M. Andrew Walker

M. Andrew Walker

Position Title

Department of Viticulture and Enology, College of Agricultural and Environmental Sciences

1106 Wickson Hall

Research Interests

Development of grape rootstocks with resistance to soil-borne pests and development of new disease resistant fruiting cultivars. Current research projects include: development of rapid screens for resistance; determining the inheritance of and mapping resistance to grape pests and pathogens; characterizing the genetic diversity of grape pests; studying the taxonomy and evolution of grape.

Grad Group Affiliations

  • Horticulture and Agronomy Graduate Group
  • Integrative Genetics and Genomics

Specialties / Focus

  • Environmental and Integrative Biology
  • Plant Breeding
  • Systematics and Evolutionary Biology

Honors and Awards

  • Louis P. Martini Endowed Chair in Viticulture


    • 1989 PhD University of California, Davis
    • 1984 MS University of California, Davis
    • 1975 BS University of California, Davis


    Forneck, A., M.A. Walker and R. Blaich. . 2000. Genetic structure of an introduced pest, grape phylloxera (Daktulosphaira vitifoliae Fitch), in Europe.. Genome. 43:669-678

    Jin, Y. and M.A. Walker.. 1999. Breeding Vitis rupestris x Muscadinia rotundifolia rootstocks to control Xiphinema index and fanleaf degeneration.. Acta Horticulturae . 528:511-515

    Grzegorczyk, W. and M.A. Walker.. 1998. Evaluating resistance to grape phylloxera in Vitis species with an in vitro dual culture assay.. American Journal of Enology and Viticulture . 49:17-22

    Wada, E.B. and M.A. Walker. 2009. Vitaceae. The Jepson Manual 2nd Edition. On line at http://ucjeps.berkeley.edu/tjm2/review/treatments/vitaceae.html

    Vezzulli, S., D. Micheletti, S. Riaz, M. Pindo, R. Viola, P. This, M.A. Walker, M. Troggio and R. Velasco. 2009. A SNP transferability survey within the genus Vitis. BMC Plant Biology 8:128

    Riaz, S., A.C. Tenscher, R. Graziani, A.F. Krivanek, D.W. Ramming and M.A. Walker. 2009. Using marker-assisted selection to breed Pierce’s disease resistant grapes. American Journal of Enology and Viticulture 60:199-207,

    Lowe, K.M., S. Riaz and M.A. Walker. 2008. Variation in recombination rates across Vitis species. Tree Genetics and Genomes 5:71-80.

    Riaz, S., A.C. Tenscher, J. Rubin, R. Graziani, S.S. Pao and M.A, Walker. 2008. Fine-scale genetic mapping of two Pierce’s disease resistance loci and a major segregation distortion region on chromosome 14 of grape. Theoretical and Applied Genetics 117:671-681.

    Riaz, S, A.C. Tenscher, B.P. Smith, D.A. Ng and M.A. Walker. 2008. Use of SSR markers to assess identity, pedigree, and diversity of cultivated muscadine grapes. Journal of the American Society for Horticultural Science 133:559-568.

    Xu, K., S. Riaz, N.C. Roncoroni, Y. Jin, R. Hu, R. Zhou and M.A. Walker. 2008. Genetic and QTL analysis of resistance to Xiphinema index in a grapevine cross. Theoretical and Applied Genetics 116:305-311.

    Riaz, S., S. Vezzulli, E.S. Harbertson, and M.A. Walker. 2007. Use of molecular markers to correct grape breeding errors and determine the identity of novel sources of resistance to Xiphinema index and Pierce’s disease. American Journal of Enology and Viticulture 58:494-498.