A series of experiments were carried out at 14 sites in the major arable areas of the UK, in the years
1993–94, 1994–95 and 1995–96 to determine the causes and extent of over-winter plant losses of two
autumn-sown cultivars of white lupin (Lupinus albus L.).
Over the three seasons frost was the major cause of plant losses. Two mechanisms (one known and
one not previously reported in the UK) of frost tolerance under field conditions were identified: (i)
lignification of the root parenchyma early in the life of the seedling, and (ii) a large vernalization
requirement of the main-stem apex, which delays stem elongation in older plants. A model was
developed that could be used to predict the susceptibility of these lupin cultivars to the first severe
frost of the winter using accumulated thermal time (above a base temperature of 3 °C).
The effect of sowing at the beginning or end of a sowing window, calculated to optimize plant
architecture the following summer, therefore varied with the weather during the autumn/winter
period. A combination of cool autumn weather and late sowing (outside of the sowing window)
resulted in plant losses due to a lack of lignification of the root parenchyma. In unusually warm
autumn conditions (1994–95 and 1995–96) plants sown at the beginning of the sowing window were
well developed before the first frosts occurred, with consequent stem elongation and plant losses.
Although losses due to pests were not severe (c. 3 to 5 plants/m2), plants were attacked during the
autumn by grey field slugs (Deroceras reticulatum Muller), bean seed flies (Delia platura Meigen), and
probably thrips (Thrips angusticeps Uzel, Noctuidae), although this has not been confirmed. The
fungal pathogens Fusarium spp. and Botrytis cinerea Pers. caused losses in conjunction with frost