Dam Das 20, a Glutinous Rice Variety

Abstract

Dam Das, a traditional glutinous rice variety, is mostly grown in Thung Song, Bang Khan and Thung Yai district, Nakhon Si Thammarat province. It has high yield, good grain physical quality, good milling quality and rather sticky texture of cooked rice. Currently, the farmer groups increase preferences on growing this variety and save their own seeds for further planting. This brings about uncertain varietal characteristics as well as low milling quality. Nakhon Si Thammarat Rice Research Center, therefore, conducted a Dam Das varietal improvement research to develop a pure line with good cooking and eating quality to be used for intercropping with young para rubber and oil palm plantation. Dam Das rice samples were collected from the original growing areas and grown for pure line selection to obtain a line, NSRC14012-20. Research have been carried out during 2014 to 2021 through the following crop improvement steps, i.e., pure line selection, varietal observation, yield and agronomic character evaluation, 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, analysis of nutritional value and farmers' acceptance evaluation. The promising line was subsequently approved by the Varietal Releasing Committee of the Rice Department to be a certified variety, “Dam Das 20". It is a photoperiod-sensitive glutinous rice with flowering date (50% flowering) around September 14th to October 4th (dry seed dibbling) and harvesting date at late October to early November. It has erect plant type, moderately strong culm, 155 cm height, 56.0 cm leaf length, 2.0 cm leaf width, 30.6 cm panicle length, mostly compact panicle, good seed setting (193 fertile seeds per panicle). The average field yields when intercropping with young oil palm and para rubber were 398 and 407 kg/rai, respectively. It has black tip and straw-colored seed hull, purple dehulled grain, slender grain shape, 8.82 percent protein content in brown rice, non-aromatic and moderately soft texture of cooked rice. Remarkable features of Dam Das 20 are high yield, good milling quality, good grain physical quality, high nutritional value and high anthocyanin content. It is recommended to be grown as an intercrop in young oil palm and para rubber plantation in Nakhon Si Thammarat and nearby provinces. Caution should be taken as this variety is moderately susceptible to blast at seedling stage and bacterial leaf blight diseases, and highly susceptible to brown planthopper.