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Flower bud and leaf samples collected from a wide range of native North American Vaccinium populations were tested for the presence of blueberry shoestring virus (BBSSV) using the enzyme-linked immunosorbant assay. The highest disease incidence was found in Michigan (14%), although a few positive samples also were found in Virginia, New Jersey, Maine, Ontario, and Quebec. Of seven species tested, only V. corymbosum L. and V. angustifolium Ait. were infected with BBSSV.

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Abstract

‘Redwing’ is a primocane-fruiting (“fall-fruiting”) red raspberry (Rubus idaeus L.) cultivar (Fig. 1) developed by the Univ. of Minnesota fruit breeding program. It typically begins fruiting 10 to 14 days earlier than ‘Heritage’, the most widely grown commercial primocane-fruiting cultivar. ‘Redwing’ is intended to supplement or replace ‘Heritage’ in situations where earlier primocane fruiting is desired.

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Abstract

‘Summercrisp’ is a cold-hardy, early-season pear (Pyrus spp. L.) cultivar introduced by the Univ. of Minnesota for use in cold climates where most pear cultivars grow poorly and do not fruit consistently. The name ‘Summercrisp’ connotes the early harvest season and that the fruit is best consumed without ripening, while the flesh is firm and crisp.

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Abstract

‘Alderman’ is a large, sweet, cold-hardy, Japanese-type plum hybrid involving Prunus salicina Lindl. and P. americana Marsh. It is being introduced by the Univ. of Minnesota Agricultural Experiment Station for use in cold climates where other high-quality, Japanese-type plums may suffer winter injury. ‘Alderman’ was named after W.H. Alderman in commemoration of his 100th birthday in 1985 and in recognition of his many accomplishments as a scientist and administrator in horticultural science at the Univ. of Minnesota.

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Abstract

A blueberry (Vaccinium spp.) breeding program was initiated at the Univ. of Minnesota in 1967 using V. corymbosum L. and V. angustifolium Ait. and hybrids between the species. The objective was to develop low-saturated, high-quality, cold-hardy cultivars for commercial as well as home garden use (3). ‘Northblue’, ‘Northsky’, and ‘Northcountry’ are the first cultivars introduced from this program.

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Abstract

Genetic variance components, narrow sense heritability, and combining ability effects of parents were determined for several traits from analysis of a partial diallel cross involving 17 parents. Parents included several Vaccinium species and interspecific hybrids. For fall growth cessation, general combining ability (GCA) effects were variable from year to year, and heritability was low. Variance due to GCA was more important than specific combining ability (SCA) variance for winter injury in each of the years. The heritability estimate over years was low for winter injury, although individual year estimates were higher. Lowbush parents had high GCA effects for winter injury in years with snow cover but low estimates for years without snow cover. Off-season flowering was observed in some progenies in both years studied. Certain V. angustifolium Ait. parents had high GCA effects for the occurrence of off-season flowering. The heritability estimate for off-season flowering in combined years was 0.47. Variation due to years and to GCA × year interaction was significant for all characters studied.

Open Access

An elite group of 38 strawberry accessions representing all subspecies of the beach strawberry [Fragaria chiloensis (L.) Miller] and the scarlet strawberry (F. virginiana Miller) was planted in a replicated design at five locations across the United States, and evaluated for plant vigor, flowering date, runner density, fruit set, fruit appearance, and foliar disease resistance. Considerable genotyp× location interaction was observed for many of these traits. However, a few genotypes were impressive at all locations including PI 551735 (FRA 368) with its unusually large, early fruit, and PIs 612486 (NC 95-19-1), 612493 (Frederick 9), and 612499 (RH 30), which were very vigorous and had unusually good fruit color. Genotypes that were superior at individual locations included PIs 551527 (FRA 110) and 551728 (Pigeon Pt.) in Maryland for their large fruit, and PI 612490 (Scotts Creek) in Oregon which had extremely large fruit, superior color, firmness, and flavor. The PIs 612495 (LH 50-4), 612498 (RH 23), and 612499 (RH 30) performed well as day neutrals at multiple sites.

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Establishing marker-locus-trait associations to enable marker-assisted breeding depends on having an extensive, reliable database for phenotypic traits of interest in relevant germplasm. A reference germplasm set of 467 apple (Malus ×domestica Borkh.) cultivars, selections, and seedlings (referred to as individuals) was identified as part of the USDA-Specialty Crop Research Initiative (SCRI) project, RosBREED. The germplasm set provides efficient allelic representation of current parents in RosBREED demonstration apple breeding programs at Cornell University, Washington State University, and the University of Minnesota. Phenotyping at the three locations was conducted according to standardized protocols, focusing on fruit traits evaluated at harvest and after 10 and 20 weeks of refrigerated storage. Phenotypic data were collected for the sensory texture traits of firmness, crispness, and juiciness as well as for instrumental texture measures. In 2010 and 2011, fruit from 216 and 330 individuals, respectively, were harvested and a total of 369 individuals were evaluated over the two years. Correlations between sensory and instrumental texture measures were high in some instances. Moderate year-to-year repeatability of trait values was observed. Because each location had a largely unique set of individuals, as well as differing environmental conditions, means, ranges, and phenotypic variances differed greatly among locations for some traits. Loss of firmness and crispness during storage was more readily detected instrumentally than by the sensory evaluation.

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