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Paul R. Cabe, Andrew Baumgarten, Kyle Onan, James J. Luby, and David S. Bedford

We used microsatellite loci to investigate the parentage of the apple cultivar `Honeycrisp', a patented University of Minnesota introduction. In an attempt to find the correct parents, we also examined other apple varieties associated with the University of Minnesota apple breeding program. Based on written records from the 1960s, the presumed parents of `Honeycrisp' were `Honeygold' and `Macoun'. We were able to exclude both of these as parents, but found that `Keepsake' was consistent as one of the parents. A second potential parent could not be discovered. `Haralson', another commercially important cultivar from the University of Minnesota, is likely from a cross between `Malinda' and `Wealthy'.

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Ricardo González-Ponce, Esther G. López-de-Sá, and César Plaza

with a high demand for P ( Kelling et al., 1998 ; Mou, 2008 ). The objective of this work was to evaluate the potential of struvite recovered by the CSIC pilot process (STR) as a source of P for the cultivation of lettuce under greenhouse conditions

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Soo-Hyung Kim and Bert Cregg

tolerances in crops. The colloquium sponsored by the ASHS STRS Working Group served as a forum to bring together several of these emerging, novel methods for diagnosing, monitoring, and mitigating crop environmental stress. An emphasis was placed on

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Terril A. Nell and Cor Vonk Noordegraaf

Miniature flowering potted `Orange Rosamini' rose plants (Rosa × hybrida) were placed directly from production into simulated transport (STR) for 3 days at 5C and then into a retail handling treatment for 0, 1, 2, or 4 days. In the retail handling treatment, plants placed at 1 W·m-2 were then moved into a final postproduction irradiance level of 4 W·m-2; plants placed at 4 W·m-2 were then moved into a final postproduction irradiance level of 1 W·m-2. Also, a no-STR control treatment, plants placed directly into final postproduction environment (no transport or retail handling treatment), was included. All plants were placed into a final postproduction irradiance level (1 or 4 W·m-2) for 3 weeks to evaluate the effects of postproduction irradiance. The retail handling and postproduction environments were maintained at 20 ± 1C, 1 or 4 W·m-2 of irradiance (12 hours daily) from cool-white fluorescent lamps, and relative humidity (RR) of 60% ± 5% to simulate retail and/or consumer home conditions. Little difference was observed due to retail handling treatment or postproduction irradiance after 1 week. At weeks 2 and 3 of postproduction, there were 40% to 50% more open flowers on the no-STR plants maintained at 4 W·m-2 than on those maintained at 1 W·m-2 or on STR plants maintained at 1 or 4 W·m-2 postproduction irradiance. At week 3 of postproduction, plants with STR maintained at 1 W·m-2 had no buds showing color, while those maintained at 4 W·m-2 had three to five buds showing color. However, the no-STR control plants had one bud showing color at week 3, regardless of postproduction irradiance level. These results indicate that the detrimental effects of transport, i.e., bud drop, likely can be minimized by high postproduction irradiance levels following transport.

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Michael Raviv, J. Heinrich Lieth, David W. Burger, and Rony Wallach

Physical characteristics of two media were studied concerning water availability to roots, as reflected in specific transpiration rate, stomatal conductance, and specific growth rate of very young leaflets of `Kardinal' rose (Rosa ×hybrida L.), grafted on Rosa canina L. `Natal Brier'. Plants were grown in UC mix [42% composted fir bark, 33% peat, and 25% sand (by volume)] or in coconut coir. Water release curves of the media were developed and hydraulic conductivities were calculated. Irrigation pulses were actuated according to predetermined media moisture tensions. Transpiration rate of plants was measured gravimetrically using load cells. Specific transpiration rate (STR) was calculated from these data and leaf area. STR and stomatal conductance were also determined using a steady-state porometer. Specific growth rate (RSG) of young leaflets was calculated from the difference between metabolic heat rate and respiration rate, which served as an indicator for growth potential. Low STR values found at tensions between 0 and 1.5 kPa in UC mix suggest this medium has insufficient free air space for proper root activity within this range. Above 2.3 kPa, unsaturated hydraulic conductivity of UC mix was lower than that of coir, possibly lowering STR values of UC mix-grown plants. As a result of these two factors, STR of plants grown in coir was 20% to 30% higher than that of plants grown in UC mix. STR of coir-grown plants started to decline only at tensions around 4.5 kPa. Yield (number of flowers produced) by coir-grown plants was 19% higher than UC mix-grown plants. This study demonstrated the crucial role of reaching sufficient air-filled porosity in the medium shortly after irrigation. It also suggests that hydraulic conductivity is a more representative measure of water availability than tension.

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M. Bergevin, G.P. L'Heureux, and C. Willemot

This research was supported by Natural Sciences and Engineering Research Council of Canada (NSERC) strategic grant no. STR0114645. M.B. was a recipient of an NSERC postgraduate fellowship. Contribution no. 49 of the Centre de Recherche en

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David C. Percival, J.T.A. Proctor, and J.A. Sullivan

Field experiments including supplementary trickle irrigation (IR), IRT-76 plastic film (PF), and straw mulch (STR) treatments were conducted during 1993 and 1994 to determine the influence of root-zone temperature and soil moisture status on carbon assimilation and dry mass distribution, and soil and plant nutrient content, during the establishment of Rubus idaeus L. `Heritage' primocane-fruiting raspberries. The IR, PF, and STR treatments were reapplied after the 1993 establishment year to examine their effects on an established, hedgerow planting. Physical environment, vegetative and reproductive data were collected. PF increased root and shoot mass, total flower number, and total berries harvested. Maximum leaf net photosynthetic (Pn) rates were observed under cool air temperatures and root-zone temperature of 25 °C. Field Pn measurements indicated that there was no seasonal decline in Pn. Mulch treatments however, were not beneficial to the established (i.e., 2-year-old) hedgerow planting. The root system of the 2-year-old planting was largely confined to an area within the foliage wall and also at a greater depth from the mulch treatments. Therefore, beneficial effects of mulch management on the growth and development of raspberries may be limited to the establishment year.

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Freddi A. Hammerschlag, Richard H. Zimmerman, Umedi L. Yadava, Sally Hunsucker, and Petya Gercheva

Ostromila str, 4004 Plovdiv, Bulgaria. We gratefully acknowledge L.D. Owens and W. Potts, both USDA-ARS, Beltsville, Md., for providing strain EHA101 pEHA101/pGT100 and for help with statistical analyses, respectively. The cost of publishing this paper was

Open access

Amir M. González-Delgado and Manoj K. Shukla

herbicide was applied and three pots with no application (overall = 21). Pots treated with rate 1 (R1 = 25 g a.i./ha of indaziflam) were labeled as HR1, PFR1, and STR1, while those treated with rate 2 (R2 = 50 g a.i./ha) were labeled as HR2, PFR2, and STR2

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Shahrokh Khanizadeh, Martine Deschênes, Audrey Levasseur, Odile Carisse, Marie Thérèse Charles, Djamila Rekika, Louis Gauthier, André Gosselin, Rong Tsao, Raymond Yang, Jennifer DeEll, and J. Alan Sullivan

Canadian Plant Breeder's Rights (certificate no. 1553, ) and a U.S. patent (U.S. patent no. 20060059592) were granted. The plants of ‘St-Jean d'Orléans’ will be available from