Peningkatan Toleransi Alumunium pada Jeruk Batang Bawah dengan Teknik Seleksi In Vitro Berulang

Aluminum Tolerance Improvement of Rootstock Citrus through Repeated In Vitro Selection. Mia Kosmiatin, Rosa Yunita, and Ali Husni. National orange productivity was trend to decrease because of pathogen attack and reducing of planting area. One of alternative ways to preserve and increase orange productivity was using marginal soil mainly acid soil. This matter pushed the breeder to prepare tolerant rootstock and stable in the acid soil. In vitro culture technique was effective and efficient methods to produce tolerant and stable rootstock in acid soil through simulation of acid soil with addition of high aluminum and low pH in the medium. By the simulation the selection could be done in cell level, so cell was selected after induction of variation. A rootstock which high compatibility with scion, useful rooting, and aluminum tolerance could be increased orange productivity through acid soil development. The research was conducted in 3 phase: (1) induction of embryogenic calli, (2) improvement of genetic variation through mutation, and (3) In vitro selection with AlCl3.6H2O for aluminum and low pH tolerant. Immature embryos of rootstock were use as explant. The result showed that the best embryogenic calli were induced on MS basal medium with MW vitamin + NAA 7,5 mg/l + kinetin 0,5 mg/l. Before selection, 1.000 rad dosage was the most tolerant dosage to growth embryogenic calli. After selection, 2.000 rad dosage was the best dosage to produce shoots which stable tolerant to aluminum. Selected 88 mutant shoots were produced after three times selection on the same medium which AlCl3.6H2O added at low pH.