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Title: | 天使花之三倍體育種及花色遺傳 Triploid Breeding and Flower Color Inheritance of Angelonia angustifolia |
Authors: | 蔡昀珊 Yun-Shan Tsai |
Advisor: | 葉德銘 Der-Ming Yeh |
Keyword: | 倍體間雜交,雜交障礙,乾旱,花色遺傳,EMS誘變, Interploidy hybridization,hybridization barriers,drought,flower color inheritance,EMS mutagenesis, |
Publication Year : | 2023 |
Degree: | 碩士 |
Abstract: | 天使花(Angelonia angustifolia)全年可開花且分枝性佳,並具耐熱耐濕特性,為臺灣夏季重要花壇植物,然其花朵較小且較不耐旱。前人透過秋水仙素誘導並選育四倍體天使花品系SWH110115 和SPU320102,具有大花且耐旱之特性;但分枝性較差且花序較不密集,觀賞性較低,因此期望透過將二和四倍體天使花雜交,得到耐旱且觀賞性佳之三倍體後代,但倍體間雜交會出現蒴果成熟率低與種子發芽率低之情形。本研究目的為釐清天使花倍體間雜交障礙之原因,且試圖克服,以利於三倍體育種,並比較乾旱及溫度對二、三及四倍體天使花生長、生理表現之影響。另外探討天使花的花色遺傳模式,並嘗試以EMS誘變得到新花形花色植株。
本研究先確立天使花倍體間雜交適合的授粉條件,二和四倍體在開花後3至4天具有最高柱頭活性,在此時期進行授粉能有最高結實率。二和四倍體之花粉體外萌發率於水浴溫度25℃處理時最高;於日/夜溫30/25℃產生之四倍體花粉萌發率可達50%以上,但低溫15/13℃會顯著降低四倍體花粉稔性。取開花後第4天之柱頭,並於溫暖環境下進行二及四倍體間雜交,可觀察到花粉管順利進入胚珠,因此天使花倍體間雜交障礙應非受精前障礙。以石蠟切片觀察二倍體‘Serena White’與四倍體SPU320102的倍體間雜交胚之發育情形,以二倍體為母本與四倍體父本雜交,胚在授粉後20天仍生長停滯,但胚乳已萎縮;以四倍體為母本與二倍體父雜交,第20天則觀察到胚體明顯萎縮敗育,胚乳亦敗育,顯示天使花倍體間雜交障礙無論正反交皆為受精後障礙。取授粉後8、12、16及20天之倍體間雜交胚珠,分別於不同蔗糖濃度、MS濃度或GA3濃度之培養基進行培養,共培養4236顆胚珠,但最終僅有9顆發芽,並得到一株三倍體後代。 取天使花‘Serena White’、‘Serena Purple’、四倍體SWH110115、SPU320102,以及前人得到之三倍體單株SWH110115 × ‘Serena Purple’,於20%及40%介質體積含水量(volumetric water content, VWC)比較乾旱下之生長情形。三倍體天使花能結合二、四倍體親本之優點,在乾旱時生物量受影響較小,在低VWC時較其親本更能維持植體水分,且在20% VWC輕微乾旱情形下有更緊密且多分枝的外觀株型,具有景觀應用之潛力。 將同樣五種天使花品系/品種於15/13、20/15、25/20、30/25及35/30℃之人工氣候室內栽培 54 天後,三種倍體數之天使花皆在25/20℃有最好的生長及開花表現,倍體數不影響天使花的生長適溫。而兩種四倍體品系在高溫下具有較好的光合作用表現,耐熱性較佳;兩種二倍體品種在15/13℃之生長有顯著差異,‘Serena Purple’的光合作用表現為五種天使花中最佳,最耐低溫,‘Serena White’的耐寒性則最差;而三倍體在不同溫度下的生長表現皆介於二、四倍體之間。另外,兩種三倍體品系在自然環境下較四倍體有更多分支數及較長的花期。 以7種紫色、粉色或白色花之商業品種天使花進行雜交,依據花色分離之結果,推測天使花之花色主要由B、W及P三對基因控制。B和W基因控制花青素的有無,且相對P基因具有隱性上位性;當上位基因為bbww時,產生白色花(bbww_ _);當B和W基因有其中一對為顯性時,花青素可合成,並由第三對基因P決定花青素之種類,若P基因為顯性P_,花色為紫色;若為pp,花朵呈粉紅色。 利用不同濃度的EMS及處理時間誘變‘Serena Rose’種子,以1.0% EMS處理12小時之組合具有較低的植株存活率及最高誘變率14.7%。誘變產生之花朵和葉片變異包含下唇瓣增生、上唇瓣消失、裂花、頂生花、斑葉及葉序改變。 Angelonia angustifolia Benth. is one of the most important summer bedding plants in Taiwan and subtropical regions, with year-round blooming, well-branching, and heat- and waterlogging-tolerance. However, drought sensitivity and smaller flower size are some disadvantages to be improved. Colchicine-induced tetraploid angelonia SWH110115 and SPU320102 have larger flowers and drought resistance, while exhibited poor branching and looser inflorescence. Crossing between diploid and tetraploid might obtain triploid progeny with drought tolerance and better ornamental traits. However, low capsule formation and low seed germination occurred during interploidy hybridization of angelonia. The objective of this study was to clarify the interploidy hybridization barriers of angelonia to facilitate polyploid breeding. Moreover, the traits of triploid were evaluated under drought and different temperatures, and compared with its diploid and tetraploid parents. In addition, this study also explored the flower color inheritance pattern of angelonia, and attempted to create novel flower colors or morphological mutants by ethyl methanesulphonate. This study first established the suitable pollination conditions for the interploidy hybridization of angelonia. The highest stigma receptivity of diploid and tetraploid were observed at 3 to 4 days after flowering, and pollination during this period resulted in the highest percentage of fruit set. The in vitro pollen germination percentage was the highest at 25℃. Pollen from tetraploid plants was easily affected by the low temperature during flowering, with significantly decreased pollen viability. Penetration of pollen tube into the ovule could be observed in interploidy hybridization between diploid and tetraploid, therefore a pre-fertilization barrier might be excluded. Capsules of interploidy-crossed Angelonia were collected and sectioned at 8, 12, 16, and 20 days after pollination (DAP). The 2x × 4x embryo remained at globular stage from 8 to 20 DAP, while the endosperm was disintegrated at 20 DAP. Aborted embryo and aborted endosperm were observed in 4x × 2x crossed ovules at 20 DAP. The ovules were taken 8, 12, 16, and 20 DAP from crossing diploid Angelonia ‘Serena White’ and tetraploid SPU320102 and were cultured on medium with different sucrose concentrations, MS concentration, or GA3 concentration, respectively. A total of 4236 ovules were cultured, but only 9 germinated in the end, and one triploid progeny was obtained. Traits of Angelonia angustifolia triploid SWH110115 × ‘Serena Purple’ under drought conditions were compared with diploid ‘Serena White’, ‘Serena Purple’, tetraploid SWH110115 and SPU320102. Triploid angelonia combines the advantages of the diploid and tetraploid parents under 20% volumetric water content (VWC). Biomass of the triploid plant was less affected during drought, and triploid plant was more able to maintain water content than its parent at low VWC, and had more compact and multi-branched appearance under mild drought, which has potential for landscape applications. Five angelonia cultivars/lines were grown at day/night temperatures of 15/13, 20/15, 25/20, 30/25, and 35/30℃ for 54 days. All angelonia showed best growth and flowering performance at 25/20℃, and the degree of ploidy did not affect the optimum growth temperature. The tetraploid lines had higher photosynthesis and better heat tolerance at high temperatures. The two diploid cultivars had significant differences in growth at 15/13℃, while photosynthesis ability of ‘Serena Purple’ was the best among five angelonias, ‘Serena white’ was the most cool-sensitive. Growth performance of the triploid angelonia at different temperatures was between diploid and tetraploid. When in field trial, the two triploid lines had more branches and longer flowering longevity than tetraploid lines. Based on segregation of progeny from selfing and crossing 7 commercial angelonia cultivars with purple, pink and white flower color, the flower color inheritance was proposed to be controlled by three genes (B, W, P). B and W genes govern the presence of anthocyanin, and showed recessive epistasis over the P gene. When the epistatic genotype is bbww, the flower color is white (bbww_ _). Anthocyanin presents whenever either B or W gene is dominant (B_ ww, bbW_ or B_W_). Dominant P (P_) resulted in purple flower color, and homogeneous recessive pp resulted in a pink flower. Seeds of angelonia ‘Serena Rose’ were treated with different concentrations of ethyl methanesulfonate (EMS), a mutagent, for different time duration. The results showed that the combination of 1% EMS for 12 h had the lowest survival percentage (76.3%), and the mutation frequency of 14.7%. Flower and leaf mutations included doubled lower lips, upper lip absent, pale flower color, split flower, the white spot near nectary bulge absent, terminal flower, variegated leaf, and changed phyllotaxy angles. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/90105 |
DOI: | 10.6342/NTU202303584 |
Fulltext Rights: | 同意授權(限校園內公開) |
Appears in Collections: | 園藝暨景觀學系 |
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