• Response of drought tolerant rainfed rice cultivars to transplanting dates under changing climatic condition in Nawalparasi, Nepal

  •   | 
  • 28/02/2016

This MSc thesis study was conducted by Dinesh Bahadur Karki, student at the Tribhuvan University, as part of the SAF-BIN project in Nepal in 2012.

Rainfed production systems are highly vulnerable to climate change. In Nepal, more than 70% of the total rice production derives from rainfed ecosystems, hence strategies to mitigate climate change effects are crucial. The aim of the study was to assess the productivity of various drought tolerant rice cultivars and appropriate transplanting dates under changing climatic scenarios. The experiment was conducted at farmers´ fields in Dhobadi VDC , Nawalparasi from June to November, 2012. 16 treatment combinations based on four different transplanting dates (July 15, July 25, August 4 August 14) and four rice cultivars (Sukkha Dhan-1, Sukkha Dhan-2, Sukkha Dhan-3 and Radha-4) were tested. The treatments were arranged in split-plot designs. Among the data collected were grain yield, number of grains per panicle, filled grains per panicle and 1000 grain weight. The yield was significantly influenced by the transplanting date, whereas, the different varieties had no substantial effect on the yield. Highest yield (2.46 t/ha) was obtained by transplanting date July 15. After that the yield decreased gradually: 12.6% by July 25 and 28.6% by August 4. The lowest yield (0.30 t/ha) was observed by the latest transplanting date, August 14, with a yield decrease of 87.9% compared to July 15. Among the reasons discussed for the significant differences are the changing climatic parameters such as temperature and rainfall. Little rainfall in August, might have caused water stress during critical growth stages and hence negatively affected the grain yield. Next to the increased yield, early transplanting (July 15-August 4) resulted also in the highest number of grains per panicle, more filled grains per panicle and highest 1000 grain weight.This study shows that early transplanting dates: July 15 to July 25 resulted in significant higher yields than later dates (August 4 to 14), independent of the rice varieties tested.  However, in order to validate the research further, more years of multi-location research are required