GENETIC ANALYSIS OF LEAF SIZE IN JAPANESE CUCUMBER (CUCUMIS SATIVUS)

Breeding for a little leaf Japanese cucumber plant, we analyzed the genetics of leaf size using the segregating populations obtained from crossings Japanese little leaf and large leaf cultivars. ‘Sakata’ and ‘Morioka No.1’ were the donors of the little leaf character and ‘Kyuuraku No.2’ and ‘NB-1’ were the large leaf donors. ‘Sakata’ is a local Japanese pickling variety, which is one of the smallest leaf cultivars in Japan. ‘Morioka No.1’ is an intermediate parental line containing the ll locus from the ‘AR79-75’ line.
In the F2 progeny, obtained from crossing ‘NB-1’ and ‘Sakata’, the distribution of the leaf size was continuative as a quantitative character.
We inferred from this that ‘Sakata’ didn’t contain the ll locus.
Whereas, in the F₂, derived from a cross between ‘Kyuuraku No.2’ and ‘Morioka No.1’, the cleavage was clearly observed between large and little leaf sizes, likely due to the ll gene.
Selfing little leaf F₂ individuals, from the ‘Kyuuraku No.2’ and ‘Morioka No.1’ cross, no large leaf individuals appeared in the F₃ progeny, although variation in leaf size was observed.
This would suggest that the variation was controlled by regulatory genes other than the ll gene.
Which is supported by the F₂ progeny derived from a cross between ‘NB-1’ and ‘Sakata’ and the F₃ progeny derived from a cross between ‘Kyuuraku No.2’ and ‘Morioka No.1’. We feel we should be able to apply this variation to Japanese little leaf cucumbers with the ll gene.

II International Symposium on Cucurbits

H. Mizusawa, N. Hirama, S. Matsuura

little leaf, large leaf, locus ll, leaf width, quantitative character

https://doi.org/10.17660/ActaHortic.2002.588.43