溫度及光質對花椰菜花球創始的影響

Effects of Temperature and Light Quality on Curd Initiation of Cauliflower

10.6342/NTU201704390

方漢強

花椰菜 ； 品種 ； 花球創始 ； 春化處理 ； 光質 ； 栽培溫度 ； Cauliflower ； Cultivars ； Curd initiation ； Vernalization ； Light quality ； Growing temperature

國立臺灣大學園藝暨景觀學系學位論文

2017年

碩士

楊雯如

繁體中文

臺灣地處熱帶及亞熱帶邊界，中南部地區秋冬冷涼乾燥氣候適於蔬菜採種，花椰菜種子(Brassica oleracea L. var. botrytis)是其中大宗，不僅供應國內市場也熱銷海外，極具商機。臺灣雖以早生、耐熱品種為優勢，但為求育種資源豐富，晚生種、極晚生種的利用有其必要。本試驗探討不同生育期品種的花球誘導特性， 於栽培時給予春化及光質處理，期增進臺灣花椰菜的基礎生理研究資料。 早生種花椰菜F1品種‘CF520’於相對較高的誘導溫度21/15 oC中育苗，會使幼苗於第三片本葉展開即陸續進入生殖生長，後續產生鈕扣花球、失去定植意義；提高育苗溫度到21/21oC或25/21oC可使植株在第5片葉展開時仍維持在營養生長狀態，定植操作建議下修至第三片本葉展開時期，莖頂基部寬度5-6 mm為分生組織生育相轉變期。中生種花椰菜F1品種‘CF17501’於生長箱21/15 oC育苗，第五片葉展開時仍維持營養生長態，於臺北冬季定植，可獲得發育完整之花球，後續花芽分化、開花與結籽狀況良好；其幼年期約結束在第13片展開葉之前，莖頂基部寬度6-7 mm為分生組織生育相轉變期。同樣育苗條件與栽培環境，晚生OP品種‘CF120’可達到花球創始階段，但花球後續皆因「逆春化」轉入營養生長態而出現帶葉花球，無商品價值也無花朵開放，顯示環境低溫可滿足其花球誘導，但後續不足；其幼年期約結束在第16片本葉展開以前，莖頂基部寬度在約7.05-9.78 mm達到轉變期，個體間特徵差異大。 花椰菜定植至花球創始之時間品種間差異大，且受栽培溫度、春化與光質處理的影響。21/15 oC栽培溫度下，早生種‘CF520’無春化需求；春化處理可顯著縮短中生種‘CF17501’定植至花球創始之時間，但HR作用效果不顯著；春化及HR處理都可縮短晚生種‘CF120’定植至花球創始之時間。提高栽培溫度到25/15 oC時，春化或HR處理對‘CF17501’有顯著縮短效果，兩者並有交感作用；對於 ‘CF120’，春化及HR處理效果都很顯著，而在LR下無春化處理者植株不會進入生殖生長。

Taiwan is located at the boundary between tropical and sub-tropical climates. In the central and south parts of Taiwan, the weather in autumn and winter is usually cool and dry which is suitable for vegetable seeds collecting. Cauliflower (Brassica oleracea L. var. botrytis)seeds, as one of the staples, are sufficient to saticfy internal demand and even to be exported, with potential business opportunities. Early-mature and cultivar with heat-tolerant character are advantages of Taiwan cauliflower, but to develop the exploitation of late-matured and extreme late-matured cultivars is indispensable in order to seeking for plentiful breeding resources. This study focuses on the curd induction character of cultivars with different growth period, which was carried by giving vernalization and light quality treatment to plants during the cultivation period, hoping to further the basic physiological research data of cauliflower in Taiwan. Raising seedlings in relatively higher inducing temperature 21/15 oC, early-mature F1‘CF520’ continually entered reproductive growth phase with three true leaves unfolded. And later ‘CF520’ had “buttoning” phenomenon, with no value to be transplanted. However, increasing the temperature to 21/21 oC or 25/21 oC made seedlings maintained at vegetative state when the 5th true leaf unfolded; thus, the timing of transplanting ‘CF520’ is recommend to when the 3rd leaf unfolds. In 21/15 oC growth chamber of raising period, medium-mature F1 ‘CF17501’ maintained at vegetative state when the 5th leaf unfolded. Transplanted in winter, Taipe, they could produce intact curds, and the floral induction, flowering and seed setting all went well. The juvenility of ‘CF17501’ ended up before the 13th leaves unfolded, and the shoot apical meristem(SAM) entered phase transition when the base of shoot apex grew to 6-7 mm in width. At the same raising and cultivation environment, the late-mature op ‘CF120’ could entered curd initiation phase; however, curds later all turned into vegetative growth with “leafy” appearance because of devernalization, losing values and not flowered at the end. This phenomenon means there was enough environmental chilling for curd induction of ‘CF120’, but not enough further. The juvenility of ‘CF120’ ended up before the 16th leaves unfolded, and the SAM entered phase transition when the base of shoot apex grew to 7.05-9.78 mm in width. Many characters beween samples were quite different probably because of OP cultivar. The time from being transplanted to curd initiation of cauliflower was quite different due to cultivars, and also affected by temperature during cultivation, vernalization treatment and light quality. In 21/15 oC growing temperature, early-mature ‘CF520’ had no vernalization requirement; vernalization treatment could obviously shorten the time from being transplanted to curd initiation of ‘CF17501’, but high-ratio redlight(HR) did not affect it distinctly. Vernalization and HR all could shorten the time from being transplanted to curd initiation of ‘CF120’. When raising the temperature to 25/15 oC, vernalization or HR had the shortening effect for ‘CF17501’, and there was interaction between vernalization and light quality. For ‘CF120’, vernalization and HR all had obvious shortening effect, and plants under LR without vernalization treatment could not enter reproductive growth.

1. 3. 沈碧君、李哖. 1983. 春化作用與GAs對植物抽苔開花的影響 第二部分 春化作用與GAs. 中國園藝. 29:243-249.
   連結：
2. 6. 陳美蘭. 2010. 青花菜AV531耐熱特性之探討. 國立臺灣大學園藝系碩士論文. 臺北.
   連結：
3. 7. 陳添來、蔡敏嘉、鄭卿蓮. 1999. 台灣花椰菜栽培面積與價格之變動分析. 桃園區農業改良場研究報告 36:43-51.
   連結：
4. 9. 張雅晶. 2015. 溫度與光對青花菜花芽分化的影響. 國立臺灣大學園藝學系碩士論文. 臺北.
   連結：
5. 12. 廖公益. 1993. 臺灣之花菜類蔬菜 貳、台灣之花椰菜. p. 202-216. 刊於：臺灣蔬菜產業演進四十年專集. 臺灣省農業試驗所專刊. 臺灣省農業試驗所編印.
   連結：
6. 13. 謝明憲、林棟樑、王仕賢. 2008a. 晚生種花椰菜春化處理技術之建立. 行政院農業委員會臺南區農業改良場研究彙報. 52：66-71.
   連結：
7. 16. Aditya, D.K. and R. Fordham. 1995. Effects of cold treatment and of gibberellic acid on flowering of cauliflower. J. Hort. Sci. 70:577-585.
   連結：
8. 17. Amasino, R. 2010. Seasonal and developmental timing of flowering. The Plant Journal 61:1001-1013.
   連結：
9. 18. Allen, B.W., P.W. Goodenough, J.S.C. Lee, and P.P. Rutherford. 1986. Evolution of cauliflower types grown in Great Britain as indicated by the isoenzyme composition of the cauliflower curds. Euphytica 35:25-31.
   連結：
10. 19. Baker, E.A. 1974. The influence of environment on leaf wax development in brassica oleracea var. gemmifera. New Phytologist 73:955-966.
    連結：
11. 21. Birkenshaw, J.E., D.C.E. Wurr, and J.R. Fellows. 1982. The Influence of Ventilation Temperature and Plant Raising Method on the Yield of Early Summer Cauliflowers. Journal of Horticultural Science 57:357-363.
    連結：
12. 22. BjÖrkman, T. and K.J. Pearson. 1998. High temperature arrest of inflorescence development in broccoli (Brassica oleracea var. italica L.). J. Expt. Bot. 49:101-106.
    連結：
13. 23. Booij, R. 1990. Effect of gibberellic acids on time of maturity and on yield and quality of cauliflower. Neth. J. Agric. Sci. 38: 641-651.
    連結：
14. 24. Booij, R. and P.C. Struik. 1990. Effects of temperature on leaf and curd initiation in relation to juvenility of cauliflower. Sci. Hort. 44:201-214.
    連結：
15. 26. Branca, F. 2008. Cauliflower and Broccoli, p. 151-186. In: J. Prohens and F. Nuez (eds.). Vegetables I: Asteraceae, Brassicaceae, Chenopodicaceae, and Cucurbitaceae. Springer, NY.
    連結：
16. 27. Buck, P.A. 1956. Origin and taxonomy of broccoli. Econ. Bot. 10:250-253.
    連結：
17. 28. Chouard, P. .1960. Vernalization and its relation to dormancy. Ann. Rev. Plant Physiol. 11:191-238.
    連結：
18. 29. Crisp, P. 1982. The use of an evolutionary scheme for cauliflowers in the screening of genetic resources. Euphytica 31:725-734.
    連結：
19. 32. Fernández, J.A., S. Bañón, J.A. Franco, A. González, and P.F. Martínez. 1997. Effects of vernalization and exogenous gibberellins on curd induction and carbohydrate levels in the apex of cauliflower (Brassica oleracea var. botrytis). Scientia Horticulturae 70:223-230.
    連結：
20. 35. Francescangeli, N., M.A. Sangiacomo, and H.R. Marti. 2007. Vegetative and reproductive plasticity of broccoli at three levels of incident photosynthetically active radiation. Span. J. Agri. Res. 5:389-401.
    連結：
21. 37. Fujime, Y and Hirose.1979. Studies on thermal conditions of curd formation and development in cauliflower and broccoli. I. Effect of low temperature treatment of seeds. J. Jpn. Soc. Hort. Sci. 48:82-90.
    連結：
22. 38. Fujime, Y. and T. Hirose. 1980. Studies on thermal conditions of curd formation and development in cauliflower and broccoli. II. Effects of diurnal variation of temperature on curd formation. J. Jpn. Soc. Hort. Sci. 49:217-227.
    連結：
23. 39. Fujime,Y. 1988. A difference of response to low temperature between cauliflower and broccoli. Acta Hort. 218:141-151.
    連結：
24. 40. Fujime, Y. and N. Okuda. 1996. The physiology of flowering in Brassicas, especially about cauliflower and broccoli. Acta Hort. 407:247-254.
    連結：
25. 41. Gray, A.R. 1982. Taxonomy and Evolution of Broccoli (Brassica oleracea var. italica). Economic Botany 36:397-410.
    連結：
26. 42. Grevsen, K. 2000. Modelling plant development of broccoli. Acta Hort. 533:567-573.
    連結：
27. 43. Gregory, F.G. and G.G. Hussey. 1953. Photoperiodic responses of Arabidopsis
    連結：
28. thaliana. Proc. Linn. Soc. Lond. 164:137–139.
    連結：
29. 44. Hand, D.J. and J.G. Atherton. 1987. Curd initiation in the cauliflower. J. Expt. Bot. 38:2050-2058.
    連結：
30. 45. Hand, D.J. 1988. Regulation of curd initiation in the summer cauliflower. PhD Thesis. Univ. of Nottingham, UK.
    連結：
31. 46. Hiller, L.K., W.C. Kelly and L.E. Powll. 1979. Temperature interaction with growth regulators and endogenous gibberellic-like activity during seedstalk elongation in carrots. Plant Physiol. 63(6):1055-1061.
    連結：
32. 47. Ian, R.H. and C. Dean. 2004. Control of Arabidopsis flowering: the chill before the bloom. The company of biologist, UK.
    連結：
33. 48. Ismail, M. R. and Ann, L. J. 2004. Effect of root cooling and shading on growth and yield of tropical cauliflower (Brassica oleracea var. botrytis) in coconut coir dust culture. Acta Hort. 644:269-274.
    連結：
34. 49. Joanne, C. 1997. Light modulation of vegetative development. The Plant Cell. 9:1225-1234.
    連結：
35. 51. John, E.P. and E.R. Paul 1993. The biology of horticulture: an introductory textbook. 2nd.Wiley, N.J., U.S.A.
    連結：
36. 52. Kempin, S.A., B. Savidge, and M.F. Yanofsky. 1995. Molecular basis of the cauliflower phenotype in Arabidopsis. Science. 267:522-525.
    連結：
37. 54. Kuçi, H., I. Tafaj, B. Bici, G. Sallaku and A. Balliu. 2012. Effect of cold treatment on Morphological characteristics and growth rate of cauliflower(Brassica oleracea VAR. botrytis L.) seedlings. Acta Hortic. 960: 219-223.
    連結：
38. 56. Lu, L., Z. Yang, S. Lisha and H. Yu. 2013. Emerging insights into florigen transport. Curr. Opin. Plant boil. 16:607-613.
    連結：
39. 58. Marshall, B. and R. Thompson. 1987. A model of the influence of air temperature and solar radiation on the time to maturity of calabrese (Brassica oleracea var. italic). Annals of Botany. 60:513-519.
    連結：
40. 60. Mathews, S. and R.A. Sharrock. 1997. Phytochrome gene diversity. Plant Cell Environ. 20:666-671.
    連結：
41. 62. Mourao, I.M.G. and P. Hadley. 1998. Environmental control of plant growth development and yield in broccoli (Brassica oleracea L. var. italica Plenck): crop responses to light regime. Acta Hort. 459:71-78.
    連結：
42. 64. Neil, S.M. and E.E. John. 2005. The impact of photoperiod and irradiance on flowering of several herbaceous ornamentals. Scientia Horticulturae. 104:275-292.
    連結：
43. 65. Nowbuth, R.D. and S. Pearson. 1998. The effect of temperature and shade on curd initiation in temperate and tropical cauliflower. Acta Hort. 459:79-87.
    連結：
44. 67. Richard, A. 2010. Seasonal and developmental timing of flowering. The Plant Journal. 61:1001-10013.
    連結：
45. 68. Rahman, H.U., P Hadley and S. Pearson. 2007a. Relationship between temperature and cauliflower (Brassica oleracea L. var. botrytis) growth and development after
    連結：
46. curd initiation. Plant Growth Regul. 52:61-72.
    連結：
47. 69. Rahman, H.U., P. Hadley, S. Pearson, and M.D. Dennett. 2007b. Effect of incident radiation integral on cauliflower growth and development after curd initiation. Plant Growth Regul. 51:41-52.
    連結：
48. 70. Salter, P.J. 1969. Studies on crop maturity in cauliflower. I. Relationship between the times of curd initiation and curd maturity of plants within a cauliflower crop. J.
    連結：
49. Hort. Sci. Biotech. 44:129-140.
    連結：
50. 71. Sadik, S. 1962. Morphology of the curd of cauliflower. Ameri. J. Bot. 49:290-297.
    連結：
51. 72. Sadik, S., J.L. Ozbun. 1968. The association of carbohydrate changes in the shoot tip of cauliflower with flowering. Plant Physiol. 43:1696-1698.
    連結：
52. 73. Schonhof, I., H.P. Kläring, A. Krumbein, W. Claußen, and M. Schreiner. 2007. Effect of temperature increase under low radiation conditions on phytochemicals and ascorbic acid in greenhouse grown broccoli. Agriculture, Ecosystems & Environment 119:103-111
    連結：
53. 74. Shepherd, T. and D. Wynne Griffiths. 2006. The effects of stress on plant cuticular waxes. New Phytologist 171:469-499.
    連結：
54. 75. Suge, H. and L. Rappaport. 1968. Role of gibberellins in stem elongation and flowering in radish. Plant Physiol. 43:1208-1214.
    連結：
55. 78. Talalay, P. and J.W. Fahey. 2001. Phytochemicals from cruciferous plants protect against cancer by modulating carcinogen metabolism. J. Nutr. 131:3027S-33S.
    連結：
56. 84. Vishnu, S. and S.S. Chatterjee. 1971. Origin and Genetic improvement of Indian Cauliflower. Economic Botany 26:381-393.
    連結：
57. 85. Wareing, P.E. and I.D.J. Philips. 1970. The control of growth and differentiation in plant, p. 196-222. Pergmon Press. Oxford.
    連結：
58. 87. Wiebe, H.J. 1975. The morphological development of cauliflower and broccoli cultivars depending on temperature. Sci. Hort. 3:95-101
    連結：
59. 88. Wiebe, H.J. 1981. Influence of transplant characteristics and growing conditions on curd size (buttoning) of cauliflower. pp. 99-106. International Society for Horticultural Science (ISHS), Leuven, Belgium.
    連結：
60. 89. Weibe, H. J. 1990. Vernalization of vegetable crops一a review. Acta Horticulture. 267:323-328.
    連結：
61. 90. Williams, C.A. and J.G. Atherton, (1990). A role for young leaves in vernalization of cauliflower: I. Analysis of leaf development during curd induction. Physiologia Plantarum. 78: 61–66.
    連結：
62. 92. Wittwer, S.H. and M.J. Bukovac. 1957. Gibberellin effects on temperature and photoperiodic requirement for flowering of some plant. Science 126:30-31.
    連結：
63. 94. Wurr, D.C.E., J.M. Akehurst and T.H. Thomas. 1981. A hypothesis to explain the relationship between low-temperature treatment, gibberellin activity, curd initiation and maturity of cauliflower. Scientia Hortic. 15: 321-330.
    連結：
64. 95. Wurr, D. C. E. and J.R. Fellows. 2000. Temperature influences on the plant development of different maturity types of cauliflower. Acta Hort. 539:69-74.
    連結：
65. 96. Yamada, A., Tanigawa, T., Suyama, T., Matsuno, T., Kunitake, T. 2008. Night break treatment using different types of light sources promotes or delays growth and flowering of Eustoma grandiflorum (Raf) Shinn. J. Jpn. Soc. Hort. Sci. 77: 69-74.
    連結：
66. 97. Yoo, K.C. and S. Uemoto. 1976. Studies on the physiology of bolting and flowering in Raphanus sativus L. II. Annual rhythm in readiness to flower in
    連結：
67. 98. Zeevaart, J. A. D., 1983. Gibberellins and flowering. In: Crozier, A. (Ed.), The biochemistry and physiology of gibberellins. Vol. 2. Praeger, New York, pp. 333-374.
    連結：
68. 1. 王真真、朱玉英. 2011. 蕓薹屬蔬菜抽薹性研究進展. 上海農業學報. 27:125-128.
69. 2. 李伯年. 1987. 十字花科蔬菜. p 69-76. 蔬菜育種與採種. 國立編譯館. 臺北.
70. 4. 香川 彰. 1964. ハナヤサイの花芽分化•発育に関する研究. 岐阜大農場集報. 4: 15-26.
71. 5. 陳甘澍、林照能. 2005. 花椰菜. p.445-450. 刊於：增修訂三版臺灣農家要覽農作篇(二). 豐年社. 臺北. 臺灣
72. 8. 張連宗. 1998. 台灣十字花科蔬菜品種改良. p.35-53. 刊於：十字花科蔬菜產業發展研討會專刊. 台灣省桃園區農業改良場編印.
73. 10. 張德純. 2016. 花椰菜. 中國蔬菜 1:84.
74. 11. 曹幸之、羅筱鳳. 2006. 花菜類, p 127-137. 曹幸之、羅筱鳳編著. 蔬菜II. 復文書局. 臺南.
75. 14. 謝明憲、劉依昌、許涵鈞、林棟樑、王仕賢. 2008b. 十字花科蔬菜耐熱育種及採種.p.67-78. 刊於：農業生技產業應用研討會專輯. 行政院農業委員會臺南區農業改良場編印.
76. 15. 農山漁村文化協會. 1982. 花椰菜. 農業技術大系─野菜篇(6).
77. 20. Baloch, A.F. 1994. Vegetable Crops Horticulture, p. 489-538. National Book Foundation, Islamabad.
78. 25. Boswell, V. R. 1949. Our vegetable travellers. Natl. Geog. Mag. 96:170-177.
79. 30. Denise V.C. and T. Björkman. 2015. Gibberellin control of reproductive transitions in Brassica oleracea curd development. J. Amer. Soc. Hort. Sci. 140:57-67.
80. 31. Dixon, G.R. 2007. Vegetable brassicas and related crucifers. CABI, Walllingford, Oxfordshire, UK.
81. 33. Fontes, M.R., J.L. Ozbun and S. Sadik. 1967. Influence of temperature on initiation of floral primordia in green sprouting broccoli. Proc. Amer. Soc. Hort. Sci. 91:315-320.
82. 34. Fontes, M.R., J.L. Ozbun. 1972. Relationship between carbohydrate level and flower initiation in broccoli. J. Amer. Soc. Horti. Sci. 97:346-348.
83. 36. Friend, D.J.C. 1985. Brassica. p. 48-62. In: A.H. Halevy (eds.). Handbook of flowering, Vol. 2. CRC Press, Boca Raton, FL.
84. 50. Joanne, A.L., D.R. Larry, M.B. Angela and T. BjÖrkman. 2006. Inflorescence Identity Gene Alleles Are Poor Predictors of Inflorescence Type in Broccoli and Cauliflower. J. Amer. Soc. Horti. Sci. 131:667-673.
85. 53. Kolbasina, E. I. 1978. The dynamics of gibberellin in grains of different winter wheat varieties in relation to vernalization. Fiziologiya i Biokhimiya Kul’turnykh Rastenii. 10(1):34-37. Cited in Plant Growth Reg. 1978. 4(12):247, No.1891.
86. 55. Lee, B.S. and G.J. King. 2000. The distribution of BoCAL-a alleles in Brassica oleracea is consistent with a genetic model for curd development and domestication of the cauliflower. Mol. Breed. 6:603-613.
87. 57. MAFF. 1980. Bolting in brassica crops, buttoning in cauliflowers. Leaflet 756. Ministry of Agriculture, Fisheries and Food, Lodon.
88. 59. Massie, I.H. 1998. Patterns of variation in the Italian landrace cauliflower and broccoli .PhD thesis, Univ. Lond., London.
89. 61. Miller, C.H., T.R. Konsler and W.J. Lamont. 1985. Cold stress influence on premature flowering of broccoli. HortScience. 20:193-195.
90. 63. Napp-Zinn, K. 1973. Low temperature effect on flower formation: Vernalization. p. 171-194. In: H. Precht, J. Christophersen, H. Hensel and W. Larcher (eds). Temperature and Life, Springer, Berlin.
91. 66. Peter, J. D. and S. Valerie. 2010. Gibberellins: Regulators of plant height and seed germination, p.583-619. In: L. Taiz and E. Zeiger(eds). Plant Physiology. 5th. Sinauer Associates. Sunderland, Mass. U.S.A.
92. 76. Swaider, J.M., G.W. Ware, and J.P. McCollum. 1993. Producing Vegetable Crops. Interstate Publishers, Danville, Ill. U.S.A.
93. 77. Taiz, L. and P.A. Wigge. 2015. The Control of Flowering and floral Development, p.591-623. In: L. Taiz., E. Zeiger., I.M. Møller. and A. Murphy (eds). Plant Physiology and Development. 6th. Sinauer Associates. Sunderland, Mass., U.S.A.
94. 79. Tan, D.K., A.H. Wearing and Birch, C.J. (2003) Buttoning in broccoli and cauliflower. Good Fruit and Vegetables, 13:54.
95. 80. Tan, D.K. 1999. Effect of temperature and photoperiod on broccoli development, yield and quality in south-east Queensland. PhD Thesis. Univ. of Queensland, AU.
96. 81. Treshow, M. 1970. Environment and plant response. McGraw-Hill, New York and Lodon.
97. 82. Thompson, K.F. 1976. Cabbages, kales, etc., Brassica oleracea(Cruciferae), p 49-52. In: N.W. Simmonds (eds). Evolution of crop plants. Longman, London.
98. 83. Valerie, M.S. and H. Peter. 2004. Gibberellin biosynthesis and inactivation. p. 63-94. In: P. J. Davies(eds). Plant Hormones: Biosynthesis, Signal Transduction, Action!. 3rd. Kluwer Academic Publishers. Dordrecht. The Netherlands.
99. 86. Wellensiek, S.J. 1960. Stem elongation and flower initiation. Proc. Kon. Ned. Akad. Wet. C. 63:159-166.
100. 91. William, G.H. and P.A.H. Norman. 2003. Photomorphogenesis: Responding to Light, p. 367-390. In: Introduction to Plant Physiology. 3rd. Wiley, N.J., U.S.A.
101. 93. Wittwer, S.H. 1963. Photoperiod and flowering in the tomato. Proc. Amer .Soc. Horti. Sci. 83:688-694.
102. Japanese radish, cultivar ‘”Wase-shijunichi”. Plant & Cell Physiol. 17: 863-865.
103. 99. Zhang, D., A.M. Armitage, J.M. Affolter and M.A. Dirr. 1996. Environmental control of flowering and growth of Achillea millefolium L. ‘Summer Pastels’. HortScience. 31:364-365.