繁星花之花冠裂片顏色及眼圈性狀之遺傳與雜交後裔之選育

Inheritance of Corolla Lobe Color and Eye Zone, and Progeny Selection in Pentas lanceolata

繁星花[Pentas lanceolata (Forsk.) Delf.]具有白、粉紅、紫及紅等花冠裂片顏色，廣為熱帶亞熱帶國家應用於景觀布置；有些品種具有次要顏色累積於眼圈(eye zone)，可增加觀賞價值；本研究探討其花色與眼圈性狀遺傳，並選育具商業價值之雜交後裔。取‘Butterfly’、‘Graffiti’、‘Kaleidoscope’、‘New Look’、‘Bismarck’及‘Starla’等品種進行自交及雜交，分析後代花冠裂片之主要顏色遺傳。結果顯示繁星花之花冠裂片顏色顯性順序為紅>桃>紫>粉紅>白，將控制紅、桃、紫及粉紅色花瓣裂片的色素基因定義為Rd、Rs、V及P基因，推測基因型為紅(Rd_ _ _ _ _ _ _)、桃(rdrdRs _ _ _ _ _)、紫(rdrdrsrsV_ _ _)、粉紅(rdrdrsrsvvP_)與白(rdrdrsrsvvpp)。取不同眼圈性狀親本雜交結果與推測基因型為：有眼圈(E_ _ _)相對於無眼圈(ee_ _)為顯性。將控制桃色眼圈的呈色色素累積之基因擬訂為PmRs，pm則為眼圈部位不累積色素，桃色眼圈(E_PmRs_)相對於白色眼圈(E_pmpm)為顯性。從雜交後代中選出具桃色眼圈品系KABRd-9，其分枝性較親本強、節間短且節位多，可供景觀或盆花布置觀賞。

Star cluster [Pentas lanceolata (Forsk.) Delf.] has many cultivars with various flower colors, and has been widely used as potted flowers or for landscaping in tropical and sub-tropical areas. This study aimed to determine the inheritance of corolla lobe colors and eye zone traits, and to select hybrid progeny lines with market potentials. Self- and cross-pollination between cultivars Butterfly, Graffiti, Kaleidoscope, New Look, Bismarck, and Starla were made. Results from the segregation of flower color of progenies, we proposed that loci determine red, rose, purple, and pink corolla lobe colors were labeled as Rd, Rs, V, and P, respectively. The dominance of corolla lobe color is red (Rd_ _ _ _ _ _ _) > rose (rdrdRs _ _ _ _ _) > purple (rdrdrsrsV_ _ _) > pink (rdrdrsrsvvP_) > white (rdrdrsrsvvpp). Self- and cross-pollination between cultivars with rose or white eyes were performed. Results showed that two loci governed eye zone trait in star cluster with pink or white corollas. Presence of eye zone (E_) is dominant over without eye zone (ee), and rose eye zone is dominant over white or without eye. Plants exhibited pink or white corolla with rose eye (E_PmRs_), rose corolla without eye (eePmRs_), pink or white corolla without eye (eepmpm), and pink or white corolla lobes with white eye (E_pmpm). A comparable study between the selected hybrid line KABRd-9 and its parental cultivar Kaleidoscope Appleblossom was conducted. Results showed that KABRd-9 is suitable for potted flowers and landscape uses, as it has more compact branches, with apparent rose eye zone.