Crop Science (1998) 38, 23-26

E.S. Halimi and D.E. Rowe (1998)
Stem-tip inoculation of alfalfa with Sclerotinia trifoliorum: II. performance of S₁ and F₁ progenies from resistant and susceptible selections
Crop Science 38 (1), 23-26
Abstract: Two types of resistance responses have been identified on alfalfa (Medicago sativa L.) for Sclerotinia crown and stem rot caused by Sclerotinia trifoliorum (Eriks) following a stem-tip inoculation. A plant with the Type 1 resistance stops the lengthening of necrotic region on the stem about eight days after inoculation, but a plant with the Type 2 resistance continues slow expansion of necrotic region for the duration of the 14 d test. This research determined the levels of resistance in progenies from crosses of selections with same and different types of resistance to Sclerotinia, from crosses of resistant and susceptible selections, and from self-fertilization of selections. The daily development of disease was measured from four to 14 d after inoculation on progenies from a diallel of six resistant selections and from a factorial cross of four resistant and four susceptible selections. The crosses among selections with Type 1 resistance produced progenies only with Type 1 resistance. Crosses of selections with Type 1 and Type 2 resistance produced four progenies with Type 1 resistance and four progenies with Type 2 resistance. Selfing the four selections with Type 1 resistance resulted in three progenies with Type 1 resistance and one with Type 2 resistance. Crosses of susceptible plants and those with Type 1 resistance resulted in low levels of Type 2 resistance. Selfing generally decreased the level of resistance in the resistant selections. For development of synthetic varieties, parents should be selected with high levels of Type 1 resistance and for self-sterility.
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Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sclerotinia trifoliorum	Alfalfa/lucerne (Medicago sativa)