Veredeling van tarwe en gerst op winterhardheid

Cold resistance appeared to be so complicated and variable, that a clear insight could be obtained only when important factors such as degree of vernalization, stages of growth and development, and hardening were considered in the experiments. For various reasons, breeders are more and more obliged to use extremely varied material in their programmes, such as of breeding for disease resistance.

In 1951 the Foundation for Agricultural Plant Breeding at Wageningen had a refrigerator and hardening equipment installed to provide private breeders with cold-resistant material and to test their new lines for this character. This gave the author the opportunity to study winter-hardiness.

It was possible to develop winter wheat varieties with sufficient winter- hardiness, slight need of vernalization and rapid spring development. Varieties of winter barley could be developed with a better winter-hardiness.

The method recommended by Hoffmann of vernalizing the seed before sowing in autumn to test and select for winter-hardiness was highly practicable. Trials on date of sowing in autumn involving seed vernalization and lengthening of the day were a valuable aid to research on cold resistance.