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Richard E. C. Layne

Abstract

‘Harogem’ is an exceptionally attractive, very firm, high quality, mid- to late season apricot (Prunus armeniaca L.) suitable for the fresh market. It is cold hardy, resistant to brown rot [Monilia fructicola (Wint.) Honey], perennial canker (Leucostoma spp.), and skin cracking but moderately susceptible to bacterial spot [Xan-thomonas pruni (E. F. Sm.) Dows]. It was introduced in 1979 to meet the need for a better adapted, more consistently productive, cold hardy and disease tolerant cultivar for the Ontario fresh market.

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Charles S. Vavrina, N. Kokalis Burrell, and J. Kloepper

Bell pepper (Capsicum annuum) seedlings treated with various biological preparations exhibited increased root and shoot growth both in the greenhouse and during subsequent field establishment. Early fruit set and pod development showed signs of possible yield improvement by the treatments, but treatment differences were not apparent at first harvest. Data from subsequent harvests did show yield increases with some preparations. Treatment organisms appeared to activate or induce systemic resistance to bacterial spot (Xanthomonas campestris) infestation though not to the level shown by Actigard (Novartis). Crop/treatment response under soil solarization, fumigation, and compost amended conditions will be discussed.

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Shawn A. Mehlenbacher, L. Fredric Hough, and Catherine H. Bailey

Abstract

‘Jerseydawn’ is an early-ripening, yellow-fleshed, semi-freestone peach [Prunus persica (L.) Batsch] for the fresh market. The fruit ripens 10-14 days before ‘Redhaven’ and was introduced to meet the need for a quality peach in this season. The tree is of medium vigor and is productive. The leaves and fruit are resistant to bacterial spot [Xanthomonas campestris pv. pruni (Smith) Young et al.]. Flower bud hardiness appears to be slightly less than that of ‘Redhaven’. Split pit has not been a problem. ‘Jerseydawn’ is performing well in trials at Geneva, N.Y.; East Lansing, Mich.; and throughout New Jersey.

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F.A. Hammerschlag

Abstract

A wick bioassay was developed to screen peach [Prunus persica (L.) Batsch] shoot cultures for resistance to bacterial spot [Xanthomonas campestris pv. pruni (E. F. Sm.) Dows)]. Three weeks after inoculation, the number of colony forming units (CFU) from 1-cm stem sections excised from highly susceptible cultivars was significantly greater than CFU from several resistant cultivars. Neither growth regulators nor the length of time that shoots were maintained in vitro prior to inoculation significantly influenced the response of these cultivars to bacterial leaf spot. This technique should be useful in screening for somaclonal variants obtained from peach cell cultures.

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Richard E. C. Layne

Abstract

‘Hargrand’ is an exceptionally large, firm-fleshed apricot (Prunus armeniaca L.) suitable for the fresh market, home canning and commercial processing, especially as puree for baby food. The tree is cold hardy and productive and tolerant to perennial canker (Leucostoma spp.). The fruits are moderately resistant to brown rot (Moniliniafructicola [Wint.] Honey), bacterial spot (Xanthomonaspruni [E. F. Sm.] Dows.) and skin cracking. ‘Hargrand’ ripens in the midseason with ‘Veecot’ and is being introduced for the Ontario fresh market to meet the need for better dual purpose cultivars in this season. It should be adapted to regions where ‘Goldcot’ and ‘Veecot’ are successfully grown.

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Wayne J. Bourgeois, Charles E. Johnson, William A. Young, and Alvin J. Adams

The peach breeding program in Louisiana was initiated in the late 1940's to develop adapted cultivars for Louisiana. The objectives of the program have been to develop large fruited disease resistant fresh market cultivars for all areas of Louisiana. The state is divided into three climatic zones in reference to the breeding program (north, south, and coastal). Cultivars have been developed that are adapted specifically for each zone. A few cultivars produce marketable fruit in all three zones. The annual chill units vary from 350 to 1000+ over the three zones. Seventeen cultivars have been released since 1969 and these are used throughout the southeast U.S. in production areas. A primary breeding objective is to develop a sequence of cultivars to service the market from late April through September. Also equally important is development of genetic disease resistance to bacterial spot, Xanthamonas campestris pv pruni.

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Fenny Dane and Marten H. Dane

A pathogenic strain of Xanthomonas campestris pv. vesicatoria, causal agent of bacterial spot of tomato (Lycopersicon esculentum Mill.), was genetically engineered to bioluminesce. In planta growth of the bioluminescent strain was similar to that of its parental strain. Movement and growth of the bioluminescent strain in susceptible tomato seedlings after wound inoculation was followed over time with a liquid-N-cooled, charge-coupled device camera. Highly significant differences in bioluminescent bacterial growth were observed in the four tomato cultivars used. Systemic bacterial movement was most pronounced in `Sunny', which showed population development not only at the inoculation sites but also on several sites in the leaves and at the leaf margins. Bacterial bioluminescence levels in `Campbell 28' remained significantly lower than those observed in `Walter' and `Sunny'. The technique offers unique possibilities for studying host-pathogen interactions and bacterial pathogenesis.

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John R. Clark, James N. Moore, and Penelope Perkins-Veazie

`White Rock' and `White County' fresh market peaches (Prunus persica (L.) Batsch) were released in 2004 by the University of Arkansas Agricultural Experiment Station. These cultivars join `White River' as recent products of the peach breeding program which is based at the University of Arkansas Fruit Substation, Clarksville. Both cultivars are sub- or low-acid types and have white flesh. `White Rock' ripens at on average 25 June, and is very firm at maturity. Average fruit weight was 142 g with 12% soluble solids and light white peach flavor. `White County' ripens on average 14 July. It is large fruited with average weight of 258 g and maintains firmness until full maturity. The fruits are freestone with an excellent white peach flavor. Both cultivars show good bacterial spot resistance although occasional lesions are seen on leaves. These new cultivars offer additional white peach cultivar choices for the mid-South and other areas of similar climate.

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Dean R. Evert, Paul Bertrand, Kerry Harrison, and John Young

Abstract

Pesticides were applied to ‘Rio Grande’ peach [Prunus persica (L.) Batsch] trees at recommended rates from bloom to harvest using three sprinkler configurations on a center pivot and an air-blast sprayer. Fruit scab infection rates with a patented sprinkler configuration (Piggy-back) that has spray nozzles mounted on a lower truss rod of the center pivot were equivalent on 12 and 23 June 1987 to those with the air-blast sprayer. Scab infection rates for standard impact-nozzles and for a deflector nozzle configuration were equivalent to each other, and tended to be lower than the infection rate for the unsprayed fruit, but higher than the rate for the air-blast sprayer or piggy-back configuration. Brown rot, bacterial spot, and insect catfacing (the other fruit defects observed at harvest) were independent of the method of pesticide application. It may be feasible to chemigate peach orchards with center-pivot irrigation systems.

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Richard E. C. Layne

Abstract

‘Harglow’ is an attractive, high-quality, medium-sized apricot (Prunus armeniaca L.) introduced in 1982 for the Ontario fresh market but also suitable for commercial processing and for home preserves. The tree is cold-hardy, late-blooming, moderately productive, and tolerant to perennial canker (Leucostoma spp.). The fruit are resistant to brown rot [Moniliniafructicola (Wint.) Honey] and bacterial spot [Xanthomonas pruni (E.F. Sm.) Dows.], and moderately resistant to skin cracking and preharvest drop. They ripen in the midseason; 6 and 3 days, respectively, after ‘Goldcot’ and ‘Veecot’ and about 3 Aug. at Harrow. ‘Harglow’ is adapted to regions of southern Ontario where apricots are grown successfully. Early reports of its performance in Michigan and Pennsylvania are promising.