INTROGRESSING sd-1 GENE INTO BASMATI 370 RICE

Abstract

Rice (Oryza sativa) is depended upon by over half of the world's population as a primary staple food. Basmati 370 rice (BS 370) is popularly grown in many parts of the world for its good aroma and long, slender grains with excellent cooking and eating quality. However, its tallness nature and weak stem structure render it susceptible to lodging, particularly when subjected to high doses of nitrogenous fertilizer which leads to grain loss. Lodging reduces the efficiency of mechanized harvesting which is commonly used for large scale rice production, and further aggravates pre-harvest losses. A transformation of BS 370 to a short stature plant was needed to address this challenge. This research initiated a breeding program to develop a semi-dwarf rice line of Basmati 370 origin while being keen to retain the aromatic qualities. To realize this, Basmati 370 being the female parent, was crossed with a semi-dwarf variety IR64, the male parent using the emasculation and dusting method. This was followed by using unique anthocyanin pigmentation for hybrid identification to distinguish successful crosses from non-successful cross breeds. Molecular marker-assisted selection was performed to confirm whether the distinctive aroma associated with Basmati rice was present. The F1s were advanced to F2s. The F2 segregation was analyzed for performance against the parental lines. The findings demonstrate the successful development of a semi-dwarf BS 370 rice line with reduced height, shortened culm length, fairly shorter leaf lengths and, anthocyanin pigmentation on the leaves, stems and tips of seeds which are a good indicator of a semi-dwarf line that will ultimately address the lodging issue once stabilized in advanced filial generations. This breakthrough offers promising prospects for reduced grain loss, and improved efficiency in mechanized harvesting. This will ultimately benefit Kenyan Basmati rice farmers and the rice industry as a whole.