Mc. Oleary et Th. Boyle, INHERITANCE AND LINKAGE RELATIONSHIPS OF ISOZYMES IN EASTER CACTUS, Journal of the American Society for Horticultural Science, 123(1), 1998, pp. 98-103
Polyacrylamide gel electrophoresis was used to study inheritance and l
inkage of isozymes in Easter cactus (Hatiora species and interspecific
hybrids). Five isozyme systems were analyzed: aspartate aminotransfer
ase (AAT), gtucose-6-phosphate isomerase (GPI), malate dehydrogenase (
MDH), phosphogluccdmutase (PGM), and triosephosphate isomerase (TPI).
F-1, F-2, BC1, and S-1 progeny were used for inheritance studies. Six
polymorphic loci (Aat-1, Gpi-1, Mdh-1, Pgm-1, Pgm-2, and Tpi-2) were i
dentified. Aat-1 and Pgm-1 were linked (recombination frequency = 26%
+/- 7%), but the other isozyme loci assorted independently. Aberrant s
egregation ratios were observed in at least one segregating family for
all sis isozyme loci. We hypothesize that segregation distortion was
due to linkage between isozyme loci and other genes subject to pre-or
postzygotic selection. The existence of five additional isozyme loci (
Ant-2, Gpi-2, Mdh-2, Mdh-3, and Tpi-1) was inferred from segregation p
atterns and by comparison of isozyme profiles from phylloclades and po
llen. These isozvme loci may prove useful for confirming hybridity in
intra-and interspecific crosses, detennining parentage of cultivars, a
nd assessing genetic diversity in germplasm collections.