Presented in International Rice Conference, Bali 12-14 Sepetember 2005.
In Vitro Selection and Identification of Drought Tolerance
of Rice Varieties Gajah Mungkur, Towuti and IR64
(Endang Gati Lestari and Ika Mariska)
The rice demand keeps increasing. Ironically, the rice production remains the same or is even decreasing caused by the long dry season and the climate unstability. In addition, the land use for industry and settlement drastically minimizes the number of productive agricultural field. One solution for the food shortcoming is that of planting rice variants with high yield and drought-stress tolerant as that of IR 64. In this attempt, mutative induction combined with in vitro culture and selection on the Gajah mungkur, Towuti and IR 64 variants have been conducted and have obtained several somaclones along with their genetic variation. Through evaluation and characterization for the drought tolerant using PEG 20% (BM 6000), several drought tolerant somaclone have been gained. Subsequently, to find out the mechanism of the respective genotype toward the drought stress resistance, root penetration and proline content analysis at the somaclone have been conducted. Being evaluated 23 Gajah mungkur somaclones, 9 Towuti somaclones and 13 IR64 somaclones have been identify as the ones with high proline content. The drought stress treatment finally obtained 9 somaclones from Towuti, 5 from Gajah mungkur and 8 from IR 64 with the better characteristics than that of the mother plants. Shorter plants with more shoots were acquired from Gajah mungkur but the seeds ripe earlier. From Towuti variants, more tiller and higher plants along with the more grain were attained. From variety of IR 64, somaclone which could produce seeds during the drought were obtained, meanwhile this did not occur with the plant originated from seed. The plants resulted from the selection produce more qualified shoot and grain than that of their parental.
Keywords: Radiation, in vitro selection, PEG, drought tolerant , Oryza sativa.