Identifikasi Aksi Gen Epistasis pada Toleransi Kedelai terhadap Cekaman Aluminium

The efectiveness of selection depends on the gene action cotrolling the character. The presence of epistatic gene action will delay the genetic gain in self pollinated crops like soybean. The objective of this research was to obtain information on genetic control of soybean tolerance to aluminum toxicity on nutrient culture. This research was conducted at green house of the University Farm IPB Cikabayan, Bogor, from April to June 2013. This research used 120 seedlings of F2 population generated from crossing between Argomulyo (Al-sensitive) with Tanggamus (Al-tolerant). Seedlings were grown in nutrient culture for 14 days with Al concentration of 1.5 mM and pH 4.0, to observe the vegetative growth under aluminum stress condition. The result showed that mean of roots length, shoot length, shoot to root ratio, wet and dry weight of root and shoot exceeded both parents mean value with moderate to high heritability. All observed characters had continue distribution pattern, and controlled by many genes. Duplicate epistasis additive gene action controlled only root length while other characters were controlled by complementary epistasis gene action

Somaclonal Putative Mutants of Rice Tolerant to Salinity

Soil salinity could significantly reduce rice yield, therefore, varieties tolerant to salinity are urgent to be developed. Mutation induction could be used to create rice mutants tolerant to salinity. The study aimed to evaluate the tolerance of somaclonal mutants of rice to NaCl salinity in a greenhouse condition and characterize their tolerance mechanism. A total of 45 putative mutants were generated by a gamma ray mutation induction followed with in vitro selection in the growth media containing different NaCl concentrations in the greenhouse experiment. The study consisted of two-factor treatments, namely three levels of NaCl concentrations and 45 rice mutants suspected to be tolerant to salinity, arranged in a completely randomized design. Proline, cations (K, Na, Ca, and Mg) content, and stomata density were evaluated. The results showed that eight mutants were tolerant to 150 mM NaCl, namely CH30, CH-4-2, II-13-42, II-13-7, II-13-10, II-13-13, II-13- 2, and IA-3-21. These tolerant mutants had a higher Na content compared to the check parent. The tolerant mutants had a high proline content, lower Na, and stable K, Mg and Ca cations as well as had a greater number of stomata and higher stomata length-width ratio. Some of the identified tolerant mutants demonstrated the tolerant mechanism against salinity stress. Further studies are required to evaluate these tolerant mutants in the field conditions under salinity stress