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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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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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Richard M. Manshardt, Cathy Mello, Sharon D. Lum, and Leanne Ta

Genetically engineered (GE), virus-resistant papaya cultivars in Hawaii are easily identified by a colorimetric assay for the β-glucuronidase (GUS) marker transgene. We used GUS to track pollen movement from a central 1-acre plot of gynodioecious GE `Rainbow' plants into seeds on surrounding border rows of non-GE `Sunrise' papaya. GUS evidence of cross-pollination occurred in 70% of female plants (43% of assayed seeds), compared with only 13% of the predominantly self-pollinating hermaphrodite plants (7% of seeds) segregating in the gynodioecious `Sunrise' border rows. The percentage of GUS+ seeds in border row plants showed a weak negative correlation (r = –0.32) with distance from the nearest GE tree (30 m maximum). In a non-GE papaya field located less than a mile downwind from the `Rainbow' source, no evidence of GUS was found in 1000 assayed seeds. In a separate study, the origin of GUS+ seed discovered in papaya fruits from an organic farm was investigated. Leaf GUS assays revealed that 70% of trees were GE, indicating that the grower had planted GE seed. The impact of pollen drift from GE trees in the same field was determined by screening seed samples from 20 non-GE hermaphrodites for GUS expression. Only three hermaphrodites (15%) showed GUS+ seeds, at low levels ranging from 3% to 6% of contaminated samples. These data indicate that the major source of GE contamination in organic fields is seeds of unverified origin, rather than pollen drift from neighboring GE fields. Organic growers are advised to: 1) plant only seed that is known to be non-GE, preferably obtained by manual self-pollination of selected non-GE hermaphrodites; 2) avoid open-pollinated seed; and 3) grow only hermaphrodite (self-pollinating) trees, removing any female or male plants from production fields.

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

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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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Paula Tennant, Manoel T. Souza Jr., Dennis Gonsalves, Maureen M. Fitch, Richard M. Manshardt, and Jerry L. Slightom

The disease resistance of a transgenic line expressing the coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) from Hawaii was further analyzed against PRSV isolates from Hawaii and other geographical regions. Line 63-1 originated from the same transformation experiment that resulted in line 55-1 from which the transgenic commercial cultivars, `Rainbow' and `SunUp', were derived. Plants of line 63-1 used in this study consisted of a population from a self pollinated R0 bisexual plant. ELISA and PCR tests provided evidence that there are at least two segregating CP loci. To allow for comparison with reactions of the previously reported line 55-1, virus isolates from Hawaii, Brazil, Thailand, and Jamaica were used to challenge seedlings of 63-1. Unlike line 55-1, a significant percentage of inoculated transgenic plants were susceptible to isolates from Hawaii. However, a proportion of plants were resistant to the non-Hawaiian isolates. In contrast, previous work showed that all plants of the hemizygous line 55-1 were susceptible to PRSV isolates from Brazil, Thailand, and Jamaica. Line 63-1, therefore, presents Hawaii with PRSV-resistant transgenic germplasm that could be used as a source of transgenes for resistance to PRSV isolates within and outside of Hawaii.