Photosynthetic and translocation pattern in contrasting winter wheat varieties

SUMMARY The rates of photosynthesis and patterns of translocation of 14C from the flag leaves of tall and semi‐dwarf wheat varieties, with and without awns, were compared in a field experiment. The rates of photosynthesis of the awnless varieties fell during the 14 days after anthesis but those of the awned varieties did not change. Wide differences in translocation pattern of 14C supplied at anthesis were also found between varieties, but the differences in distribution pattern of 14C supplied 14 days later were less. At anthesis, the high yielding semi‐dwarf selection translocated most carbohydrate to the ears and awned selections least. It is suggested that varietal differences in translocation pattern are determined by differences in the capacity of the grain to store carbohydrate.