Question

high yielding varities are produced by biological control , crop rotation,mixed cropping hybridisation​

Answer 1

Answer:

High-yielding varieties are found naturally less resistant to pests in comparison with their progenitors. Each year, insects destroy about 25% of food crops worldwide. The introduction of plant monocultures and indiscriminate and widespread application of chemical pesticides resulted in an insurgence of pests, development of resistance, and occurrence of residual toxicity. To overcome these problems, development of resistant crop varieties through a transgenic approach will contribute to a reduction in pest attack and decrease the use of chemical insecticides (Slater et al., 2003).