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  • Author or Editor: R.L. Bell x
  • Journal of the American Society for Horticultural Science x
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Narrow-sense heritability estimates were computed for five fruit quality characteristics and their weighted total index. Grit content and skin russeting were moderately heritable traits, while flesh texture, flavor, appearance, and the weighted total score were of relatively low heritability. Within sub-populations of crosses, defined by the species ancestry of the parents, the relative magnitudes of heritabilities for each trait varied, but were in general agreement with those for the entire population. The general combining ability variances were 4.5 to 12.0 times those for specific combining ability, although both were statistically significant for all traits and the weighted quality index. The species ancestry of a parent had no effect on its general combining ability rank. While selection of individual seedlings on the basis of their own phenotype will result in genetic improvement for grit and russet, selection based on a combination of full-sib family means and individual phenotypes is recommended for flavor, texture, appearance, and overall fruit quality.

Free access

Abstract

Sample sizes for detection of differences of flower bud survival in peach and nectarine [Prunus persica (L.) Batsch] were chosen on the basis of theoretical confidence intervals (Cl) and least detectable differences (LDD) for the binomial distribution. Theoretical Cl and LDD for 1000-bud samples were comparable to Cl and Duncan's multiple range test separation computed from an analysis of variance for 1000 buds, based upon 10 replicates of 100 buds. Variability in survival was a function of eultivar, height of bud in canopy, and bud type. Variability may be minimized by sampling a given bud type (single, double, distal) at >1.5 m above ground level.

Open Access

Abstract

No consistent trend towards increased inbreeding has existed within the U.S. Department of Agriculture pear breeding program over 17 years of crosses based on the mean inbreeding coefficient and the percentage of non-inbred progenies. Selections did not tend to be more or less inbred than the population of all seedings. There was consistent, but small, trend towards a reduction in seedling vigor with increased levels of inbreeding as measured by 5th year stem diameter. A significant positive, but small, association between increased inbreeding and improved flavor, grit, and texture were observed, even after correction for the effects of parental values for these characters. Limited inbreeding does not adversely affect improvement of fruit quality and appears to be of some benefit in facilitating selection of favorable alleles.

Open Access