اثر زمان کاشت بر فیلوکرون و مراحل فنولوژیک ارقام برنج

In order to investigate the effects of environmental conditions on phenological parameters of rice cultivars, a split plot experiment was conducted based on randomized complete block design with three replications at the Research Farm of Guilan University in 2013. Factors were: transplanting dates in main plots (three times with 15 days intervals) and rice cultivars in three levels (Hashemi, Khazar and Gohar) in sub plots. The results showed that phyllochron and leaf appearance rate was significantly affected by transplanting date, cultivars and their interaction. The highest value of phyllochron obtained with average of 7.6 days in Gohar and second transplanting while the lowest amount of that resulted with average of 5.4 days in Hashemi and second transplanting. The maximum rate of leaf appearance achieved with average of 0.214 leaves per day in Hashemi and second transplanting. Cultivars, transplanting dates and their interaction significantly affected days to panicle initiation, 50% flowering and maximum tillering. Regression analysis toward the mean temperature during the period of vegetative growth traits showed that the increase in mean temperature decreased number of days to panicle initiation, 50% flowering and maximum tillering. The results showed that rice varieties with longer growth period had lower leaf appearance rate and higher phyllochron that increasing in mean temperature accelerated the process and other phenological traits.