Use of Agrobiodiversity for Pest and Disease Management Carlo Fadda, Bioversity International ODDG Seminars, 19 May 2011
Overview of the Project
The project idea
Farmers need to face several biotic and abiotic stresses. Traditional crop varieties as one of the few resources available to poor farmers :
Make use of the intra-specific diversity among the traditional varieties maintained by farmers to reduce pest and disease pressures
Build on existing knowledge (farmer and researcher)
Exploit the natural resistance that results from the co-evolution of pest and host species
Provide farmers with low-input options through reduced use of pesticides
We can not predict that a new pest or pathogen will develop
But we can use local genetic diversity and have a diverse set of crop varieties for farmers to reduce their risk of crop loss from pests and diseases
A diverse set of varieties with:
Less probability that migrations of new pathogens or mutations of existing pathogens will damage the crop
Crops (foodsecurity of smallfarmers; differentbreedingsystems)
Coverage of different resistance gene system (where resistance is controlled by both major and minor genes)
Transmission systems: seed-borne, soil-borne, and air-borne
Plant organ affected: leaf, stem, seeds and roots
Outcome: Benefits to local communities
Reduced crop vulnerability
Reduced crop loss
Increased capacity and leadership abilities
Benefit sharing protocols with communities
Focus Group Discussion;
Technical Evaluation (laboratory and field analysis).
Focus Group Discussion More than 1500 farmers attended the FGD globally
Based on the information from FGD;
Sixty farmers randomly selected interviewed in each community for each crop;
More than 2000 farmers were interviewed worldwide
Information on diversity is combined with field observations (option 1).
Amount and distribution of bean varieties Results – Farmers’ Knowledge Kabwohe Rubaya Nakaseke HH richness 2.21 2.20 2.556 HH Simpson 0.32 0.375 0.432 Community richness 23 26 16 Community Simpson 0.85 0.914 0.799 Divergence 0.62 0.59 0.46
Farmers’ Knowledge (Cont.) Dalixiang Baiyangnuo Magu Variation of resistance to rice blast in different traditional rice varieties 1-S 2-MS 3-MR 4-R
Results - Option 1 10 sample points were taken randomly in a field and these points’ for panicle blast different levels of resistance. Its range of variation was from 7% to 25%. Average disease incidence of 10 sample points for Dalixiang
Results - Option 1 (Cont.)
Biotic diversity regulates pests and diseases Crop genetic diversity in farmer’s fields – reducing vulnerability Reducing the probability of crop loss from pest and diseases now and in the future Weighted Damage Index = Crop loss (household) Variety richness at household level Variety Evenness at household level Household Damage Index Higher variety richness/evenness – less variance in damage: a risk minimizing argument for crop variety diversity in the production system Peng et al., 2011
Results – Option 2 Of 63 varieties, 3 didn’t flower .HR, R and MR accounted for 5%, 1.67% and 15%, respectively. The remaining 78.33% ranged from MS to HS (56.67%). HR 3 Qiena, Zhangmeleng-1, Chujing-27 R 1 Modelong-1 MR 9 Chengnuo-88 ， Nuoyou-9 ， Baiyangnuo ， Qiejiaba ， Qiege ， Chujing-24 ， Bendipinzhong ， Dulong-1 ， Xiangnuo
Option 2 (Cont.)
Within varieties, the resistance of different individual to rice blast was various.
For example, Shanyou-63 was susceptible to panicle blast, but its 30 individuals had different performance on resistance to blast, which was from HR to HS. So did other varieties.
Results – Option 4 Disease grade of leaf blast Disease grade of panicle blast Resistance R MR MS S MS S HS No. 25 13 14 6 11 13 27 Precentage 43.10 22.41 24.14 10.34 21.57 25.49 52.94 No. of varieties 58 51 Seedling nursery Field identification nursery
Isolates of Rice Blast Fungus
212 isolates were collected in farmer fields and in trials.
Results - option 5 Cultivars Isolates Frequency of virulent on cultivars 143-7a 08-SL-1-21 9-3 Y2009-31-1-6 S-2009-10-1-5 G2009-7-1-1 G2009-6-1-3 Hongyang-3 R R R R R S S 28.57 Yijing-1 R S S R R R R 28.57 magu S R R S R R R 28.57 Tuobeigu R R R S S R R 28.57 Changnuo-2 R R S R S R - 33.33 Hejing-7 R S S S R R R 42.86 Zaogu S R R S S R R 42.86 Xiangnuo R R R S R S S 42.86 Yinuo931 R S R S R S R 42.86 Chujing27 S R S S R R R 42.86 tuojiangnuo R S S R S R R 42.86 Chujing24 S R R S R S R 42.86 dulong-2 R S S S R R S 57.14 Chengnuo88 R S R S S S R 57.14 Yuelianggu S S R R S S R 57.14 Zimigu S R S S R S R 57.14 Nuoyou-9 S R S S S R R 57.14 zhangmeleng-2 R R S R S S S 57.14 zhangmeleng-3 R S S S R S R 57.14 Aijiaogu S R - S R S S 66.67 kaomolao S S S - R R S 66.67 Baiyangnuo R R S S S S S 71.43 Dianza31 S R R S S S S 71.43 Amoqie S S S S R R S 71.43 Hongjiaogu S S S S R R S 71.43
Three cultivars were R and two cultivars were MR when varieties are inoculated with isolates from Guizhou All the others were susceptible. These five cultivars are traditional cultivars from Yunnan.
The twelve cultivars that are more resistant when inoculated with Yunnan isolates are different from the 5 varieties resistant to the Guizhouinoculum. This showed that genetic and pathotypic structure of rice blast fungus population from Yunnan and Guizhou might be different.
Option 5 (Cont.)
Conclusions 2009 wet; 2010 dry Ochoa et al., 2010, unpublished data Anthracnose Ascochyta ALS Rust 2009 2010 2009 2010 2009 2010 2009 2010 Average 2.98 2.45 4.84 3.54 1.57 3.28 3.88 3.62