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  • Author or Editor: K.E. Bedford x
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Traditionally, American ginseng (Panax quinquefolium L.) seeds are stratified for 18 to 22 months, before seeding, in a sandbox buried outdoors in late August or early September. Uncontrolled fluctuating temperature and moisture levels and the presence of pathogenic organisms in the seed box can cause seeds to sprout prematurely, rot, dry out and die. A study was initiated to shorten the lengthy stratification period, and to increase seed viability and percentage of germination by stratifying seeds indoors under a controlled environment. Seeds were subjected to various periods of warm [15 or 20 °C (59 or 68 °F)] and cold [2 °C (35.6 °F)] temperature stratification regimes in growth chambers. Embryo growth and viability, and seed moisture content were tested periodically during stratification. The best warm regime for embryo development, seed viability and germination after subsequent cold treatment was 15 °C (59 °F). The first “split” seeds, indicating incipient germination, were observed after 3 months of warm [15 °C (59 °F)] and 4 months of cold [2 °C (35.6 °F)] treatment, when average embryo length reached 6 mm (0.24 inch). Greenhouse germination of stratified seeds was as high as 80%. The results from this study indicate that good germination is possible when ginseng seeds are stratified indoors under a controlled environment and seeds can be made to germinate at any time of the year.

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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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Wooden fruit bins are a source of diapausing codling moth and postharvest pathogenic fungi. The redistribution of codling moths within bins is a problem where codling moth populations are being controlled by areawide codling moth sterile release programs, mating disruption programs, or both. Laboratory and fumigation chamber trials were carried out to determine the impact of relatively low levels of carbon dioxide on late-instar codling moth (Cydia pomonella L.) and two postharvest fruit pathogens, Penicillium expansum Link ex Thom and Botrytis cinerea Pers. ex Fr. Fumigation of diapausing codling moth with 40% CO2 in laboratory trials resulted in over 60% mortality after only 6 days of exposure and mortality increased with time of exposure. Significant mortality (68%) of diapausing codling moth larvae occurred after 14 days of exposure in the laboratory to 13% CO2 and a mean of 88% mortality was recorded after fumigation for 20 days. A significant number of P. expansum (46%) spores failed to germinate after laboratory exposure to 13% CO2 for 12 and 18 days respectively. Close to 100% of the P. expansum spores failed to germinate by day 20. When diapausing codling moth larvae and spores from both plant pathogens were placed in wooden fruit bins and fumigated for 21 days at 13% CO2, 75% of the diapausing codling moths died and 80% of the P. expansum spores failed to germinate. No effect on B. cinerea was observed.

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