Cucurbit Genetics Cooperative Report 10:6 (article 4) 1987
Blunt Leaf Apex, a Cucumber Mutant Induced by a Chemical Mutagen
R. W. Robinson
Horticultural Sciences Department, New York State Agricultural Experiment
Station, Geneva, NY 14456
Seed of 'Wisconsin SMR 18' was soaked in 1.0% ethyl methane sulfonate
for 21 hours. Plants grown from the treated seed were self pollinated, and
the next (M2) generation was screened for mutants.
Among the mutants found was one that appears useful as a marker gene
since it has a distinctive, easily recognized phenotype at all stages of
development and has good vigor and fertility. The leaf apex of the mutant
is more obtuse than normal. The gene reduces leaf lobing and serration.
Leaves at lower nodes of the main stem are trigonous, and leaves developing
later become more elongated. The mutant can be recognized in the early seedling
stage, but classification is easier later. F2 segregation of
74 normal: 23 mutant agreed closely to 3:1. Hence, it is concluded to be
due to a single recessive gene, which is designated bla for blunt
leaf apex.
Isogenic lines differing for leaf shape can be useful for physiological
and other studies. Since bla was induced in 'Wisconsin SMR-18' and
self pollinated, it is isogenic to that cultivar.
