The Yangmai 19, Chinese Spring, Pubing3228, Shannong23 and Zhengmai9405 varieties were sown at the experimental station of the Institute of Genetics & Developmental Biology, CAS in Beijing, China in October 2014; three rows of each variety were planted. The length of each row was 2 m, and the row-to-row distance was 20 cm. The plants were managed in accordance with standard agronomic practices; irrigation and fertilizer were supplied for optimal growth. Twelve- day-old flag leaves of five plants from each variety were harvested and stored at −80 °C. Unfertilized grains were collected from each variety 1–2 days before flowering (DBF). Fertilized grains were collected from each variety at 5, 10, 15, 20 and 25 days after flowering (DAF). The flag leaf and developing grain samples were processed for the preparation of total RNA as described previously . Three biological replicates that were collected from different plants were analyzed separately for each variety for quantitative RT-PCR evaluation. For TaFlo2-A1 transcripts analysis, the primer set eTaFlo2, which is specific for TaFlo2-A1 (Table 1), was designed and used. Quantitative RT-PCR was then carried out as described by Feng et al. . The wheat actin gene was used as an internal control. The relative expression level of TaFlo2-A1 in each flag leaf and in each sample of developing grains was calculated using the data of three technical replicates as described previously . Statistical comparisons of TaFlo2-A1 expression levels (presented as the mean ± SD) among different samples were made by ANOVA using SPSS 13.0.