Assessment of Genotype x Management Interaction to Enhance Rice Productivity in Southern Thailand

Abstract

Rice is a major cereal crop, is a staple food, and is the source of calories, protein, and nutrients and significantly contributes to the dietary needs in Thailand. Seasonal variations in weather patterns caused by climate change and increased intensity of drought intervals have impacted rice production potential in Thailand. In addition, antiquated production technology, improper agronomic management and traditional farming practices adopted by farmers led to decline in rice production. Objectives of the two years experimental study aimed at contributing for stable, sustainable, and profitable rice production in Thailand comprised of, i) identification of drought tolerance in lowland rice, and ii) agronomic management of nitrogen (N) fertilization according to planting date (PD) for upland rice. Genotypes including Look Pla, Pathum Thani−1, Hom Pathum, Dum Ja, Sang Yod, and Lep Nok were identified as local lowland drought stress tolerant genotypes that can be recommended in drought prone lowland areas to stabilize rice productivity and can be used for further research in rice breeding program for exploring desired traits. Strong associations of stress response indices including GMP, STI, MPRO and MHAR with grain yield under well−watered and terminal water stress conditions, indicated that these indices could be used as rapid identifiers to indicate stress tolerance in rice crop breeding program. Ideal agronomic management for identification of optimal N fertilizer rate (NFR) synchronized with ideal PD is an important strategy to enhance resource use efficiency and productivity of upland rice. Results indicated that N application enhanced upland rice performance and productivity and fertilization of 90 kg N ha–1 at PD2 (end of September or start of October) improved the yields and performance of yield attributes, enhanced straw N and grain N content and total plant N uptake as well as improved crop water productivity. Nitrogen fertilization increased profitability and application of 90 kg N ha–1 resulted in maximum profit at all PD. Based on the results, it was suggested that 90 kg N ha–1 should be applied, and upland rice should be planted at the end of September or the start of October for enhancing resource use efficiency, improving productivity, and maximum profitability. Furthermore, since a linear relationship between NFR, agronomic traits of upland rice, N uptake and crop water productivity was observed, and a significant seasonal effect indicated, long–term field investigations considering a range of NFR and adoption of forecasting measures i.e., rainfall forecasting and yield prediction using crop simulation and modeling techniques to adjust seasonal planting dates are recommended for upland rice cultivation in Thailand.