Environmental and Cultural Factors Affecting the Production of Myoga (Zingiber Mioga Roscoe) in Australia
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Environmental and cultural factors affecting the production of myoga (Zingiber mioga Roscoe) in Australia by Krjsten Joy Stirling B.Agr.Sc. (Hons.) University of Tasmania Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy University of Tasmania Hobart November 2004 ii Declaration I declare that this thesis contains no material which has been accepted for the award of any other degree or diploma in any other tertiary institution and to the best of my knowledge and belief, contains no copy or paraphrase of material previously published or written by any other person except where due reference is made in the text of the thesis. Kristen Stirling Authority of Access This thesis may be made available for loan and limited copying in accordance with the Copyright Act 1968. Kristen Stirling 111 Publications Refereed journal articles Section 1: Stirling, K.J., Clark, R.J., Brown, P.H., Wilson, S.J. (2002) Effect ofphotoperiod on flower bud initiation and development in myoga (Zingiber mioga Roscoe). Scientia Horticulturae 95: 261-268 Section 2: Stirling, K.J., Clark, R.J., (submitted) Effect oflow temperature on photoinhibition of photosynthesis in Japanese Ginger (Zin giber mioga Roscoe). Australian Journal of Agricultural Research Conference publications Section 1: Stirling, K.J., Clark, R.J. (in press) The importance of photoperiod in cultivar and site selection for production of myoga (Zingiber mioga Roscoe). Acta Horticulturae - XXVIth International Horticultural Congress, Toronto, August 2002 Section 2: Stirling, K.J., Clark, R.J. (in press) Investigation of photoinhibition in Japanese Ginger (Zingiber Mioga Roscoe). Conference Proceedings - Australian Society of Horticultural Science, Sydney, September 2002 iv Zingiber mioga Roscoe Botanical drawing courtesy of Mr. Dennis Morris, Tasmanian Herbarium, Department of Museum and Art Gallery. A Base of plant showing rhizomes, pseudostems and an inflorescence bud; B Flower, front view C Flower, side view D Section through flower v Abstract Myoga (Zingiber mioga Roscoe) is a new vegetable crop in Australia, cultivated for its edible flower buds. Originating from Japan, the crop was introduced into Australia with the expectation that it could be produced over the summer months, with flower buds then exported to Japan, where they retail at a high out-of-season price. fudustry has identified a number of challenges to the successful commercialisation of this crop in Australia. The majority of these relate to cultural aspects ofmyoga production and manipulation of the growing environment to control crop performance, in particular, extension of harvest season. A lack of knowledge of the effect of environmental factors on the production of myoga flower buds has hampered initial efforts to successfully cultivate this crop in the Australia. Photoperiod was identified as a potentially important environmental factor affecting the production of myoga flower buds. A series of trials conducted within controlled environment cabinets determined that myoga had dual photoperiod requirements for successful flower bud production, with flower bud initiation having a quantitative short day requirement while flower bud development had a qualitative long day requirement. Differences in the critical daylength required for successful flower bud development in cultivar S and I myoga plants was identified as the reason why cultivar I plants senesced prematurely when field cultivated in Southern Australia. The critical daylength for flower bud development in cultivar S plants was determined to be approximately 13 hours, while cultivar I plants required a daylength closer to 14 hours. Low night temperatures were observed to interact with photoperiod, resulting in successful flower bud development in daylength conditions that at higher night temperatures would have been too short. From the results of these trials, photoperiod was deemed to be a crucial determinant of the location of future production sites and the timing of production seasons. Environmental factors affecting general plant growth and development were also deemed important areas of research, in particular the tolerance of myoga plants to Vl strong light conditions. There have been reports of variations in the shade requirement of myoga plants grown in different climatic regions. This led to the hypothesis that these plants were susceptible to cold induced photoinhibition of photosynthesis. This was confirmed during a number of trials which used chlorophyll fluorescence techniques to investigate the function of photosynthetic systems within myoga plants when placed into stressful conditions. Exposure ofmyoga to light intensities greater than 750 µmol m-2s-1 resulted in the engagement of photoprotective mechanisms to prevent photodamage occurring. Sensitivity to low temperatures meant that these plants became photoinhibited at far lower light intensities and the engagement of photoprotective mechanisms was sustained, when plants were exposed to low temperatures in conjunction with light. The acclimation of these plants to low temperature and the successful engagement of photoprotective systems within the photosystem indicate that myoga can cope with strong light intensities over a short term period. However exposure to strong light intensities at warm temperatures or moderate light intensities at low temperatures, for an extended period of time, is likely to result in permanent photodamage occurring. Additional cultural factors affecting commercial production of myoga flower buds were identified during the first two years of cultivation. At Albion Park, NSW it was determined that myoga plantings remaining in the ground for longer than one year did not require artificial chilling, and with correct management of vegetation could produce higher flower bud yields than first year plants. Production trials conducted in Rockhampton, QLD investigated the effect of daylength and temperature on flower bud production, and confirmed that myoga was well suited to cultivation in a sub tropical environment provided due consideration was given to photoperiod and the potential need for artificial chilling. Recommendations based on the above research findings have already been adopted into commercial production protocols and as such many of the challenges to myoga production in Australia have now been successfully resolved. Vll Acknowledgements I would like to thank the many people who made this project possible; • Professor Rob Clark who has guided and encouraged me throughout this project. • Richard Warner for being a wonderful industry partner. • Drs. Phil Brown, Steve Wilson and Alistair Gracie who provided me with excellent technical advice and help. • Phil Andrews who took fantastic care of my plants and assisted with many trials. • Dr. David Ratkowsky for help with statistical analysis of data. • Dr. Mark Hovendon for technical advice and assistance with interpretation of chlorophyll fluorescence data. • Sarah Purdy and Professor David Midmore for providing project support in Rockhampton. • My fellow students who have assisted with a myriad of problems. • Mark, who not only provided practical assistance whenever needed but also provided much needed emotional support. • Finally a big thanks to my friends and most importantly my family; Joy, Peter, Fiona and Andy. TABLE OF CONTENTS ACKNOWLEDGEMENTS -------------------'"=vii GENERAL INTRODUCTION Botanical description and cultivation of Myoga.________ ~1 Production in Japan__________________ --=-1 Production in the Southern Hemisphere and research impetus. ____-=2 Outline of thesis structure-----------------=- 3 GENERAL MATERIALS AND METHODS Location'-------------------------=-- 5 Environmental Monitoring, ________________,_? Statistical Analysis _________________~? SECTION 1: PHOTOPERIOD SECTION INTRODUCTION______________ ----=-8 LITERATURE REVIEW Photoperiodism.__________________ --"'-"'-10 -critical Daylength__________________ --=1=2 Daylength Response Types. _______________1"'--=2 Temperature___________________ -=13 Juvenility____________________ --'1"-'-4 Industry Application'-------------------=-=-15 Northern Hemisphere Research. ______________.1=5 Southern Hemisphere Research._____________ -=1'-'-7 SECTION MATERIALS AND METHODS Plant Material ---------------------=1=-=-7 Controlled Environment Cabinets (C.E.C) __________--'1::._:_7 EXPERIMENTAL WORK: IDENTIFICATION OF THE PHOTOPERJODIC NATURE OF MYOGA Introduction.___________________ ~18 ix Materials and Methods 19 Plant Material 19 Photoperiod Treatments 19 Results First Harvest (104 DAP) 20 Second Harvest (201 DAP) 21 Discussion 23 EXPERIMENTAL WORK: DETERMINATION OF CRITICAL DAYLENGTH REQUIRED FOR FLOWER BUD PRODUCTION IN MYOGA Introduction 26 Materials and Methods Planting Material 27 Photoperiod Treatments 27 Results Vegetative Growth 28 Reproductive Growth 3 3 Discussion 35 EXPERIMENTAL WORK: DETERMINATION OF THE PHOTOPERIOD SENSITIVE PHASES OF MYOGA Introduction·-------------------------'"-= 3 8 Materials and Methods Plant Material --------------------=-=--39 Dayle ng th Treatments _______________=..=:_39 Harvests 40 -------------------~ Results Transfer Plants __________________4~0 Dissection Plants---------------------'= 43 Discussion 45 ·---------------------~ EXPERIMENTAL WORK: EFFECT OF TEMPERATURE ON THE PHOTOPERIODIC SENSITIVITY OF MYOGA Introduction 51 ~------------------------'=-= Materials and Methods Planting Material ________________~52 Photoperiod Treatments _______________5"-=2 Results First Harvest