Abstract
Value of CCN was measured by a non-destructive quantitative analyzer (CCN-05A; Satake Corp., Japan) during the ripening period (from the beginning stage of ear-drooping to maturing stage) to estimate leaf nitrogen content by near-infrared transmission method in the rice cultivar Koshihikari. This value was compared with the SPAD value estimated by a non-destructive method (SPAD-502; Konica Minolta Sensing Inc., Japan), and the nitrogen content determined by the Kjeldahl method. A high correlation coefficient (0.942***) was found between the SPAD (x) and CCN (y) values with a linear regression equation: y = 0.105x-0.460. Thus, the SPAD value of leaves can be estimated from the CCN values with good precision (estimated error from the regression equation: se=0.19%). In addition, a high correlation coefficient (0.837***) was obtained between the CCN values (x) and the nitrogen content (y) in the flag leaf determined at the dough stage (28 days after heading) with a quadratic regression equation, y = 16.12-2.70x+1.51 x2 (se=1.96). From this analysis, we concluded that the CCN value was a good index of the nitrogen content of flag leaves in cv. Koshihikari during the ripening period.
