RD103 (Hawm Chai Nat 72), a Non-glutinous Rice Variety

Abstract

The area of rainfed rice fields in lower northern and central regions is about 4.27 million rai, an area with sufficient potential to increase rice production. Farmers in this area grow rice for consumption and sale to increase thier income. Most of grown rice varieties are photoperiod sensitive rice varieties, which are good for cooking and eating. However, the age of rice is quite long, as it is a moderately maturing rice variety which is not suitable for areas where a quick harvesting is required. In addition, severe outbreaks of rice diseases cause the quality of the rice to deteriorate and the yield to drop by 20-50%. Therefore, rice varieties need to be improved to ensure quality for the consumption of soft, sticky and aromatic rice. This includes early maturity, high yields, good quality and resistance to leaf blight and bacterial leaf blight disesaes. The variety is suitable for cultivation in rainfed rice growing areas in the lower northern and central regions. Therefore, the rice variety has been developed by three-way crossing between lines KLG88028-22-1-2-2 with the F₁ hybrids of SPR88096-17-3-2-2 and IR60. The F₁ and F₂ were planted and selected at Phitsanulok Rice Research Center. Later they were planted and selected by using the pedigree method. From F₃ to F₆, the PSL97060-17-CNT-1-2-1 line was bred at Chai Nat Rice Research Center. The breeding process was then continued with yield trials tests of resistance to rice diseases and insect pests, nitrogen response, physical and chemical properties of grain, milling quality and cooking and eating quality. On the occasion of His Majesty the King Rama 10’s 72^nd birthday in 2024, the Rice Department’ s Certified Variety Committee decided to release this variety as a certified variety. It is the rice variety “RD103” (Hawm Chai Nat 72) which is photoperiod sensitive and early maturing (flowering), has a height of 139 centimeters, a panicle length of 30.9 centimeters and an average yield of 596 kg/rai. The number of good grains per panicle is 178, the length of the brown rice is 8.22 millimeters, domancy period 6-7 weeks, low chalkiness, very good milling quality (54% milling head), low amylose content (17.3%). The cooked rice is white, soft, sticky and it has an aromatic (2AP content = 0.98-1.25 ppm). It is relatively resistant to leaf blast and bacterial blight diseases in the central region. Suitable for cultivation in rainfed areas in the lower northern and central regions, both in the lowlands and highlands. In terms of caution, It is quite susceptible to leaf blast and bacterial leaf blight diseases in the lower northern region. It is also relatively susceptible to brown planthopper and whitebacked planthopper.