RD97 (Hawm Rangsit), a Non-glutinous Rice Variety

Abstract

Currently there are expanding markets for soft textured rice and aromatic rice. Though the Rice Department has recommended aromatic varieties such as Jao Hawm Supanburi, Jao Hawm Klongluang 1 and Pathum Thani 1, it is not sufficient for changes in consumer market which brings about increasing Thailand loss of market share in the world rice market. To develop a photoperiod-insensitive and aromatic rice variety with high yield, blast resistance, good grain physical quality and eating and cooking quality as required by consumers and entrepreneurs, crossing was made between Pathum Thani 1 and RD43 followed by F₂ to F₈ pedigree selection to obtain a promising line PTT13038-15-1-1-2-5-1. Research had been carried out through the following crop improvement steps, i.e., observation, yield 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 the farmers, entrepreneurs and exporters’ acceptance evaluation. The promising line was subsequently approved by the Varietal Releasing Committee of the Rice Department to be a certified variety, “RD97” (Hawm Rangsit). It is a photoperiod-insensitive, non-glutinous rice with the average yield of 727 kg/rai, 111-114 days to harvest (transplanting), 106 days to harvest (pre-germinated broadcasting), 116-117 cm height, intermediate culm angle, green leaf blade, well exserted panicle, 25.5 cm panicle length, mostly compact panicle, heavy secondary branching, 153 healthy seeds per panicle, low panicle shattering, and easy threshability. It has straw-colored husk with a paddy grain size of 10.99 mm length x 2.86 mm width x 2.08 mm thickness, white and slender dehulled grain shape of 7.74 mm length x 2.32 mm width x 1.78 mm thickness and milled rice grain size of 7.57 mm length x 2.23 mm width x 1.73 mm thickness, less chalkiness (0.58), 1,000-grain weight of 29.52 g, paddy weight of 9.8 kg/20 litres., good milling quality with 46.4 percent of whole kernel and head rice, low amylose content (15.25 percent), low gelatinization temperature, soft gel consistency, normal cooked rice elongation, soft and slightly sticky cooked rice, and scented cooked rice. Remarkable features of RD97 are photoperiod-insensitive and non-glutinous rice, low amylose content, high yield as Pathum Thani 1 but maturing 7-10 days earlier, high yield potential of 976 kg/rai, moderate resistance to blast and suitable for irrigated paddy fields. Caution should be taken as this variety is susceptible to bacterial leaf blight and brown planthopper.