IJSRP, Volume 4, Issue 7, July 2014 Edition [ISSN 2250-3153]
Ranawake A.L., Amarasinghe U.G.S.
Days to flowering determines the agronomic traits of rice cultivars. One agronomic trait of rice may effect on another trait in different degrees in yield determination. The quantitative effect of one agronomic trait on another trait is not constant in different days to flowering (DF) groups of rice. In the present study more than one hundred traditional rice cultivars with different days to flowering were grouped as 70- 80-, 90- and 100- days to flowering. Agronomic traits of 80 plants in 4 plots of individual rice cultivars were evaluated in field conditions. Path analysis was done to understand the effect of one trait on another trait in different DF groups of rice cultivars. It was found that effect of number of total tillers on number of fertile tillers and effect of number of total spikelets/panicle on number of fertile spikelets/panicle were equally higher in each DF group. Effect of bio mass, number of tillers, panicle length and number of spikelets/panicle on the final yield greatly varied with the DF groups. The negative effect of plant height on harvest index was also varied in DF groups. Effect of panicle length on panicle weight was exceptionally highest in the 80 DF group while the effect of bio mass weight on harvest index was the highest in 90 DF group. It can be concluded that effect of a trait on the yield and on other traits in rice could not be discussed without considering the age group of the rice cultivar.