Abstract

Effect of different attributes on grain and protein yield of bread wheat was assessed using 20 genotypes. Randomized complete block design with three replications was used. Relationship among measured traits was assessed by Pearson's correlation coefficient and factor analysis. Correlation analysis showed the significant relation of grain and protein yield with all the traits except correlation of grain filling duration and peduncle length with grain yield as well as spike yield and peduncle length with protein yield. Factor analysis based on principal component analysis method and varimax rotation indicated that four important factors accounted for about 98% of the total variation among traits studied. The first factor assigned 48% of total variation between traits and was significantly related with traits grain yield, biological yield, protein yield and protein percentage. This factor was regarded as quantitative and qualitative yield improvement factor. Other factors accounted for 20, 16 and 14% of variation between traits so were entitled as spike yield, grain filling ability and photosynthesis reservoir enhancement factors, respectively. In conclusion, results revealed effect of grain filling rate, biological yield, number of grains/spike, spike yield and protein percentage on grain and protein yield. Hence, these traits are recommended as indirect selection criteria for genetic improvement of grain yield especially in early generations.