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Open access

Alfred Jones

Abstract

The applicability of the method of correlated responses to selection of sweetpotatoes in a breeding program is illustrated by use of previously determined correlations between 21 traits Examples of the kinds of changes that might be expected due to correlated responses are pointed out. It is further demonstrated that knowledge of such responses can assist plant breeders in making prudent selections and in the design of improved breeding procedures. Agreement of predicted and realized correlated responses indicates that this technique is suited to use with the sweetpotato. Through mass selection procedures, cultivars with most any combination of traits desired should be possible.

Open access

Hugh A. Daubeny

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.

Free access

Creighton L. Gupton and Barbara J. Smith

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.

Free access

John M. Ruter and Jeff L. Sibley

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'.

Open access

G. M. Sapers, J. G. Phillips, H. M. Rudolf, and A. M. DiVito

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

Chemda Degani, Anat Goldring, Shmuel Gazit, and Uri Lavi

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

M.E. Lyons, M.H. Dickson, and J.E. Hunter

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.

Free access

Melvin R. Hall and Mark K. Ehlenfeldt

A rabbiteye blueberry selection, T-285, appears parthenocarpic when grown in the greenhouse and sparsely seeded when grown in the field. This semi-seedless character was analyzed to determine the nature and degree of its cross- and self-fertility in comparison to its parents, `Tifblue' and `Delite'. Ovule numbers from T-286 were similar to those of `Tifblue', but lower than those of `Delite'. Seed numbers of open-pollinated `Tifblue' and T-286 were similar, and lower than `Delite', but T-286 was notable in having fruit 60% larger than `Tifblue' and 10% larger than `Delite'. Both `Tifblue' and T-286 had a tendency to produce some open-pollinated fruit with few or no seed present. None of the selections produced significant amounts of fruit when self-pollinated. When cross-pollinated, all selections set more seed, but this was less pronounced with T-286 than with either of its parents.

Free access

Shahrokh Khanizadeh and Deborah J. Buszard

Promising 1989 strawberry selections from the Agriculture Canada/McGill Univ. breeding program have been evaluated since 1990 at three different sites in Quebec. `Kent', `Glooscap', `Honeoye', `Bounty', and `Veestar' were used for comparison. Yield, average fruit weight at each harvest, firmness, color, taste, and other fruit characteristics were evaluated. SJ89288-2 had the highest yield with large fruit. SJ89700-1 and SJ89264-6 produced similar yield to `Kent' and `Glooscap', with firm and large fruit. SJ89700-1 had bright red skin color and SJ89264-6 had bright pale red color. Both are suitable from fresh-market and pick-your-own (PYO). SJ8976-1, another selection, had a firm, large, bright pale red fruit. All four selections have good shelf life quality and will be tested at four sites during 1993–95.

Free access

Nobuhito Mitani, Atsushi Kono, Masahiko Yamada, Akihiko Sato, Shozo Kobayashi, Yusuke Ban, Toshihito Ueno, Mikio Shiraishi, Shinya Kanzaki, Tomoyuki Tsujimoto, and Keizo Yonemori

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