Studies in Vernalisation of Cereals

Abstract

Experiments are described which were designed to test whether the unvernalised condition of winter rye grain produced by fully vernalised parent plants is due to de-vernalisation occurring during maturation and ripening of the seed. The results show clearly that drying of the grain does not account for the un-vernalised condition. Parent ears exposed from the time of their emergence to a range of non-vernalising temperatures (12–20° C), i.e. including ‘neutral’ levels which are neither vernalising nor de-vernalising, still produced unvernalised grain. Even plants raised from grain which had been developed at mildly vernalising temperatures (9° C) benefited from further cold treatment applied during their early growth. It appears, therefore, that the vernalisation requirement in winter rye arises very early in the formation of the seed, i.e. possibly at meiosis or fertilisation, and that there is no subsequent transmission of the vernalisation stimulus from the parent plant. Additional observations on plant height, ear size, &c., also indicate marked effects of temperature and daylength treatments.