Abstract: Primer Psy02 was designed according to conservative areas of Psy gene sequence of Ttiticum, and partial sequence of Psy gene of wheat was cloned . The results showed that , two different PCR products were amplified with 196 bp and 233 bp, both of which covered whole sequence of the second exon of wheat Psy gene, and the 37 bp difference between two bands was an insertion sequence of the second exon of Psy gene, which display different YPC in wheat . Verification test showed , that among 248 wheat micro core collections, 153 samples amplified 196 bp band while the rest samples
amplified 233 bp band which accounted for 61.7% and 38.3% respectively. The YPC average value of 153 samples was 7.314mg kg^-1 which belong to high YPC rang and that of 95 smaples was 5.207mg kg^-1 which belong to low YPC rang. Variance analysis showed that the YPC difference reached 1% significant level , which proved the 37 bp insertion sequence was one of the reasons of different YPC in cultivars , in a word , the YPC of wheat was significantly affected by the Psy gene and, primer Psy02 was an important molecular marker to identifying YPC .

Key words: Wheat