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Studies on Interspecific Hybridization and Screening for Ethylene-insensitive Cultivars of Kalanchoe
Kalanchoe blossfeldiana Poelln.,regulation of flowering,gibberellic acid,colchicine,fertility restoration,
|Publication Year :||2019|
|Abstract:||燈籠草屬(Kalanchoe)為景天科(Crassulaceae)的多年生或2年生肉質草本植物，極少數為1年生，屬內約有140種。其中，長壽花(K. blossfeldiana Poelln.)為重要花卉作物之一，本研究以燈籠草屬之物種及長壽花商業品種，探討花期調節、種間雜交、提升雜交後代稔性及篩選乙烯不敏感之品種。
花期調節試驗中，‘103-1’(K. garambiensis ‘Type 1’ × K. nyikae)處理GA3及對照組植株皆能於當年開花，開花率皆達100 %，到花日數在GA3各濃度處理下皆與對照組無顯著差異，結果顯示GA3處理未能有效調節‘103-1’之花期。K. laetivirens在GA3處理和對照組之開花率分別為100%和0%，此外噴施25 mg∙L-1 GA3已足夠使K. laetivirens開花。K. laetivirens之到花日數受到株齡與GA3濃度兩因子影響，變方分析皆達極顯著(P ≤ 0.001)，然而到花日數不受GA3噴施次數之影響，此外到花日之株高則不受株齡、GA3噴施次數及GA3濃度任一因子之影響。結果顯示GA3對K. laetivirens開花之調節有助於在商業生產上調節花期或育種之用，且由繁殖到開花的日數以2個月株齡之植株噴施二次200 mg∙L-1 GA3之組合最短，其日數為173.8天。
燈籠草屬物種或品種可透過種間雜交獲得新性狀以達到改良的目的，在種間雜交試驗中，與K. synsepala var. dissecta相關的雜交組合種子發芽率皆為0%，無法獲得後代。與K. spathulata相關的雜交組合皆可獲得種子，且皆以K. spathulata作為母本之每蒴果種子較多，除了在以K. blossfeldiana ‘African Velvet’作為母本之每蒴果種子較多。與K. spathulata相關的雜交組合在與K. sexangularis、K. longiflora及K. nyikae的雜交組合中，無論正反交種子皆不發芽，而在與K. lobata、K. velutina及‘African Velvet’的雜交組合種子發芽率差異較大，其範圍為0.04%-78.5%。與K. garambiensis相關的雜交組合皆可獲得種子，且皆以K. garambiensis作為母本之每蒴果種子較多，除了在以K. lobata作為母本與K. garambiensis ‘Type 2’雜交之每蒴果種子較多。與K. garambiensis相關的雜交組合在與K. lobata、K. nyikae及K. velutina的正反交皆可獲得後代，種子發芽率範圍在2.8%-72.6%，僅在K. nyikae作為母本之種子不發芽。與‘103-2’ (K. spathulata × K. garambiensis ‘Type 1’)相關的雜交組合皆可獲得種子，且在有正反交的組合中皆以‘103-2’作為母本之每蒴果種子較多。與‘103-2’相關的雜交組合在與K. nyikae、K. garambiensis ‘Type 1’、K. velutina、K. blossfeldiana ‘African Love’及K. blossfeldiana ‘Cher’的正反交組合皆可獲得後代，種子發芽率範圍在7.3%-57.9%，僅在K. nyikae作為母本之種子不發芽。與K. lobata相關的雜交組合多可獲得種子，僅在以K. velutina或K. nyikae作為母本時雜交無法獲得種子。且於所有雜交組合中僅與K. nyikae雜交無法獲得後代植株。與K. nyikae相關的雜交組合多可獲得種子，且於所有雜交組合中僅與K. lobata和K. spathulata雜交無法獲得後代植株。K. gastonis-bonnieri與Kalanchoe節物種雜交時，皆是以K. gastonis-bonnieri作為父本才可獲得種子，然而所有組合多不能獲得後代植株，僅K. garambiensis ‘Type 1’作為母本時之種子發芽率為22.7%，其餘皆為0%。而K. gastonis-bonnieri與Kalanchoe節商業品種雜交則無法獲得種子。與K. laetivirens相關的雜交組合結果率在以K. laetivirens作為父本時較高，結果率為96%-100%，而在以K. laetivirens作為母本時結果率為0%-16.7%。K. laetivirens與Kalanchoe節物種間雜交之每蒴果種子範圍為0-16.5粒，然而發芽率皆為0%，無法獲得後代植株。結果顯示在節內雜交與節間雜交中，皆有部分雜交組合出現單向雜交不親和的特性。節內雜交組合中大多可獲得後代，而在K. synsepala var. dissecta、K. gastonis-bonnieri或K. laetivirens相關的種間雜交組合中則大多不能獲得後代。
探討燈籠草屬節內之種間雜交後代能否透過回交及秋水仙素處理提升稔性，可有助於後續育種之進行。‘103-1’具早花、分枝少及植株高等性狀，適合作為切花育種之親本使用，然而經檢測不具正常花粉，且回交無法改善其稔性，以‘103-1’作為母本與K. garambiensis ‘Type 1’或K. nyikae回交之結果率皆為100%，然而皆無法獲得種子。‘103-1’經秋水仙素塗抹頂芽之存活率隨著處理濃度上升而下降，於0、10000、15000及20000 mg∙L-1處理下之存活率分別為100%、94.9%、78.6%及63.3%，此外以10000 mg∙L-1秋水仙素處理已足夠改善‘103-1’之花粉稔性，且於mutant 7植株有最高之花粉發芽率為86.7%，另外使用‘103-1’恢復稔性之植株作為父母本進行育種皆可獲得後代。
為建立方便且快速之方法用以篩選乙烯不敏感之品種，及探討乙烯敏感性與實際單花壽命之間的關係，本試驗使用33種長壽花品種和4種原生種之單朵花經24和48小時處理0、0.5、1及10 μL∙L-1乙烯，處理乙烯後與對照組花朵直徑無顯著差異者視為乙烯不敏感，結果顯示不同品種對乙烯之敏感性不同，乙烯濃度越高或乙烯處理時間越長則篩選出之乙烯不敏感品種越少，表示提高乙烯濃度或處理時間造成乙烯不敏感品種之篩選壓力增加，其中以篩選壓力最小的為24小時0.5 μL∙L-1乙烯之處理，所篩出的品種有‘粉撲’、‘繽紛’、‘Sia’、‘Penelope’、‘Margrethe’、‘Julianne’、‘Heidi’、‘Madonna Q3’、‘Kerinci’、‘African Femme’、‘Ida’、‘Lea Q2’及‘Tender White Meadow’，而以篩選壓力最大的為48小時10 μL∙L-1乙烯之處理，所篩出的品種有‘Margrethe’和‘Julianne’。單朵花於乙烯處理後之花朵直徑與盆花上的花朵壽命之間皆呈現正相關，顯示花朵壽命越長者，其乙烯處理後之花朵直徑越大。以24小時處理0.5 μL∙L-1乙烯後之花朵直徑與盆花之單朵花壽命相關性最低，其r = 0.6945，而以24小時處理10 μL∙L-1乙烯後之花朵直徑與盆花之單朵花壽命相關性最高，其r = 0.7849。而無論在24或48小時乙烯處理下，當乙烯濃度越高，所篩出的乙烯不敏感品種較有機會具有花朵壽命範圍較集中且較長的特性，且在24小時處理0.5或1 μL∙L-1乙烯所篩出之乙烯不敏感品種具有單朵花壽命範圍較不集中的現象，其花朵壽命範圍介於30.8-69天，而提升至10 μL∙L-1乙烯後，所篩出之乙烯不敏感品種其花朵壽命範圍介於54.6-69天。
Kalanchoe genus, containing about 140 species, of Crassulaceae family includes perennial or biennial succulent herbaceous, and very few annual plants. Among them, K. blossfeldiana Poelln. is one of the important ornamental crops. In this study, species of Kalanchoe and cultivars of K. blossfeldiana were studied for regulation of flowering, interspecific hybridization, improving the fertility of hybrid progeny, and screening for ethylene-insensitive cultivars.
In the study of regulation of flowering, ‘103-1’ (K. garambiensis ‘Type 1’ × K. nyikae) treated by GA3 and control plants were able to flower in the same year, and the flowering rate was 100%. Days to flowering was not significantly different from the control group under each treatment of GA3 concentrations, indicating that GA3 treatment failed to effectively regulate the flowering of ‘103-1’. The flowering rates of K. laetivirens in the GA3 treatment and the control group were 100% and 0%, respectively. Furthermore, the spraying of 25 mg∙L-1 GA3 was sufficient to cause K. laetivirens to flower. Days to flowering in K. laetivirens was affected by both plant age and GA3 concentration, and the analysis of variance (ANOVA) were both extremely significant (P ≤ 0.001). However, days to flowering was not affected by the GA3 spraying times, and plant height is not affected by plant age, GA3 spraying times and GA3 concentration. The results showed that the flowering regulation of GA3 for K. laetivirens contributed to the regulation of flowering for commercial production and breeding uses. Furthermore, for Kalanchoe laetivirens, the combination of 2-month-old plant, twice spraying, and 200 mg∙L-1 GA3 treatment had the lowest days from propagation to flowering (173.8 days).
Species or cultivars of Kalanchoe genus could obtain new traits through interspecific hybridization for improvement purposes. In the study of interspecific hybridization, the seed germination of the hybrid combination associated with K. synsepala var. dissecta were 0%, so the offspring could not be obtained. All the hybrid combinations associated with K. spathulata could harvest seeds, and it could harvest more seeds from each capsule when K. spathulata was being as maternal parent except for K. blossfeldiana ‘African Velvet’. When K. spathulata reciprocal crossed with K. sexangularis, K. longiflora, or K. nyikae, the seeds could not germinate. However, when K. spathulata crossed with K. lobata, K. velutina, or ‘African Velvet’, the seed germination was range from 0.04% to 78.5%. All the hybrid combinations associated with K. garambiensis could harvest seeds, and it could harvest more seeds from each capsule when K. garambiensis was being as maternal parent, except for K. lobata being as maternal parent by crossing with K. garambiensis ‘Type 2’. When K. garambiensis reciprocal crossed with K. lobata, K. nyikae, or K. velutina, the seed germination was range from 2.8% to 72.6%, except for seeds which could not germinate when K. nyikae was being as maternal parent. All the hybrid combinations associated with ‘103-2’ (K. spathulata × K. garambiensis ‘Type 1’) could harvest seeds, and it could harvest more seeds from each capsule when ‘103-2’ was being as maternal parent. When ‘103-2’ reciprocal crossed with K. nyikae, K. garambiensis ‘Type 1’, K. velutina, K. blossfeldiana ‘African Love’, or K. blossfeldiana ‘Cher’, the seed germination was range from 7.3% to 57.9%, except for seeds which could not germinate when K. nyikae was being as maternal parent. Most of the hybrid combinations associated with K. lobata could harvest seeds, except for K. velutina or K. nyikae being as maternal parent. Besides, only the hybridization between K. lobata and K. nyikae failed to obtain the progeny. Most of the hybrid combinations associated with K. nyikae could harvest seeds. Furthermore, only the hybridization between K. nyikae and K. lobata or K. spathulata failed to obtain the progeny. Hybridization between K. gastonis-bonnieri and species of section Kalanchoe could harvest seeds only when K. gastonis-bonnieri was being as pollen parent. However, most hybrid combinations failed to obtain the progeny, except for the hybridization with K. garambiensis ‘Type 1’ being as maternal parent, and the seed germination was 22.7%. However, hybridization between K. gastonis-bonnieri and cultivars of section Kalanchoe could not harvest the seed. Hybrid combinations associated with K. laetivirens had higher fruit set when K. laetivirens was being as pollen parent (96%-100%). In contrast, when K. laetivirens was being as maternal parent, the fruit set was range from 0% to 16.7%. Besides, the seeds per capsule range from 0 to 16.5 as K. laetivirens crossed with species of section Kalanchoe. However, all the hybrid seed germination were 0% and indicating that no progeny could be obtained. The results showed that for intra- and inter-sectional hybridization, partial hybrid combinations had unilateral incompatibility. Most of the intra-sectional hybrid combinations could obtain progenies. However, most of the hybrid combinations associated with K. synsepala var. dissecta, K. gastonis-bonnieri, or K. laetivirens could not obtain the progeny.
It could contribute to breeding to investigate whether the fertility of the progeny crossed by species within the same section could be improved by backcrossing or colchicine treatment. ‘103-1’ had traits of early flowering, less branchs, and tall plant height, and it was suitable for being the parent of cut flower breeding. However, ‘103-1’ was found without normal pollen, and backcrossing could not improve the fertility. Using ‘103-1’ as maternal parent to cross with K. garambiensis ‘Type 1’ or K. nyikae had 100% fruit set, but it could not harvest any seed. The percentage of survival apical bud of ‘103-1’ treated at apical buds with colchicine was decreased with the increase of colchicine concentration. The percentage of survival apical bud treated by 0, 10000, 15000, and 20000 mg∙L-1 colchicine were 100%, 94.9%, 78.6, and 63.3%, respectively. In addition, treated with 10000 mg∙L-1 colchicine was sufficient to improve the pollen fertility of ‘103-1’, and the highest pollen germination in mutant 7 was 86.7%. Furthermore, using plants which fertility were improved as maternal parent or pollen parent in breeding could all successfully produce progenies.
To establish convenient and fast method for screening ethylene-insensitive cultivars, and to investigate the relationship between ethylene sensitivity and the real longevity of single flower, single detached flowers of 33 cultivars and 4 species were treated with 0, 0.5, 1, and 10 μL∙L-1 ethylene for 24 and 48 hours. Cultivars or species which flower diameter was not significant to control group after ethylene treatment were considered as ethylene-insensitive. The result showed that different cultivars had different sensitivities to ethylene. Higher ethylene concentration or longer treatment time would screen out less cultivars which were insensitive to ethylene. It indicated that the increase of ethylene concentration or treatment time led to an increase in the screening pressure of ethylene-insensitive cultivars. Among them, the minimum screening pressure was 0.5 μL∙L-1 ethylene treatment for 24 hours, and the ethylene-insensitive cultivars screened out were ‘Pink Puff’, ‘Colorful’, ‘Sia’, ‘Penelope’, ‘Margrethe’, ‘Julianne’, ‘Heidi’, ‘Madonna Q3’, ‘Kerinci’, ‘African Femme’, ‘Ida’, ‘Lea Q2’, and ‘Tender White Meadow’; the maximum screening pressure was 10 μL∙L-1 ethylene treatment for 48 hours, and the ethylene-insensitive cultivars screened out were ‘Margrethe’ and ‘Julianne’. The flower diameter of single detached flower after ethylene treatment had positive correlation with flower longevity of single flower from pot plant, suggesting that the longer the flower longevity was, the larger the flower diameter would be after ethylene treatment. The flower diameter after treatment with 0.5 μL∙L-1 ethylene for 24 hours had the lowest correlation with the flower longevity of potted flower, r = 0.6945. Besides, the flower diameter after treatment with 10 μL∙L-1 ethylene for 24 hours had the highest correlation with the flower longevity of potted flower, r = 0.7849. Whether treated for 24 or 48 hours, as the ethylene concentration became higher, the ethylene-insensitive cultivars screened out presented longer and more concentrative longevities. The ethylene-insensitive cultivars treated by 0.5 or 1 μL∙L-1 ethylene for 24 hours had less concentrative flower longevities, and they range from 30.8 to 69 days. However, when the ethylene concentration increased to 10 μL∙L-1, the ethylene-insensitive cultivars screened out had the flower longevities ranges from 54.6 to 69 days.
|Appears in Collections:||園藝暨景觀學系|
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