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

Abstract

Rice is the staple food for about half of the world's population. Preferred by consumers, aromatic rice is a special type of rice with great commercial value. Cooking and eating qualities and aroma are the major grain qualities favored by most consumers. Currently, most of the available aromatic varieties have low yields and some undesirable agronomic traits. Thus, there is an urgent need to develop better aromatic rice varieties. This work aims to identify rice germplasm lines that have good grain quality and to develop new varieties with desirable traits. Thirty-six out of 188 germplasm lines were found to have betaine aldehyde dehydrogenase 2 (badh2) controlling the aroma and were analyzed for their 2-acetyl-1-pyrroline (2AP) contents. Then, 17 of those lines were found to have alleles for low amylose content and low gelatinization temperature, controlled by waxy and starch synthase IIa (SSIIa), respectively, suggesting that they are aromatic rice lines with high cooking and eating qualities. A total of 158 F7 recombinant inbred lines (RILs) generated from five crosses of the selected germplasm lines were planted for phenotypic and yield observations, 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 three F9 RILs were aromatic rice lines with high amylose content and high yield. Because consumer preferences for grain quality vary depending on regions and ethnic groups, the high-yielding aromatic RILs generated from this study can be used to increase the yield of Thai rice and to raise market value and farm profits.

Keywords

• germplasm
• functional marker
• aromatic rice
• badh2
• waxy
• SSIIa