Abstract
Photosynthetic characteristics of nine varieties and their relation to dry-matter-production were investigated under two levels of manuring on the field, the results being as follows : 1) Different features were found with different varieties in their photosynthetic ability both on field area basis and on leaf area basis, their total leaf area, their light-receiving-coefficients, and their relations between photosynthetic activity and respiration of unit leaf area. 2) The authors' experimental formulae expressing the composision of the field photosynthetic ability or the light curves of field photosynthesis, were shown to be applicable to different varieties as well. 3) The dry-matter-production of varieties at their later stages is determined mainly by the difference in their photosynthetic ability on unit field area so long as the solar radiation is abundant, while it is governed mainly by the difference in their respiration when the solar radiation is scarce.
