تعيين مهم ترين جزء عملكرد دانه گندم در تاريخ هاي كاشت مختلف

Determination of the most important yield component of wheat in different sowing dates

In order to determine the most important yield component of two wheat (Triticum aestivum) cultivars (Zagros and Koohdasht), a RCBD experiment was conducted with five sowing dates (14 December, 20 Januery, 18February, 20 March, 16 April) with three replications. In this research, grain yield/plant was considered as a function of grain No/plant and mean single grain weight. While grain No/plant was considered as a function of three components (spike No/plant, Spikelet No/spike and fertile floret/spikelet). Our results based on onthogenic relationships and path analysis coefficients revealed that both cultivar and sowing dates can affect the most important yield component. Our results indicated that cultivars have different responses to sowing dates and these differences were clear for some characteristics as the most important yield component, the most important component of grain No/plant, and compensatory effects of yield components, specially for mean grain weight and grain number. In this respect results indicated that for Koohdasht cultivar, grain No/plant is more important than mean grain weight to determine grain yield / plant and fertile spikelet/spike was the most component which affected grain No/plant, while the effects of sowing dates on the most determinant component of grain yield / plant was completely variable, but similar to Koohdasht cultivar, spikelet No/spike was the most important component that affected grain No/plant in Zagros cultivar.