PERFORMANCE OF SPRING RICE CULTIVARS AGAINST PLANTING METHODS IN WESTERN TERAI, NEPAL

Abstract

Rice, the major staple food crop in Nepal, contributes significantly to the livelihood of a majority of people. The production of main season rice is insufficient for food self-sufficiency, where spring rice can be an alternative if better cultivars and planting methods can be identified. An on-station trial was conducted at the Agronomy Farm of Paklihawa Campus, Rupandehi from February to July 2021 to evaluate spring rice cultivars’ growth and yield performance against the planting methods. The trial was set up in a split-plot design consisting of two crop establishment methods: Direct seeded rice (DSR) and Transplanting rice (TPR) as the main factor and seven cultivars as sub-factor, each replicated three times. The cultivars include five released varieties (Hardinath-1, Hardinath-3, Hardinath Hybrid-1, Hardinath Hybrid-3, and Chaite-5) and two promising varieties (IR-15L-1008, and PR-126). 100% spikelet sterility was observed at the maturity stage (115~125 DAS) in all the cultivars and planting methods due to high temperature-induced heat stress, as the average maximum temperature during April was 370 C and the daily maximum temperature throughout the last week of April was above 370 C, coinciding with the flowering stage. Plant height (94.89 cm), leaf area index (5.02), and panicle weight (1.39 g) at 120 DAS were significantly higher in TPR. Spikelet fertility was observed at 150 DAS, when yield attributing characters like panicle length (22.05cm), grains per panicle (130.13), thousand-grain weight (19.79 g), above-ground biomass yield (8.2 tons/ha), and spikelet fertility (75.6%) were found better in TPR than DAR. Thus, TPR was better than DSR in terms of growth, yield attributes, and spikelet fertility parameters. IR-15L-1008 had better plant height (94.54cm), panicle weight (1.39 g), and grains per panicle (130.13); however, it couldn’t fit the cropping system due to its long duration. Chaite-5 (84.47%) and PR-126 (84.62%) had significantly(p<0.005) higher spikelet fertility at 150 DAS, so these could be promising cultivars for the spring season. Cultivars exhibited different responses for various growth and yield attributing parameters due to high-temperature stress. The upcoming research should focus on the selection of elite heat-tolerant cultivars and adjustment of sowing dates that could escape the critical period of high temperature during the reproductive phase of spring rice at Western Terai of Nepal.