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Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda
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Genetic diversity of common beans as impacted on By farmer variety selection for the management Of bean root rots in south western uganda

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  • 1. GENETIC DIVERSITY OF COMMON BEANS AS IMPACTED ON BY FARMER VARIETY SELECTION FOR THE MANAGEMENT OF BEAN ROOT ROTS IN SOUTH WESTERN UGANDA STEPHEN BUAH MSc. Student CIAT-Uganda Gines-Mera Memorial Workshop, Cali 13 – 14 May 2010
  • 2. Background • Common bean is a major source of proteins and calories in human and li h d livestock di t worldwide t k diets ld id • In Eastern Africa average consumption is 66 Kg/person per Africa, year • Smallholder farmers, especially women, depend on Common bean as a cash crop for sustaining their livelihoods • In 2007 Uganda produced about 545, 000 metric tonnes of beans worth over US $ 237 million thus p y g a vital role in playing the country’s economy
  • 3. Background cont’d • Despite its importance, common bean production in African is curtailed by several biotic and abiotic constrains • In SW Uganda, bean root rot, caused by a complex of Pythium species, is the most devastating disease —100% yield loses • Traditionally farmers in this area cultivate mixed varieties for various reasons including disease management • The practice has resulted in a vast array of seed and plant types • However, the impact of root rots on the genetic diversity of these mixtures is not known. known
  • 4. Objectives • The roles of cropping system and practice on bean root rot management and diversity of beans in SW Uganda. • The specific objectives of the study were: 1. To study farmer practices of using bean mixtures in bean root rot management. 2. To analyze genetic diversity associated with bean mixtures in South-western U S th t Uganda. d
  • 5. Materials and Methods Seed collection from farmers Mixtures and stockists, Questionnaire Separation by seed phenotype Morpho-agronomic M h i characterization Clustering 3 2 3 3 Sub-sampling from each cluster, 20% l t Morpho-agronomic characterization Pythium screening Single plants randomly chosen Microsatellite Molecular analysis Analysis
  • 6. Results • Why do farmers mix bean varieties? 100 80 ponses (%) 60 Resp 40 20 0 Differential Land Differential Culture High yield High Better taste survival shortage maturity demand Reasons for mixing varieties
  • 7. How do farmers select planting materials? 100 80 Response (%) 60 es 40 20 0 Healthy Highy yield Early Adapted High Taste Fast Resistance seeds maturity seeds demand cooking Local knowledge
  • 8. Does selection vary from seasonal to season? 120 100 Respo nse (% ) 80 es First season 60 Second season 40 20 0 Rain Large seeds Drought Climbing resistance resistance varieties Attributes used
  • 9. Survey conclusion • Small scale farmers have capacity to utilise available g p y genetic resources to manage disease and maintain bean production. • Farmers are aware of the benefits of applying integrated management approaches for root rot management.
  • 10. Genetic Diversity 1. Selectable markers • Seed phenotypes • Morpho-agronomic characterization 2. Neutral Markers • SS SSRs • Phaseolin
  • 11. Relationships based on Selectable traits 3 44 33 65 57 51 23 67 42 46 29 98 35 5 19 60 77 8 26 Mesoamerican 55 RWR 719 11 84 69 92 15 58 52 41 61 95 50 74 94 4 7 6 96 20 28 27 80 16 17 85 83 CAL 96 48 53 21 24 99 Andean 56 18 34 78 47 43 49 68 31 73 72 79 0.33 0.50 0.67 0.83 1.00 Similarity coefficient
  • 12. Group characteristics • Mesoamerican group were largely more tolerant to Pythium with 56% moderately resistant and 22% purely resistant. Overall disease score for this group was 4 7 4.7 • Andean Group had 40% of the genotypes susceptible to Pythium root rots and another 50% were only moderately resistant. t d th l d t l i t t • Overall, this study found , y • 16 Pythium resistant lines (mostly from Kisoro district), • 26 susceptible and • 58 intermediates with disease scores of 4-to-6.
  • 13. Molecular characterisation District Kabale Kisoro Populations*/indices Bub Buf Ham Rub Kya Muk Nya Nyz Nyu Kan Mean No. of samples 14 12 9 11 10 8 6 5 14 5 9.4 Polymorphism (%) 82.9 82.9 85.4 80.5 73.2 58.5 70.7 48.8 69.4 65.1 71.7 Mean pairwise 13.5 14.8 16.1 12.7 12.8 8.3 10.7 10.4 11.1 10.6 12.1 differences Average gene 32.9 36.2 39.2 31.0 31.2 20.2 26.2 25.4 30.8 25.9 29.9 diversity over loci (%) *Bub = Bubare, Buf = Bufundi, Ham = Hamurwa, Rub = Rubaya, Kya = Kyanamira, Muk = Muko, Nya = Nyakabande, Nyz = Nyarusiza, Nyu = Nyundo, Kan = Kanaba.
  • 14. Relationships based on SSR analysis Distance 0.1 20 6 44 66 Clone I 42 83 52 89 8 93 76 79 94 78 Clone II 27 68 63 73 69 99 erican 92 Clone III 26 71 23 4 esoam m 1 RWR_719 7 76 68 53 M 96 18 5 71 28 3 73 60 17 58 65 13 93 57 100 16 61 51 48 35 29 Clone IV 21 77 74 77 55 56 19 37 69 15 80 41 77 11 dean 46 43 And 38 74 99 24 84 Clone V 80 CAL_96 31 64 50 49 47 MAIZE
  • 15. AMOVA Source of variation % of Variance Fixation indices P-value Among districts 0.00 0.000 (FCT) >0.05 Among sub counties 0.00 0.000 (FSC) >0.001 within districts Within sub counties 100.00 0.000 (FST) <0.001 •No significant differentiation between the districts of Kabale and Kisoro (FCT = 0.000, P > 0.05) •No significant genetic variability among sub counties within each of the two districts (FSC = 0.000, P > 0.001) •Overall proportion of variation (100%) was due to differences within populations at the sub county level
  • 16. General Conclusions • Farmers’ knowledge on bean production was good and variety mixtures are used as broad insurance against total crop loss including disease loss, management. • As farmers select for higher y g yields, they invariably select for root rot , y y resistance as well and this could aid breeding • Resistance to PRR was highest in Kisoro district & decreases towards Kabale district probably due to more fertile volcanic soils and adoption of climbing beans • Root rot intermediate genotypes ( g yp (58%) highest compared to susceptible ) g p p (26%) and resistant (16%) beans • The maintenance of the susceptible and moderately resistant genotypes in bean mixtures could be attributed to market demand and other cooking qualities
  • 17. Acknowledgements • We thank GINES-MERA Fellowship Fund for generously providing the financial support fi i l • Supervisors: Dr. Robin Buruchara and Dr. Patrick Okori • CIAT-Uganda provided the research facilities and administered the funds
  • 18. Many thanks for your Attention!!

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