An improved anther culture procedure for obtaining new commercial Mediterranean temperate japonica rice (Oryza sativa) genotypes

Rice is one of the greatest calorie supply for the world population, especially since its production is almost entirely destined to direct human consumption and its demand will increase along with the world population. There are efforts worldwide to increase rice yields by obtaining new improved and stabilized rice lines. The rice anther culture, a fast and cheap technique, allows to obtain double haploid lines in less than one year. We report its application with an improved protocol in four Mediterranean japonica rice genotypes at F-2 generation. We performed a screening test for cold-pretreatment at 5.0 +/- 0.1 degrees C and concluded that the optimum duration was 9 days as it produced the higher rate of anther-derived callus induction. This revised protocol was successfully applied to the four genotypes, obtaining good results in all the procedure's steps. At the end, more than 100 of double haploid green plants were generated. Moreover, 9 lines obtained from the anther culture procedure showed good qualities for the Spanish market at the growing, farming and grain production level during the field assays. Therefore, we report an improved anther culture procedure for obtaining double haploid lines from temperate japonica rice genotypes showing high commercialization expectance.