No abstract

Interspecific OxG hybrids of African palm Elaeis guineensis Jacq. and the American palm Elaeis oleifera Cortes produce high-oleic palm oil (HOPO) with low saturated fatty acid content. OxG hybrids are highly productive, grow slowly, and are resistant to bud rot disease. However, OxG hybrid pollen presents low viability and germinability, so assisted pollination is a must. Hybrids can produce parthenocarpic or seedless fruits, with the exogenous application of plant growth regulators. Thus, naphthalene acetic acid (NAA) effects on parthenocarpic fruits induction, bunch formation, and oil quality were evaluated. The OxG hybrid Coari x La Mé was used. NAA doses, frequency, number of applications, and the phenological stages for the treatments were defined. A total dose of 1200 mg L−1 NAA applied three or four times produced bunches with better fruit set, similar average bunch weight, and oil to dry mesocarp than those obtained with assisted pollination. At a semi-commercial scale, 1200 mg L−1 NAA induced bunches that consisted of 93% or more of seedless fruits. Bunch number (2208 ± 84 versus 1690 ± 129) and oil to bunch (32.2 ± 0.7 versus 25.3 ± 0.8) were higher in the NAA induced bunches than in the assisted pollination. However, the average bunch weight was lower (12.2 ± 0.4 versus 14.9 ± 0.6). NAA increased oil to bunch in 36% (8.7 ± 0.1 versus 6.4 ± 0.3). Thus, with this technology, it is plausible to reach more than 10 tons per hectare per year of HOPO. Potentially, without increasing the planted oil palm area, OxG hybrids and NAA applications could alone meet the world’s fats and oil demands.

No abstract

Bud rot (BR), caused by Phytophthora palmivora, is one of the most devastating diseases affecting oil palm. It has destroyed oil palm plantations in countries throughout Latin America. To assess their resistance to BR, two cultivars of African oil palm (Elaeis guineensis Jacq.) and two interspecific OxG (E. oleifera × E. guineensis Coari × La Mé and Coari × Pobè) hybrids were planted under field conditions in a plantation with a strong presence of BR. Incidence and severity data were recorded for 1812 days from the date of planting; the disease index was estimated, and progress curves were constructed and adjusted to monomolecular, logistic and Gompertz models. Severity progression and incidence progression rates for each cultivar were estimated using a simple linear regression. Statistical comparisons of the parameters were performed using Student's t-tests. Survival analyses were performed for each of the cultivars. Log-rank statistics were used to compare the responses of the cultivars to BR. Severity progression in the interspecific hybrids was significantly slower than that in the E. guineensis cultivars. No statistically significant differences were found in the progression rates among the hybrids; however, the survival analysis did show statistically significant differences. The Coari × Pobè hybrid had the longest survival time. Considering that partial resistance does not prevent plants from becoming infected but does slow disease progression, the two evaluated hybrids may have commercially valuable levels of resistance.

Palms planted in an area with a high bud rot disease (BR) inoculum pressure were evaluated monthly for a six-year period to determine their tolerance, resistance, or susceptibility to the disease. Dura-type E. guineensis and OxG (E. oleifera × E. guineensis) interspecific hybrids Coari × La Me were evaluated. Of the two types of genetic material evaluated, the progenies of the E. guineensis palms showed the highest levels of incidence, reaching 90% affected palms in less than two years of evaluation. Although the hybrids showed susceptibility, they had a lower degree of affectation than the dura-type palms. The severity assessment of both genetic materials showed that the dura-type palms had the highest degree of affectation, reaching the highest values after over two years of evaluation. However, the hybrids, which were not homogeneous in terms of the level of severity, did not exceed, on average, severity level 2. According to the scale, severity level 2 is indicative of tolerance to the disease.