Hayes and Garber - Cucurbit Breeding

34 BREEDING CROP PLANT*
Group 4. Vegetatively propagated: Potatoes, sugar cane,
many fruits.
NATURAL CROSSING WITH SELF-FERTILIZED PLANTS
Flower types are adapted for various degrees of self- or crossfertilization.
This in itself is a field- in which much study mightbe
made. The plant breeder, however, is chiefly interested in
the final result.
FIG. 10. Natural hybrids in wheat. 1. From right to left: Spike of a pure
variety produced from a cross of Turkey winter wheat and Wellman's Fife spring
wheat. This is a bearded variety with smooth chaff. The progeny of a single
plant of this variety gave 48 bearded, smooth chaffed plants and 2 plants with
intermediate (tipped awns) and hairy chaff. 2. From right to left: Preston
spring wheat; an Fi natural hybrid with intermediate awns and hairy chaff.
The parental varieties from which these natural hybrids were obtained were
grown alternately with Haynes Blue Stem the preceding year.
Wheat. The 1 individual florets of wheat and barley are
much alike. The envelope of a floret of wheat, for example,
consists of the flowering glume or lemma and an inner glume or
palea. The sexual organs consist of a pistil with a two-branched,
1 POPE has reviewed much of the literature for cereal crops.
See
Amer. Soc. Agron., 8: 209-227.
Journ.