Frequency distribution of days to heading in the 114 F₂ plants from a segregating population growing under SD conditions with a vernalization treatment.

<p>The F₂ population was derived from a cross between ‘Chogokuwase’ and ‘Norin 61’. White boxes indicate the plants with homozygous <i>wpcl1</i> alleles at three homoeoloci. Black boxes show the plants having one or more functional <i>WPCL1</i> homoeoalleles. Arrows indicate days to heading in ‘Chogokuwase’ and ‘Norin 61’, respectively.