The Effect Of The Starch-synthesizing Genes On Cooking And Eating Quality In Rice (Oryza Sativa L.)

Rice is an important crop cereal, and provides staple food for more than 50% of the world's population. The demand for superior grain quality, especially cooking and eating quality, has become priority for rice market. Amylose content (AC) is one of the key determinants to cooking and eating quality, however there existed a very large difference in cooking and eating quality, such as starch viscosity, among cultivars with similar amylose content. The Rapid Visco Analyser (RVA) has been used widely to measure starch viscosity characteristics in cereal, and proved useful in the estimation of rice eating and cooking qualities in rice breeding programs. RVA profile consists of five primary measurements peak viscosity (PKV), hot viscosity (HPV), cool viscosity (CPV), peak time(PeT), paste temperature(PaT) and three secondary measurements: breakdown value (BDV, =PKV-HPV), setback value(SBV, =CPV-PKV) and consistency value (CSV, =CPV-HPV). It may be much precise to select the individuals by using two indices, AC and RVA profile, to determine their eating and cooking quality, but such measurement is very heavy, and their genetic characteristic is complex, implied that selection of phenotype might have a low efficiency in the process of rice quality improvement. Recent development of molecular biology provided a valuable tool, such as the Marker-Assisted Selection (MAS), for rice quality improvement.Starch amounts to 90% in milled rice, indicating that starch-synthesizing genes may have a correlation with cooking and eating quality. Starch is composed of amylose...