EFFECT OF SOWING DATES ON RICE (Oryza sativa L.) YIELD AND YIELD COMPONENTS OF (BHUR KAMBJA-1) VARIETY AT SOUTHERN BHUTAN

Abstract

Generally, rice is sown late March-April in high altitudes, early May-June in mid altitudes and June-early July in low altitudes in Bhutan. Sowing times of rice in Bhutan are often driven by the monsoon and are frequently delayed with no specific varieties developed for delayed sowing. Thus, the research was conducted at ARDC-Samtenling research station in 2017 to study effect of sowing dates on performance of widely adopted Bhur Kambja1 rice variety to identify zonal specific optimum sowing window. Field experiment was laid out in a randomized complete block design with three replications having net plot size of 5 × 2 m. Experiment comprised of five different sowing dates that are 30 th May, 14 th June, 29 th June, 14 th July and 29 th July at an interval of 15 days. Some agronomical traits such as plant height, days to maturity, number of productive tillers per hill, panicle length at harvest and grain yield were measured and analyzed. The result indicated that effect of sowing dates on plant height, days to maturity, panicle length and grain yield were statistically significant at 0.05 probability level while number of productive tillers per hill showed no significant differences among different dates of sowing. Sowing at 30 th May and 14 th June resulted significantly higher yield of 3.53 t ha -1 and 3.40 t ha -1 respectively. The findings revealed that sowings at 29 th June, 14 th July and 29 th July yielded low of 2.37 t ha -1 , 2.97 t ha -1 and 2.83 t ha -1 respectively. This elucidates that late sowing and transplanting cause yield reduction which could not be recommended among farmers.