SBIR-STTR Award

We propose to test three species of milkweed and their ecotypes in the greenhouse for resistance, tolerance or both to black spot and bacterial blight caused by the fungal pathogen, CercosDora ~. and Xanthomonas car IDestris pv ascleDiadis. These two diseases are the principal obstacles to the establishment of a commercial milkweed industry. They can reduce the yield of floss by 75%. Results from some preliminary studies in the greenhouse and observation in the field indicate that some of the ecotypes of two species of milkweed, AsleDais svriaca. A. sDeciosa and A. viride may provide resistance to these two diseases. However, a rigorous test in the greenhouse involving an environment conducive to the development of black spot and bacterial blight is required to determine whether the two species of milkweed possess true resistance to these diseases. Methods have been successfully established for growing inoculum and for inoculating and infecting milkweed plants with the pathogens of black spot and bacterial blight. Thus, this project will focus on collecting and analyzing the responses of the three species of milkweed. Information gained from this study will provide the basis for field testing of promising ecotypes of the three species of milkweed for resistance to black spot and bacterial blight. A field disease nursery has been established for conducting such studies in a Phase II effort.Applications:The proposed research has potential for the selection of ecotypes of two species of milkweed that are resistant, tolerant or both to black spot and bacterial blight. Such disease resistant plants will have a great impact in the expansion of milkweed production and in the establishment of a commercial industry of milkweed by providing a constant and ample supply of floss for the manufacturing of a variety of products.

Black spot and bacterial blight caused by Cercospora sp. and Xanthomonas campestris pv. asclepiadis, respectively are the most destructive diseases of cultivated milkweed in Nebraska. These two diseases reduce potential yields by as much as 75 % and keep milkweed pod yields below the economic threshold level of 250 pounds per acre.==In Phase I, initial greenhouse experiments and disease nursery field trials demonstrated that selected milkweed seedling ecotypes have tolerance/resistance to black spot, but no ecotype showed tolerance to bacterial blight. Other disease control measures, such as the use of companion crops and elimination of disease hosts, were also analyzed. Phase II will: confirm black spot tolerance/resistance in adult, pod producing plants; identify for field trails a milkweed ecotype that is tolerant/resistance to black spot and has yield potential of 2000 pounds of pods per acre; and screen additional milkweed ecotypes for disease resistance, especially to bacterial blight. Research on companion crops and chemical control measures is also planned.

Anticipated Results:
Natural Fibers was founded in 1987 to create a major new industry based on cultivated milkweed. Milkweed pods, raw materials, and finished products are produced. The Company employs 10 people and achieved over $300,000 in sales of milkweed comforters, pillows and planting seed. Projected 1997 sales requires production from 2,000 acres of cultivated milkweed. Increased milkweed pod yields reduces raw material costs and opens industrial fiber markets in nonwovens, yarn, and pulp and paper. Disease resistant milkweed germplasm is a key to higher pod yields.