Genetic Profiling of a Pistachia Vera L. ‘Kerman x Peters' Orchard.

Pistachio is a member of the Anacardiaceae or Cashew family and consists of at least eleven species. Of these P. vera is the most economically important species for nut production; other species are primarily used as rootstock (P. integerrima, P. mutica, and P.terebinthus) or as a pollen source (P. terebinthus).  In California,  pistachio orchards are planted primarily with male P. vera  ‘Peters’, and female ‘Kerman’; other cultivars include female ‘Golden Hills’, ‘Lost Hills’,  and the male ’Randy’ and ‘Chico’.  However, pistachio growers have observed spatial and temporal variation in these ‘Kerman’ X ‘Peters’ orchards.  Analysis of the California State University, Fresno pistachio orchard has confirmed the presence of such phenotypic variation, specifically in tree growth and fruiting density. These observed variations may be due in part to random mutagenesis that occurred during clonal propagation (budding) over the past fifty years.  However, the amount of genetic variability in the field, and the likely presence of superior/inferior ‘Kerman’ trees are not well understood. Recent studies have demonstrated that RAPD markers are marginally more informative than Inter Simple Sequence Repeat (ISSR) in the assessment of genetic diversity in Iranian pistachio cultivars. This is due to the poly-allelic nature of RAPD markers and their distribution throughout the genome and association with functionally important loci. The objective of this present study was to utilize RAPD markers to assess the level of genotypic variability in this pistachio orchard.  Preliminary data suggests the presence of polymorphisms and the results of these analyses will be presented. Such information is widely applicable to California’s rapidly expanding pistachio industry.