Technology of storage and primary processing of agricultural products

16- LABORATORY WORK.

Topic: Mutational variabilityto study

The purpose of the work. It consists of studying the changes in symptoms as a result of the influence of various physical and chemical factors on the body.
The content of the work. It is well known that variability is one of the key factors in evolution and is the source of material for artificial and natural selection . There are 2 types of variability , non- genetic ( modification) and hereditary (mutation).
The variability associated with a change in an organism’s genotype is called a mutational variability, and some changes are called mutations. Genotype change is observed in mutational variability, and phenotype change is observed in modification. Mutational variability is a source of natural selection, while modification variability can have very little effect on the evolutionary process.
The soil, external climatic conditions, various agrotechnical measures that affect the growth and development of cotton, sometimes form a variety of modification variables that are not preserved in the next generation . External climatic factors of cotton crop was ripening, and sometimes valuable economic impact on the length of the fiber. But further normalization of conditions reduces change. Mutational variability is of course related to changes in the genetic material in a cell . The difference between this variability and the modification variable is that it persists under any external conditions, as well as in subsequent generations, because the mutation is associated with a chromosome change. Mutation can be both beneficial and harmful. For example, chlorophyll-free cotton is harmful, and germinating seedlings die from lack of nutrients during the emergence of seed leaves. This mutation is formed under the influence of only one recessive gene .
Different branching mutations in cotton can be called beneficial mutations.
When a zero-type branching mutation occurs, the fruiting branches disappear completely and the cocoon settles in the leaf axils of the main stem through its own band . This type of mutation is a recessive mutation that occurs under the control of a gene. In tetraploid cotton , a shortening mutation of the main stem joint space and sympodial branches was detected. The result was low-growing plants. Shorter plants allowed to increase the number of seedlings in the field. The gene controlling this trait has been proven to be the dominant gene. The large size of the cotton ball is a beneficial mutation. A natural mutation or the body's physiological and biochemical factors that influence formation is called a spontaneous mutation. A mutation that occurs under the influence of specific physical and chemical mutagens is called an inductive mutation. Radiation rays, some toxic chemicals, ultrasound high temperatures and others are called mutagenic factors.