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C.R. Clement and R.M. Manshardt

The pejibaye (Bactris gasipaes Kunth) is being evaluated in Hawai'i for its fresh heart of palm, a gourmet vegetable. Seven half-sib progenies of the Putumayo land race were planted in a split-plot design, with densities (3333, 5000, 6666 plants/ha) as the main plots, progenies as the sub-plots, three replications, and nine plants/plot. Precocity was defined as “days from planting to harvest”; relative growth rate (RGR) and unit leaf rate (Ea) are possible causes of precocity and were estimated for the period from 6 months after planting to harvest. Density effects were never significant, suggesting that competition is not significant before harvest. Mean precocity ranged from 610 to 712 days; Va accounted for 14% of the phenotypic variance (Vp), with h2 = 0.57, similar to fruiting precocity in African oil palm (Elaeis guineensis Jacq.). Mean Ea ranged from 1.89 to 2.21 g/m2 per day, Va accounted for 8% of Vp, with h2 = 0.33 Mean RGR ranged from 0.0086 to 0.0102 d–1; Va accounted for 9% of Vp, with h2 = 0 35 Neither RGR (r = 0.20) nor Ea (r = 0.19) are significantly correlated with precocity. Heart, edible stem, and total edible product weights did not present significant progeny effects, probably because of the criterion used to determine harvest (height = 1.3 m). Precocity is easiest to work with and should give acceptable genetic gains.

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Hameed Jasim Aljuburi

The study was carried out at the Experimental Station of Agric. Sci. College at Al-oha region. Eight hundred seedlings (7 months old) were chosen for each following cultivars, Lulu, Boman, Barhee and Khalas. The seedings for each cultivars were irrigated weekly with 0, 6, 12, 18 g I.-1 Nacl solution.

The results revealed fresh weight of stems, roots and number of leaves/plant of Lulul, Barhee and Khalas cultivars progressively reduced with increasing Nacl concentration in irrigation water, while dry matter percentage of stems and roots increased and increasing salinity in irrigation water. The results also declared that the seedlings of four date palm cultivars has similar behavior, when exposed to high Nacl concentration in irrigation water during long term.

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Catherine G. Cavaletto, Natalie Y. Nagai, Charles R. Clement and Richard M. Manshardt

Fresh pejibaye palm heart samples were evaluated from 1) progenies from the Benjamin Constant population of the Putumayo landrace and 2) progenies from the Yurimaguas population of the Pampa Hermosa landrace. Favorable sensory characteristics included sweetness, tenderness, crispness, and moistness. Negative sensory characteristics found in some samples were astringency and acridity. Sensory scores for astringency and acridity were significantly different (p=.05) between sections of the heart Basal sections appear to be more acrid and astringent than the apical sections. Differences in acridity also exist between plants within a progeny (p=.05). Percent total soluble solids ranged from 3.0 to 6.6, but no obvious pattern was apparent. Samples were also provided to chefs in upscale restaurants where they received favorable comments.

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Aref A. Abdul-Baki, S. Aslan, S. Cobb, E. Beardsley and T. Burke

A 3-year experiment was conducted to identify problems in Coachella Valley date palm (Phoenix dactylifera) orchards that limit vegetative growth, yield, and fruit quality. Major problems that were identified included soil compaction and stratification that restrict water permeation into the root zone, and low fertility as reflected by the low organic -matter content of the sandy soils. To eliminate the impact of these stresses on plant growth, yield, and fruit quality, a no-tillage alternative management system was introduced to replace the conventional practice of tillage that compacts the soil. No-till was coupled with the use of cover crops to enrich the soil with organic matter, fix N, recycle nutrients, and improve water holding capacity of the sandy soil. In already established orchards, an additional treatment—slip plowing—was also implemented to loosen the soil at lower depths to facilitate water permeation. The positive effects of the alternative system on the soil, tree growth, yield, and fruit quality will be presented.

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Charles R. Clement and Richard M. Manshardt

The pejibaye (Bactris gasipaes, Palmae) is being evaluated in Hawaii as a source of fresh hearts of palm. Nine open-pollinated progenies from the Benjamin Constant population of the Putumayo landrace are planted at three sites in a RCB. The best site started yielding at 15 months after planting, the intermediate at 16 months, the poorest at 18 months. During the first four months of harvest at the best site, 25% of the plants were cut; during three months at the intermediate site, 15% were cut; during the first cut at the poor site, 1% were cut. Progeny harvest percentages ranged from 7 to 53% at the best site, with only three progenies above average (33, 47, 53%). These are considered to be precocious. These three progenies produced average size hearts (172±36, 204±57, 203±44 g/plant, respectively; experimental mean±SD = 205±53 g), but yielded above average at 5000 plants/ha (275, 480, 524 kg/ha, respectively; exp. mean = 272 kg; corrected for % cut). Potential yields of these progenies were near the mean (871±198, 1018±280, 983±197 kg/ha, respectively; exp. mean = 986±381 kg/ha), but their precocity provides early returns to the farmer.

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William J. Carpenter, Eric R. Ostmark and John A. Cornell

High synchrony, rate, and germination of needle palm [Rhapidophyllum hystrix (Pursh) H.A. Wendle & Drude] seeds were achieved only after removing the sclerotesta and embryo cap, which imposed physical dormancy. After scarification, recently harvested seeds or seeds stored for 12 months at 5C and 100% relative humidity had 96% and 98% final germination (G), with 9 to 11 days required to achieve 50% of final germination (T50) at 30C. Germination temperature controlled G, T50, and days between 10% and 90% of final germination (T90 - T10) of scarified seeds, with respective values of 98%) 9 days, and 5 days at 30C, and 18%, 31 days, and 12 days at 15C. Seeds with 36% moisture at harvest had no reduction in G until moisture was <14%. Germination of seeds with 19% moisture declined from 80% if stored at 0C to 33% if stored at -l0C; no seeds germinated after storage at less than -l0C.

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Charles R Clement and Richard M. Manshardt

The pejibaye (Bactris gasipaes, Palmae) is being evaluated in Hawaii as a source of fresh hearts of palm. Nine open-pollinated progenies from the Benjamin Constant population of the Putumayo landrace are planted at three densities: 1.5 × 2 m (3333 plants/hectare); 1 × 2 m (5000 pl/ha, the commercial density in Costa Rica); 1 × 1.5 m (6666 pl/ha). Harvest started at 15 months after planting and four months later 25% of the plants had been harvested, with 25%, 30% and 21% at 3333, 5000, and 6666 pl/ha, respectively. Mean heart diameters were unaffected by density (mean±SD = 3.2±0.4 cm). Heart lengths were similar (24±5 cm, 23±6 cm, 26±5 cm, respectively), as were heart weights (200±41 g, 187±44 g, 224±42 g, respectively). This relative uniformity was unexpected, as density effected all of these yield components in earlier experiments in Latin America. Potential yields were different (667±136 kg/ha, 835±221 kg/ha, 1491±275 kg/ha, respectively), and are comparable to yields reported from Costa Rica. Actual precocious yields, however, were not different (167 kg/ha, 278 kg/ha, 385 kg/ha, respectively).

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Aref A. Abdul-Baki, Clyde Wilson, George E. Brown Jr., Lidia M. Carrera, Sam Aslan, Sam Cobb and Tim Burke

The mineral concentration of bearing `Mejhool' date palm (Phoenix dactylifera L.) trees was investigated with the objective of identifying the cause of browning and dieback of distal parts of the fruit-bearing strands. Tissue analyses of leaves, fruits, healthy and dead portions of fruit-bearing strands indicated that tissue browning and dieback appeared to be associated with a high concentration of certain mineral elements. A comparison of mineral concentration between healthy and dead tissue of the fruit-bearing strands showed no significant increase in K, Cu, B, Zn, and Na, but very high increases in the concentrations of P, Ca, Mg, S, Mn, and Fe. The levels of P, Ca, Mg, S, Mn, and Fe in the distal part of the fruit-bearing strand over a 3-year average were 5, 18, 12, 3, 11, and 2 times, respectively, higher than those in the healthy, proximal part of the strand. Mineral concentrations of leaves and mature fruits were determined for comparison with those in fruit-bearing strands.

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Yousef I. Dlaigan, A.E. Said and M.A. El-Hamady

Several trials were conducted with the objective of obtaining an explant for the establishment of date palm root culture in vitro. These trials included disinfecting and germinating seeds of three cultivars on several autoclaved culture media, the influence of incubation temperature on different germination parameters, and the quality of roots before excision and after culture in nutrient media. Three culture media were used: distilled water only; minimal organics that consisted of MS salts, 3% sucrose, modified White's organics, 0.01% inositol, and 0.15% activated charcoal; and 1/2 MS salts mixture, 3% sucrose, and 1/2 modified White's organics. All three media were solidified with 0.7% agar. The seeds were incubated at 25 or 35C for germination. The study revealed the difficulty of seed disinfection. We immersed seeds in 20% to 40% Clorox, with two to four drops of Tween-20, for 30 to 60 minutes and then rinsed them four to five times in deionized distilled water before culturing. The minimal organics medium supported optimal growth of excised roots, and incubation at 35C significantly improved germination. The use of 10-mm-long root tips as explants for culture initiation gave the best growth and elongation. In addition, the growth and elongation of excised root tips increased significantly as the distance from it to the apex of the cotyledonary sheath increased.

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A.C. Arcinas, B.S. Sipes, A.H. Hara and M.M.C. Tsang

Exporters of potted nursery stock face strict quarantine regulations against the burrowing nematode, Radopholus similis. Currently, there are no treatments approved by quarantine authorities to disinfest plants of R. similis. Interceptions of the nematode lead to significant economic loss and curtailment of trade, therefore hot-water drench treatments were investigated for quarantine utility. Drenches with 50 °C water were applied for 10 to 16 minutes to two economically important palm species, rhapis (Rhapis excelsa) and fishtail (Caryota mitis). Plants were inoculated with 5,000 mixed life stages of R. similis and allowed to establish for 14 weeks before drench treatments. In rhapis, a moderately good host to R. similis, a 16-minute hot water drench had high efficacy, achieving 99.6% mortality. In fishtail, a poor host, all treatments longer than 10 minutes at 50 °C eliminated R. similis from the plants. Probit regression estimates of the LT99, were 16.9 and 10.3 minutes respectively. However χ2 goodness-of-fit tests were significant (χ2 = 21.136, df = 3, p < 0.0001) for rhapis. Since most observed values were between the 95% fiducial limits, this suggests that the large χ2 value was caused by variability in response or insufficient repetitions rather than an inappropriate model. A χ2 statistic could not be computed for fishtail because poor host status led to variances that were nearly equal to zero. The high efficacy of hot water drenches for the control of R. similis is approaching the Probit 9 standard of 99.9968% mortality required for approval as a quarantine treatment.