Biochemical and Molecular Screening of Different Rice Genotypes for Temperature Characteristics of Starch Gelatinization

Gelatinization temperature is one of the most important characteristics of determining cooking time and an important indicator of rice grain quality. Gelatinization temperature is defined as the temperature at which rice starch granules begin to irreversibly lose their crystalline nature and order. In this research, phenotypic and molecular screening of 50 different genotypes of local and improved varieties of rice was done in order to separate selective varieties of rice based on the difference in gelatinization temperature.

The required seeds for the study were obtained from the collection of the Rice Research Institute of Iran, and after cultivation in the research field of the Rice Research Institute, the produced seeds were harvested and the gelatinization temperature of the rice seeds was measured based on the phenotypic test. It was done with 1/7% potassium hydroxide method and molecular evaluation was done using the marker (Alk) (from the genes controlling the gelatinization temperature) and the logistic regression model was used to analyze the correlation between genes and phenotype.

Based on the phenotypic evaluation based on the biochemical trait of gelatinization temperature created for different rice samples, it was determined that out of 50 genotypes, 33 cultivars had a gelatinization temperature of 3-5 and 17 cultivars had a gelatinization temperature of 6-7 were. In the molecular evaluation, the marker (Alk) separated 33 cultivars with a gelatinization temperature of 3 to 5.

Potassium hydroxide method has 1/7% efficiency to differentiate genotypes with different gelatinization temperature. The marker (Alk) also has the necessary efficiency in separating genotypes with medium gelatinization temperature.