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  • Author or Editor: Deborah Dean x
  • Journal of the American Society for Horticultural Science x
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Cracking and scarring of pepper (Capsicum annuum L.) fruit are under genetic control in families having the cultivar Serrano Chili as the P1 parent. Fruit of `Serrano Chili' exhibited slight cuticle cracking or scarring, with no wall cracking, for an average rating of 2.2. Fruit cracking ratings of the P2 parents (`Anaheim Chili', `Red Cherry Small', and `Keystone Resistant Giant') were 1.0, 1.0, and 1.8, respectively, whereas ratings for F, (`Serrano Chili' × `Anaheim Chili'), F1(`Serrano Chili' × `Red Cherry Small'), and F, (`Serrano Chili' × `Keystone Resistant Giant') were 3.5, 2.8, and 3.5, respectively—an indication of overdominance. Cracking ratings in F2 and BCP2 populations were very similar and shifted toward the mean of the P2 parent within each family, while ratings in the BCP1 populations were similar to the F1 mean. Estimates of gene effects for cracking were mostly dominant, with some additive effects in `Serrano Chili' × `Anaheim Chili' and `Serrano Chili' × `Keystone Resistant Giant' families, and additive × additive epistasis in `Serrano Chili' `Keystone Resistant Giant'. Plants selected from segregating generations for either high and low scarring or high and low cracking produced progeny the following year with lower ratings than their respective mother's rating the previous year. Since cracking and scarring were significantly correlated with length, diameter, and length: diameter ratio of fruit in only a few generations and in segregating progeny of selected plants, fruit shape has minimal relationship to cracking and scarring.

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Viburnum rufidulum is a deciduous tree native to North America that has four-season appeal, which provides commercial horticultural value. In addition, the plant has unique and attractive red pubescence on leaf buds and petioles, common to no other Viburnum species. As habitat undergoes development and subsequent fragmentation of native plant populations, it is important to have baseline genetic information for this species. Little is known about the genetic diversity within populations of V. rufidulum. In this study, seven microsatellite loci were used to measure genetic diversity, population structure, and gene flow of 235 V. rufidulum trees collected from 17 locations in Kentucky and Tennessee. The genotype data were used to infer population genetic structure using the program InStruct and to construct an unweighted pair group method with arithmetic mean dendrogram. A single population was indicated by the program InStruct and the dendrogram clustered the locations into two groups; however, little bootstrap support was evident. Observed and expected heterozygosity were 0.49 and 0.78, respectively. Low-to-moderate genetic differentiation (F ST = 0.06) with evidence of gene flow (Nm = 4.82) was observed among 17 populations of V. rufidulum. A significant level of genetic diversity was evident among V. rufidulum populations with most of the genetic variations among individual trees (86.37%) rather than among populations (13.63%), and a Mantel test revealed significant correlation between genetic and geographical distance (r = 0.091, P = 0.001). The microsatellites developed herein provide an initial assessment or a baseline of genetic diversity for V. rufidulum in a limited area of the southeastern region of the United States. The markers are a genetic resource and can be of assistance in breeding programs, germplasm assessment, and future studies of V. rufidulum populations, as this is the first study to provide genetic diversity data for this native species.

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