Stress-associated protein(SAP)has functions in maintaining plant cell elongation,embryo development and response to abiotic stresses.TaSAP1-A1,one of the Triticum aestivum SAP1(TaSAP1)members located on wheat chromosome 7A was isolated for polymorphism analysis.HapIII of TaSAP1-A1 was found significantly associated with thousand-grain weight(TGW)in multiple environments.In this study,HapIII also made a positive contribution to TGW in Population 2.The distribution of TaSAP1-A1HapIII was tracked among varieties released in different years and geographical environments of China.The frequency of HapIII showed an increasing trend during the breeding process in two different populations.The HapIII was gradually selected and applied from 6.36%in landraces to 13.50%in modern varieties.These results exhibited that TaSAP1-A1 HapIII was positively selected during wheat breeding,which is beneficial for grain-yield improvement.The preferred HapIII was initially selected and applied in the higher latitude areas of China in accord with the long day season and longer grain filling stage in these areas.Moreover,the frequency of HapIII in recent modern varieties was still quite low(19.29-26.67%).It indicated a high application potential of TaSAP1-A1 HapIII for improving grain yield in wheat breeding. Stress-associated protein (SAP) has functions in maintaining plant cell elongation, embryo development and response to abiotic stress. SaSAP1-A1, one of the Triticum aestivum SAP1 (TaSAP1) members located on wheat chromosome 7A was isolated for polymorphism analysis. TaSAP1-A1 was found significantly associated with thousand-grain weight (TGW) in multiple environments. In this study, HapIII also made a positive contribution to TGW in Population 2. The distribution of TaSAP1-A1HapIII was tracked among varieties released in different years and geographical environments of China. The frequency of HapIII showed an increasing trend during the breeding process in two different populations. The HapIII was gradually selected and applied from 6.36% in landraces to 13.50% in modern varieties. sese results ie that TaSAP1-A1 HapIII was positively selected during wheat breeding, which is beneficial for grain-yield improvement. The preferred HapIII was initially selected and applied in the higher la titude areas of China in accord with the long day season and longer grain filling stage in these areas. Moreover, the frequency of HapIII in recent modern varieties was still quite low (19.29-26.67%). It indicates a high application potential of TaSAP1- A1 HapIII for improving grain yield in wheat breeding.