CHARACTERIZATION OF THE BLUNT LEAF APEX (BLA) TRAIT IN CUCUMBER

A further characterization of the cucumber (Cucumis sativus L.) mutant 'Wisconsin SMR-18' bla (blunt leaf apex) revealed a new character ass ociated with the previously described leaf phenotype. The attachment o f the blade to the petiole of bla plants is flat across, as opposed to the cordate or indented attachment in the wild-type 'Wisconsin SMR-18 ' plants. The new character (truncate leaf base) was easier to score a nd becomes distinctive earlier in development than previously describe d leaf apex characters. It was expressed consistently in homozygous bi n plants. Segregation analysis of 1159 F-2 seedlings arising from self -pollinated 'Wisconsin SMR-18' x 'Wisconsin SMR-18' bla F, plants sugg ested that the leaf base and leaf apex character were controlled by a single locus or two tightly linked ones with a maximum distance betwee n the two of 0.03 cM. In a field study of growth and fitness character istics, the two genotypes did not differ significantly for flower or f ruit count. The similar flowering and fruiting characteristics, along with the reliable early occurring truncate character, likely will make the two genotypes useful for pollination and gene movement studies.