湛水表面散播栽培에서 벼 品種 뿌리 分布形態와 뿌리倒伏과의 關係

Relationship between varietal difference of root distribution and root lodging in direct seeded rice on flooded paddy surface

To obtain the basic informations for the selection of lodging resistant variety in direct seeded rice on flooded paddy surface, vertical and horizontal root distribution of 23 rice varieties or lines were examined in silty loam soil of alluvio-fluvial marine soil. Root lodging resistant varieties were characterized by the higher vertical deep root distribution ratio, especially over 110㎎ root dry weight per stem or 16% of total root amount in 10 to 25㎝ soil depth from the culm base. High lodging resistant varieties(lodging degree : 0) had higher ratio of deep root distribution only between hill than moderate resistant ones(lodging degree : 3) and both below hill and between hill than susceptible ones(lodging degree : 7~9). Lodging degree showed negative correlation with each layer’s root distribution ratio in every 10cm soil depth from the soil surface below hill and in 10~30㎝ soil depth between hill but positive correlation with the root ratio in 0~10㎝ soil depth between hill. Vertical root distribution is seemed to relate with root lodging, in that root lodging in direct seeded rice on flooded paddy surface owned negative correlation with each layer’s root ratio in every 10cm soil depth of total root amount(below+between hill), and especially, significant correlation with the ratio in 10~20㎝ soil depth and highly significant, in 20~30㎝, while horizontal root distribution is not so, in that root lodging didn’t have any correlation with each layers root ratio in 10~30㎝ soil depth in below/between hill. 23 varieties or lines were classified into three groups. First group was characterized by higher vertical deep root distribution ratio in 10~30㎝, lower distribution ratio in 0~10㎝ between hill and lodging resistance, including five lines, second, intermediate of 1st and 3rd groups, including 13 varieties of lines and third, the opposition of 1st group, including five varieties and lines.