Role of Various Genetic Concepts and Principles in Crop Improvement
1) Mitosis:
Essential for normal growth and development of living organisms. Leads to production of identical progeny in asexually propagated crop.
2) Meiosis:
It generates variability through recombination and segregation of genes, also maintains chromosome number constant in a species.
3) Chromosome Number:
Useful in transfer of genes from one species to another and structure development of hybrid and development of alien addition and alien substitution lines.
4) Structural Chromosomal:
Play an important role in formation of new species and change transfer of small chromosome segment from one species to another.
5) Numerical Chromosomal:
It is useful in inter specific and inter generic gene transfer, overcoming sterility in such hybrids, conservation of heterosis, development of new crop species etc.
6) Gene Interaction:
It helps in the study of inheritance and gene transfer. Sometimes, it leads to production of new phenotypes.
7) Linkage:
Linkage affects genetic variances, genetic correlation between characters and efficiency of selection.
8) Chrossing- over:
It releases genetic variability by forming new gene combinations. Variability is essential for improvement by selection.
9) Pleiotropy:
It affects the efficiency of selection. If the side effects of a gene are desirable, it helps in crop improvement and vice versa.
10) Penetrance and Expressivity:
Help in selection of elite types in the breeding population.
11) Cytoplasmic Inheritance:
It helps in the development of cytoplasmic male sterility for use in development of hybrids. Also adds to variability through mutation of plasma genes. i.e Chloroplast and mitochondria DNA.
12) Mutations:
They are useful in improving yield, quality, resistance to biotic and abiotic factors, generating new variability developing male sterility , overcoming self incompatibility etc.