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- Author or Editor: Adam Dale x
- Journal of the American Society for Horticultural Science x
Abstract
Pedigrees of 134 North American strawberry (Fragaria × ananassa Duch.) cultivars introduced since 1960 were used to calculate 1) the genetic contribution of founding clones to these cultivars; 2) genetic relatedness among these cultivars; and 3) inbreeding coefficients of these cultivars. Fifty-three founding clones accounted for the pedigrees of these cultivars, with a mean genetic contribution ranging from <0.1% to 11%. Cultivars were clustered according to the genetic contribution into groups strongly related to geographic region of origin. Cultivars developed in California plus those derived in large part from California germplasm were a distinct cluster. The remaining cultivars divided strongly into two geographical divisions, with cultivars of a western or northern origin primarily in the first division, and cultivars of a southern or eastern origin primarily in the 2nd division. Cluster groups within each division also were related to the region of origin of cultivars. Cultivars also were clustered on the basis of Wright’s coefficient of relationship, a measure of genetic relatedness. Cluster groups from this analysis were strongly related to region of origin of cultivars, and were similar in content to groups based on genetic contributions. Inbreeding coefficients ranged from 0.0 to 0.875, but were <0.5 for all cultivars developed from cross-fertilization. Inbreeding coefficients were related partly to region of origin of the cultivars, but this relationship was probably an indirect result of unequal numbers of generations of controlled hybridization from common ancestors. For example, cultivars developed in California, which resulted from more generations of hybridization, generally had higher inbreeding coefficients. Strategies are suggested for maintaining and increasing genetic diversity of North American breeding populations.
Pedigrees of 137 red raspberry (Rubus idaeus L.) varieties released throughout the world since 1960 were used to calculate: 1) the genetic contribution of founding clones to these varieties; 2) genetic relatedness among them; and 3) their inbreeding coefficients. Fifty founding clones contributed to the pedigrees of these varieties with a mean genetic contribution ranging from <0.1% to 21%. Varieties were clustered according to the genetic contribution into groups strongly related to geographical origin. Varieties developed in the former USSR and derived from `Novost Kuzmina' formed a distinct cluster. The remaining varieties were clustered in groups based mainly on whether they were of North American or European origin. Varieties were clustered also on the basis of Wright's coefficient of relationship-a measure of genetic relatedness. Cluster groups were related to their geographical origin and the varieties within the groups could be traced to similar intermediate parents. Inbreeding coefficients ranged from 0.0 to 0.625 and were related, in part, to the numbers of generations of controlled hybridization from common ancestors. The British group, with the largest number of generations of breeding, had a low mean inbreeding coefficient, indicating that inbreeding can be minimized with attention to the mating system. Strategies are suggested for maintaining and increasing the genetic diversity in the world's red raspberry breeding populations.
Abstract
A trial of six raspberry (Rubus ideaus L.) cultivars was established to study the effects of primocane removal, using dinoseb, on yield and its components. In 1982 through 1984, sprays were applied using both single and multiple follow-up treatments with and without shielding the primocanes in the immediate stool area. The effects of cultivars and treatments on yield components were studied by two-dimensional partitioning of the variation in marketable yield. When primocanes were removed, the cultivars had fewer canes, larger fruit, and increased marketable yield. Cultivars differed in their requirements for treatment because some cultivars produced canes more readily than others. Higher-yielding cultivars generally had fewer canes and greater length of laterals. Chemical name used: 2-(1-methylpropyl)-4,6-dinitrophenoI (dinoseb).