Dale N. Moss

Photosynthesis and Crop Production

Publisher Summary The relationship of photosynthetic capability and crop yield is not a simple one. Yield is an integration of the effects of numerous factors on many physiological processes and morphological components. Indeed, a direct cause–effect relationship between photosynthesis and yield has yet to be established. This chapter reviews the large volume of recent work on photosynthesis and evaluates these results in terms of the relationship of net carbon dioxide fixation and yield of various crops to assess the potential to improve crop yield by developing varieties with enhanced capacity to fix CO 2 . Net photosynthesis is defined operationally and is measured by analyzing the change in CO 2 , content in air surrounding the leaves or plants under investigation. To learn manipulating crop canopies to enhance their photosynthesis, or to be most efficient in breeding varieties with enhanced photosynthesis, it is must to know the reasons that limit photosynthesis in crops growing in the field. An abundance of information has been published on this topic within the past decades resulting in significant changes in the thinking of many physiologists and plant breeders who are concerned with crop yields. The chapter also discusses the concepts of breeding for photosynthetic efficiency, selecting for photosynthetic rates within crop species, breeding for plant type, and managing photosynthesis.

Carbon Dioxide Compensation Points in Related Plant Species

Both high and low C02 compensation concentrations were found in the plant genera-Panicum, Cyperus, and Euphorbia. Within each genus, however, high and low compensations were found in different subgenera. Thus, they may not be genetically closely related. No significant differences in CO2 compensation were found among 100 genetic lines of Triticum aestivum L. or among 20 lines of Hordeum vulgare L.