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  • Author or Editor: Gregory L. Powell x
  • Journal of the American Society for Horticultural Science x
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Peach [Prunus persica (L.) Batsch (Peach Group)] trees infected with peach latent mosaic viroid (PLMVd) have been associated with phenological changes including delay in bloom, reduced shoot vigor, and early autumn defoliation. In order to further characterize the changes occurring in trees inoculated with PLMVd, total fatty acid content was measured for floral buds during release from dormancy in `Coronet' peach trees. Palmitic (16:0), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids were the major fatty acids in dormant and releasing peach buds of both control and PLMVd-inoculated (VI) trees. The degree of unsaturation increased immediately following release from dormancy in both the control and VI trees. However, desaturation of linoleic acid to linolenic acid was significantly inhibited in VI trees, which was accompanied by a concomitant delay in the resumption of growth. The disparity between the control and VI trees in the progression of increased fatty acid unsaturation continued through petal fall. The presence of PLMVd in `Coronet' peach trees slowed membrane fatty acid desaturation during release from dormancy and suggested that metabolic pathways involving fatty acid desaturation were linked to the delayed phenology of the VI trees.

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Intensive selection to improve vase life was performed on a sample population of Gerber ×hybrida Hort. from a broad source of germplasm. Progeny of a 5 × 5 diallel cross yielded estimates of narrow sense heritability (h2 = 0.28) and broad sense heritability (H2 = 0.28) for vase life based on a mean of 1.96 measurements per plant. Additive gene action is postulated to control this character since the difference between total genotypic variance and additive genetic variance components was small. Repeatability (r = 0.57) based on a single measurement per plant was moderately high. Heritability estimates were also determined based on 1, 2, 3, 5, and ∞ measurements per plant. Heritability ranged from 22% to 39%.

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