Optimization of Media and Cold Pretreatment for Anther Culture Using Japonica/indica and Indica/Indica Hybrids and their Callus Induction Comparisons in Different Rice Crosses

Rice (Oryza sativa) is pivotal to the lives of a large number of people around the world. Nowadays, anther culture is widely used in rice improvement as it can increase the selection efficiency. By optimizing the induction media and preservation time for cold pre-treatment, a significant improvement of embryogenic potential of the callus has been obtained in 3 different crosses of indica and japonica rice cultivars. It was observed that medium 2A was the best among the others as it was capable to induce a great number of calli while the addition of silver nitrate to the N6 medium doubled up the production of embryogenic calli. Analysis of variance indicated that there was a significant interaction between medium and cold pre-treatment. Seven days of preservation time showed much better callus production in N6 medium compared to MS medium. Significant differences of the callus induction were observed among indica cultivars. Therefore, seven days cold pre-treatment in the combination of silver nitrate in N6 medium can be used in practicing anther culture technique in indica rice. Anther culture technique was also used in twelve rice genotypes that consisted of three different rice crosses namely indica aromatic × japonica aromatic, indica aromatic × indica aromatic, and indica non-aromatic × indica aromatic to produce and comparisons of callus induction. It was found that MRQ50×Rambir Basmati genotype grew faster than other genotypes. Meanwhile, MR219×Rato Basmati took longest time to grow up and MR219×Sadri produced more callus than other genotypes. In addition, the indica non-aromatic×indica aromatic cross had the highest frequency in callus formation. Finally, the genotypes that produced more callus could be used as potential breeding material.