Bulked-population method of handling cereal hybrids
1929
Florell, V.H.
The bulked-population method of handling cereal hybrids consists essentially of creating populations by hybridization, growing the hybrids in bulk for six or eight generations until they have become homozygous or nearly so, and then making head or plant selections for comparative testing in the usual way. Nineteen crosses were handled by this method in an experiment at University Farm, Davis, Calif., in all or part of the years from 1923 to 1926, inclusive. Two generations were grown in each year. Head selections were made in 1926 and were grown in head rows in 1927. The best head rows were sown in replicated 16-foot triple rows in 1928. The average yields of 33 of the 45 selections grown in 1928, or 73.3% of the total number, were above the average yield of all (33) check rows. As a group the selections showed marked resistance to lodging and shattering. Hard-kerneled types predominated. The number of generations required before selection depends on the number of character differences involved. Ordinarily, seven or eight generations are sufficient. The area used for a bulk population should be large enough so that, at the rate of seeding employed, all combinations expected in a cross maybe included. On the average, wheat contains 10,500 kernels per pound. From 1 to 2 pounds should be sown when dealing with crosses of ordinary complexity. The method is adapted for the development of strains possessing such characters as winterhardiness, rust resistance, smut resistance, etc., in the close-fertilized cereals.
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