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Wis. Blackstem and Associated Diseases of Forage Legumes . 



(1) Obtain more information concerning pathogens involved. 



(2) Learn more about the nature of resistance to these 

 diseases and its mode of inheritance. (3) Develop technics 

 for the creation of artificial epidemics needed for evaluation 

 of resistance. (4) Develop needed breeding technics. (5) Try 

 to locate resistance to blackstem diseases and to use resistamt 

 materials in a breeding program or make them available for use. 

 (6) Explore other methods of blackstem control. 



PI. Path. 1020 (NC-37) Coop. ARS 



Alfalfa 



Alaska Breeding Alfalfa Varieties Resistant to the Blackstem 



Complex . To develop strains of alfalfa resistant to black- 

 stem caused by several organisms in that complex, and to 

 investigate genetic nature of resistance to blackstem, using 

 diploid Medicago falcata. 200-300 selections of diploid 

 M. falcata will be screened for resistance to this disease 

 in greenhouse in 1955* S]_ progenies of about 100 of these 

 are available for testing in the seedling stage. Matings of 

 resistant and susceptible clones will be made to study 

 inheritance of resistance. From these results, hypotheses 

 will be formulated which apply to tetraploid lines and they 

 will be tested by the use of tetraploidized resistant and 

 susceptible clones. 



Agron. 44(R) (NC-37) Coop. ARS 



Ariz. Diseases of Roots and Root-Crowns of Alfalfas in Arizona 

 Induced by Soil-Inhabiting Pathogens . (l) Survey alfalfa 

 growing areas to learn more about fungi and bacteria present 

 and to learn etiological significance of noted organisms. 



(2) Study pathogenicity of various isolated organisms. 



(3) Learn control of root- and crown-attacking fungi through 

 changes in cultural practices and use of soil fumigants. 



(4) Study microorganisms in root rhizospheres of alfalfa 

 varieties. (5) Investigate possible control measures. 



PI. Path., Agron. 227 



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