Title: Introduction of the semi-dwarfing gene (sd-1) into rice commercial landraces and development of a semi-dwarf segregating population
Author: Alireza Nabipour
Abstract: Local varieties of rice in Iran, which include famous cultivars such as Tarom, Hashemi, Domsiah, etc., due to their good grain and cook qualities enjoy good market share and are favored by farmers and end users. Despite that, because of their tall stature and low fertilizer tolerance, they are susceptible to lodging that decreases the quantity and quality of grain yield. By reducing plant height without affecting grain quality, the yield would increase and farmers would welcome the new short variety. Semi-dwarfing gene sd1 is involved in a specific biochemical cascade that only shortens the plant height and improves fertilizer tolerance while having no unfavorable effect on the plant and its yield and quality. In this study, which aimed to reduce the plant height in Iranian local rice varieties and development of segregating varieties for the sd1 semi-dwarfing gene, six local rice varieties, namely, Tarom Mahalli and Tarom Hashemi from Mazandaran Province and Hassan Saraee, Sadri, Hashemi, and Domsiah from Guilan Province were crossed with IR8 and IR64 varieties that include sd1 allele. During the second to fourth years, back-crosses were made with local parents to produce BC1 to BC3, respectively. In the fifth year, some plants were back- crossed again with respective local varieties to produce BC4, while some other plants were self-fed to produce BC3F2.
Keywords: Rice, Semi-dwarf stature, Back-cross, Marker Assisted Selection