Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/2/2007
Publication Date: 8/16/2007
Citation: Bell, D.J., Drummond, F.A., Rowland, L.J. 2007. Use of est-pcr markers to answer the question: does genetic relationship matter in crosses between lowbush blueberry clones?. Meeting Abstract.
Technical Abstract: Lowbush blueberry (Vaccinium angustifolium Ait.) is a tetraploid hybrid (2n = 4x = 48) and is an economically important fruit crop of the northeast regions of North America. It is cultivated from wild stands and requires bees for pollination. The overall variation among individuals is very high with adjacent individuals which are referred to as clones showing as much as 12-15 fold differences in berry yield. The species is generally viewed as self-incompatible but this varies. Little is known quantitatively of the reproductive system or the genetic basis for these differences. The genetic structure of individuals within a field is completely unknown. Further significant advancements in management by conventional techniques are likely limited because of this lack of fundamental knowledge of the reproductive system, precluding further improvements in yield by bee management or filling in fields with high yielding clones. Overall, the goals of this research are: 1) to show that EST-PCR (Expressed Sequence Tag-Polymerase Chain Reaction) markers developed for highbush blueberry can be used reliably in lowbush blueberry as a genetic fingerprint and to estimate levels of genetic similarity between lowbush clones, 2) to use these markers to describe genetic structure within a field(s) and 3) to use this genetic relationship data to interpret yields from crosses based on genetic similarity differences. Specifically, one of the hypotheses being tested is that, since observed selfing rates are lower than outcrossing rates, nearer related individuals should be less productive when crossed together than more unrelated individuals, possibly due to a combination of a pre-zygotic incompatibility system and/or post-zygotic inbreeding depression. Here we report preliminary results on testing the utility of EST-PCR markers (developed from highbush blueberry) in reliably characterizing lowbush structure. Genomic DNA was extracted from 10 individuals and PCR amplification products were scored as dominant markers (present/absent). Using 23 EST-PCR developed primers, 64 polymorphic bands were scored. The average number of bands per primer was 3.9. Using a Sahn clustering algorithm in NTSYS (v. 2.2), 2 groups of 5 closely growing clones, each separated by 2 km in a commercial field, clustered together. The clustering of the 2 groups was found to be strong (Mantel t-test, r=0.912). Levels of genetic similarity ranged from 0.22-0.71. An analysis of molecular variance (AMOVA) showed the majority of variability (85.11%, p=0.0064) to be within groups which tends to indicate a largely outcrossing species. These molecular techniques should prove very powerful in giving insight into the structure of these wild populations as well as shed light on the complex reproductive system and what factors drive yield.