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In this article we will discuss about the interrelation between phenotype and genotype.
Genotype is the genetic makeup of the individual. It is decided by the genes, which are inherited from the parents. Phenotype is what is expressed. Genes as well as environment, both are responsible for the phenotype. This can be understood by the following example. If we have two identical twins, the one brought up in cold climate, away from strong sunlight will have lighter skin colour, whereas the one brought up in strong sunlight develops dark skin colour.
In this case, the genotype of both the individuals is identical, but with the changing environment the phenotype changes. This effect can also be seen in the same individual. This proves that phenotype is not completely controlled by genotype, but environment plays a very vital role. The same expression is seen in plants (Fig. 2).
Improved Management Practices:
Green plants are the only living organisms, which can harness solar energy. These plants need minerals like calcium, phosphorus, carbon, hydrogen, oxygen and nitrogen for growth. They also require proper quantity of water, air and soil. To satisfy all these conditions manure and fertilizers are required.
Along with this pesticide, weedicides and fungicides are also required for healthy growth and improvement of plants. This means that other than environment, these factors also play a vital role in production. All these practices are known as improved management practices.
Improvement of Genotype:
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As man started domesticating plants and animals, the need arose to improve the desired traits or characters. Trait or character is any anatomical, morphological, behavioural or biochemical feature of an organism. In nature, the wild variety of fruits have small size, whereas fruits of larger sizes are required.
Wild varieties show small seed size, shattering of pod and grains at maturity. This is not a desirable trait as far as human requirement is concerned. So, from the existing variety of wild plants, man selected those traits, which were desirable, i.e. large fruit and seed size and non-shattering of pod.
By careful selection, man has been able to get yield of desirable characters. This has led to accumulation of selected traits and improvement of genotype. Modifying the genotype of an organism to make it more beneficial for man is known as breeding. When it is done with plants it is called as plant breeding and when it is with animals it is called as animal breeding. This is one of the oldest methods of improving the variety of domesticated animals and plants.
