Effect of sowing date in morphologic traits of three sunflower genotypes

Abstract

A field trial was conducted at Abu-Ghraib research station , Baghdad, Iraq , The objectives were to study the effect of sowing dates on the performance of three sunflower genotypes . A split-plot lay in a randomized complete block design with three replications were used . Five sowing dates ( 16th Jan , 4th , 14th and 26th of Feb. and the 15th of March ) were assigned to main plots , where as genotypes in sub-plots .Any delay in sowing dates after the 16th Jan . Hastened the physiological processes of the developmental stages of the crop . and reflect , the effects of environmental factors such as ( higher temperature , longer photoperiod and lower relative humidity ) , consequently the optimum periods of the life cycle of the crop was shortened . The plant sowed at the fifth sowing date 15/3 had the highest plant where as the first sowing date 16/1 had the lowest plant height , there were no significant variation in leaves number. For the plant with all sowing dates, the plants sowed at the first and second sowing date had the highest LA and LAI. while the 5th sowing date plants had the lowest LA and LAI. The plants from the 1st sowing date had highest dry matter weight at the flowering and maturity comparing with the late dates the fifth sowing had the lowest dry matter weight. The genotype Pan7392 gives highest plant and leaves number. for plant where as Euroflor gives highest LA,LAI and dry matter weight at the flowering and maturity stages, but the dry matter weigh for Euroflor did not varied significant from Pan7392 which has lowest leaves number. Manon genotype showed lowest LA,L AI and dry matter weight at the flowering and maturity ,Interaction between genotypes and sowing date were also detected genotype Euroflor gave the highest LA,LAI and dry matter at flowering while the 5th sowing date gave lowest leaves number and dry matter at flowering . Manon genotype at the second sowing date highest leaves number and dry matter weight at maturity but the lowest LA,LAI and dry matter weight at maturity at 5th sowing date.