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Planning breeding programs for impact

IRRI: Planning breeding Programs for Impact. Generally, to produce a cultivar that is superior to farmers' varieties in a particular target population of environmentsSpecific objectivesReplace a specific cultivarDevelop a new productChange a single trait. What is the general objective of a bree

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Planning breeding programs for impact

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    1. Setting goals and identifying target environments Planning breeding programs for impact

    2. IRRI: Planning breeding Programs for Impact Generally, to produce a cultivar that is superior to farmers varieties in a particular target population of environments Specific objectives Replace a specific cultivar Develop a new product Change a single trait What is the general objective of a breeding program? Question to the groupQuestion to the group

    3. IRRI: Planning breeding Programs for Impact Higher yields Under high-inputs? Under lower inputs (farmer management)? Under favorable climate? Over all possible climates? Quality Experiment station vs. on-farm performance When is a cultivar superior? brainstormingbrainstorming

    4. IRRI: Planning breeding Programs for Impact Will be grown by the farmer because it performs better (or obtains a better price) than the existing cultivar Under management practices currently used or available to the farmer A superior cultivar is one that:

    5. IRRI: Planning breeding Programs for Impact Be in close touch with the farmers Know the contraints in the target environment Know the market requirements Know the plant traits considered important by the farmers What makes a successful breeder? DiscussionDiscussion

    6. IRRI: Planning breeding Programs for Impact TPE = variable set of future production environments (Cooper and Byth, 1996) Variability among fields/farms Variability over seasons Results in genotype by environment interaction (GEI) Objective should be to develop a cultivar superior to the farmers cultivar in most seasons and most fields Target population of environments: definition

    7. IRRI: Planning breeding Programs for Impact Example of predicted frequencies of stress environments within a TPE Sub=submergedSub=submerged

    8. IRRI: Planning breeding Programs for Impact Geographical region Ecosystem Subdivide if necessary based on Environmental parameters Currently used cultivars Analyses of multi-environment trials Breeder and farmer knowledge Defining the target environment

    9. IRRI: Planning breeding Programs for Impact Exercise: Criteria for group environments into TPE ?Name 2 examples for each column: Every participant writes 2 examples on 2 pieces of paper that have a different colorEvery participant writes 2 examples on 2 pieces of paper that have a different color

    10. IRRI: Planning breeding Programs for Impact Cluster or principal components analysis on genotype means or genotype x environment interaction effects, also known as pattern analysis Tests of fixed environmental effects Examination of correlations of cultivar means across sites Statistical analyses of multi-environment trials to define the TPE

    11. IRRI: Planning breeding Programs for Impact

    12. IRRI: Planning breeding Programs for Impact

    13. IRRI: Planning breeding Programs for Impact What can we conclude from inspection of correlations?

    14. IRRI: Planning breeding Programs for Impact Determining the selection environment (SE) The chosen SE should maximize the power of the nursery to predict performance in the TE May need more than one SE if TE is highly variable SE is not equal to TE, so the relationship must be monitored

    15. IRRI: Planning breeding Programs for Impact The SE must predict performance in at least some seasons and locations within the TPE - genetic correlation (rG) between TPE and SE must be high. The SE must clearly and repeatably differentiate among genotypes under evaluation - heritability (H) for screening in the SE must be high. The SE must permit relatively large numbers of genotypes to be screened at low cost - the SE must permit a high selection intensity (i) to be achieved. Requirements for the SE

    16. IRRI: Planning breeding Programs for Impact Easy, well-known: Submergence tolerance Bacterial blight resistance Difficult, not well understood Drought tolerance Examples of SE for specific requirements

    17. IRRI: Planning breeding Programs for Impact Can anyone briefly summarize this unit? Question to the groupQuestion to the group

    18. IRRI: Planning breeding Programs for Impact Focus group discussions: Farmers are asked about positive and negative features of present cultivars Preference analysis: Farmers are asked to rate experimental lines in a trial In some cases, future farmer preferences must be predicted (i.e., they may not be aware of new options/technologies) Breeding goals: 1. Farmers preferences

    19. IRRI: Planning breeding Programs for Impact Deficiencies of currently grown varieties List of required traits with parents that are sources of these traits Ranking of traits in terms of importance and ease of improvement Strategy for selecting for generating populations and selection for the desired traits Breeding goals: 2. Specific traits and strategies

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