日日春[Catharanthus roseus (L.) G. Don]多透過雜交選育盆花品種，利用雄不稔親本可免去雄有利雜交授粉，而了解花色遺傳模式有助於育種。本研究探討日日春雄不稔之成因及眼圈顏色之遺傳，並利用雄不稔植株進行雜交，選育眼圈與花冠顏色對比明顯、大花、早花、低矮緊密及免摘心之盆花品系。取日日春‘Cora Cascade’系列自交後代之雄不稔植株開花當天之花粉，以掃描式電子顯微鏡觀察顯示其形態明顯皺縮。取雄不稔植株縱徑1-3 mm花苞之花藥進行石蠟切片螢光染色觀察，結果顯示雄不稔花藥囊腔中胼胝質分解不完全。將紅色及深紫色眼圈品種進行自交及雜交，結果顯示眼圈顏色之顯性順序與其推測之基因型分別為：紅色(Pe_Re_)>深紫色(Pe_ rere)>橘紅色(pepe_ _ )。本研究選育出一純系TP1714009及由TP1716057 × TP1701033之一個雜交種，皆具深紫色眼圈、大花、株型低矮緊密、分支多且免摘心，具盆花商業生產之潛力。

Commercial cultivars of potted periwinkle [Catharanthus roseus (L). G. Don] have been largely released through hybridization. A better understanding of the inheritance of flower color facilitates breeding. The aims of this study were to explore the causes of male sterility, determine the inheritance of eye zone colors, and use male sterile plants for cross-pollination to select new compact potted flower lines with large flowers exhibiting contrast colors between corolla and eye zone. Microscopical observation revealed that all the fresh pollen grains were collapsed in male sterile progenies of selfed ‘Cora Cascade’ series. Callose dissolution was incomplete in male sterile anther locules, as observed with fluorescence staining from paraffin sections of the anthers from 1-3 mm floral buds. Periwinkle cultivars with red and deep purple eye zone were self- and cross-pollinated. Results showed that the order of dominance and the proposed genotype of eye zone was red (Pe_Re_)> deep purple (Pe_ rere)> orange (pepe_ _). A pure line TP1714009 and a hybrid progeny from TP1716057 × TP1701033 were selected because these plants were compact and self-branched, with large flowers and deep purple eye zone.