EVALUATION OF RICE MUTANTS IN MULTI-LOCATION TRIALS CONDUCTED IN THE SOUTHEAST ASIAN REGION

Authors: Eizenga, Georgia; PADOLINO, T - PHILRICE, PHILIPPINES; AZAM, M - BINA, BANGLADESH; BRAR, D - IRRI, PHILLIPPINES; CHEEMA, A - NIAB, PAKISTAN; ISMACHIN, A - P3TIR-BATAN, INDONESIA; ISMAIL, A - MARDI, MALAYSIA; KOH, H - SEOUL NATL UNIV, KOREA; SENGHAPHAN, R - PTRRC, THAILAND; SHU, Q - INAS, ZHEJIANG UNIV, PRC; TUAN, V - CLRRI, VIETNAM; WU, D - INAS, ZHEJIANG UNIV, PRC; ZHU, X - CNRRI, PRC; MALUSZYNSKI, M - FAO/IAEA, AUSTRIA

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 2/19/2004
Publication Date: 2/1/2005
Citation: Eizenga, G.C., Padolino, T.H., Azam, M., Brar, D.S., Cheema, A.A., Ismachin, A., Ismail, A., Koh, H.J., Senghaphan, R., Shu, Q., Tuan, V.D., Wu, D., Zhu, X., Maluszynski, M. 2005. Evaluation of rice mutants in multi-location trials conducted in the Southeast Asian region [abstract]. Rice Technical Working Group Meeting Proceedings. Abstract p. 71-72.

Interpretive Summary:

Technical Abstract: Induced mutation is an important tool for rice breeders to use to incorporate new variation into currently used rice (Oryza sativa L.) varieties. The specific objective of this IAEA/FAO sponsored project was to evaluate, identify and utilize promising rice mutants from the germplasm assembled in the Regional Rice Mutants Multi-location Trial (RRMMT). The eleven countries/institutes that participated in this project included Bangladesh, P.R. China, India, Indonesia, IRRI, Rep. of Korea, Malaysia, Myanmar, Pakistan, the Philippines, Thailand and Vietnam. The entries selected for evaluation included 19 mutant lines, the 16 parent lines the mutants were derived from, and 'IR64' as a universal check. Trials were replicated three or four times over three years at 16 locations in nine countries. The entries were compared for yield, days to heading, plant height and number of productive tillers. Other characteristics observed included lodging, harvest date, management, environmental conditions and disease pressure. Starch characteristics related to rice quality measured were apparent amylose content, alkali spreading value, gel consistency and starch viscosity. Data were collected from 46 yield trials with three or four replications at 19 locations in the participating countries over one to four growing seasons (2000 to 2002). Geographically, the locations were spread from 5o N to 37o N latitude and 89oE to 127oE longitude with elevations ranging from 2 to 900 m above sea level. Data were analyzed using the SAS procedures General Linear Models and REGression. Of the 35 entries included in the study, it was determined that parent MutSM-268/PSJ x IR36 (MutSM) and mutant Shwewartun had poor germination. The germination of MutSM was so poor that it was not included in the trial. The parents, Tai Nguyen and Tep Hanh, were photoperiod sensitive so limited data were collected on these entries. Pooled data across countries revealed significant variations among entries. Location mean yield ranged from 2224.6 to 6861.2 kg/ha. Mutant RD25-86-G1-Cs-PTT-31-1-2-1-1 (RD25 mutant) from Thailand produced the highest yield but not significantly different from mutant Binadhan 4 with 6626.1 kg/ha. These two mutants were comparable as to heading date, plant height and productive tillers. Other top yielding mutants with at least 6000 kg/ha were Binadhan 6 and R3027. R3027 matured earlier by about 11 days than Binadhan 6 but Binadhan 6 was taller by 27 cm. All these mutants were significantly better in yield than their parent varieties. When compared to the international check, additional mutants and parent varieties gave a significant yield advantage. Among the mutants, PR26768-PJ(T)4, TNDB 100, THDB, and PR26305-M32 produced yields ranging from 5707.9 to 5818.0 kg/ha or at least a 5% yield advantage over IR64. While among the parents Tainan3, IR8 and BR4 showed significantly better yields than IR64 and their mutant progeny. The yield stability analysis of each entry over all locations was evaluated using the slope of the regression line denoted as 'slope' and root mean square (RMSE). The most stable entry was international check, IR64, with a slope of 1.06 and a RMSE value of '1' thus, IR64 showed wide adaptability across environments. The high yielding RD25 mutant and its parent also showed stability, though the response in each environment was more variable. This variability in yield could be attributed in part to reactions to local insect pests and diseases. The measurement of characteristics related to starch quality showed the mutants to be similar to their original parent in amylose content except for the low amylose mutant, Hwacheong du 2, from Korea. There were no changes in alkali spreading values between mutants and parents. Changes were observed in gel consistency between the mutant(s) and their corresponding par