Seed germination, kanamycin sulfate selection, and the influence of nitrogen treatments on an insertional mutant population of Fragaria vesca

Abstract

With the goal of creating faster and more efficient methods of generating unique Ac/Ds insertional mutants in a population of Fragaria vesca, various methods of seed germination, kanamycin screening, and the effects of varying nitrogen fertilization on diploid strawberry have been examined. Seed germination was improved to 42% in B5 liquid medium compared to _ on MS solid medium. Kanamycin screening during germination was most effective in liquid B5 medium as well. A readily discernable phonotypic difference between sensitive (necrotic radical) and resistant (branched roots) seedlings was observed in the B5 liquid medium and the frequency of escapes was reduced from __ on solid MS to __ in liquid B5. Although there were few phenotypic differences due to nitrogen application over the tested treatments (25-300 ppm) runner initiation was suppressed and chlorophyll was increased in the high (300 ppm) nitrogen treatment. There was limited evidence to suggest an increased rate of transposition in the high (300 ppm nitrogen) treatment level compared to those plants receiving lower levels of nitrogen. The selection efficiency and greater germination of the B5 liquid medium over MS medium would be expected to reduce the cost of screening thousands of seedlings because of the need for fewer disposables and medium transfers during the 5 week germination process. The use of B5 liquid medium, as well as treating plants with high levels of nitrogen (300 ppm), may be facilitate high throughput production of transposon tagged mutants in a population of F. vesca.