In order to increase the supply of assimilated carbon to grain, a new stay-green wheat cultivar, Chuannong17 (CN17), with delayed leaf senescence, carrying wheat-rye 1RS.1BL translocated chromosome was developed. CN17 exhibited distinct differences in net photosynthetic rate (Pn),chlorophyll (ChI) content, malondialdehyde (MDA)content, activity of both superoxide dismutase (SOD)and catalase (CAT) during the grain filling stage, and flag leaf senescence compared with the control. The new cultivar maintained longer and higher photosynthetic competence compared with the control, and this aspect correlated with the difference in chloroplast development. Moreover, the stay-green phenotype of CN17 was also observed under natural growth conditions. Consequently, the coordination of the physiological, biochemical, and structural aspects in the stay-green cultivar produced higher seed weights and per-plant yield compared with the control cultivar.