Environmental Effect on Variations in Flowering Time and Yield Related Traits in Sri Lankan Traditional Rice Variety 'Masuran’

Growing Sri Lankan traditional rice (Oryza sativa L.) in the short day (Maha) season is crucial for the flowering initiation of most of the accessions. Masuran is a traditional rice variety with a high yielding potential including health-promoting attributes and premium price. This study was conducted to determine the effect of selected environmental factors of the season on the number of days to flowering (DF), plant height at flowering (PH) and selected yield components of two accessions of the ‘Masuran’ variety (Acc. No. 4132 and Acc. No. 5530). Planting was carried out on the 05th day of every month for a period of one year. Average daily rainfall (RF), temperature and photoperiod of each month were recorded. The effect of environmental factors on selected agronomic traits was analysed. Days to flowering, PH, Total Effective Tiller Number (TTN) and Number of Spikelets per First Panicle (NSFP) varied from 65 to 110 days, from 85.7 to 158 cm, from 3 to 8 and from 142 to 199 in Acc. No. 4132, respectively while those parameters varied from 60 to 89 days, from 80.3 to 170 cm, from 3 to 16, and from 119 to 283 in Acc. No. 5530, respectively during the experimental period. The analysis of the effect of photoperiod, rainfall and temperature of the first month of each planting revealed that the effect of photoperiod and temperature is significant on DF. The first month of each planting was observed as the photoperiod-sensitive phase of rice accessions. Correlation analysis for DF and NSFP resulted in a strong positive relationship suggesting a multi-factor environmental effect on NSFP of the variety, Masuran when it was grown throughout the year. The above results will be important in introducing a novel aspect for optimizing planting schedules and selecting suitable genotypes to enhance rice productivity under different environmental conditions.