Premium
Stem‐Tip Inoculation of Alfalfa with Sclerotinia trifoliorum: II. Performance of S 1 and F 1 Progenies from Resistant and Susceptible Selections
Author(s) -
Halimi E. S.,
Rowe D. E.
Publication year - 1998
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1998.0011183x003800010004x
Subject(s) - biology , sclerotinia , selfing , inoculation , diallel cross , sclerotinia sclerotiorum , resistance (ecology) , horticulture , plant disease resistance , botany , hybrid , agronomy , genetics , population , demography , sociology , gene
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.