Genetic Analysis of Physical and Chemical Characteristics Associated With Grain Quality in Rice

In order to study the gene actions and heritability of the physical and chemical characteristics associated with appearance and cooking quality of rice grain, generation mean analysis was performed using a cross between two Iranian rice cultivars, Deylamani and Sepidroud, having different quality characters. Seeds of the parental lines and F1, F2, BC1 and BC2 generations were grown in randomized complete block design with three replications in farm. Twelve chemical and physical traits including: paddy length, paddy width, paddy length to width ratio, head rice percent, broken rice percent, white grain length, white grain width, white grain length to width ratio, 100-grain weight, amylose content, gelatinization temperature and protein content were measured. The analysis of variance showed significant differences between generations for all studied traits. According to generation mean analysis, additive dominance model was fit for all traits and the epistatic effects were not significant. Degree of dominance showed that the paddy length and white grain width were controlled by over-dominance, white grain length to width ratio and gelatinization temperature by complete dominance and the other traits by partial dominance effect. Average broad-sense heritability ranged from 0.36 to 0.93 for paddy width and gelatinization temperature, respectively, and average narrow-sense heritability varied from 0.32 to 0.76 for paddy width and amylase content, respectively. In conclusion, the results of this study showed that to improve paddy length, paddy width, white grain length to width ratio and gelatinization temperature in population resulting the cross between Deylamani and Sepidroud, the heterosis and hybrid production method will be suitable, but for other studied traits, selection after crossing can be used at first to increase the favorable genes and then hybridization between the lines with good performance will be performed to utilize the dominance gene effects.