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  • Author or Editor: J. L. Perry x
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In 1987, the NC 140 Regional Rootstock Testing Committee established sweet and sour cherry rootstock trials in 16 locations in North America. This paper will present preliminary results on the performance of Hedelfingen (sweet) and Montmoreney (sour) cherry cultivars at the New York and Michigan sites. The rootstock under test include 3 clones from Gembloux, Belgium, Colt, 4 MxM hybrids, and 9 to 13 interspecific hybrid clones from Giessen, West Germany. Clonal rootstock also under test for Montmorency include St. Lucie 64, 275 and, in New York, Holly Jolivette. Rootstock treatments differ slightly among sites and are replicated 7-8 times in a randomized complete block design. The Giessen rootstock 148/1 and 195/1 have, to date, demonstrated excellent influence on sweet cherry precocity. Sweet and sour cherry on Colt and the MxM hybrids have been most vigorous at both sites. Montmorency is most precocious on Mahaleb seedling followed by Giessen 148/1 at both locations. Data for 1990 on rootstock performance will be included in the oral presentation.

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Seeds of Asparagus densiflorus (Kunth) Jessop ‘Sprengen’, Brassaia actinophylla Endl., and Musa balbisiana Colla., were exposed to 5 durations of ultrasonics at a frequency of 60 Hz. Some seeds were then given a 12 hour water soak before sowing. No differences were noted in germination rates for all species. The only significantly improved germination percentage occurred with seeds of Musa balbisiana given a 30 second exposure and no water soak. Seeds of Asparagus densiflorus ‘Sprengeri’, Brassaia actinophylla, Cordyline australis (G. Forst.) Hook, f., and Philodendron lundii Warm., were given 15 minute soaks in 3 concentrations of 3 fungicides before sowing but no significant differences in final germination percentage or germination rate were observed among treatments.

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Effects of 5 soilless media and 2 sowing depths, 4 pH levels and 3 medium temperatures on tropical foliage plant seed germination were analyzed using germination rate and final percentage germination. Cordyline australis had highest germination percentages in highly organic media, Philodendron selloum germinated well in all media at a depth of twice the seed diameter, Asparagus densiflorus ‘Sprengeri’ and Brassaia actinophylla germinated equally well in all media and at depths of 2 and 4 times the seed diameter. Most deeper sown seeds took longer to emerge. Best germination occurred in Brassaia actinophylla, C. australis and Philodendron lundii without bottom heat (27°C), and in Nephthytis ‘Emerald Gem’ with bottom heat (30°-33°). Species germinated well between pH 3.7 and pH 6.2 except for Musa balbisiana at pH 3.7.

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The influence of two rootstocks on leaf nutrient concentrations of ‘Montmorency’ sour cherry (Prunus cerasus L.) was studied at two locations for 4 years. Trees on Mazzard (Prunus avium L.) rootstocks were generally higher in leaf K, Ca, B, N, and Mn concentrations, but lower in leaf Mg than trees on Mahaleb (Prunus mahaleb L.) rootstocks. Differences due to rootstocks did not appear to be related to crop load or tree vigor.

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Abstract

Blackberry pollen germination in vitro decreased linearly with increased duration of storage at 22°C. Time required to reach 50% nonviability varied among cultivars from 2.5 to 10 days. Storage at 6° more than doubled the time required to reach 50% non viability. A 20% sucrose-agar medium was satisfactory for germination assay of pollen from tetraploid blackberries but gave poor results on a diploid clone.

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Abstract

No differences in percentage fruit set resulted from self or cross pollination in 8 tetraploid cultivars of erect blackberry (Rubus subgenus Eubatus), but 2 selections with diploid ancestry showed decreased fruit set from self-pollination. In some cultivars, self-pollination resulted in reduced fruit size and generally resulted in decreased seed number per fruit. Fluorescence microscopy showed no differences in rate or extent of pollen tube growth from self or cross pollen within blackberry styles. Caging experiments indicated that blackberries are not dependent on insects for pollination, but wind dispersal of pollen is important in securing uniform fruit set.

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Abstract

Three diploid taxons (Vaccinium darrowi Camp, V. elliottii Chapm., and interspecific V. darrowi x V. elliottii) were treated with various colchicine concentrations and treatment durations to determine the best method for inducing autopolyploidy in in vitro blueberry cultures. Shoot-tip cuttings were the best in vitro planting material for induction of shoots with increased diameter, an indicator of polyploidy. Tetraploids were produced at colchicine concentrations from 0% to 0.20%. The best treatment combinations were genotype-dependent.

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The root distribution of peach trees [Prunus persica (L.) Batsch cv. Redhaven/Halford] as affected by six orchard floor management treatments was evaluated after 3 years of growth. Two treatments were maintained vegetation-free and four had vegetative covers in the alleyway with a 1.2-m-wide herbicide strip in the tree row. The profile wall method was used to determine root distribution. Trees maintained vegetation-free with herbicide had the most roots. Trees in the vegetation-free plots, maintained with herbicide or cultivation, produced more roots 1.2 m from the tree than trees in the vegetative covers. The number of roots, 1.2 m from the tree, was lowest in the tall fescue treatment. The number of roots were higher in the Kentucky bluegrass (Poa pratensis L.) or alfalfa (Medicago sativa L.) than with tall fescue (Festuca arundinacea, Schreb.).

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Fine root dynamics, timing of the events, and their relationship with soil conditions are of major interest because the understanding of these phenomena will permit a better synchronicity between nutrients and plant uptake. The goal of this research is to study the effect of different soil conditions, generated from two ground floor management systems, on fine root dynamics of apple trees under organic protocol in Michigan. The research has been conducted at the Clarksville Horticultural Experimental Station (CHES) of Michigan State University (MSU), in the organically certified (by OCIA) orchard of “Pacific Gala” grafted on M9 NAKB 337, established in May 2000. The orchard floor management systems being studied are: 1) a mulch made of alfalfa hay on the tree rows, with a width of 1.8 m and 2) the “Swiss Sandwich System” (SSS) that consists in superficial tillage of two strips 80 cm wide at each side of the tree row, leaving a 40 cm strip in the middle (on the tree row, under the canopy) where volunteer vegetation is allowed to grow. Root dynamics are studied on four replicas of two trees per each of the two ground treatments (16 in total) in a block design. For each tree in the trial four clear butyrate minirhizotrons have been installed (64 in total) at a 45° angle facing the tree, in the summer of 2002. Root dynamics, measured through pictures taken with a Bartz Technology digital camera and analyzed with a new software under development at MSU. During the 2003 season differences between the two systems have been found depending on the parameter taken in consideration. Mulch had different root distribution compared to SSS. Mulch treatment showed shallower roots even if below 90 cm the two systems didn't show any difference.

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Understanding the effect of catastrophic disturbances on natural communities is necessary and vital to planning and executing development and to reclamation and restoration projects. Two nearby sites one catastrophically disturbed by flooding and one undisturbed area were compared. Field vegetation analysis three years after the flood in the disturbed area showed changes in the community structure along the stream, no overstory and a majority of obligate emergent wetland vegetation. In the undisturbed site, community structure along the stream is uniform; the overstory is well-developed, and herbaceous plants are predominantly facultative wetland but with few emergents. The field water quality analysis of temperature, pH, dissolved oxygen and specific conductivity are compared in the areas. GIS (Geographic Information System) analysis used the USGS 1:24,000 maps of the area and SCS county soil survey maps to analyze erosion risk, soil types, topography and vegetation potential in the 200 km2 Miller Springs Natural Area and the immediately surrounding 5 10 km2 watershed.

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