The polymorphic 34-bp deletion (Vrn1g) was tested using primers VRN1G_F (5¢-ACAGCGGCTATG CTCCAG-3¢) and VRN1G_R (5¢-TATCAGGTG GTTGGGTGAGG-3¢) flanking this deletion. Linkage between spring growth habit and the 493-bp insertion in the first intron of PI 306540 (Vrn1h Vrn2) was tested using primers VRN1INT1_F (5¢-ATGAAACTCCGGCATGA AGA-3¢) and VRN1INT1_R (5¢-CAAAATAAA GCCGGCAAGC-3¢) flanking the repetitive ele- ment insertion. VRN2 alleles were determined with molecular markers developed before (Yan et al., 2004b).