Genetic studies on quantitative traits in peach /
The objectives of this research were to study variance
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1996.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=739364281&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The objectives of this research were to study variance components and heritabilities (h 2) of several each traits, evaluate genetic and phenotypic correlations among traits, predict correlated response to selection and determine parental breeding values. Seedlings of one hundred-eight crosses among 42 peach cultivars and selections were evaluated for several plant and fruit characteristics in 1993, 1994 and 1995. The data were analyzed by using a mixed linear model, with years treated as fixed and additive genotypes as random factors. Best linear unbiased prediction (BLUP) was used to estimate fixed effects and predict parental breeding values (BVs). Restricted maximum likelihood (REML) was used to estimate variance components, and a multiple trait model was used to estimate genetic and phenotypic covariances between traits. Genetic and phenotypic correlations > 0.65 and < 0.30 were considered strong or very strong and weak, respectively. Heritability estimates ranged from 0.23 to 0.48 for plant traits. For fruit traits, the range in h2 estimates was from 0.31 to .94. Ripe date, fruit development period (FDP), bloom date and fruit blush had the highest h 2 estimates, whereas fruit cheek, titratable acidity (TA), fruit weight and percent soluble solids had the lowest estimates. The predicted selection response indicates that for most traits genetic advance is possible. Most genetic correlations within both groups of traits were equal to or greater than 0.30. The phenotypic correlations were, in general, much lower than the corresponding genetic correlations. For many combinations of traits genetic correlations were very strong and indicate that in a multiple trait selection important role in dictating genet' program, correlated response will play an IC advance. For plant traits, direct selection for flower density would result in a correlated response greater than direct response for flowers per node and % VGN (vegetative + blind nodes). For fruit traits, percent soluble solids and TA would be the traits most affected by direct selection for ripening or FDP. The predicted parental BVs indicate a high range in genetic values for most traits under study. |
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| Item Description: | Vita. "Major Subject: Plant Breeding". |
| Physical Description: | xii, 161 leaves ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 129-142. |