Quality Deterioration of Rice Grains under High Temperature Stress

Abstract

High temperatures, which cause a decline in grain weight and quality, are one of the most significant environmental concerns checking productivity of rice in tropical areas. To combat these problems, understanding the consequences of high temperature stress on nutritional qualities of rice is imperative. An experiment was conducted at Regional Agricultural Research Station, Pattambi during 2019-2020 with rice variety Jyothi cultivated during five dates of planting [June 1st (D1), June 30th (D2), October 1st (D3), October 30th (D4) and January 1st (D5)] under open condition (O) and climate-controlled green house (GH). Grains obtained from different treatments were analyzed for different quality parameters like milling percentage, head rice recovery, starch, amylose, protein, fat and mineral (Ca, Fe, Zn, P) content. Highest milling percentage, head rice recovery, starch, amylose, protein, fat and mineral (Ca, Fe, Zn, P) content were observed during June 1st planting and lowest during January 1st planting. When comparing the two growing conditions, grains obtained from open condition had high milling percentage, head rice recovery, starch, amylose, protein, fat and mineral (Ca, Fe, Zn, P) content than that under climate-controlled greenhouse. The study shows that high temperature stress on plants can be managed by early sowing of rice cultivars in all the three seasons viz. virippu, mundakan and puncha and rice grains obtained from virippu sowing gives good quality grains as compared to that of mundakan and puncha planted grains.