彩葉草之葉片性狀遺傳及遮光對商業品種及雜交後代生長之影響

Inheritance of Leaf Characteristics and Effects of Shading on Growth of Coleus Cultivars and Progenies

夏文茹(Wen-Ju Hsia)

指導教授 ： 葉德銘

國立臺灣大學/生物資源暨農學院/園藝學研究所/碩士(2010年)

https://doi.org/10.6342/NTU.2010.03264

摘要

彩葉草為耐高溫多雨之優良花壇作物，其雜交歧異度大，具育種潛力，但品種間對光度之耐受性不同，且葉色表現隨環境光度而變化，進而影響觀賞品質。若暸解商業品種性狀之基因型，將有利於育種時親本之選擇，而探討不同葉色彩葉草之適合光度範圍，將有利景觀應用。本研究以彩葉草商業品種進行雜交，觀察後代性狀分離情形以推論親本性狀之基因型，並以不同遮光程度處理雜交後代及商業品種，探討遮光程度處理對彩葉草生長及觀賞品質之影響。
取種子繁殖系彩葉草 ‘Wizard Mosaic’ 及營養繁殖系彩葉草 ‘Black Cloud’、‘Green Cloud’、‘The Line’、‘Defiance’ 與 ‘Cardinal’ 共六品種進行八組正反交，共 16 個雜交組合。除以 ‘The Line’ 為種子親、‘Black Cloud’ 為花粉親之組合，果莢種子數及結種率最低外，雜交所得果莢內平均有 2 粒種子，結種率介於 26.6% - 70%。以 ‘Black Cloud’ 與 ‘Green Cloud’ 之正反交組合，種子發芽率較低，其餘雜交組合之種子發芽率皆可達 76%，其中以 ‘Black Cloud’ 為種子親，‘The Line’ 為花粉親，及以 ‘Defiance’ 為種子親、‘The Line’ 為花粉親之雜交組合，種子發芽率皆可達 100%。
依前人研究，預測控制各親本葉片性狀之基因型，‘Black Cloud’ 及 ‘Green Cloud’ 之葉緣 (深缺刻)、葉面 (皺摺) 及葉脈 (交合型) 表現型皆為顯性，預測基因型分別為 L_、C_ 及 G_。而 ‘The Line’、‘Defiance’、‘Cardinal’ 及 ‘Wizard Mosaic’ 之葉緣 (淺缺刻)、葉面 (平滑) 及葉脈 (規則型) 表現型皆為隱性，預測基因型分別為 ll、cc 及 gg。以 ‘Green Cloud’ 及 ‘Black Cloud’ 進行正反交，所得後代包括顯性及隱性表現之後代，可知控制二品種葉緣、葉面及葉脈性狀之基因型皆為異質結合顯性 (Ll、Cc 及 Gg)，而若以葉緣、葉面及葉脈皆為隱性之品種 (‘The Line’、‘Defiance’、‘Cardinal’、‘Wizard Mosaic’) 為親本互相雜交，所得後代之葉緣、葉面及葉脈性狀亦皆為隱性，因此可確定四品種中控制三種性狀之基因型皆為同質結合隱性 (ll、cc、及 gg)。以 ‘Defiance’ 與 ‘Cardinal’ 兩雙色葉斑品種進行正反交，後代的葉斑可分為紅黃雙色性狀及淺綠色性狀，雙色性狀的基因型可能為 pp 或 ppm，而 pmpm 為淺綠色葉片基因型之ㄧ，因此推測 ‘Defiance’ 與 ‘Cardinal’ 之雙色性狀基因型皆為 ppm，而後代之淺綠色性狀基因型為 pmpm。
以 0% (765 μmol•m-2•s-1 PPF)、48% (398 μmol•m-2•s-1 PPF) 及 67% (252 μmol•m-2•s-1 PPF) 遮光處理五個種子繁殖系、五個營養繁殖系彩葉草商業品種及十個雜交後代 37 天，雜交後代除 97-6 為種子及營養繁殖系品種之雜交後代外，其餘皆為營養繁殖系之雜交後代。五個種子繁殖系彩葉草品種於 67% 遮光環境下，植株較高，葉片長、寬較大，新生葉片數較少，總葉面積較大，乾物重較少，而於 0% 遮光環境下，植株較矮，新生葉片數雖較多但葉片明顯較小，觀賞品質亦不佳，於 48% 遮光環境之表現則多介於其餘二處理表現之間，觀賞品質較佳。五個營養繁殖系品種於各遮光處理下之生長反應變化較不明顯。除營養繁殖系雜交後代 97-9 之生長會受遮光程度影響外，其餘後代表現均和營養繁殖系相似，較不受遮光影響。結果顯示遮光會顯著影響種子繁殖系彩葉草品種之生長表現，但營養繁殖系品種及其後代對光度適應較廣。而種子繁殖系和營養繁殖系雜交所得後代之光度適應性可能較種子繁殖系親本更廣。各品種及雜交後代葉片之綠色部分於 0% 遮光環境下皆較明亮，而紅色部分則較濃。於 67% 遮光環境下，綠色部分較濃，而紅色部分則較明亮。

關鍵字

花青素 ； 葉綠素 ； 乾重 ； 葉片斑紋

並列摘要

Coleus has become an important landscape plant due to their tolerance to heavy rain and high temperature. Various leaf colors and variegations make hybridization breeding of great potential. Differential responses to irradiance exist in coleus and shading could affect leaf color in some cultivars. To investigate the genotypes of cultivars would facilitate coleus breeding. Information of growth responses to shading in cultivars is essential for landscape uses. Thus, the objectives of this study were 1) to determine the leaf genotypes from the phenotype segregations of cross progenies, and 2) to investigate the effects of shading on growth and ornamental quality of coleus cultivars and cross progenies.
For crossing between cultivars, the parents were seed-propagated coleus ‘Wizard Mosaic’ and vegetatively-propagated coleus ‘Black Cloud’, ‘Green Cloud’, ‘The Line’, ‘Defiance’, and ‘Cardinal’. In this study, 16 cross combinations were obtained, with eight reciprocal crosses. Average seed per capsule was two and average seed formation rate per capsule was between 26.6% - 70%, except significantly lower number of seed per capsule in ‘The Line’ (♀) × ‘Black Cloud’ (♂). Seed germination percentage of most cross combinations could reach 76%, except significantly lower germination in reciprocal crosses of ‘Black Cloud’ and ‘Green Cloud’. The seed germination percentage could reach 100% in crosses of ‘Black Cloud’ (♀) × ‘The Line’ (♂), and ‘Defiance’ (♀) × ‘The Line’ (♂).
We determined leaf characteristic genotypes of parents by crossing between cultivars. According to the references, deep lobed margin, crinkled surface, and anastomosis vein of ‘Black Cloud’ and ‘Green Cloud’ were all dominant types, so the expected genotypes were L_, C_, and G_, respectively. Shallow lobed margin, smooth surface, and regular vein of ‘The Line’, ‘Defiance’, ‘Cardinal’, and ‘Wizard Mosaic’ were all recessive types, so the genotypes should be ll, cc, and gg, respectively. Progenies from reciprocal crosses of ‘Black Cloud’ and ‘Green Cloud’ had both dominant and recessive phenotypes. Thus, the genotypes of two cultivars should be Ll, Cc, and Gg. The leaf margin, surface, and vein genotypes of parents were all recessive, with genotypes of ll, cc, and gg in ‘The Line’, ‘Defiance’, ‘Cardinal’, and ‘Wizard Mosaic’, and the phenotypes of reciprocal progenies were also all recessive. Genotype of leaf with pattern variegation included pp and ppm, when the only one solid green genotype which relative to pattern genotype (pp or ppm) was pmpm. Leaf color of reciprocal progenies from ‘Defiance’ and ‘Cardinal’ expressed as pattern and solid green. Thus, the pattern genotype of ‘Defiance’ and ‘Cardinal’ should be ppm, and the genotype of solid green progenies should be pmpm.
Five seed-propagated cultivars, five vegetatively-propagated cultivars, and ten cross progenies were grown under 0% (765 μmol•m-2•s-1 PPF), 48% (398 μmol•m-2•s-1 PPF), and 67% (252 μmol•m-2•s-1 PPF) shading in greenhouse conditions for 37 days. Except 97-6, a progeny between seed-propagated and vegetatively-propagated cultivar, all other progenies were hybrid between vegetatively-propagated coleus cultivars. Seed-propagated coleus cultivars had higher plant height, wider leaves, fewer new grown leaves, bigger total leaf area, and lower dry mass under 67% shading level. Seed-propagated coleus cultivars under 0% shading level were short, with small new grown leaves and poor quality. Seed-propagated coleus cultivars under 48% shading had better growth performance than under 0% or 67% shading levels. Growth responses of vegetatively-propagated cultivars to shading were not so significant as seed-propagated coleus cultivars. Except cross progeny 97-9, growth under various shadings did not differ significantly in cross progenies from vegetatively-propagated coleus cultivars. The vegetatively-propagated coleus cultivars or progenies had wider adaptability to shading than seed-propagated coleus cultivars. In general, the crossing progenies between vegetatively-propagated and seed-propagated coleus cultivars had wider light adaptability than seed-propagated coleus cultivars. When under 0% shading level, the green leaf portions of commercial cultivars and cross progenies were lighter, while the red leaf portions were darker. In contrast, when under 67% shading level, the green leaf portions of leaves of commercial cultivars and cross progenies were dark-green, while the red portions were brighter.

並列關鍵字

anthocyanin ； chlorophyll ； dry weight ； leaf variegation

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