Molecular breeding of “Swarna,” a mega rice variety for lodging resistance

Lodging of the crop is one of the major constraints in cyclone-prone coastal rice areas. The feasibility of conventional breeding approaches for lodging resistance is limited due to high influence of structural and weather parameters. Stem lodging is the major risk for irrigated low land areas. In the present study, F 2 population derived from the cross between lodging-susceptible Swarna variety and lodging-resistant advanced breeding line MTUII 110-9-1-1-1-1 was used for QTL mapping. A total of five QTLs were identified for culm diameter, culm thickness, culm strength, bending stress, and panicle length. The phenotypic response and QTLs identified from the above population elucidate that culm diameter and culm thickness play key role in lodging resistance. Gene prediction in the mapping region of culm diameter and thickness on chromosome 6 revealed that gene sets of microtubule-based movement LOC_0s06g45900 and potassium transporter LOC_0s06g45940 might be putative candidate genes responsible for lodging resistance. Near isogenic line (NIL) with wider and thick culm in Swarna background was developed using marker-assisted backcross breeding. Developed lodging resistant line in the background of widely adopted mega rice variety Swarna would enhance the rice productivity even under adverse climatic conditions.