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Abstract

Variations in self-fertility, expressed as percentages of drupelets set, were observed among 69 red raspberry cultivars or selections. The incidence of reduced self-fertility was particularly prevalent among some of the older cultivars but was also observed in several selections. In a particular cultivar or selection reduction of self-fertility usually followed both self- and open-pollination. Reductions from self-pollination seemed mostly to involve self-incompatibility although at least one was due to reduced pollen-fertility. Reductions from open-pollination probably involved reduced numbers of functional embryo sacs.

Open Access

In 1991, a cooperative project with the U.S. National Arboretum in Washington, D.C., was initiated in Tifton, Ga. (USDA hardiness zone 8a) to evaluate red maples (Acer rubrum L.) potentially suitable for the coastal plain region of the southeastern U.S. Greatest annual height growth across all cultivars over 6 years was for `Alapaha', a seedling selection from southern Georgia with annual height growth of 35 inches (88.0 cm), and several seedling selections from northern Florida with annual height increases in excess of 33 inches (86.0 cm). Selections showing the least average annual height growth were NA-56024 and NA-57772 (`Red Rocket'). For commercially available cultivars, the most dependable for fall color in Tifton was `October Glory'®. In addition, two new selections from the National Arboretum have also shown excellent fall color—`Somerset' and `Brandywine'.

Free access

Eight cultivars, including five recent releases, five selections from the Florida AES, and 16 selections from the Georgia AES were planted in the muscadine germplasm working collection at McNeil, Miss., in 1992. All cultivars and one replication of the selections were evaluated in 1997. None of the new cultivars yielded as much as `Fry', the standard fresh fruit cultivar. The percent dry picking scar of `Dixie' and `Fry' was low. `Tara', `Polyanna', and `Fry' produced the largest berries. Percent soluble solids was lowest in `Fry', `Nesbitt', and `Alachua' but highest in `Dixie' berries. `Fry', `Alachua', and `Polyanna' had the lowest and the other cultivars did not differ in number of seed per berry. One selection, 33-1-4, appeared to have the qualities of a potential cultivar. Incidence and severity of berry rots were generally low.

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Abstract

Samples of 45 cranberry clones (Vaccinium macrocarpon Ait.) were analyzed for factors relating to fruit quality and processability to develop selection procedures for breeding programs. High correlations were obtained between tristimulus reflectance measurements on whole or pureed cranberries and the juice color, determined by spectrophotometric or tristimulus transmission measurements. Differences between cranberry samples in the proportions of individual anthocyanins were small and not correlated with berry or juice color. A 3-stage sequence of simple measurements, entailing minimal sample preparation, was developed for selection. First- and second-stage selections were based on the application of discriminant analysis to tristimulus reflectance data obtained with whole and pureed cranberry samples, respectively. In the third stage, selections were based on analytical measurements performed on juice prepared from samples selected in the preceeding stages.

Open Access

Abstract

Evidence is presented suggesting that genetic selection could be an important factor in avocado fruitlet abscission. ‘Ettinger’ embryos (Persea americana Mill.) at different stages of fruit development were classified according to their leucine aminopeptidase (LAP) electrophoretic pattern in the Lap-2 locus. Analysis of several fruitlet populations showed significant deviations from the expected Mendelian ratio. The genotypic ratios at the different stages indicate genetic selection during fruitlet abscission.

Open Access

preservation of plant resources and to selection of wild fruit genotypes from natural populations ( Ercisli et al., 2007 ; Tosun et al., 2009 ). The cornelian cherry is a semi-domesticated plant that can be used as both food and medicine. In folk tradition, it

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cultivars or from crosses among non-PCNA local cultivars of Japanese origin ( Ikeda et al., 1985 ). When a non-PCNA cultivar, Nishimurawase, was crossed with six PCNA cultivars and selections, no PCNA offspring were yielded among 95 offspring ( Yamada and

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Abstract

Recurrent selection was used to breed Phaseolus species for resistance to white mold disease, caused by Sclerotinia sclerotiorum. Twenty diverse genotypes selected for resistance to white mold formed the cycle 0 population. These lines were intercrossed in a partial diallel, and the F2 progeny were tested for resistance to white mold using a detached blossom/ascospore technique. Twenty single-plant selections were made, and the F3 progeny of these selections formed the cycle 1 population. A 2nd cycle of intercrossing, evaluation, and selection was completed, and genetic gain was determined by evaluating disease resistance of the selfed progeny derived from the cycle 0, 1, and 2 populations. There was a highly significant linear improvement in mean disease response from cycle 0 to cycle 2. When a subjective rating was used to assess disease response, the average gain/cycle was 0.52 rating units, and the percentage gain from cycle 0 to cycle 2 was 31%. When measurement of lesion length (centimeters) on the main stem was used to assess disease response, the average gain/cycle was 1.96 cm, and the percentage gain from cycle 0 to cycle 2 was 50%. The results of this study indicate that recurrent selection may be a useful technique for the development of resistance to white mold in Phaseolus species.

Open Access

( Goldblatt and Manning, 2008 ). There are ≈70,000 known Iris cultivars, and more than 1000 new cultivars are produced by selection and hybridization every year ( Hu and Xiao, 2012 ). Few of those cultivars bloom in early spring (late March to mid-April in

Open Access

Suspension cultures of grape hybrids (Vitis spp.) were used to select cold tolerant cell lines. The cultured cells were subjected to selection pressures by cooling at 2° C/h to various temperatures below the average lethal temperature (LT50) of the cell population. The cold tolerant lines were selected based on the distribution of lethal temperatures in the population. The small fractions of cells which were more cold tolerant than the LT50 of the population were enriched by many selection cycles. After two selection cycles, the cold tolerant lines of all three cultivars survived -9 and -9.6°C (LT50), whereas the control population survived between -2.5 and -3.2°C. The increased cold tolerance in selected lines was due to shifts in the frequency and distribution of lethal cell injury in the selected population as compared to the unselected control.

Free access