Baird, A. M.2011-12-112011-12-111985https://hdl.handle.net/10182/4132The pepino (Solanum muricatum Aiton) is a fruit crop of South American origin that was introduced to New Zealand in the 1950’s. The cultivar ‘Lincoln Gold’ is adapted to the short growing season found in Canterbury, however, improvement of the fruit’s quality is desirable. The induction of mutations has the potential to improve this vegetatively propagated crop. The aims of this study were to evaluate the effects of gamma radiation on pepino cuttings and to determine the suitable dose for a breeding programme. Rooted cuttings of ‘Lincoln Gold’ were exposed to gamma radiation (5, 15, 25 or 35 Gray, dose rate 230cGy min⁻¹). Plants were arranged in randomised blocks in a glasshouse and their vegetative and reproductive development were studied. The 5 Gy treatment produced some stimulation in plant development, although only seed number was significantly affected (P≤.05). Pollen viability was significantly altered by the 15 Gy exposure. The 25 Gy treated plants had fewer shoots and branches and experienced a period of growth inhibition. Flowering was also delayed and pollen viability reduced, but fruit development was normal. Vegetative growth, flowering and fruiting behaviour were significantly altered by the 35 Gy dose. Shoot length was reduced to 35% of the control a month after exposure, 12% of shoots failed to flower, shoot 1 pollen viability was reduced by 23% and fruit set and development were inhibited. Plant survival was 100% in all treatments. A dose range of 25-35 Gy is recommended for mutation induction programmes conducted under similar conditions. Production of the VM2 generation is recommended from basal regions of shoot 1, decapitated one to two weeks earlier, using the whole of the shoot population.enhttps://researcharchive.lincoln.ac.nz/pages/rightspepinoSolanum muricatumgamma irradiationinduced mutationsvegetatively propagated plantsVM1 generationdamageplant developmentplant improvementThesisDigital thesis can be viewed by current staff and students of Lincoln University only. If you are the author of this item, please contact us if you wish to discuss making the full text publicly available.ANZSRC::070305 Crop and Pasture Improvement (Selection and Breeding)ANZSRC::070303 Crop and Pasture Biochemistry and PhysiologyQ112846006