Plant Breeding for Disease Resistance: Conventional Breeding - Practice Questions & MCQ

• Fungal, bacterial, viral and nematode pathogens attack the cultivated crops. Crop losses can be upto 20-30%.
• In this situation, breeding and development of cultivars resistant to disease enhances food production. 
• This also helps reduce the dependence on use of fungicides and bactericides.
• Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant.

Methods of breeding for disease resistance:

• It can be done through:
  • Conventional breeding
  • Mutation breeding

Conventional Breeding:

• The conventional method of breeding for disease resistance is that of hybridisation and selection.
• The various sequential steps in conventional breeding are:
  • screening germplasm for resistance sources
  • hybridisation of selected parents
  • selection and evaluation of the hybrids
  • testing and release of new varieties
• Some of the varieties developed through conventional breeding are shown in the table below:

Disadvantages of conventional breeding:

• Conventional breeding is often constrained by the availability of a limited number of disease resistance genes that are present and identified in various crop varieties or wild relatives.