RD26 (Chiang Rai 72), a Glutinous Rice Variety

Abstract

Glutinous rice is one of the major crop productions in the upper north of Thailand, occupying about 70% of the total rice area in this region. Its production is mainly used for commercial purposes and domestic consumption. San Pa Tong 1 is the most popular variety because of its outstanding cooking quality with high yield and leaf blast disease resistance. However, this variety has a long growth duration of more than 130 days causing farmers’ unacceptability. Though, the release of many glutinous rice varieties to this area but those are vulnerable to blast disease leading to low yield potential. The objective of this study is to develop a photoperiod insensitive glutinous rice variety with short growth duration and blast resistance while remaining good cooking quality. A single cross between a glutinous rice line PRE98002-PAN-B-12-1-1 as a female parent and San Pa Tong 1 (a high yield glutinous rice variety, with blast resistance and good cooking quality) as a male parent, was made at Chiang Rai Rice Research Center in 2013. The promising line named CRI13055-1-1-2-1 outperformed other lines in the same pedigree. During 2014-2023, it had been under the processes of selection of progenies, yield trials as well as evaluation for resistance to major diseases and insect pests, nitrogen response, physical and chemical properties of grain, milling and cooking quality together with stakeholders’ perception. Recently, The Thailand Rice Variety Board agreed to introduce it in the name of RD26 (Chiang Rai 72). It is a glutinous rice variety, has resistance to leaf blast disease, non-photosensitivity with short growth duration at about 130 days from planting to maturity, erect clump with an average plant height of 111 cm. The average yield from multiple field trials was 780 kg/rai (potential yield at about 1,152 kg/rai). In addition, this variety has straw color paddy, eight weeks seed dormancy and paddy length of 10.67cm, with the length of brown rice 7.55 mm, 2.44 mm width, and 1.93 mm thickness were considered as slender shape. The new variety has excellent milling recovery (milling head is 57.8%) and good cooking quality. Though, RD26 is a non-aromatic variety but it has soft texture after cooking. It is resistant to leaf blast disease in the upper north. Therefore, it is recommended to be grown predominantly under those irrigated conditions where leaf blast disease always occurs. However, it is susceptible to panicle blast disease, bacterial blight disease, rice gall midge, brown planthopper, and whitebacked planthopper.