Interrelationship of grain filling rate and other traits that affect the yield of wheat (Triticum aestivum L.).

Knowledge of the relationship between grain yield and yield components is very important for efficient breeding for yield, considering that it is the most important economic trait and has a very complex mode of inheritance and low heritability. The aim of this study was to determine the correlation and the direct and indirect effects of grain filling rate and the traits that affect the yield of wheat. The experiment was conducted during two growing seasons 2008/2009 and 2009/2010 with 20 different varieties of common wheat. Weight and number of grains per spike, 1000 grain weight, plant height, duration and rate of grain filling were analyzed. Correlation coefficients were calculated as well as the direct and indirect effects of these traits on grain yield. Highly significant positive correlation was found between the rate of grain filling and 1000 grain weight, grain weight per spike and number of grains per spike. Also, a significant positive correlation was found between 1000 grain weight and grain weight per spike. According to the path analysis, the duration of grain filling, grain filling rate and grain weight per spike showed a positive but not significant direct effect on grain yield. The plant height had the greatest direct negative effect on yield. According to the results, it was concluded that traits such as grain filling rate together with plant height, might be of importance as criteria in the selection of future breeding for yield in the particular agro-climatic conditions.