RD95 (Dok Jao Praya), a Non-glutinous Rice Variety

Abstract

The main rice producing areas of Thailand are irrigated paddy fields in the upper northern, lower northern and central regions. Varieties grown in these areas are mostly photoperiod-insensitive, short plant type, high yielding and well responded to factors of production. However, more than 15 million rai of areas in the regions are facing problems on repeated flooding, wet season floods and disease and insect destruction, which lead to yield damage. To provide alternatives for the farmers in such areas, research was conducted to develop a photoperiod-insensitive, non-glutinous rice variety with high yield, early maturity and resistance to brown planthopper and blast. Crossing was made between PSBRc54 (brown planthopper resistant variety) and PSL00526-21-1-1-5 (blast resistant line) followed by F₂ to F₆ pedigree selection to obtain a promising line, CNT07001-35-3-2-1. The research had been carried out by Chai Nat Rice Research Center during 2007 to 2021 through the following crop improvement steps, i.e., yield trials, yield stability trials, evaluation on rice disease and insect pests, response to N fertilizer application, analyses for grain physical and chemical quality, milling quality, cooking and eating quality, and farmers’ acceptance evaluation. The promising line was subsequently approved by the Varietal Releasing Committee of the Rice Department to be a certified variety, “RD95” (Dok Jao Praya). It is a photoperiod-insensitive, non-glutinous rice with 95-100 days to harvest (pre-germinated broadcasting), 102-110 days to harvest (transplanting), erect plant type, 110 cm height, moderately strong culm, green-colored leave, just-exserted panicle, intermediate panicle type, 29.3 cm panicle length, 132 healthy seeds per panicle and moderately high shattering. The average farmer field yield was 885 kg/rai with 1,000-grain weight of 33.25 g, straw-colored husk with a paddy grain size of 10.91 mm length x 2.72 mm width x 2.14 mm thickness, slender dehulled grain shape of 8.26 mm length x 2.28 mm width x 1.89 mm thickness and milled rice grain size of 7.87 mm length x 2.21 mm width x 1.85 mm thickness. It has good milling quality with 52.67 percent of whole kernel and head rice, high amylose content (29.78 percent), soft gel consistency, medium gelatinization temperature, creamy white and slightly sticky cooked rice. Remarkable features of RD95 are early maturity (95 days), high yield, blast resistance, moderate resistance to brown planthopper, high yield potential of 1,213 kg/rai, good grain physical quality, slender grain shape, less chalkiness and good milling quality. It is recommended for irrigated paddy fields in the lower northern and central regions. Caution should be taken as this variety is susceptible to bacterial leaf blight and whitebacked planthopper.