Relationship of morphological traits and yield components with seed and protein yields in Iranian bread wheat (Triticum aestivum L.) cultivars

Correlation analysis showed the significant relation of seed and protein yield with all the traits except correlation of grain filling duration and peduncle length with seed yield as well as spike yield and peduncle length with protein yield. Factor analysis indicated that four important factors accounted for about 94.31% of the total variation among traits studied. The first factor assigned 34.99% of total variation between traits and was significantly related with traits seed yield, biological yield, protein yield and protein percentage. This factor was regarded as quantitative and qualitative yield improvement factor. Other factors accounted for 43.70, 27.90 and 22.40% of variation between traits so were entitled as spike yield, grain filling ability and photosynthesis reservoir enhancement factors, respectively. Overall, results revealed effect of grain filling rate, biological yield, number of seeds/spike, spike yield and protein percentage on seed and protein yield. Hence, these traits are recommended as indirect selection criteria for genetic improvement of seed yield especially in early generations.