| Abstract: | This dissertation reports on three separate studies: related versus unrelated graft partners, fast versus slow growing rootstocks and clonal roots tock screening. The study of related versus unrelated partners had four relationship classes in which the scion and rootstock were: of the same genotype, related as full sibs, related as half sibs, and unrelated. Only graft combinations of the same genotype had significantly better survival and less incompatibility after four years than the other relationship classes. Graft combinations of the same genotype had a mean survival of 86 percent and 3 percent incompatibility while the other three relationship classes had a mean survival of 69 percent and 17 percent incompatibility. No significant difference were observed in scion growth among those grafts that lived. The study of fast versus slow growing rootstocks used seedling rootstocks from families which had shown above or below average growth rates in progeny tests. The scion material was from clones which had shown high rates of compatibility or incompatibility in previous grafting trials. After one year no differences were observed in survival or scion growth between the fast and slow growing rootstocks or between the compatible and incompatible scions.. |
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