Biplot Analysis of diallel crosses for yield and some morphological traits in durum wheat

Six varieties of durum wheat were included in a full diallel mating design during 2003-2004 and 2004-2005 cropping seasons in the farm of Maragheh Dryland Agricultural Research Institute (DARI), Iran. Parental durum wheat genotypes and their complete diallel progenies were grown in a randomized complete block design with two replications in the growing seasons of 2005-06. The highest values of number of seeds per spike, one hundred seed weight and seed yield were obtained in Gerdish. The GCA effects indicated that Zardak was an ideal general combiner for one hundred seed weight, coleoptile length, number of germinated seeds, number of seeds per spike, growth vigor and radicle length. Crosses of Knd1149//68/ward × Waha and Zardak × Chehel daneh exhibited the highest value of seed yield and significant heterosis. Graphic analysis indicated that the hybrid between Knd1149//68/ward and Waha was the best hybrid for seed yield, because it integrated the four genes (A2, D1, D2 and probably D3) for seed yield. Zardak, Knd1149//68/ward and Gerdish can be used either as the best parents for selection programs based on their GCA effects, or as a superior parent in hybrid programs based on their SCA effects.