Hayes and Garber - Cucurbit Breeding

POTATO IMPROVEMENT 225
freely, although the general belief is that all varieties may bloom
under certain conditions of environment. East (1908a) classified
varieties as follows:
"1. Varieties whose buds drop off without opening.
" 2. Varieties in which a few flowers open, but which immediately
fall.
"3. Varieties whose flowers persist several days, but which rarely
produce viable pollen.
"4. Varieties which under most conditions always produce viable
pollen,"
In 487 out of 721 varieties under observation the buds fell off
before the flowers opened. Stuart, however, obtained a much
higher percentage of varieties which produced flowers in which
the blossoms opened before the buds fell. These results are
given to emphasize the fact that conditions widely influence
seed production.
The lack of fertile or healthy pollen in many varieties prohibits
their use as parents. The relation between the percentage
of healthy pollen and fruit production was determined by East
(1908a) for a considerable number of crosses (see Table LIV).
TABLE LIV.
RELATION BETWEEN PERCENTAGE OF VIABLE POLLEN AND
FRUIT PRODUCTION
Viability