(a) What is plant breeding? List the two steps the classical plant breeding involves.
(b) How has the mutation breeding helped in improving crop varieties? Give one example where this technique has helped.
(c) How has the breeding programme helped in improving the public nutritional health? State two examples in support of your answer. (5)
(a) Plant breeding: Plant breeding is the purposeful manipulation of plant species in order to create desired plant types that are better suited for cultivation, give better yields and are disease resistant. Classical plant breeding involves the following two steps:
1. crossing or hybridisation of pure lines
2. artifical selection to produce plants with desirable traits of higher yield, nutrition and resistance to disease.
(b) Inducing mutation in plants helps in producing desirable genes for disease resistance. Plants having desirable genes can either be multipiled directly or can be used in breeding, e.g., in mung bean, resistance to yellow mosaic virus and powdery mildew were induced by mutations.
(c) Biofortification: Breeding crops with higher levels of vitamins and minerals or higher protein and healthier fats is the most practical means to improve public health. In biofortification protein, oil, vitamin, micronutrient and mineral content and their qualities are improved.
1. In 2000, maize hybrids that had twice the amount of amino acids lysine and tryptophan compared to existing maize hybrids were developed.
2. Wheat variety Atlas 66 having a high protein content, has been used as a donor for improving cultivated wheat. (5)