Study of relationships between yield and some physiological traits of spring rapeseed cultivars

In order to evaluate the rapeseed cultivars regarding to the characteristics such as earliness, lodging resistance and also high yield potential, eight rapeseed cultivars were investigated in a randomized complete blocks design with three replications in Rice Research Institute of Iran in 2005-6 cropping year. Results of analysis of variance showed significant difference among cultivars regarding to all studied traits. The grain yield mean comparison of cultivars showed that cultivar Hyola308, Hyola420 and RGS-003, respectively, with average yields of 3/44, 3/01 and 2/84 tons per hectare were superior than the other cultivars so that the Hyola308 compared to Syn-3 had a superiority of a 52/62 percent. In terms of earliness among the studied cultivars, hybrid Hyola330 had a 13/78 percentage superiority than the Option504 delayed cultivar. Also, the investigation of grain yield components showed that the highest number of seeds per pod (26/23 seeds) was associated to Syn-3 and the highest number of pods per plant was related to the RGS-003 cultivar with 117 pods. Grain yield had a significant and positive correlation with flowering period duration to maturity and had a significant and negative correlation with pod length. According to the path analysis results, flowering period trait to maturity had the most direct positive effect on grain yield while traits the length of pod and pod number per main stem had a negative direct effect on grain yield.