| Summary: | 碩士 === 國立臺灣大學 === 園藝暨景觀學系 === 106 === Currently, most commercial cultivars of potted periwinkle [Catharanthus roseus (L). G. Don] are released through hybridization. Emasculation can be omitted when using male sterile plants as seed parents for cross-pollination. Understanding of inheritance of flower color facilitates breeding. The aims of this study were to explore the causes and the stability of male sterile periwinkle, determine the inheritance of corolla and eye color, and breed and select new cultivars with deep purple or large white eye, dwarf, well-branched, and large flowers.
The anthers in 1.0-3.0 mm floral buds were sampled and sectioned from male fertile and male sterile progenies of selfed periwinkle ‘Cora Cascade’ series. Tetrads in male sterile anther locules were observed after meiosis of microspore mother cells. Anthers in 2.0-2.9 mm floral buds of male sterile plants were observed with a transmission electron microscope. Results revealed that the secretion globules flowed out of the tapetal cells. Fresh pollen from male sterile plants all collapsed, as observed with a scanning electron microscope. Thus, defective pollen might result from abnormal tapetal development. Paraffin sections of the anthers from 3.0 mm floral buds and 1, 2, 3 days before 3.0 mm floral buds. Results showed that callose dissolution was imcomplete in male sterile anther locules, as observed by fluorescence staining.
Pollen of some male sterile progenies from self-pollinated periwinkle ‘Cora Cascade’ series could germinate at 20/17℃. Male sterile plants were propagated by cutting and placed at 20/15℃, 25/20℃, and 30/25℃ under natural phytotron conditions to measure pollen nonabortion and pollen germination percentages. Fruit set percentage and seed number were recorded from selfing male sterile plants and crossing between male sterile and fertile plants at each temperature. Pollen nonabortive and pollen germination percentages in male sterile plants were lower than 1% when grown at 30/25℃ and 25/20℃, as compared with 13.7% and 4.0% in plants at 20/15℃, respectively. Selfed male sterile plants had fruit set at 20/15℃ but did not produce any seeds. Highest fruit set and most hybrid seeds were recorded when cross-pollinated at 25/20℃.
Anthocyanidin extracts from corolla with deep purple, cherry, pink, or apricot, and eye zones with red or orange red were analyzed using a liquid chromatograph tandem mass spectrometer. Anthocyanidins of apricot corolla were cyanidin derivatives, whereas other corollas or eye zones were delphinidin derivatives. Deep purple, cherry, and pink corolla periwinkle cultivars were self- and cross-pollinated, and the segregation of corolla colors in the progenies showed that apricot corolla was recessive to cherry, pink, orange red, and deep purple corolla. Apricot corolla was controlled by a single nuclear locus hf, which delphinidin derivatives are not produced in corolla. Red and deep purple eye periwinkle cultivars were self- and cross-pollinated. Results showed that deep purple eye was recessive to red eye, and dominant to orange red eye. Red, deep purple, and orange red eye were controlled by two nuclear loci Re and Pe.
Eleven periwinkle cultivars were placed at 30/25℃ under natural phytotron conditions. Small, medium, and large eye were defined as <1 cm, 1-2 cm, and >2 cm diameters, respectively. Large and medium white eye cultivars had white broad eye, whereas small white eye cultivars had white narrow eye. White broad eye and white narrow eye cultivars were self- and cross-pollinated. Results showed that white broad eye was dominant to white narrow eye. White broad eye was controlled by a single nuclear locus W.
Dwarf, early flowering, and large flowers with deep purple eye periwinkle were selected from F2 progenies of ‘Cora Cascade Strawberry’ × ‘Jams `N Jellies Blackberry’, ‘Cora Cascade Cherry’ × ‘Jams `N Jellies Blackberry’, ‘Ray’ × ‘Nirvana Cascade Pink Splash’, and‘Cora Cascade Strawberry’ × ‘Summer Mikan’. These were self-pollinated thereafter until F4 or F5, and cross-pollinated. Three pure lines and three hybrids were obtained. After examination of plant performance, one pure line and one hybrid with commercial potential were selected in this study.
|
|---|
