Effect of Sowing Dates on Development, Seed Yield and Quality of Some Peanut (Arachis hypogaea L.) Genotypes

A field study was conducted at the experimental farm of the College of Agriculture, University of Salahaddin- Erbil / Iraq, during growing season of 2012, to evaluate the effect of sowing dates on crop growth cycle, seed yield and quality of peanut. A split-plot arrangement in a randomized complete block design with three replicates was used. Sowing dates were assigned to main plots, and genotypes to the sub-plots. The planted crop needed at the first date (April 22) more days to attain emergence and flowering stage (16.3 and 57.8 days respectively), than the other three dates. It is pointed out that the plants of June, 3 date required longer period from flowering to maturity than those of April, 22 (150.1 and 137.8 days respectively). Plants needed more accumulated heat units to reach emergence when planted in April, 22, to reach flowering at May, 20 date and to reach maturity at June, 3 date. Soodary genotype took the longest period for flowering and from flowering to maturity, and accumulated the highest quantity of heat units up to mature stage. The third date (May 20) and the genotype ICGV8623 gave the highest pod, seed yield, oil and protein yields (3.2, 2.0, 0.836 and 0.398 t/ha) and (3.3, 1.9, 0.784 and 0.394 t/ha) for the same date and the genotype respectively. Seeds of last date (June 3) and Soodary genotype were recognized by high oil content (44.3% and 45.7%) respectively. First date (April 22) surpassed in protein percentage (22.0%). A highly significant negative relationship was found between number of days from flowering to maturity and number of days from sowing to flowering (r = -0.557), the seed yield was positive and significantly correlated with seeds /pod and 100-seed weight (r = 0.341 and 0.385) respectively, and there was a positive, high significant correlation between seed yield and pod yield (r = 0.695).