Special Methods in Plant Breeding

1. Special Methods in Plant Breeding Taryono Faculty of Agriculture Gadjah Mada University

2. Plant evolution vs breeding? Plant breeding: • selection is predominantly artificial • natural combined • objectives and strategies are defined on the basis more or less secure scientific knowledge

3. Plant Breeding • An election made by man of the best plants within a variable population as a potential cultivar • A selection made possible by the existence of variability • Plant evolution directed by man • Applied genetics • Applied evolution

4. Objective • economically and biologically reasonable • Increase yield by improvement of the potential productivity followed by the successful expression of that potential • Improve quality • Make crops more amenable to mechanical handle • Adapt crops to new microclimate area

5. Breeding work step • What parent to include and why • What pattern of crossing and passage through the generation to adopt (mating and propagation systems) • What methods of selection to use • How to decide upon the ultimate release or discard of the product

6. Product of Breeding Work Variety A plant differing from other member of the species to which it belongs by the possession of some hereditary traits • Clone variety • It is maintained by vegetative propagation • Line Variety (Open pollinated variety) It is maintained by self fertilization • Pan-mitic variety It is propagated by cross-fertilization • Hybrid variety It is produced by directed crosses

7. Open pollinated variety • Once new seeds are developed, they can be freely propagated by farmers or other seed suppliers • Later generations maintain their productivity

8. Hybrid Variety • It is produced by crosses of different varieties even different species and done in very controlled conditions • It shows hybrid vigor (heterosis) • Later generations of hybrid seeds are much less productive • Farmer must purchase seeds every plant seasons

9. Heterosis The increased vigor of growth, survival, and fertility of hybrids as composed with two homozygotes It is always associated with the increased heterozygosity • F1 yielding more than the mean of the parents (mid-parent heterosis) • F1 yielding more than the best yielding parents (better parent heterosis = heterobeltiosis) • F1 yielding more than the best yielding variety (Standard heterosis)

10. Why private seed industry interested in hybrid seeds? • A firm considering the possibility to develop a new open pollinated seed variety seeds needs to include the development costs into the selling price of the seeds • But a competing seed supplier can simply by a small sample of seeds from the innovator and sell the seeds that cover the propagation costs only, not the development cost • Knowing that potential competitors will have this cost advantage, no individual firm is interested to develop new open pollinated varieties

11. Course Contain • Reproduction system • Heterosis • Quantitative genetic of heterosis • Genetic diversity and heterosis • Hybridization • Male sterile • Future out look

12. Grading system Grade : 0 – 100 • A > 80 • B – D → 45 – 80 (Normal distribution) • E < 45 Grade composition