Internal or Genetic Factors
Genetic makeup decided the crop growth & its production. Crops vary in the genetic makeup which included desirable & undesirable characters as well. Breeders try to incorporate maximum desirable characters in one strain of crop & also try to exploit the hybrid vigour.
Desirable characters include:
1. High yielding ability under given environment condition.
2. Early maturity
3. Better resistance to lodging
4. Drought, flood & salinity tolerance
5. Greater tolerance to insect & diseases
6. Chemical composition of grains (Oil & Proteins)
7. Quality of grains (Fineness coarseness etc)
8. Quality of straw (Sweetness juiciness)
These characters are inherent in each individual and are transmitted from one generation to another by genes.