Selection for the absence of photorespiration,usually associated with photosynthesis by the c4 pathway ,can be done effectively,but Moss and his colleagues have screened about 2500 soybeen genotypes,10000 oat seedling and 50000 wheat seedlings without finding a single plant with a low carbon dioxide compensation point,nor have any been found among species of Beta or TRITICUM. DISAPPOINTING as this may be we should,in the light of the discussion above,reconsider the objective of such selection.In essence it is that plant lacking photo respiration,like those with the C4, will have higher photosynthetic rates and therefore higher yields.