SCIENCE ASIA

Volume 46, No. 02, Month FEBRUARY, Year 2020, Pages 157 - 168

Evaluation of japonica rice (oryza sativa l.) varieties and their improvement in terms of stability, yield and cooking quality by pure line selection in thailand

Pawat Nakwilai, Sulaiman Cheabu, Possawat Narumon, Chatree Saensuk, Siwaret Arikita, Chanate Malumpong

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Many companies in Thailand have encouraged farmers, especially those in the northern regions, to cultivate DOA1 and DOA2 japonica rice varieties. Recently, the agronomic traits of DOA1 and DOA2 were altered, affecting yield and cooking quality. Thus, the objectives of this study were to evaluate the agronomic traits and cooking quality of DOA1 and DOA2 and those of exotic japonica varieties in different locations, including the Kamphaeng Saen and Phan districts (WS16). DOA2 was improved by pure-line selection. The results showed that the Phan district was better suited to grow japonica varieties than the Kamphaeng Saen district and that DOA2 produced high grain yields in both locations. Furthermore, DOA2 was selected by the pure-line method in four generations, after which five candidate lines, Tana1 to Tana5, were selected for yield trials. The results of yield trials in three seasons (WS17, DS17/18, WS18) confirmed that Tana1 showed high performance in terms of its agronomic traits and grain yield. Moreover, the cooking quality of Tana1 was the same as that of DOA2. When the genotypes of the five candidate lines were compared with those of DOA1, DOA2, Akitakomachi, Sasanishiki and Koshihikari, it was found that Tana1 slightly differed from DOA2. In addition, the japonica varieties introduced from Japan were also different from DOA1 and DOA2. These results suggest that the genotype of DOA2 changed greatly from that of the original variety, Akitakomachi. Thus, pure-line selection can slightly alter the genetics of DOA2, improve agronomic traits and increase grain yields.

Keywords

japonica rice, pure-line selection, agronomic traits, cooking quality

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