Relationships among Durations of Vegetative and Grain Filling Phases, Yield Components, and Grain Yield in Durum Wheat Cultivars¹

Abstract

In order to study the relationships among grain yield, yield components, and duration of the vegetative (pre‐anthesis) and grain filling (post‐anthesis) periods in durum wheat ( Triticum turgidum L.), field experiments were conducted in 1978 and 1979 under rainfed and in 1979 under irrigated conditions at Saskatoon. Path coefficient analysis of pooled correlation coefficients revealed a complex pattern of relationships among the six characteristics measured. This pattern was partly hidden in the superficial study of correlation coefficients. Duration of the vegetative period had a positive influence on kernels per spike (r = 0.29) and on kernel weight (r = 0.42) which in turn had positive effects on yield. An increase in number of spikes per m 2 appears to be associated with shorter grain filling periods (path coefficient, P = &0.31), fewer kernels per spike (P = ‐0.34), and lighter kernels (P = ‐0.50). The negative correlation (r = −0.51) between spikes per m' and length of the vegetative period imparted an additional complexity to these relationships.