Question

Genetic diversity in agricultural crops is threatened by
A. Introduction of high yielding varieties
B. Intensive use of fertilizers
C. Extensive intercropping
D. Intensive use of biopesticides

Answer 1

Hint: Genetic variation is the total number of genetic features in a species 'genetic makeup, varying widely from species to species variations, which can be related to the species' survival period.

Complete Answer:
- In the genetic structure of a species, genetic variation refers to the total number of genetic characteristics. It is distinct from genetic variability, which defines the propensity to differ between genetic features.
- Crop diversity is the difference in the genetic and phenotypic features of plants used in agriculture. Crops may vary in terms of seed size, branching pattern, height, flower colour, fruiting time or flavour.
- Less evident attributes, such as their reaction to heat, cold or drought, or their ability to resist particular diseases and pests, can also differ. In almost every imaginable attribute, including nutritional qualities, preparation and cooking methods and, of course, how a crop tastes, differences can be discovered.
- And if a feature can not be discovered in the crop itself, it can also be discovered in a wild relative of the crop; a plant which has similar species, which has not been cultivated or used in agriculture, but which still exists in the wild.
- Diversity in a crop can also result from different growing conditions: a crop growing in nutrient-poor soil is likely to be shorter than a crop growing in more fertile soil.
- Furthermore, and perhaps most significantly, a harvested plant 's diversity may be the product of genetic differences: a crop may have genes that provide early maturity or resistance to disease. The introduction of high-yielding varieties is the biggest obstacle to genetic diversity in agricultural crops.

The correct answer is option (A) Introduction of high yielding varieties.

Note: The foundation for plant survival in nature and for crop improvement is genetic diversity. Diversity in plant genetic resources provides plant breeders with the ability to grow new and improved cultivars with desirable features, including both farmer-preferred features (high yield capacity, large seeds, etc.) and breeder-preferred features (resistance to pests and diseases and photosensitivity, etc).