traits like number of stems and tubers in each plant, the average weight of tuber, number of eyes in each tuber and the yield in each Hectare were determined. Considering the depth of planning, planting date, varieties and mutual influence of factors, there was a significant difference among most traits. The most positive correlation was between the number of stems and tubers in each plant (r=0.85**), also between yield in each Hectare and average of tuber weight (r=0/72**) and between yield in each Hectare with number of tubers in each plant (r=0/67*). The most negative correlation was between number of eyes in each tuber and number of stems in a plant (r=-0/82**) also between average tuber weight and number of tubers in each plant (r=-0/60*). So in talking about seeding tubers, we should pay attention to the number of stems trait in plant. Because the more the number of stems, the more the number of tubers, since in seed production the number of tuber is more important than tuber weight, so in breeding we should pay attention to this factor. On the other hand, with an increase in the number of stems, number of eyes in tuber will decrease; and since these tubers will be used for yielding production number of eyes in tuber seems not to be important.