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Title: Lignin reduction in alfalfa (Medicago sativa) does not affect foliar disease resistance

item Samac, Deborah - Debby
item AO, SAMADANGLA - University Of Minnesota
item Dornbusch, Melinda - Mindy
item GREV, AMADA - University Of Minnesota
item WELLS, M SCOTT - University Of Minnesota
item MARTINSON, KRISHONA - University Of Minnesota
item SHEAFFER, CRAIG - University Of Minnesota

Submitted to: International Congress of Plant Pathologists
Publication Type: Abstract Only
Publication Acceptance Date: 3/28/2018
Publication Date: 7/29/2018
Citation: Samac, D.A., Ao, S., Dornbusch, M.R., Grev, A.M., Wells, M., Martinson, K., Sheaffer, C.C. 2018. Lignin reduction in alfalfa (Medicago sativa) does not affect foliar disease resistance. International Congress of Plant Pathologists. July 29-August 3, 2018, Boston, Massachusetts.

Interpretive Summary:

Technical Abstract: Disruptions in the lignin biosynthetic pathway have been shown to reduce disease resistance in a number of crops. Recently, genetically modified alfalfa (Medicago sativa) varieties have been marketed with reduced lignin and improved forage quality traits, including increased digestibility by ruminants at later stages of plant maturity. The objective of this study was to compare foliar disease resistance in three reference alfalfa varieties, 54R02, DKA43-22RR, WL355.RR, and the reduced lignin variety, 54HVX41, to evaluate the effect of the reduced lignin trait on foliar disease resistance. Alfalfa plants in research plots at three locations in Minnesota were evaluated for percent defoliation caused by foliar pathogens at four maturity stages; early bud, bud, early flower, and flowering; with natural inoculum. Spring black stem and leaf spot, Leptosphaerulina leaf spot, and common leaf spot were observed from June through September in all locations on all varieties. Summer black stem and leaf spot was most prevalent in August on all varieties at one location. The amount of defoliation increased with maturity stage for all varieties. When harvest was delayed until the flowering stage, moderate to severe (32 to 64%) leaf loss occurred, depending on location. Alfalfa varieties did not differ in percent defoliation at any maturity stage indicating that the reduced lignin trait did not affect foliar disease resistance.