Studies on the varietal difference in the characters of high-yielding rice- Varietal difference in bleeding rate

The varietal difference in bleeding rate was investigated using 10 Japanese varieties (J group) and 10 high-yielding varieties of rice bred in Asian c ountries (H group). The relationship between bleeding rate and yield charac ters was examined. Bleeding rate at the heading time (BR1) and maturing tim e (BR2) ranged from 2.20 to 3.92, and from 1.50 to 2.62 (g h(-1) hill(-1)), respectively. There were no significant differences in BR1 and BR2 between the two groups. The reduction rate of bleeding rate (RRB) during the ripen ing period shown by 1-BR2/BR1 was significantly higher in the W group than in the J group. BR1 was not significantly correlated with the number of the phytomers (TPN), but showed a significant positive correlation with BR1/TP N. BR1 also showed a significant positive correItion with the shoot dry wei ght at the heading lime. There was a significant positive correlation betwe en RRB and the decline of leaf color (DLC) during the ripening period. More over, a significant negative correlation was found between RRB and the perc entage of ripened grain. These results imply that the variety with a higher RRB and DLC has a lower ripening ability.