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Verónica Raga, Guillermo P. Bernet, Emilio A. Carbonell, and Maria J. Asins

hybrids included in both treatments in all years ( InfoStat, 2004 ). Considering rootstocks as a random effects factor, broad-sense heritability (H 2 ) was estimated for all traits evaluated in 2008 only for nucellar rootstocks (repetitions) derived from

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Shawn A. Mehlenbacher and David C. Smith

Abstract

Hazelnut kernels from which the pellicle can be removed easily by dry heat are highly desirable for the international kernel market. Cultivars vary from no to complete pellicle removal after heating. Nut samples of 951 seedlings representing 62 parental combinations were roasted at 130°C for 13.5 min, rubbed, and scored for degree of pellicle removal. Narrow sense heritability, estimated by regression of progeny means on midparent values, was 48% (±10%). This moderately high heritability estimate indicates that selection of easy-to-blanch seedlings should result in rapid progress.

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

( Whitaker et al., 2011 ). Although SSC and TA varied widely among genotypes, clear trends over time could not be observed for these traits. Until recently, there have been no published reports of genetic parameters such as heritabilities and genetic

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Dennis Ray, Steven Smith, and Mark Hurlburt

Lettuce (Lactuca Sativa L.) seeds imbibe water but most fail to germinate, This phenomenon now termed “thermodormancy” is prevalent in arid and semiarid climates like the southwest desert regions, Inheritance studies of thermodormancy were performed in two lettuce cultivars, Dabora (Dutch butterhead) and PI 251245 (a plant introduction from Egypt). Dabora will germinate up to 27 C and PI 251245 up to 36C. Reciprocal crosses were made. Pericarp color was used as a marker to determine successful crosses. Dabora X PI 251245 was used to estimate the heritability of thermodormancy by germinating seed from 10 F3 families and 160 F4 families at “high” temperatures.

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Creighton Gupton and James Spiers

To determine whether manganese tolerance in rabbiteye blueberry (Vaccinium ashei Reade) is heritable, a 10-parent diallel cross was produced. A 250 ppm Mn solution (200 ml/plant) was applied to a sand culture, of the progeny daily. Visual ratings (1 - dead plant - 13 - no Mn toxicity symptom) were made after 6 weeks. Shoot weight and Mn content of leaves were determined. Narrow-sense heritability estimates (h2) were 0.45±0.28 for Mn content, 0.49±0.27 for visual ratings, and 0.37± 0.21 for shoot weight. The genetic correlation between neither shoot weight nor visual rating and Mn content (0.11 and -0.15, respectively) was very high; however, the correlation between shoot weight and visual ratings (1.00) was extremely high. This suggests that visual ratings provide an estimate of Mn effects on plans equal to objective measurements of shoot weight. Though h2 estimates for Mn content and visual ratings were similar, the lack of genetic correlation between the traits indicates that tolerance to Mn toxicity is independent of Mn content. The high h2 for visual ratings suggests mass selection as the method of choice for improving Mn tolerance in a rabbiteye blueberry population.

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Creighton L. Gupton and Barbara J. Smith

A study was conducted to determine if blackberry cultivars Humble, Rosborough, and Brazos transmit rosette (incited by Cercosporella rubi) resistance and to estimate heritability (h2). Plants of parents and offspring involving these cultivars were rated for rosette severity on a whole plant basis from 0 = no rosette to 7 = all buds infected or plant dead. An estimate of h2 was computed by regression of cross means on parental means. The mean rosette severity rating of plants from crosses was always intermediate between the cultivar and other parents. Only `Humble' transmitted enough rosette tolerance to be usable although `Rosborough' crosses were more tolerant than the other parents. The h2 estimate of 0.48 was fairly high but low variability among parents other than `Humble' would suggest little progress from mass selection.

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M. Joseph Stephens, Jessica Scalzo, Peter A. Alspach, Ron A. Beatson, and Ann Marie Connor

are certain components that are likely to be better correlated with yield and are more heritable. Dale and Daubeny (1985) showed that high yield in raspberries was closely related to high lateral numbers in Abbotsford, British Columbia, Canada, and

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

antioxidants found in relatively high concentrations in raspberries ( Barritt and Torre, 1975 ) and may contribute to high health properties of raspberry ( Olsson et al., 2004 ). These compounds are genetically inherited and have high heritability in raspberry

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Dilip R. Panthee, Chunxue Cao, Spencer J. Debenport, Gustavo R. Rodríguez, Joanne A. Labate, Larry D. Robertson, Andrew P. Breksa III, Esther van der Knaap, and Brian B. McSpadden Gardener

multivariate ANOVA option of PROC GLM. Broad-sense heritability ( H ) of the trait was estimated by the entry mean basis ( Nyquist, 1991 ) as follows: where H represents the heritability, is genetic variance, is genotype-by-environment variance, is

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Abe Shegro Gerrano, Patrick Olusanmi Adebola, Willem Sternberg Jansen van Rensburg, and Sonja Louise Venter

, however, requires information on the genetic variability that exists among available germplasm. Information on the genetic heritability and genetic advance of the targeted traits is also important for efficient selection. This study was therefore carried