DefinePK

Abstract

Hybrid rice breeding increases yield by hitchhiking on heterosis, a trait in an offspring that is better than the parents. Use the three-line (CMS) or two-line (EGMS) protocol. Hollingshead describes a three-line CMS system with male-sterile A, maintenance B, and fertility restorative R lines. The hybrid seed is created by crossing the two lines, with the A line maintained by the B-line. The two-liner EGMS uses TGMS or PGMS to achieve male sterility and remove the maintainer line. This is why the hybrid seed is generated from EGMS lines under sterility-inducing conditions. CMS hybrid rice breeding involves establishing and maintaining A, B, and R lines, testcrosses to find restorers and maintainers, backcrosses to improve the A-line, and combining ability tests to choose high-yielding hybrids. Digenic interactions affect complete genes, with epistatic interaction contributing most to heterosis. Hybrid rice has naturally inherited biological intellectual property rights that encourage private seed production. However, high seed costs, grain quality, and pest and disease vulnerability should be addressed. Therefore, wisely and properly managing agronomic requirements is necessary to maximize hybrid rice yields.