Genotype of a plant variety determines the ability to produce, regional adaptability, resistance to pests / diseases and quality. While the environment can cause a variety of properties of ornamental plants. Example: a variety that has the ability to produce high but if water and nutrient needs are not met and the weeds are not controlled, then the varieties that can not provide high yields.
Some components of environmental factors are important in determining growth and crop production include: solar radiation, temperature, soil, water.
A. Solar radiation. Solar radiation is the main factor among other climatic factors, not only as a primary energy source but because of its influence on the situation of other factors such as temperature, humidity and wind. The response of plants to solar radiation can be basically divided into three aspects, namely: intensity, quality and fotoperiodisitas. This third aspect has a different effect from one to another, as well as the situation in nature, so as to details will be described separately. 1. Light Intensity. The intensity of light is the number of energy received by a crop per unit area and per unit time (kal/cm2/day). Understanding the intensity here has included a long irradiation, which is long the sun shines in a single day, because the unit's time to use a day.
Magnitude of the intensity of light received by plants is not the same weeks to every place and time, because it depends on: a. The distance between the sun and the earth, for example in the morning and evening intensity is lower than in the daytime because the sun farther distances. Also in sub-tropical regions, its intensity is lower than the tropics. Similarly, on a mountaintop in intensity (1.75 g.kal/cm2) higher than in the lowlands (above sea level = 1.50 g.kal / cm2). b. Depending on the season, for example in the rainy season due to a lower intensity of solar radiation that falls partially absorbed by clouds, while in the dry season is generally a little cloud so that the higher intensity. c. Geographical location, for example on the slopes of the mountain region north / south is different from the slopes east / west. At the plant receives less sunlight than the north / south for a long time due to shorter penyinarannya blocked by mountains. Even the west and east slope itself too often there is a difference, especially in the rainy season. This is because the rainy season is usually a lot more that afternoon than the morning cloud, as a result the western slopes of the new meneroma afternoon sun will get the radiation intensity is very low.
Effect of light intensity on plant growth and development is closely linked to the extent to which the process of photosynthesis. In this process the light energy required for the ongoing unification of CO2 and water to form carbohydrates. The greater Juml; ah energy available will increase the amount of photosynthesis up to the optimum (maximum). To produce the maximum dry weight, plants require full light intensity. However, the intensity of light reaching the plant canopy on the surface varies greatly, this is one cause actual crop production potential is unknown. The amount of strong light on the target area there is a claim by the unit foot candles (ft-c) of the UK.
2. Quality of Light The sunlight through the canopy or the canopy of plants not everything can be utilized, some of the light is absorbed, in part transmitted, or reflected back. The quality of light is determined by the relative proportions of the wavelength, in addition to the quality of light is not constant but varies from season to season, geographical location and changes in the composition of air in the atmosphere. Definition of light associated with the visible radiation (visible) to the eye, and only a small fraction of the total radiation received from the sun. Solar radiation is divided into two, namely the corrugated (long wave radiation) and the short-wave (short wave radiation). Closing of the short-wave radiation is ultraviolet radiation, while the deadline for long-wave radiation is infrared light. The sunlight that reaches the earth only partially, the remaining light is filtered by several components of the atmosphere or reflected back into space. Short-wave sunlight filtered and absorbed by the ozone layer (O3) in the atmosphere, while the wave length of light filtered by water vapor in the air, the light of other wavelengths solved and reflected by clouds and dust layers above the earth's surface. Effect of light quality on plant growth and development has been widely investigated, with the known spectrum of visible (visible) is required for plant growth. When plants were grown in blue light just leaves will develop normally, but the trunk will show signs of stunted growth. When plants were grown on a yellow light alone, the branches will grow tall and skinny with a book (internode) long and leaves into small pieces. From these studies have proven that blue and red light plays an important role for the process of photosynthesis.
3. Fotoperiodisitas Fotoperiodisitas or day length is defined as the length or duration of daylight was calculated from sunrise to sunset plus the length of the dim state (time lapse before sunrise or after sunset when the sun is at a position 60 below the horizon). Length of day is not affected by clouds as in the old state of irradiation can be reduced if the sun covered with clouds, day length is fixed. The length of day change uniformly throughout the year according to the declination of the sun and different at each place according to latitude. At the equator day length of about 12 hours per day, the farther from the equator day length can be more or less in accordance with the movement of the sun. In general it can be said that the longer the plants get the sunlight, intensified the process of photosynthesis, so the result will be high. However, this phenomenon is not entirely true because some plants require a different exposure time to encourage the flowering phase. Fotoperiodisitas not only affect the amount of food produced by a plant, but also determine the time of flowering in many plants. Based on the responses of plants to long days (fotoperiodisme) then the plants can be classified into three groups: a) Group long-day plants (long day plants), b) short-day plants (short day plants) and c). Day-neutral plants (neutral day plants). Besides, also known as the critical day length is the maximum length of day (for a short-day plants) and minimum (for the long day plants) where the initiation of flowering is still happening. Critical day length varies according to species and even varieties of plants. If the short-day plants grown in long days, would generate a lot of carbohydrates and proteins used for the development of stems and leaves. Therefore the short-day plants grown on long days in the extreme will grow vegetatively, not able to form flowers and fruits. Conversely, if the long-day plants grown in short days will produce less carbohydrates and protein so weak vegetative growth and not flowering. Plant responses to day length is often associated with flowering, but in fact many aspects of plant growth is influenced by, among others: (a) Initiation of interest, (b) Production and fertility of pistil and tepungsari, eg on maize and soybean, (c) The formation of tubers on potato, garlic and potatoes to another, (d) Dormancy of seeds, especially seeds and germination of weed seeds to plant flowers, and (e) the overall growth of plants, such as the establishment of seedlings, branching and elongated growth.
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