Shorten rice breeding cycle and developing new promising lines

Abstract

Accelerating rice breeding can be accomplished through various approaches, including molecular or conventional techniques. In this regard, some rice breeding programs around the world have changed to use rapid generation advancement (RGA) as a new breeding method. The objectives of this investigation are to establish and implement RGA techniques at the Rice Research & Training Center (RRTC) to develop new, improved, blast disease-resistant, and high-yielding varieties more quickly and at a low cost. Three F 2 populations, (Giza177 x Sakha Super300), (IR75589-31 x Giza178), and (Giza179 x IR59673-93-2-3-3-2), were advanced to F 2 and evaluated in Lines Stage Trials (LST) and preliminary yield trials (PYT). RGA facilities were installed at the greenhouse of the RRTC, and the F 2 plants of each population were harvested individually. One seed from each panicle was used to cultivate the next generation (F 3 ) according to the single seed descent (SSD) method. The RGA technique was successfully implemented at RRTC with simple multipot trays and the maintenance of the greenhouse and screen house. The early generations (F 2 , F 3 , F 4 , and F 5 ) showed good performance in the greenhouse; the narrow space and low fertilizer led to early flowering. promising RGA lines, SK-RGA2-5, SK-RGA2-9, and SK-RGA3-6, revealed grain yields of more than 11.0 t/ha compared with the check varieties, Giza177, Giza178, and Sakha super300, which gave 9.57, 10.17, and 10.50 t/ha, respectively. For grain quality traits, most of the test RGA lines and check varieties have low to medium amylose content, ranging between 17.83 and 23.13%. RGA lines and check varieties gave desirable values for hulling and milling. In general, hulling% ranged between 80.0 and 85.0%, and milling% ranged between 69.43 and 73.0%.