Studies on the Breeding of High Yield Variety in Air-cured Tobacco. : II. Relations among Plant Type, Growth Habit and Assimilation Rate in Some Bred Lines

Abstract

Investigations were made on the relation between photosynthetic activity and the related characters, i.e. chlorophyll content and specific leaf area. Furthermore, the difference in those relations were discussed in particular references to plant types and growth habits of the used varieties and bred lines. 22 air-cured tobacco varieties and bred lines were investigated on their photosynthesis of detached 10th leaf from the top at 60 days after transplanting. Varietal correlations between photosynthesis and characteristics mentioned above were calculated. Chlorophyll content showed most intimate relation with photosynthesis of all. Other characters also seemed to be related with photosynthesis to some extent. Differences in those four characters were compaired arnong high yielding bred lines classified in four plant types and Japanese domestic cultivars. Photosynthesis and chlorophyll contents were higher in PT 3 having cylindrical plant type with erected leaves than in the other plant types. Specifc leaf area was higher in PT 1 having pyramidal plant type, and its photosynthetic activity was lower than that of the others. Difference in photosynthetic activity between Japanese domestic cultivar and its isogenic lines having Yellow Burley character was considered to originate from difference of chlorophyll level. From the view points of photosynthetic activity of single eaf and assimilation system of plant, the varieties belonging to PT 3 plant type were expected to be bred for high productivity.