Recently observed hybrid populations of peach [Prunus persica (L.) Batsch] provide evidence for the presence of a single gene controlling full red skin color. The fruit of seedling populations of `UFQueen' × `Springbaby', `UFQueen' × `Springprince, FL93-12C × `Springprince, FL92-22C × BY79P1945, and AP98-18 o.p. were rated for percent red skin color at full maturity. At this stage of development, “full red” phenotypes display red color over the entire surface of the fruit, including the stem cavity and portions of the fruit shaded by leaves or stems. Both crosses with `UFQueen yielded populations displaying a 1:1 segregation ration for partial red: full red. All other crosses produced populations that did not deviate significantly from a 3:1 segregation ratio. These data are consistent with the hypothesis that the “full red” phenotype is a single gene recessive trait. We propose the gene symbols of fr and Fr for the recessive full red and dominant partial red (wild-type) alleles, respectively.
T.G. Beckman and W.B. Sherman
P.C. Andersen and W.B. Sherman
T.G. Beckman, G.W. Krewer, and W.B. Sherman
Ien-Chi Wen, K. E. Koch, and W. B. Sherman
Two peach-to-nectarine mutants were compared with their peach progenitors to quantify physical and biochemical characters associated with this conversion. Both nectarine mutants showed pleiotropic effects that included smaller, rounder, and more-dense fruit with redder skin and altered sugar and organic acid composition relative to those found in their peach progenitors. In addition, one of the nectarine mutants exhibited a later bloom time, a less pronounced change in fruit size, a shorter fruit development period, and an associated capacity to develop red fall leaf color.
I-C Wen, W.B. Sherman, and K.E. Koch
Peach-to-nectarine mutations are associated with broad pleiotropic effects. The present study addresses the heritability of nectarine-specific effects in three hybrid families. A comparison of peach and nectarine siblings showed that nectarine fruit were smaller (less fresh weight), rounder, darker, redder, and had higher levels of sugars and organic acids. These heritable characteristics are similar to effects of spontaneous peach-to-nectarine mutations described previously.
M.G. DeWald, G.A. Moore, and W.B. Sherman
Genetically characterized isozyme loci are useful for taxonomic studies. In an initial study a few Ananas genotypes were used to determine which enzyme systems would give well-resolved banding patterns on starch gels. The enzyme-staining systems that resulted in well-resolved banding patterns were used to survey more Ananas genotypes to identify and characterize isozyme polymorphism. Genetic studies were performed using seedling populations to determine the basis of variability observed among genotypes. Two peroxidase loci and three phosphoglucomutase loci were identified and characterized. Information from these studies, was used to formulate a system by which species and plant introductions could be identified and distinguished.
P.M. Lyrene, W.B. Sherman, and R.H. Sharpe
C.A. Weber, W.B. Sherman, and G.A. Moore
Segregating F2 peach populations in the Univ. of Florida breeding program were analyzed to determine linkage relationships among five qualitative traits: flower type, Sh/sh, flesh type, M/m; flesh color, Y/y; leaf gland type, E/e; and pubescence, G/g. Independent segregation was confirmed between flesh color and leaf gland type, between pubescence and flesh color, and between flower type and pubescence. Previously undocumented independent segregation was found between leaf gland type and flesh type and between pubescence and leaf gland type in our populations. The relationship between these latter characteristics should be investigated in other breeding populations. No correlation was found between fruit development period and flesh type. Also, no correlation was found between chilling requirement and flesh type.
P.C. Andersen, W.B. Sherman, and R.H. Sharpe
J.K. Brecht, K. Cordasco, and W.B. Sherman
Two nonmelting flesh (`GUFprince' and `UF2000') and two melting flesh (`Tropic Beauty' and `Rayon') peach cultivars were segregated into ripeness categories at harvest according to initial flesh firmness and prepared as fresh-cut slices as described in Gorny et al. (HortScience 33:110–113), except that there were no “overripe” (0-13 N flesh firmness) stage nonmelting flesh fruit. Slices were stored at 1, 5, or 10 °C for 8 days and were evaluated for visual and taste quality, flesh firmness and color, and respiration and ethylene production rates every other day during storage. The optimal ripeness for preparing fresh-cut slices from the melting flesh cultivars was the “ripe” (13-27 N flesh firmness) stage; less-ripe melting flesh slices did not ripen at 1 or 5 °C and riper melting flesh slices and those held at 10 °C softened excessively, became discolored, and decayed. The optimal ripeness stage for the nonmelting flesh cultivars was 40-53 N flesh firmness, which corresponded to physiologically ripe (climacteric rise) for nonmelting flesh fruit, but melting flesh fruit at that firmenss were physiologically only mature-green (preclimacteric). Storage of nonmelting flesh slices was limited by surface desiccation at 1 °C, and by flesh discoloration at 5 and 10 °C, which was more severe in riper slices. The best storage temperature for both fruit genotypes was 1 °C, which prevented discoloration and decay over the 8-day storage period. Nonmelting flesh peach cultivars are better suited for fresh-cut processing than melting flesh cultivars because their firmer texture allows the use of riper fruit with better flavor than the less ripe fruit that must be used for fresh-cut melting flesh peaches.