gathered from those combined sources is assembled into summary charts that are used as a guide for rootstock selection ( Castle et al., 1993 , 2006 ; Ferguson et al., 1990 ; Newcomb, 1978 ). It is uncommon that additional or better selection criteria
William S. Castle, James C. Baldwin, Ronald P. Muraro, and Ramon Littell
Ryan J. Hayes, Karunakaran Maruthachalam, Gary E. Vallad, Steven J. Klosterman, and Krishna V. Subbarao
section was interpreted as a positive result (infected) for that plant. Accessions evaluated. Selection for Verticillium wilt resistance was conducted in two independent populations of accessions (Populations A and B) ( Table 1 ). Each population was
Hsuan Chen, Lan Xue, Tong Li, and Ryan N. Contreras
fertile control. Flower size, petal number, flower color, and flower shape are important ornamental plant attributes because these traits directly influence the consumer appeal. Independent selection of two correlated floral traits may lead to biased and
Christopher M. Richards, Gayle M. Volk, Patrick A. Reeves, Ann A. Reilley, Adam D. Henk, Philip L. Forsline, and Herb S. Aldwinckle
, core collections have been determined based on geographical and phenotypic characteristics ( Crossa et al., 1993 ), but increasingly, genetic data has also been used to make selections ( Liu et al., 2003 ; Marita et al., 2000 ; Ronfort et al., 2006
Jessica L. Gilbert, James W. Olmstead, Thomas A. Colquhoun, Laura A. Levin, David G. Clark, and Howard R. Moskowitz
consumer-assisted selection in horticultural breeding programs. Consumer-assisted selection is an approach to product development that seeks to identify which features are of most importance to the end user, an ambition that can be sometimes be diluted
A. Maaike Wubs, Yun T. Ma, Ep Heuvelink, Lia Hemerik, and Leo F.M. Marcelis
., 2003 ; Daymond and Hadley, 2008 ; Garriz et al., 2005 ; Marcelis, 1992 ; Tadesse et al., 2002 ). However, these functions have different properties with respect to their shapes. Comparison of different sigmoid functions and model selection should be
Vicente W. D. Casali and E. C. Tigchelaar
Computer simulation was used to compare breeding progress under self fertilization with pedigree or mass selection, single seed descent (SSD) and combinations of early generation pedigree or mass selection with SSD. Pedigree selection was the most effective selection method at high (75%) and moderate (50%) heritabilities. At low (25%) and very low (10%) heritabilities, mass selection and SSD respectively yielded the best single F6 line. Early generation pedigree selection to F4 followed by SSD was not significantly different from pedigree selection alone at all heritabilities simulated.
SSD offers greatest benefits in situations where simultaneous selection is required for several characteristics under different heritabilities. SSD alone or in combination with mass selection retained greater genetic variability for line selection in F6. Pedigree or mass selection for highly heritable characters in early generations (F2 and F3) followed by SSD and F6 selection on the basis of line performance for characters of low heritability would appear to maximize progress for most breeding situations.
Joseph G. Sullivan and F. A. Bliss
Recurrent mass selection based on a desired gain index was employed to increase simultaneously seed yield and seed protein percentage in the common bean. Seed protein was increased from 21.9 to 24.6% after 2 cycles of selection. Mean seed yields of selected populations were not significantly greater than the mean of the unselected parents, but high yielding individual families were identified. Of particular interest was the family 2-4-1, with seed yields equal to the highest-yielding parent, and seed protein percentage higher than all parental lines in both years in which the experiments were conducted. Modifications in the selection procedure were proposed which should increase the efficiency of selection for seed yield.
Vicente W. D. Casali and E. C. Tigchelaar
Estimation of breeding progress in 9 tomato populations subject to 4 generations of pedigree selection revealed significant generation differences for 5 of 12 variables measured. Cross effects were of greater magnitude than generation effects with response to pedigree selection measurable only for highly heritable characters.
Mean value of lines derived from 2 or 3 generations of pedigree selection followed by single seed descent (SSD) to F6 or F7 were similar to their corresponding pedigree lines and approximately 50% of SSD lines derived following selection to F4 surpassed pedigree lines in weighted value. Early generation pedigree selection to F4 followed by selection among F6 SSD derived lines appears to be the most rapid and effective means of sampling variability in segregating populations.
Wilbur Reil, David Ramos, and Ronald Snyder
Three selections from different bud sources of Bartlett pear were planted in a split block experiment grafted to five rootstocks in 1971. In 1992 and 1993, significant yield and yield efficiency differences occurred between the three selections. The highest yielding selection produced 51 and 40% greater weight then the lowest. The lowest yielding selection also had smaller fruit and lower soluble solids.
Differences of 37 and 52% occurred between the highest and lowest yielding rootstocks. There were also significant differences in trunk cross sectional area, yield efficiency. fruit pressure and soluble solids between rootstocks.