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A Newsletter for Professionals Growing Greenhouse Crops in the Rocky Mountain Region |
Cooperative Extension |
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| November 1999 |
Vol.
11, No. 1
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Contents |
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New Newsetter Format |
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Chris Freeman has a variety of experiences leading up to this position. The requirements for his Master of Agriculture in Horticulture were completed at Texas A&M University in August 1999. His studies focused on greenhouse crop production and management, especially related to hydroponically grown vegetables. Specific interests include niche market targeting, in particular greenhouse production of fresh herbs, fancy lettuces and edible flowers for direct marketing to gourmet restaurants. Previous employment was growing hydroponic tomatoes with Colorado Greenhouse Holdings, LLC. Other experience includes growing hydroponic (NFT) lettuce, herbs and edible flowers with Magin Farms in Western New York, as well as a wide variety of laboratory teaching experience in the Horticulture Department at Texas A&M University. Having lived and worked in a variety of Latin American countries, Chris has a strong command of Spanish, which will facilitate the creation of educational programs for greenhouse employees. Chris can be
reached at: Steven
E. Newman, Ph.D. |
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Root and Stem Rots of Poinsettias |
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Whether a fungus is causing the root system to rot, the stem to rot, or both, symptoms begin as yellowing or browning of lower leaves and/or leaf drop. As the disease progresses, the symptoms eventually become that of a wilt. Rhizoctonia root and stem rot is the most common disease of poinsettias in Colorado. Stems are attacked at the soil line and develop dark brown cankers or lesions that eventually become soft and mushy. Roots are usually affected, as well. When examined the roots will be discolored, root mass will be decreased, and often the outer covering of the root will be soft and mushy. The disease is favored by high available moisture and high temperatures. Anything that will weaken the poinsettia will also favor the disease. Sanitation is key in managing this problem. Many fungicides are labeled for control including: Banrot, Chipco 26019, Terraclor, Cleary's 3336, SoilGard, and Mycostop. Pythium root and stem rot usually begins in the root tips. Roots tips will turn brown, the cortex of the root will slough off. Eventually the disease progresses up the roots to the stem. The disease is favored by excess moisture and poorly drained media. Rogue (pull and destroy) infected plants to help manage the problem. Fungicides such as Terrazole, Truban, Banrot, Chipco Aliette, SoilGard, Subdue, Banol, or Mycostop are labeled for control. Thielaviopsis black root rot is not as common as it once was because of the increase in use of soilless mixes. When affected by this disease roots will be very dark to charcoal black. Stem bases may crack open. The disease is favored by wet conditions and cool temperatures. Lowering pH and raising temperatures help inhibit the growth of the fungus. Fungicides labeled for control include Banrot, Cleary's 3336, Domain, and Terraguard.
Laura
Pottoff |
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Improving Floriculture Crops Using Biotechnology |
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What is biotechnology?
How can Biotechnology Benefit Floriculture?Biotechnology has many potential applications that would benefit the floriculture industry. Genetic engineering offers benefits that would increase production and quality by creating plants with enhanced resistance to diseases, insects or viruses and increased tolerance to environmental stresses like salinity, temperature or drought. In addition, biotechnology can provide health and environmental benefits and reduced costs by reducing the use of chemical pesticides and herbicides. Many of these traits have been demonstrated in agronomic crops and the technologies are applicable to floriculture crops. While floriculture research in the past has focused on increasing production, the current focus is turning towards extending vase-life, minimizing postproduction losses, and creating novel products. Consumers are interested in quality and new flower forms and colors and genetic engineering offers a means to these ends. Creation of novel floriculture crops using biotechnologyA long sought after prize by many plant breeders has been the elusive blue rose. An extensive search of 670 rose cultivars has revealed that none of them contain delphinidin, the blue pigment in flowers. In light of these results, it is very unlikely that a blue rose could be bred by conventional methods. Researchers are finding out that color is a very complicated trait. While the genes responsible for the synthesis of delphinidins (blue-genes) have been identified, it is not as simple as putting them into roses or other flowers. In addition to delphinidin, specific co-pigments and a high vacuolar pH in the plant cells are also required. An Australian biotech company, Florigene, has made progress in identifying pH genes and modifying vacuolar pH. While their first "blue" carnation is actually a mauve/ violet color it is a step in the right direction and we may be seeing an influx of blue flowers on the market in the near future. Modification of plant and flower architecture and fragrance though only in preliminary stages of research have great potential for generation of desirable novel products. Genes that are responsible for determining the identity of flower organs have been identified from the weed Arabidopsis and have been shown to effectively alter flower architecture in other species. With these genes it is possible to design flowers with any of the desired flower organs in any position of the flower. For example, it is now possible to generate double varieties by merely replacing the anthers with petals. While some cut flowers have a determinate inflorescence that produces only a single flower, others like petunia, generate an indefinite number of flowers (indeterminate). Mutations in a single gene can result in the conversion of an indeterminate meristem into a determinate structure. Knowledge of the genes involved in meristem identity may lead to the creation of more prolific flowering varieties by converting determinate infloresences into indeterminate structures. Researchers have identified the chemical structures of many floral-fragrance compounds and are currently identifying genes involved in the biosynthesis of these compounds. Although there are no reports of the modification of floral-scent by genetic engineering, the isolation of the genes involved will make it feasible in the near future to alter scent production in flowers. Using Biotechnology to Increase the Life of Flowers:
Once identified, those genes that function by suppressing senescence can also be placed into plants so that their gene products are made all the time. This will also serve as a means to delay the death of the flowers. The gaseous, plant hormone ethylene is known to be a key regulator of flower senescence and as such is a good target for increasing flower life. I am also interested in the developmental and environmental stimuli that induce flowers to produced ethylene and how flowers respond to this ethylene. An understanding of the regulation of ethylene in flowers will lead to development of the best means of decreasing ethylene sensitivity in the flower without inhibiting other developmental processes like germination and rooting that are also regulated by ethylene. Commercialization of transgenic flowersGenetic engineering of plants is entering a period of very rapid application and offers a means of expanding the market for ornamentals in the near future. The development of bedding plants and potted plants that retain blooms longer and cut flowers with a longer vaselife would allow growers to increase the range of shipping and open up new markets. It would also increase the amount of time that these plants are saleable in the retail market and decrease postproduction losses at this step in the marketing chain. The opportunities for improvement of floriculture crops and creation of novel crops is unlimited, and in the near future we will begin to see many new and exciting varieties created by biotechnology. Michelle
L. Jones, Ph.D. |
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Easter
Lily Production Schedule
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Easter for 2000 is late, April 23, which will prove to be a challenge for many growers. This will be primarily related to dealing with the logistics of growing both an Easter lily crop and starting a bedding plant crop. Also, it will be a challenge to prevent lilies from blooming to early. There are six schedules that a grower can use listed below. The schedules have been designed for the traditional wholesale grower as well as the retail grower. Also, there are schedules provided for wholesale and retail growers who wish to flower their lilies earlier and store them in a cooler until marketing time. Point your browser to the schedule that best suits your needs and production demands.
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Upcoming Events |
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1999 Poinsettia Open House |
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Colorado
State University College of Agriculture Commencement Dr. David Hartley will be the commencement speaker |
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ProGreen
Expo Denver, Colorado |
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Wyoming Groundskeepers and
Grower's Association |
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Colorado
Floriculture Foundation Hall of Fame Dinner Boulder Dinner Theater Boulder, Colorado |
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Colorado Garden and Home Show |
Most
of you who have regularly receive the Mile High Growing Newsletter know
that Dr. Karen Panter left Colorado State University Cooperative Extension
for the Statewide Extension Specialist position in Wyoming. With her departure,
we took a hiatus from publishing a newsletter for the greenhouse industry
in Colorado until her replacement was hired. Beginning November 1, 1999,
I am happy to report to you that Karen's replacement has been hired and
we all need to welcome Chris Freeman. Our newsletter will now continue
with the added inclusion of an electronic version delivered via the ghex@colostate.edu
listserv. Electronic versions can be accessed by directing your browser
to: 
Root
and stem (crown) rot diseases of poinsettias are caused by several different
fungi living "below ground" (i.e. in soil or potting media). Not only,
are these diseases the most common problems we see on the crop in Colorado,
but also have a lot of similarities in terms of diagnosis. 
Good
sanitation practices are essential in helping manage or minimize these
disease problems. The
following should be used in prevention as well as in conjunction with
fungicide applications when root diseases appear:
Biotechnology
is the process of modifying cells or genes (DNA) in order to genetically
improve living organisms and produce products of commercial importance.
This process may also be referred to as genetic engineering or recombinant
DNA technology. Genetic engineering allows for the modification of specific
traits by adding genes or altering the genetic code within cells. For
years farmers and researchers have been using traditional breeding to
select for and enhance desirable traits. While breeders have been able
to create new varieties with desirable color, vase-life, and resistance
to pests and diseases, traditional breeding is limited to the gene pool
of a single species. Biotechnology now offers a wider choice of genetic
traits (genetic material from all species) that can be manipulated quicker
and with more precision and reliability than traditional breeding. Biotechnology
is a modern tool applied to an old science of plant (or animal) improvement.
The
postproduction quality of many horticultural crops is limited by the longevity
of individual flowers. Petal senescence (death) is also a very complicated
process and is precisely regulated by the combined effects of sets of
genes that activate the death program and sets of genes that act to suppress
cell death. I am interested in identifying those genes that are involved
in regulating senescence. I have previously identified a gene that is
involved in degrading proteins in senescing flower petals. This gene,
in addition to newly identified genes will be studied to determine their
roles in flower senescence. Ultimately those genes involved in initiating
and coordinating the processes of petal senescence will be used to generate
transgenic plants that have increased flower longevity. When these genes
are engineered and placed back into the plant in the opposite orientation
(antisense), the expression of the endogenous gene is inhibited and the
process of senescence can be delayed.