HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Halimi, E. S. Articles by Rowe, D. E. Search for Related Content PubMed Articles by Halimi, E. S. Articles by Rowe, D. E. Agricola Articles by Halimi, E. S. Articles by Rowe, D. E.

Stem-Tip Inoculation of Alfalfa with Sclerotinia trifoliorum: II. Performance of S₁ and F₁ Progenies from Resistant and Susceptible Selections

Dep. of Agronomy, Univ. of Sriwijaya, Kampus Unsuri Indralaya (OKI), Sumsel, Indonesia
USDA-ARS, Crop Science Res. Lab., Forage Res. Unit, P.O. Box 5367 Mississipi State, MS 39762

^* Corresponding author (e-mail: derfru{at}ra.msstate.edu).

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 st em-tip in oculation. 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 I resistance produced progenies only with Type 1 resistance. Crosses of selections with Type 1 and Type 2 resistance produced four progenies with Type I 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.

Received for publication December 11, 1996.