RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM DIFFERENCES AMONG ILLINOIS LONG-TERM SELECTION OIL STRAINS

Restriction fragment length polymorphism (RFLP) analysis was used to c haracterize variability in the Illinois Long-Term Selection Experiment oil strains. Considerable polymorphism was detected within each oil s train and among oil strains. Fifty-two individual plants from each of the Illinois High Oil (IHO), Illinois Low Oil (ILO), Reverse High Oil( RHO) and Reverse Low Oil (RLO) strains were sampled to determine RFLP allele/variant frequencies. Generation 90 was sampled for IHO, RHO, an d RLO whereas generation 87 was sampled for ILO. Forty-nine RFLP probe s distributed throughout the maize genome were used. Chi-square analys is was performed to determine if RFLP genotypes at each of the 49 RFLP loci were significantly different among strains. Oil strains that hav e been separated for 90 generations showed high levels of significantl y-different RFLP genotypic frequencies. The comparison of ILO vs RHO g ave only significant chi-square values while the comparisons of IHO vs RLO and RHO vs RLO had 11:1 ratios of significant to non-significant chi-square values. Strains that have been separated for only 42 genera tions showed a lower level of significantly-different RFLP genotypic f requencies. The comparisons of IHO vs RHO and ILO vs RLO both had only a 3:2 ratio of significant to non-significant chi-squares values. Det ection of multiple RFLP alleles/variants among the oil strains was com mon with 59% of the RFLP loci examined exhibiting multiple variants. A number of RFLP loci in RHO (3) and RLO (11) were associated with a tr end in RFLP allele/variant frequencies consistent with a response to r everse selection for oil concentration.