Development of new aromatic rice lines with high eating and cooking qualities

Abstract

Rice is the staple food of about half of the world’s population. Preferred by consumers, aromatic rice is special rice with great commercial value. Cooking and eating quality and aroma are major grain qualities favored by most consumers. Currently, most of the available aromatic varieties have low yield with some undesirable agronomic traits. Thus, there is an urgent need to develop better aromatic rice varieties. This work aims to identify rice germplasm lines having good grain quality and to develop new varieties with desirable traits. Thirty-six out of 188 germplasm lines were identified to have betaine aldehyde dehydrogenase 2 (badh2) controlling aroma and were determined for their 2-acetyl-1-pyrroline (2AP) contents. Then, 17 of these lines were identified to have alleles for low amylose content and low gelatinization temperature, controlled by waxy and starch synthase IIa (SSIIa) respectively, suggesting that they were aromatic rice lines with high cooking and eating quality. A total of 158 F7 recombinant inbred lines (RILs) generated from five crosses of selected germplasm lines were planted for phenotypic and yield observation, resulting in 27 F8 RILs selected for yield evaluation and genotyping. Finally, four out of the seven F9 aromatic RILs showed high yield, high 2AP production, and low amylose content, in agreement with their genotypes. The other 3 F9 RILs were aromatic rice lines with high amylose content and high yield. Because consumers’ preference for grain quality varies depending on regions and ethnic groups, the high-yielding aromatic RILs generated from this study can be used to increase yield of Thai rice and to raise market value and farm profit.