Species and Varieties: Their Origin by Mutation : Lectures Delivered at the University of California

Hugo de Vries

1904 оны 1-р сар · Open Court Publishing Company

Энэ электрон номын тухай

From time to time the idea has suggested itself to some of the best authorities on the amelioration of plants, that this atavism was not due to an innate tendency, but, in many cases at least, was produced by crosses between neighboring varieties. It is especially owing to Verlot that this side of the question was brought forward. But breeders as a rule have not attached much importance to this supposition, chiefly because of the great practical difficulties attending any attempt to guard the species of the larger cultures against intermixture with other varieties. Bees and humble-bees fly from bud to bud, and carry the pollen from one sort to another, and separation by great distances would be required to avoid this source of impurity. Annotation Published: February 2014.