Cucurbit Genetics Cooperative Report 3:9 (article 5) 1980
An Apetalous Male Sterile Mutant in Cucumber
Glasshouse Crops Research Institute, Littlehampton, BN16
3PU, United Kingdom
A sterile plant with misshapen fruit was found in a crop
of 'Butchers Disease Resisting' grown at the Rothamsted
Experimental Station, Harpeden, Herts, U.K. Plants obtained
from cuttings were grown under glass at this institute for
observation and test crossing.
The stems and leaves of the mutant were normal but the
flowers and fruit were abnormal. The corolla of both staminate
and pistillate flowers was reduced to a whorl of five green,
reflexed appendages identical to sepals. The flowers, therefore,
appeared to have ten sepals in two whorls of five.
The staminate flowers never matured and usually fell off
while they were still small. The pistillate flowers developed
to their usual size and, if left unpollinated, produced
parthenocarpic fruit, as is usual in the parental cultivar.
The ovaries of the pistillate flowers were inferior but
the usual narrow attachment between the base of the sepal
and the ovary was absent. In this respect, the flowers resembled
hermaphrodite flowers, but there were no anthers and the
ovary was of a normal length. The base of the ovary was
usually tri-locular but the number of locules increased
to four, five, or sometimes six at stigmatic end and resulted
in a club-shaped ovary with irregular ribbing.
Pollinations were made using pollen from normal plants
of 'Butchers Disease Resisting.' Since all the "sepals"
were reflexed from a very young stage, the immature stigma
was exposed and it was difficult to judge when it was receptive
to pollen; thus , pollination was repeated on several successive
days when ovary size and stigma appearance suggested that
the latter might be receptive.
F1 seed was obtained from the cross mutant x wild
type. All the F1 plants were normal. In the F2 family
14 plants were normal and five showed all the characters
of the original mutant. It seems that the character is controlled
by a single recessive allele. The name apetalous and the
symbol ap are suggested.