Cucurbit Genetics Cooperative Report 10:6 (article 4) 1987
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.