Genetic and Phenotypic Screening of Different Rice Genotypes According to the Functional Marker Related to the Semi-Dwarfing Sd1 Gene

Creating semi-dwarf plants is one of the most important goals in rice breeding. The decrease in the quality and quantity of the  crope produced due to the dormancy of the rice plant has a negative effect on the farmers' economy. In order to stabilize the cultivated area and also to supply rice for the country's consumption, it is recommended to introduce cultivars of local origin with semi-dwarfing traits, along with increasing yield. The first step to transferring this trait to local cultivars is screening to identify suitable parents for transferring the semi-dwarf gene and also identifying efficient markers for the advancement of backcrossing projects with the help of markers. For this purpose, this research was carried out for the phenotypic evaluation and molecular screening of the available genotypes based on the functional markers related to the semi-dwarfing trait.

In this research, 50 local and improved rice genotypes were prepared from the collection of the Rice Research Institute of Iran And the dwarfing trait was investigated based on phenotypic and molecular evaluations in the field related to the band pattern created by a pair of specific primers (semidwarfing gene = sd1) contiguous with the gene locus controlling the semi-dwarfing trait. The generalized linear logistic regression model was used to analyze the observed correlation between genes. Also, the hypothesis of  a genetic relationship between the sd1 gene allele and plant height was tested through a logistic regression model.

Based on the genetic evaluation, 26 cultivars were found to have the allele of the semi-dwarfing gene and 24 cultivars did not have the allele of this gene, and the used marker is able to predict and differentiate the  cultivars for future breeding  programs with high confidence and accuracy. The logistic regression results also confirmed this result.

According to the observed results, the used functional marker sd1 can be used as an efficient marker for the screening of separating populations to improve the semi-dwarfing trait.