Selection Effectiveness of Lodging Tolerance by using Pushing Resistance for Improving Rice Cultivar adapted to Direct Sowing Culture in Flooded Paddy Fields

Abstract

This study was undertaken to find the selection effectiveness of lodging tolerance by using pushing resistance for improving rice cultivar adapted to direct sowing culture in flooded paddy fields. The lines used in the experiment ware F₄ and F₅ breeding lines of Aoinokaze // Lemont / Hinohikari; 47 lines and Yumehikari // Lemont / Hinohikari; 29 lines that ware medium maturity lines. There was a significant negative correlation between the pushing resistance of F₄ lines in transplanting culture and lodging degree of F₅ lines in direct sowing culture. Even though the selection rate of pushing resistance in F₄ was changing from 10% to 40%, thre was a distinct difference in lodging degree under direct sowing culture in F₅. A few F₅ lines selected by using pushing resistance in transplanting culture ware superior in lodging tolerance and yielding ability under direct sowing culture. There ware comparatively few deviations of yielding ability and grain quality by using pushing resistance for the selection of lodging tolerance in an early generation. These results lead to the conclusion that it is possible to breed high lodging tolerance cultivar adapted to direct sowing culture by using pushing resistance under transplanting culture in an early generation.