Cucurbit Genetics Cooperative Report 4:19-20 (article 9) 1981
A Cucumber Mutant with Increased Hypocotyl and Internode
Length
R. W. Robinson and J. W. Shail
New York State Agricultural
Experiment Station, Geneva, NY 14456
A cucumber plant with a three-fold increase in hypocotyl
length was found in the F2 generation after treatment of
seed of 'Lemon' with thermal neutron radiation. Discrete
segregation occurred in the F2 generation of crosses with
the mutant. On the basis of F2 ratio of 33+:11 long hypocotyl,
from a cross with 'MSU 713-5', and other data, it is concluded
that a single recessive gene is involved. The symbol lh,
for long hypocotyl, is proposed.
Length of the internodes as well as the hypocotyl is increased
by lh (Table 1). Despite its marked effect on internode
elongation, it had no apparent effect on other phytohormone-mediated
development. The mutants were normal in sex expression,
fruit length, leaf shape, and other characteristics.
Previously genes have been reported to reduce internode
length of the cucumber, but this is the first cucumber gene
reported to increase length of internode and hypocotyl.
Its unique nature, ease and reliability of classification
in the seedling stage, good viability and fertility, and
freedom from interference with classification for other
genes makes it a useful seedling marker for the cucumber.
Table 1. Length of hypocotyl and first two internodes of F2 segregants.
|
|
Hypocotyl |
Internode 1 |
Internode 2 |
Class |
Mean |
Range |
Mean |
Range |
Mean |
Range |
Lh |
5.8 |
2.0-9.0 |
5.4 |
2.0-8.5 |
7.6 |
3.3-10.0 |
lh |
16.3 |
14.5-20.0 |
16.3 |
10.0-22.0 |
12.9 |
10.0-20.0 |
