Length of vernalization period affects flowering time in three lupin species

With 2 figures and 2 tables

Lupin is a long‐day plant, and its flowering time can be affected by prolonged exposure to cold, ambient temperatures and photoperiod. The vernalization response was investigated in three species of lupins, Lupinus albus L., L. luteus L. and L. mutabilis Sweet., under varying vernalization regimes in glasshouse conditions over summer. A range of genotypes were included from each species. Three weeks after emergence, each line was vernalized for 0–4 weeks in a cool room at 6°±1°C with 14h photoperiod. Vernalization did not affect flowering time in early‐season genotypes of all lupin species. However, significant differences occurred in mid to late‐season genotypes. All genotypes including very late wild types flowered after 2 weeks of vernalization, indicating 2‐week cold treatment was enough to induce flowering. Vernalization synchronized flowering for mid and late‐season genotypes of L. luteus, giving greater flexibility of phenology in long growing season environments where vernalization occurs naturally. Vernalization reduced leaf node number in late‐flowering lines of all species including mid‐season L. luteus.