SN02-3 and SN05-3 and their CHA-male sterile lines were used to study the effects of BAU9403 on the net photosynthetic rate(Pn) and the accumulation and transportation of photosynthates in the flag leaves in the process of wheat grain filling and illustrate the reasons for the thinness of CHA-male sterile hybrid grains.The results showed that the Pn of CHA-male sterile lines was higher than that of their fertile lines and the export rate of dry matter was just 41.88% of that of their fertile lines at the ea...