Regulation of Crop Growth and Development Based on Environmental Factors

Abstract

Production of h. orticultural crops by growers is becoming increasingly difficult as markets write detailed specifications for products both in time of delivery and quality factors such height and flower number. Such specifications require growers perform proper cultural procedures at the proper time. Environmental variation between and among seasons means proper cultural procedures will vary with every crop. All growers, especially those with little experience in a crop, benefit from information that assist in making proper cultural-procedure decisions. Decision-support tools based on environmental, chemical, or biological data can help provide such information. This presentation will describe examples of biological concepts associated with plant growth and developmental processes that especially lend themselves to decision-support. Types of decision-support tools developed from this information will be presented. For example, development of plants is highly temperature dependent. Relationships between temperature and development rate are often useful as they can be described by a linear relationship over a wide temperature range from the base temperature to near the optimum temperature. Degree-day decision-support tools can be developed from such information. Growth retardant chemicals are used widely in commercial production of flowering plants to meet height-control specifications. Simulation models incorporated into decision-support tools may be useful to maximize efficacy of applications as there is increasing pressure to minimize the use of growth retardants. Biological models relating plant morphological development to the environment, e.g., bud length and temperature to time to flower, can also be useful in creating decision-support tools for accurate crop timing.

Effect of Light Conditions and Temperature on Fresh Yield of Some Spice Plants Grown in Containers

“…Dry weight production is correlated with the total radiation absorbed by plants and depends on the effective PAR transformation during the process of photosynthesis (Charles-Edwards 1978; Masson et al 1991;Aufhammer 1998). The authors' own research and well as experiments carried out by other researchers indicate that, in order to obtain an effective plant biomass increment in the shortest time, it is important to select an appropriate proportion of light to temperature (Heins et al 2000). In the case of plants used in the described experiments, the most optimal RRT value ranged from 0.22 to 0.25. spice plant fresh mass yields than the photon flux, with the exception of the salad onion.…”

Modeling the Effect of Temperature on the Flower Development Rate of Hybrid Impatiens

“…ADT is the most common measure of temperature used to regulate a number of plant developmental responses, such as flowering or leaf unfolding (Roberts and Summerfield, 1987). Through the manipulation of temperature, crop timing can be altered to appropriately hit specific market windows (Heins et al, 1998). The amount of time necessary for a specific plant developmental response is most often presented as a function of ADT, and events can be expressed as the number of days to reach a particular stage of plant development.…”

Influence of Day and Night Temperature and Radiation Intensity on Growth, Quality, and Economics of Indoor Green Butterhead and Red Oakleaf Lettuce Production

“…Regression analysis equations and r 2 or R 2 for mean leaf number, dry and fresh mass, growth index, and chroma in response to MDT(20,23, and 26 • C) and PPFD (150 and 300 µmol•m −2 •s −1 ) of green butterhead lettuce 'Rex' and red oakleaf lettuce 'Rouxaï RZ'. All models are in the form of: ƒ = y 0 + a•MDT + b•MDT 2 .…”