Thailand's Best Deepwater Rice Variety

By: Udompan Promnart,  Peera Doungsoongnern, and Reunreudee Keawcheenchai
18 August 2014

This rice variety, RD45, stays alive in deep water for 2 to 3 months and comes out with its aroma still intact, great for desserts.

RD45 deepwater variety
RD45 deepwater variety

Thai women prefer RD45 when they cook it as dessert because of its milder stickiness compared with that of glutinous rice. 

A climate-change-adaptable variety

Every now and then, Thailand faces flooding with  disastrous impact. In 2011, for example, floods covered a significant portion of the country’s rice fields, raising concerns about the effect on global rice prices and supply. But rice market analysts say a record harvest, global surplus, and a second crop should prevent any dramatic disruptions.”

The country, however, is boosting its rice supply by dedicating 3,200 ha or 10% of the total deepwater rice area to cultivation of RD45.

Features of RD45

Parents. The variety is bred by a single crossing of PCRBR83012–267-5 (Hawm Nai Pon/IR46) and KDML 105. IR46, used here as a parent, comes from the International Rice Research Institute.  RD45 was first developed/bred in 1989; it was only in 2010 that it was released.

RD45 is a photoperiod-sensitive variety. Harvesting period is from 25 November to 2 December. Average plant height is 170 cm and panicle length is 27.7 cm. Average grain length and width are 10.2 mm and 2.73 mm, respectively. The average brown rice length and width are 7.44 mm and 2.33 mm, respectively. Milling quality is about 55.4 % of head rice. The average yield is 3.2 t ha-1 in deep water (50-100 cm) and 4 t ha-1 in shallow water (<50 cm).

Annual seed production is about 125 t (85 t from PRRC and the agricultural co-operative of Prachinburi Province and 40 t from farmers). Total yearly production is about 2,500 t. Normally, farmers keep these as seed for the next cropping season. Part of it is consumed by the household and the rest sold to rice mills and neighbors.


Of the 99 farmer-interviewees, 92 said they liked RD45 for its ability to survive in deep water. They also said that they were impressed with RD45’s other traits: big panicles, high yield, slender-shaped grains, gentle aroma, and softness when cooked.

Dessert with RD45 as main ingredient

Let’s Cook Rice Dessert: Khao Jao Kaew


RD45 (milled rice) - 2 cups
water -  2 ½ cups 
coconut milk -  3 cups  
sugar-  1 ½ cups 
salt -  1 teaspoon 
roasted sesame seeds

How to cook:
  1. Steam-cook RD45. When done, let it cool and be a little bit dry.
  2. Boil coconut milk at low temperature. 
  3. Add  sugar, salt and food color, constantly stirring it until it becomes syrupy.  For green food color, use pandan (Pandanus amaryllifolius) leaves; for pink, watermelon; and for purple, butterfly pea (Clitoria  ternatea).
  4. Mix rice with syrup and stir lightly.
  5. Pour in small cups and top with sesame seed.

Makes 15 servings.

Udompan Promnart, Peera Doungsoongnern, and Reunreudee Keawcheenchai work at Prachinburi Rice Research Center, Bureau of Rice Research and Development, Rice Department. THAILAND