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  • Author or Editor: R.M. Manshardt x
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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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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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Fifty-six accessions involving five taxa of Nephelium (N. Iappaceum varieties lappaceum and pallens, N. hypoleucum, N. ramboutan-ake, and N. cuspidatum) were fingerprinted and evaluated for genetic diversity using isozyme polymorphism. All five taxa were polymorphic for most of the enzymes encoded by 10 putative loci. Number of alleles per locus ranged from three for Pgi-1 to nine for Pgi-2 with a total of 57 alleles. Thirty-eight accessions out of 56 possessed unique isozyme genotypes, indicating a high level of diversity in the collection. On average, 80% of the loci were polymorphic and the expected and observed heterozygosities were 0.374 and 0.373, respectively. The cluster analysis of the isozyme data revealed five distinct clusters representing the five taxa included in the study. Genetic differentiation within N. Iappaceum var. Iappaceum was evident from the cluster analysis. Isozyme data indicated that N. ramboutan-ake is the closest relative of N. Iappaceum var. Iappaceum, followed by N. hypoleucum, N. Iappaceum var. pallens, and N. cuspidatum. Interestingly, the varieties of N. Iappaceum exhibited genetic divergence far beyond that of the congenerics, N. hypoleucum and N. ramboutan-ake and may require a taxonomic revision.

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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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Twenty transgenic Carica papaya plants ('Sunset', Roclone 55-l) carrying the coat protein gene (cp) of papaya ringspot virus (PRV) strain HA 5-l have remained symptomless and ELISA-negative for 18 mo. after inoculation with Hawaiian PRV under field conditions. Control plants showed disease symptoms within 1 mo. after manual inoculation or within 4 mo. when aphid populations were the inoculum vectors. Trunk diameter was significantly greater in cp + plants (14.3 cm) than in PRV-infected controls (9.3 cm). Fruit brix, plant morphology, and fertility of cp + plants were all norm al. Segregation analysis in R1 seedlings indicated that 55-1 contains a single transgenic insertion site. PRV resistance in R1 plants was linked with the cp gene, although in some progenies, up to 50% of cp + plants developed mild PRV symptoms more than 3 mo. after inoculation. Preliminary tests suggest that this is not due to genesis of virulent mutant strains of PRV.

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