Plant & Animal Genome IX Conference

Workshop: Forest Tree Genome Mapping
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INTERSPECIFIC TESTING OF GENDER-ASSOCIATED SCAR MARKERS IN SALIX

¹ Environmental Sciences Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6034, USA

² College of Environmental Science and Forestry, 1 Forestry Drive, State University of New York, Syracuse, New York, 13210, USA

Through segregation analysis and testing of RAPD primers, we have derived two SCAR markers (SCAR 354₅₂₀ and SCAR AE08₈₀₀) flanking one of two putative epistatic loci involved in sex determination in Salix viminalis, and are currently testing marker utility in other willow species and pedigrees. Gender of 282 F1 S. eriocephala clones representing 35 families was determined in December 1999. Family sizes are small, averaging eight progeny, with sex ratios ranging from all female to 1.25:1 female: male. Markers are either both present or both absent in four of seven female and four of eight male S. eriocephala parental clones from which these families were generated, resulting in a total of five families derived from parents that are polymorphic for the two marker loci. In three families the mother expresses both markers, which are absent in the father. The opposite is true in the other two families. A goodness-of-fit test of marker presence/absence and relationship to gender suggests that the occurrence of SCAR AE08₈₀₀ differs significantly (alpha=0.05) from expected in the five families (Chi-square = 21.05, d.f. =1) and may be linked to gender in S. eriocephala. However, the occurrence of SCAR 354₅₂₀ is not significantly different (Chi-square = 3.18, d.f. =1) from the expected 1:1 ratio of marker presence: absence in the progeny tested. Further testing of families should validate our results and confirm the potential of at least one of the markers in predicting gender beyond the original S. viminalis pedigrees.