تجزيه عليت متوالي شاخص تحمل به تنش خشكي در كلزا

Sequential Path Analysis of Stress Tolerance Index (STI) in Rapeseed (Bras sic a nap us L.)

In order to study the cause and effect relationships airr g agronomic characters in water stress and non-stress conditions with Stress Tolerance Index (STI), a research was conducted in the experimental field of Agriculture Faculty of Zanjan University in 2002. The Experimental design was a split block design based on RCBD with three replications in which irrigation with two levels (non-stress and stress) was the main factor and rapeseed varieties in sixteen levels comprised the sub factors. Results of sequential path analysis indicated that in order to breeding for grain yield STI under non-stress conditions, essentially selection should applied in favor of increasing main stem siliqua and decreasing of plant height and seeds per siliqua. Due to relationships between these three characters, it is necessary to put them in equilibrium together. Also, for breeding under water stress conditions, increasing of main stem siliqua and siliqua per plant and decreasing of seeds per siliqua and plant height would be beneficial. Indirect breeding for oil yield STI in non-stress conditions is possible by breeding toward increasing of days to flowering and main stem siliqua and decreasing of seeds per suiliqua, while under water stress conditions, breeding for increasing of main stem siliqua and siliqua per plant and decrease of seeds per siliqua should be considered.