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Sven E. Svenson and Timothy K. Broschat

The influence of copper hydroxide [Cu(OH)2] application to interior container surfaces on root growth at the container-medium interface was studied using Carpentaria palm [Carpentaria acuminata (H. Wendl. & Drude) Becc.]. Cu(OH)2 (0, 100, 200, or 400 g) was mixed with one liter of either white latex house paint, or NuFilm-17 surfactant, and applied to all surfaces inside 0.5 liter containers. Plants were grown in untreated containers, in containers treated with paint or NuFilm-17 only, or in containers treated with Cu(OH)2 in paint (100 g rate only) or NuFilm-17 (100, 200 or 400 g per liter). When applied in paint or NuFilm-17, Cu(OH)2 reduced root growth at the container-medium interface, controlling the circular growth pattern commonly observed in container-grown plants. Controlling circling root growth at the soil-container interface did not influence shoot or root dry weight, but did reduce total root length. Application of Cu(OH)2 with paint was unsightly, while application with NuFilm-17 was almost unnoticeable.

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Timothy K. Broschat

Twenty-two preemergent herbicides were applied at their maximum labeled rates and twice those rates to determine their safety and effectiveness on areca palm [Dypsis lutescens (H. Wendl.) Beentje & Dransf.], pygmy date palm (Phoenix roebelenii O'Brien), and mexican fan palm (Washingtonia robusta H. Wendl.). Two products, dichlobenil and metolachlor showed consistent phytotoxicity on all three species. Several of the remaining products caused death of the apical meristem in mexican fan palms and reduced growth rates in pygmy date palms, but most caused little damage to areca palms. Herbicides applied as sprays generally remained effective for 2 to 4 months, whereas granular products, especially those containing oxyfluorfen plus another chemical, were effective for up to 8 months.

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Timothy K. Broschat

Mature pygmy date palms (Phoenix roebelenii O'Brien) having a minimum of 90 cm of clear trunk were transplanted into a field nursery at their original depth or with 15, 30, 60, or 90 cm of soil above the original rootball. Palms planted at the original level or with the visible portion of the root initiation zone buried had the largest canopies, highest survival rates, and lowest incidence of Mn deficiency 15 months after transplanting. Palms planted 90 cm deep had only a 40% survival rate, with small, Mn-deficient canopies on surviving palms. Palms whose original rootballs were planted 90 cm deep had very poor or no root growth at any level, but had elevated Fe levels in the foliage. None of the deeply planted palms produced any new adventitious roots higher than 15 cm above the visible portion of the root initiation zone.

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Jose P. Morales-Payan and Bielinski M. Santos

Experiments were conducted in the Dominican Republic to determine the effect of physical and chemical treatments on the germination of the ornamental palms Roystonea hispaniolana Bailey (Royal palm), Acrocomia quisqueyana Bailey (Corozo palm), Sabal umbraculifera Mart (Cana palm), Phoenix canariensis (Canary Islands date palm), Veitchia merrillii (Becc) Bailey (Manila palm), Chrysalidocarpus lutescens Wendl (Areca palm), and Caryota urens (Fishtail palm). Treatments were seed immersion in water or gibberellic acid 3 (GA3) solution for 72 hours, immersion in concentrated nitric acid for 5 minutes, or cracking of the seed coat. Rate and percentage of emergence 90 days after treatment were measured. The best results for Roystonea, Phoenix, Veitchia, Caryota, and Chrysalidocarpus were obtained soaking the seeds in water or a 200-ppm gibberellic acid solution. Nitric acid and seed coat cracking significantly reduced the germination percentage in all the species, except Acrocomia guisqueyana and Sabal umbraculifera. Seeds of Acrocomia did not germinate as a response to any of the treatments tested. Sabal seeds germinated only after coat cracking or nitric acid treatment.

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Timothy K. Broschat

Pygmy date palms (Phoenix roebelenii `O'Brien') growing in a pine bark-Canadian peat-sand container medium and in a sandy field soil were fertilized with one of five commercially available Mn sources. Fertilization with Mn sulfate plus ammonium sulfate consistently increased Mn uptake above that of control palms. Four soluble Mn sources were applied to the foliage of container-grown palms, but only Mu sulfate consistently increased Mn concentrations in the leaves. Addition of urea, calcium hydroxide, or dimethylsulfozide did not improve Mn uptake from foliar sprays, and foliar sprays and soil applications were equally rapid in their effects on leaf Mn concentration.

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Timothy K. Broschat

Royal palms [Roystonea regia (HBK.) O.F. Cook], coconut palms (Cocos nucifera L. `Malayan Dwarf'), queen palms [Syagrus romanzoffiana (Chamisso) Glassman], and pygmy date palms (Phoenix roebelenii O'Brien) were grown in a rhizotron to determine the patterns of root and shoot growth over a 2-year period. Roots and shoots of all four species of palms grew throughout the year, but both root and shoot growth rates were positively correlated with air and soil temperature for all but the pygmy date palms. Growth of primary roots in all four species was finite for these juvenile palms and lasted for only 5 weeks in royal palms, but ≈7 weeks in the other three species. Elongation of secondary roots lasted for only 9 weeks for coconut palms and less than half of that time for the other three species. Primary root growth rate varied from 16 mm·week-1 for coconut and pygmy date palms to 31 mm·week-1 for royal palms, while secondary root growth rates were close to 10 mm·week-1 for all species. About 25% of the total number of primary roots in these palms grew in contact with the rhizotron window, allowing the prediction of the total root number and length from the sample of roots visible in the rhizotron. Results indicated that there is no obvious season when palms should not be transplanted in southern Florida because of root inactivity.

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Timothy K. Broschat

Germination rate was significantly improved by removing the thick, hard endocarp from Butia capitata (pindo palm) fruit. Time to 50% of final germination rate was not affected by endocarp removal. Afterripening storage did not improve germination rate or time. Germination at 104 °F (40 °C) was superior to that at 93 °F (34 °C).

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Jaladet M.S. Jubrael, Sripada M. Udupa and Michael Baum

Currently, the identification and characterization of date palm varieties rely on a small number of morphological traits, mainly of fruit, which are complex and greatly influenced by the environment. As a result, different varietal names may actually refer to the same variety while different varieties may have the same name. Therefore, new descriptors like molecular markers are required to identify, characterize, and estimate genetic diversity in this crop. Here we used amplified fragment length polymorphism (AFLP) markers to discriminate 18 Iraqi date palm varieties and to estimate the genetic relationship among the varieties. A total of 122 polymorphic AFLP loci were scored, with an average of 17.4 polymorphic loci per primer combination. The use of any one of the four combinations, P101(aacg)/M95(aaaa), P74(ggt)/M95(aaaa), P73(ggg)/M95(aaaa), or P100(aacc)/M95(aaaa), was sufficient to uniquely identify all the varieties. Jaccard's genetic similarity index ranged from 0.108 to 0.756, indicating moderate to diverse relationships. Estimation of average proportion of fixed recessive AFLP loci indicated that most of the loci in variety `Chipchab' were fixed, whereas most of the loci in `Jamal Al-Dean' could be heterozygous and in-between in other varieties. Unweighted pair group method with arithmatic mean (UPGMA) analysis ordered the date palm varieties first into two broad groups at 27% similarity levels. One group consisted of seven varieties and the second group consisted of the remaining 11 varieties of date palm. These results showed that the AFLP technique is an efficient method for varietal identification and estimating genetic relationships in date palm.

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Timothy K. Broschat

Queen palms (Syagrus romanzoffiana) were grown in containers of sand to determine the effects of irrigation water salinity and liming rate on cation uptake by the plants. Dolomite was incorporated at rates of 0, 3, or 6 kg/m3. Within each lime rate palms were irrigated with a solution of NaCl and CaCl2 (molar ratio =5Na:1Ca) at conductivities of .25, 1, 2, 4, or 6 dS/m. Plant height and dry weight and leaf Mg were decreased with increasing irrigation water salinity, whereas leaf Ca was increased at higher salinities. Leaf Mn and Zn increased, then decreased as salinity was increased. Leaf Ca and Mg increased with increased lime, but leaf Mn and Cu were decreased by increasing the lime rate. Leaf K increased, then decreased as lime rate was increased.

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Timothy K. Broschat

Queen palms (Syagrus romanzoffiana) were grown in containers of sand to determine the effects of irrigation water salinity and liming rate on cation uptake by the plants. Dolomite was incorporated at rates of 0, 3, or 6 kg/m3. Within each lime rate palms were irrigated with a solution of NaCl and CaCl2 (molar ratio =5Na:1Ca) at conductivities of .25, 1, 2, 4, or 6 dS/m. Plant height and dry weight and leaf Mg were decreased with increasing irrigation water salinity, whereas leaf Ca was increased at higher salinities. Leaf Mn and Zn increased, then decreased as salinity was increased. Leaf Ca and Mg increased with increased lime, but leaf Mn and Cu were decreased by increasing the lime rate. Leaf K increased, then decreased as lime rate was increased.