Effect of Days to Flowering on Plant Height and Yield of Rice (Oryza sativa L.)

Aims: To study effect of days to flowering on the plant height and yield of rice.
Study Design: Experiment was carried out according to the complete randomized block design. Four replications were designed for the experiment and each replicate consisted of 3 lines and twenty plants were included in to each line. Data were collected in 80 plants of the each middle line of four replicates.
Place and Duration of Study: Faculty of Agriculture, University of Ruhuna, Mapalana, Sri Lanka, From 2011 November to 2013 November
Methodology: Days to flowering (DF) has been used for plant height (PH), and yield/plant (g) (YLD) were measured in 102 traditional rice cultivars. Eighty plants of each cultivar in four replicates were selected for data collection. Rice cultivars were grouped as 70, 80, 90, 100 DF. Path analysis was done using IBM SPSS AMOS statistical software. Path correlations were calculated to determine the total effect of DF on the PH and YLD.
Results: The effect of DF on the PH and YLD was greatly varied with the DF. Effect of DF on PH was highest when DF was the shortest. Effect of DF on both YLD and PH were maxima at 80 DF. The DF on the YLD was a cubic relationship of days to flowering with a minimum and a maximum value which is fitted with the equation
Conclusion: The DF on the YLD was a cubic relationship of days to flowering with a minimum and a maximum value which is fitted with the equation y = 0.158x3 - 1.365x2 + 3.596x - 2.78, while the relationship between DF and PH was a quadratic which can be explained by the equation y=0.127x2 - 0.734x + 1.077.