of inheritance of fruit softening. Resemblance among relatives is a basic genetic phenomenon, and the degree of resemblance determines heritability, which in turn facilitates the choice of a breeding method for use in genetic improvement ( Falconer
influencing the slow development of the crop in the region. Precise estimates of genetic parameters, such as the components of variance and narrow-sense heritability for economically important population characteristics in breeding programs, allow us to
.0, whereas the most orange fruit had a value near 0.5. The leaf color data were transformed using the formula R + B-G. Using transformed data, the blackest leaves had a value near 60, whereas the greenest leaves had a value near 4. Heritability
fruit size. Although all yield components interact with environmental influences to produce total yield, from a breeding point of view, there are key components that are likely to be better correlated with yield and are more heritable. We found few
Abbreviations: CR, chilling requirement; CU, chill unit; GDH, growing degree hours; H 2 , heritability; I 50 , index of bud activity; OP, open-pollinated. 1 Present address: IAPAR-lnstituto Agronômico do Paraná, P.O. Box 2301, Curitiba, PR, Brazil
of inheritance, heritability, and the possible candidate genes are all unknown for this crop. These factors are critical impediments to efficient breeding of watermelon cultivars in a changing environment, and especially for the United States where
. Our analysis combined data from 2 later years, when the trees were more mature (2005 and 2007), for the calculation of heritability estimates for five color traits, fruit weight, fruit length, fruit width, and anthracnose resistance. No data were
heritability of BRR was estimated using the data from the 78 hybrid trees. Theoretically, the phenotypic value can be determined by the genotype and environment. Here, the phenotypic variance ( S ) was calculated as the hybrid population total variance. The
Realized heritability estimates of bolting percentage, pink root and fusarium basal rot severities and incidences, and percentage of single-centered bulbs were estimated for half-sib families of an intermediate-day, open-pollinated onion (Allium cepa L.) population using selection response analysis. Half-sib families were selected based upon an index that equally weighted bolting percentage, pink root and fusarium basal rot severities and incidences, percentage of single-centered bulbs, and bulb quality. Families were subjected to one cycle of half-sib family recurrent selection. Pink root and fusarium basal rot severity was reduced by 17% and 7%, respectively, with realized heritability estimates of 1.28 and 0.65, respectively. More progress for pink root severity was made than was selected. Disease incidence was reduced by 18% and 12%, respectively, with heritability estimates of 0.65 and 0.60, respectively. Very little progress was made for the percentage of single-centered bulbs and this was reflected in a heritability estimate of 0.17. Selection based upon multiple characters at the same time may reduce the effectiveness of making improvements in a single trait. However even with low to moderate heritability, improvements were made, and suggest that further improvements can be made through selection.
Abbreviations: G × E, genotype × environment; h 2 , heritability. 1 Professor. 2 Associate Professor. Florida Agricultural Experiment Station Journal Series no. R-02374. This research was supported in part by the U.S. Dept. of Agriculture under CSRS