抄録
Lodging indices, date of heading, plant height, number and weight of panicles per hill, and grain yield per unit area of eight varieties of rice were studied in individually space-planted (IS), normally transplanted (i. e. three plants per hill) (NT), and directly seeded plots (DS), each in six replications of randomized blocks (Tab.1). The F values for comparing variety and error mean square, calculated by the analysis of variance, exceeded the 1 or the 5 per cent points (Tab. 2). The correlations between the characters of rice-plants in IS and those in NT were significantly high except the weight of panicles per hill (Tab. 3). The correlation coefficients between the characters of ric-plants in IS and those in DS, however, were not significantly high except for lodging indices, date of heading and plant height. It may therefore be concluded that, while the behavior of individually spac-planted plot as a criterion of behavior in normally transplanted plot seems to be considerably reliable, the former as a criterion of behavior in the directly seeded plots seems unreliable except for lodging, date of heading and plant height. Moreover, the correlation coefficients between the grain yield of DS or NT and the number or weight of panicles per hill in IS (Tab. 4) show, in so far as my present materials are concerned, that the grain yield of varieties directly seeded or normally transplanted cannot surely be predicted from the number or weight of panicles in individually space-planted plots.
