Cucurbit Genetics Cooperative Report 3:4 (article 2) 1980
Rosette, A Spontaneous Cucumber Mutant Arising from Cucumber-Muskmelon
Mentor Pollination
A.C. de Ruiter and B.J. van der Knap
DeRuiterzonen Seed Co., Bleiswijk, The Netherlands
R.W. Robinson
New
York State Agricultural Experiment Station, Station, Geneva,
NY 14456
An interesting variant, given the acronym "megurk"
from the combined Dutch words for cucumber and muskmelon,
was obtained when cucumber plants were pollinated with a
mixture of cucumber and muskmelon pollen (2). The plants
had shorter internodes, more obtuse leaf lobing, and smaller
length-diameter fruit ratio that the cucumber parent, and
in some respects, were intermediate to normal cucumber and
muskmelon plants. The possibility of interspecific origin,
however, was refuted by electrophoretic evidence (1).
Crosses between the "megurk" and normal cucumber
plants were fully fertile and normal in appearance. The
F2 segregated 483 normal to 162 mutant plants, in close
agreement to 3:1 ratio (p= .95). Seven of 11 normal F2 plants
that were self pollinated produced segregating progeny and
the four other F3 lines were homozygous normal, agreeing
with the 2:1 ratio. It is concluded that a single recessive
gene is involved.
The non-Mendelian ratio in the original cross (2) is attributed
to mixed pollination involving several homozygous normal
cucumber plants and a single cucumber plant heterozygous
for a spontaneous mutation. The Mendelian ratio expected
for the selfed progeny of the heterozygote was distorted
by the mixture of self- and cross-pollination, the selfed
progeny would be expected to segregate but those from crosses
would all by phenotypically normal.
The mutant is named rosette after its short internodes
and closely spaced upper leaves, with the symbol ro.
Literature Cited
- Robinson, R.W., J.T. Puchalski, ad A.C. de Ruiter. 1979.
Isozyme Analysis of the megurk. Cucurbit Genetics
Coop. Rpt. 2:17-18
- van der Knap, B.J. and A.C. de Ruiter. 1978. An Interspecific
Cross Between Cucumber (Cucumis sativus) and
Muskmelon (Cucumis melo). Cucurbit Genetics
Coop. Rpt. 1:6-8.
