GENETIC-ANALYSIS OF THE MORPHOLOGY OF SIL ICA BODIES FROM MOTOR CELLSIN RICE (ORYZA-SATIVA L.)

Genetic analysis of the morphology of silica bodies from motor cells i n rice (Oryza sativa L.) was conducted by examining an F-2 population and a set of 3 x 5 NC II dialIel crosses. Segregation for the four mor phological characters-vertical length, horizontal length, lateral leng th and shape coefficient (bia)- of silica bodies in the Fz population showed a countinous and a wide distribution exceeding the ranges of th e two parents (Fig. 2), suggesting that the morphological characters o f silica bodies were quantitative and controlled by several genes. In the NC II diallel analysis, the heterogeneity of W'r+1/2Vr between arr ays was not significant for all the morphological characters but b/a, and the heterogeneity of W'r-1/2Vr was not observed for all the charac ters tested (Table 4). The regression coefficients of W'r on Vr were n early 0.5 but significantly different from zero (Table 5), indicating that the shape of the silica bodies was controlled by an additive-domi nance genetic system. The heritabilities in a broad sense for the four characters were in the range of 0.43 similar to 0.73 and those in a n arrow sense in the range of 0.29 similar to 0.54 (Table 6).