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Paul G. Thompson, J. C. Schneider, Boyett Graves, and B. K. Kim

Twenty-four half-sib sweetpotato families were field tested for freedom from injury by sweetpotato weevil and other soil inhabiting, injurious insects (WDS). Three pairs of adult male and female weevils were applied to the crown of each plant at the beginning of storage root enlargement. Naturally occurring numbers of WDS were high enough for considerable injury from those insects. WDS injury free roots ranged from 19% in Centennial, the suceptible control, to 57% in Regal, the resistant control. The highest family mean for percent non-injured by WDS was 55%. Weevil injury free roots ranged from 67% in Centennial to 90% in Regal with 3 families producing mean weevil non-injured roots of 89%. The genetic correlation between weevil injury free and WDS injury free roots was 0.69 ± 0.28. That estimate is preliminary and based on data from one environment. Evaluations will be repeated in 1994 for estimates of GXE to derive genetic correlation estimates with less environmental interactions.

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Valdomiro A.B. de Souza, David H. Byrne, and Jeremy F. Taylor

Heritability estimates are useful to predict genetic progress among offspring when the parents are selected on their performance, but they also provide information about major changes in the amount and nature of genetic variability through generations. Genetic and phenotypic correlations, on the other hand, are useful for better planning of selection programs. In this research, seedlings of 39 families resulting from crosses among 27 peach [Prunus persica (L.) Batsch] cultivars and selections were evaluated for date of full bloom (DFB), date of ripening (DR), fruit period development (FDP), flower density (FD), node density (ND), fruit density (FRD), fruit weight (WT), soluble solids content (SS), apical protuberance (TIP), red skin color (BLUSH), and shape (SH) in 1993 and 1994. The data were analyzed using the mixed linear model. The best linear unbiased prediction (BLUP) was used to estimate fixed effects and predict breeding values (BV). Restricted maximum likelihood (REML) was used to estimate variance components, and a multiple-trait model to estimate genetic and phenotypic covariances between traits. The data indicates high heritability for DFB, DR, FDP, and BLUSH, intermediate heritability for WT, TIP, and SH, and low heritability for FD, ND, FRD, and SS. They also indicate year effect as a major environmental component affecting seedling performance. High correlation estimates were found between some traits, but further analysis is needed to determine their significance.

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Guo-Liang Jiang, Laban K. Rutto, and Shuxin Ren

conclusively established ( Brar and Carter, 1993 ). Interestingly, the genotypic correlation between edamame yield and fresh or dried 100-seed weight at R6 stage was very low in this study. The results implied that seed size might not be genetically correlated

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Valdomiro A.B. de Souza, David H. Byrne, and Jeremy F. Taylor

Thirteen peach [Prunus persica (L.) Batsch] fruit characteristics were investigated for 3 years, 1993, 1994, and 1995, in College Station, Texas, to determine heritability, genetic and phenotypic correlations, and predicted response to selection. Seedlings of 108 families resulting from crosses among 42 peach cultivars and selections were used in the evaluations. A mixed linear model, with years treated as fixed and additive genotypes as random factors, was employed to analyze the data. Best linear unbiased prediction (BLUP) was used to estimate fixed effects. 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. Date of ripening, fruit development period (FDP) and date of full bloom had the highest heritability (h2) estimates, 0.94, 0.91, and 0.78, respectively. Fruit cheek diameter and titratable acidity (h2 = 0.31) were the traits with the lowest estimates. Fruit development period, fruit blush, and date of ripening had the highest predicted selection responses, whereas fruit suture, fruit cheek, L/W12 (ratio fruit length to average fruit diameters), and fruit tip had the lowest values. Most genetic correlations were ≥0.30 and were, in general, much higher than the corresponding phenotypic correlations. All four measures of fruit size were genetically and phenotypically very strongly correlated. Important genetic correlation estimates were also observed for date of ripening with FDP (ra = 0.93), date of ripening and FDP with fruit blush (ra = -0.77, ra = -0.72), SS (percent soluble solids) (ra = 0.63, ra = 0.62) and TA (ra = 0.55, ra = 0.64), and SS with TA (ra = -0.56). Direct selection practiced solely for early ripening and short FDP is expected to have a greater effect on correlated traits than direct selection for early bloom and large fruit mass.

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Valdomiro A.B. de Souza, David H. Byrne, and Jeremy F. Taylor

Seedlings of 108 families from crosses among 42 peach [Prunus persica (L.) Batsch] cultivars and selections were evaluated for six plant 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. Restricted maximum likelihood (REML) was used to estimate variance components, and a multiple trait model was used to estimate genetic and phenotypic covariances among traits. The narrow-sense heritability estimates were 0.41, 0.29, 0.48, 0.47, 0.43, and 0.23 for flower density, flowers per node, node density, fruit density, fruit set, and blind node propensity, respectively. Most genetic correlations among pairs of traits were ≥0.30 and were, in general, much higher than the corresponding phenotypic correlations. Flower density and flowers per node (ra = 0.95), fruit density and fruit set (ra = 0.84) and flower density and fruit density (ra = 0.71) were the combinations of traits that had the highest genetic correlation estimates. Direct selection practiced solely for flower density (either direction) is expected to have a greater effect on fruit density than direct selection for fruit density.

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James Nienhuis, Steve Schroeder, and Gretchen King

An accession of the wild species of tomato, L. pennellii (Cor.) D'Arcy, LA 1077 is much more water-use efficient (WUE) than the cultivated tomato. The F1 hybrid between L. esculentum cultivar UC82 and LA 1077 was backcrossed to UC8 2 and selfed. S1 families (BC1S1) were evaluated for fruit quality characteristics at the Heinz Research Farm, Stockton, CA. Broad sense heritabilities were estimated as follows: Fruit weight, 0.52 ± .28; Soluble solids 0.56 ± .27; viscosity 0.63 ± .27; pH 0.43 ±.29 Color L 0.59 ± .27 and Color A/B ratio 0.50 ± .28. The following phenotypic correlations were observed in the BC1S1 generation between expression of soluble solids and fruit quality characteristics: Fruit weight (g), 0.15; viscosity, -0.65; pH -0.52; Color L, -0.53 and Color A/B ratio 0.02.

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Vance M. Whitaker, Luis F. Osorio, Tomas Hasing, and Salvador Gezan

) correlations among the traits of interest; and 3) predict genetic gains from multivariate selection. Materials and Methods Mating and field designs. Twenty-five biparental crosses were generated for testing by controlled pollination among 17 parents. Nineteen

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David M. Czarnecki II, Madhugiri Nageswara Rao, Jeffrey G. Norcini, Frederick G. Gmitter Jr, and Zhanao Deng

analysis. Bootstrap analysis was performed in TFPGA ( Miller, 1997 ) for 1000 replicates to test the robustness of the nodes in the dendrogram. To assess correlation between geographical distances (in kilometers) and genetic distances, pairwise F st

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Deborah Dean, Phillip A. Wadl, Denita Hadziabdic, William E. Klingeman, Bonnie H. Ownley, Timothy A. Rinehart, Adam J. Dattilo, Brian Scheffler, and Robert N. Trigiano

correlation between genetic and geographic distance was analyzed with the Mantel test for isolation by distance with 10,000 permutations ( Mantel, 1967 ) using GenAlEx version 6.4.1 ( Peakall and Smouse, 2006 ). An unweighted pair group method with arithmetic

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M. Joseph Stephens, Peter A. Alspach, Ron A. Beatson, Chris Winefield, and Emily J. Buck

genetic variance averaged overall estimates for that trait. Genotypic and phenotypic correlations were estimated from the additive genetic variance–covariance matrix of the bivariate analysis. se s for the heritabilities were estimated using the Taylor