The barley plant for whole crop forage is advantageous to have traits with higher photosynthetic rate, biomass, lodging resistance, and awnless spikes. The objective of this study is to investigate performance of near-isogenic line pairs for the awned and awnless in the field, and to observe the variations in photosynthetic rate, yield and their related traits under removal of flag leaf and awns. Grain yield was 6% higher, but biomass and photosynthetic rate were 6～16% and 6% lower in the awned line than those in the awnless grown in the field ,respectively. Defoliation of flag leaf resulted in approximately 3～4%, and 5～6% decreases in 1,000 kernels and grain weights, respectively. Deawning at the heading stage of the long awned line decreased 1,000 kernels and grain weights by 7% and 15%, respectively, The removal of both assimilative tissues caused 14 and 21% decrements in 1,000 kernels and grain weights. Apparent photosynthetic rate of leaf blade in awnless line was 6.1 -9. 7 $CO_2$$_2$ ${mu}$mole $m^{-2}$ $s{-1}$, much higher than that in awned line. The relative rates in the second and third leaves were about 93% and 55～63%, respectively as compared with that in the flag leaf. The results of the experiments suggest that the awnless line selected for whole crop forage is a potential plant type with higher photosynthetic rate, leaf area and greater biomass.