Statistical analysis of durum wheat yield under semi-warm dryland condition

Eight statistical procedures including simple and compound variance, covariance analyses, coefficients of genetic variation, broad sense heritability and genetic advance, simple correlation, stepwise multiple linear regression and path analysis were used to study the relationship between grain yield of spring-type durum wheat and its components under semi-warm dryland condition of Iran. In order to identify relationship of some agronomical traits including yield components with grain yield of durum genotypes, 24 durum wheat genotypes were studied in RCBD design with 3 replications during 2004-2005 and 2005-2006 wheat growing season in Gachsaran Dryland Agricultural Research Station in the southwest of Iran. The results showed that the measured traits varied in genotypic and phenotypic coefficients of variations, heritability and genetic advance. Thousand kernel weight had positive significant correlation coefficient and great positive direct effect on grain yield, so it can be considered as indirect selection criteria for better yield in durum breeding programs. The spike number per square meter (S/m(2)) through direct effect on grain yield and via thousand kernel weight can be defined as another indirect selection criterion. Meanwhile, decreasing and nullifying the negative indirect effect of kernel number per spike by decreasing seed weight should be considered in direct selection for thousand kernel weight and spike number per square meter. It can be concluded that differences among genotypes for days to heading, spike number per square meter, flag-leaf area, flag-leaf weight and grain yield were mainly controlled by environmental variance. The existence of high heritability for growth vigor, days to maturity, plant height, peduncle length, number of kernel per spike, flag leaf senescence, spike length, thousand kernel weight and test weight traits, indicated that effective selection can be done on these traits through breeding programs.