Ppd gene effects on frost
Day length (photoperiod) affects plant flowering time. QTL for frost and
the time of anthesis and maturity were repeatedly detected on
chromosomes 2A, 2B and 2D. The Ppd1_2A allele was tightly linked
to the frost QTL on 2A. Remarkably, four out of five frost QTL (next to
anthesis QTL) were detected in the
proximity of Ppd1_2B in five populations. Due to thePpd1_2B copy number differences between parental lines of these
four DH populations, it is likely that the significant frost QTL were
contributed by the segregation of Ppd1_2B gene copy numbers,
with a high copy number of Ppd1_2B shortening the days to
anthesis and inducing early flowering, thus contributing to the frost
QTL. Ppd1_2D did not segregate in our six populations and no
strong linkage to the frost QTL on 2D was detected.