Monitoring of grain length gene (GS3) in composite cross populations of rice by molecular marker

Grain appearance quality mainly, is defined by grain length, grain width and long to width rations, which have an important role in marketability. Since determination of grain shape in the early stage of growth is not possible, marker assisted selection is a basic step to improve the quantitative and qualitative traits in rice. In this study, two local high quality rice cultivars (Shastak and Domsiah) and two improved high yielding rice varieties (Fajr and Nemat) were used to improve the quality-related traits in new released variety (Ghaem), through classical methods and MAS. For the MAS, firstly the accuracy of the GS09 primer was confirmed by utilizing in silico studies and analyzing correlation of banding pattern with parental phenotype. Thus shastak variety with short grain phenotype created unique banding patterns than other parents. Banding patterns of GS3 in the cross 1 (Fajr / Ghaem // Shastak / Ghaem), cross 3 (Nemat / Ghaem // Shastak / Ghaem) and cross 4 (Shastak / Ghaem // Domsia / Ghaem) were used for distinction the heterozygous plants containing shastak allele (unfavorable) from other plants. Therefore, long grain plants should be studied for achieving pure lines in progressive generations. The results indicated that the GS3 locus markers can be used as a quick and inexpensive method to improve the quality of grain length.