RD31 (Pathumthani 80) Rice Variety

Abstract

Although rice cultivation in irrigated area is rather small but it is a major area for commercial rice production and exportation. Continuous rice growing with high inputs in that area periodically causes serious problems of rice disease and insect pest damages. Since few favorite rice varieties are being grown in this area, thus new variety improvement for increasing genetic diversity becomes necessary. The requirement of new variety is high yield with good grain quality complementary with resistance to important diseases and insect pests. RD31, new variety had been developed since 1993 at Suphan Buri Rice Research Center. Its previous elite line designated SPR 93049-PTT-30-4-1-2 was derived from a single cross between SPR85163-5-1-1-2 and IR54017-131-1-3-2. Its yielding ability had been evaluated in observational yield trial, intra-station yield trial, inter-station yield trial, on-farm yield trial under irrigated area of the central region. The elite line SPR 93049-PTT-30-4-1-2 had been tested for disease and insect resistance and characterized for its agronomic characters, i.e. physical grain properties, chemical grain properties and cooking qualities. The whole process took 13 years from 1993 to 2006 and finally, this elite line was recognized and released as RD31. RD31 is a photoperiod - insensitive, compact tillering, strong culm and high yielding variety. RD31's plant height is 117 cm and its maturity is 111-118 days after sowing. RD31 yielded 745 kg/rai when transplanting method is applied. When pre-germinated seed broadcasting method is applied, it gave 738 kg/rai. Its brown rice is white color with 7.39 mm in length and slender in shape. RD31 has more uniform grain quality compared to SPR1, the favorite high yield variety. RD31 is resistant to whitebacked planthopper and moderately resistant to brown planthopper, bacterial leaf blight, brown spot and dirty panicle. It is recommended for irrigated areas of the central region with precaution of its susceptible to leaf blast, ragged stunt virus and yellow orange leaf virus.