Search Results

You are looking at 1 - 9 of 9 items for

  • Author or Editor: R. Fernández-Escobar x
Clear All Modify Search

Abstract

Cross-pollination with ‘Manzanillo’, ‘Lechin de Sevilla’, and ‘Picudo’ increased initial fruit set in ‘Gordal Sevillana’ (synonymous ‘Sevillano’) but did not affect final set under favorable conditions for fertilization. However, the results suggest that under other conditions, cross-pollination with ‘Picudo’ can increase yield. Crop quality was improved with cross-pollination, as there was a reduction in shotberries.

Open Access

Abstract

Experiments with heavily-flowering olive trees showed only one period of abscission of flowers and fruit in the 5-6 weeks following full bloom. This abscission of flowers and fruit is responsible for the small percentage of fruit retained to maturity. Most of the fruit drop was concomitant with initial fruit growth for all cultivars. There were no differences in the number of fruit per inflorescence among cultivars, but the percentage of inflorescences with fruit at harvest was related negatively to final fruit size for each cultivar. Thinning of perfect flowers within the inflorescence did not affect fruit set at the inflorescence level; thus, the inflorescence behaved as a unit of fruitfulness. Competition among fruits played a significant role in fruit set. Initial setting induced by pollination and fertilization is counteracted early by fruit abscission originated by competition among fruit. In light of this early abscission, the use of fruit set to indicate response to pollination in previous experiments is questioned.

Open Access

Change in B content of olive (Olea europaea L.) leaves during anthesis reveals the appearance of a potent B sink. This phenomenon was more marked in young leaves of bearing trees with a high degree of flowering than in nonbearing trees with a low degree of flowering. Applying B to the leaves at the time of anthesis increased the B concentrations in leaf blades, petioles, bark of the bearing shoot, and flowers and fruit 3 days after treatment. The results suggest that B is mobilized from young leaves during anthesis to supply the requirements of flowers and young fruit.

Free access

Chlorotic `Manzanillo' olive (Olea europaea L.) trees and `Maycrest' peach [Prunus persica (L.) Batsch] trees were injected with Fe solutions using an apparatus that consisted of a plastic injector and a pressurized latex tube containing the solution to be injected. Injections were made on various dates from Sept. 1987 to July 1988. All treatments increased chlorophyll content compared to that of the control. Ferrous sulfate was the most effective Fe compound in alleviating chlorosis; its effect lasted for two seasons in peach and for at least three seasons in olive. Also, ferrous sulfate increased vegetative growth and affected cropping the year following injections. Ferrous sulfate at 0.5% to 1% is recommended to reduce the risk of foliar burning. The injection method effectively introduced Fe compounds into olive and peach trees.

Free access

A low-pressure injection method for introducing chemical formulations into trees is presented. The apparatus consists of a plastic injector and a tube providing a pressure of 60 to 80 kPa, which is below the injurious level for the xylem. The efficiency of the method was determined by injecting PTS, a marker of apoplastic flux dye solutions, and rubidium chloride into young trees, main scaffolds, or tree trunks. The depth of the hole drilled) and the number of injections necessary to distribute the solutions was also determined. The injected solutions moved mainly upward through the older rings of the xylem, suggesting that uptake is directly controlled by the transpiration rate. A single injection was enough to distribute solutions in scaffolds with a diameter of 8 cm, but two injections were necessary for 17-cm-diameter trunks. According to the results, the injection method was effective in introducing chemicals into olive (Olea europaea L.) trees. The method is easy to use, safe and economical and does not involve special equipment. Chemical name used: trisodium, 3-hydroxi-5,8,10-pyrenetrisulfonate (PTS).

Free access

Olive shoots were collected at monthly intervals during an off and an on year from nonirrigated, mature `Picual' olive trees fertilized or nonfertilized with nitrogen. Young and mature leaves and stems and flowers and fruit developed during the on year were removed separately from the shoots to determine N concentration and N content per organ. N concentration decreased in young leaves and stems in spring and summer, and increased during the autumn in both off and on years. N concentration in old leaves and stems remained almost constant during the off year, and drops from April to October during the on year. The new tissues accumulated N during the off year and mobilized it during the on year to support growth. Leaves stored larger amounts of N than stems, and fruit developed during the on year became the main sink for N of the bearing shoot. Although the adjacent, mature leaves may have supported part of the N demand from the fruit, nitrogen must also have been mobilized from other storage organs to support fruit growth. No differences between fertilizer treatments were observed in the allocation pattern of N, although N reserves increased in shoots of fertilized trees.

Free access

The influence of sodium and boron excess in the irrigation water on shoot growth and on the distribution of these elements within various leaf types was studied on rooted olive cuttings (Olea europaea L.). `Lechín de Granada' was more tolerant than `Manzanillo' to sodium excess, as indicated by greater shoot growth and lower accumulation of sodium, especially in the young leaves. `Picual' was more tolerant to boron than `Manzanillo', with less accumulation in adult leaves. The results suggest the avoidance of toxicity by an ionic exclusion mechanism that is more effective in some cultivars than others. Also, the results reveal cultivar differences in the tolerance of olive to sodium and boron excess in the culture medium.

Free access

GA3 scaffold injections applied between May and November to nonbearing olive (Olea europea L.) trees inhibited flowering the following year, increased shoot width when applied in May, June, and July, and increased inflorescence length when applied in November and February. Fruit removal and seed destruction were effective in improving the return bloom in `Manzanillo' olives when done before endocarp sclerification. Depending on-the year, endocarp sclerification takes place 7 to 8 weeks after full bloom (AFB), usually about 1 July. Fruit removal had no effect on flowering when done after this time. Scaffold injection of paclobutrazol applied to bearing trees between May and September did not affect flowering the following year. The results of our research supports the hypothesis that olive flower induction occurs around the time of endocarp sclerification. Chemical names used: gibberellic acid (GA3), (2RS,3RS)-1-(4-chlorophenyl)-4-dimethyl-2-1,2-4-triazol-1-yl) pentan-3-ol(paclobutrazol).

Free access

Mature `Picual' olive (Olea europaea L.) trees growing in two different localities of Córdoba and Jaén provinces, southern Spain, were subjected to annual applications of 0, 0.12, 0.25, 0.50, or 1.0 kg N/tree in the Cordoba's experiment, and to 0 or 1.5 kg N/tree in the Jaén's experiment. Nitrogen was applied 50% to the soil and 50% through foliar application in Córdoba, and 100% to the soil in Jaén. Three years after the initiation of treatments, when the trees showed differences among them in nitrogen content, fruit were sampled at maturity from each experimental tree during six consecutive seasons to determine the effect of nitrogen fertilization on olive oil quality. Tree nitrogen status was always above the threshold limit for deficiency even in control trees, indicating that most treatments caused nitrogen over fertilization. Nitrogen in excess was accumulated in fruit and, consequently, polyphenol content, the main natural antioxidants, significantly decreased in olive oil as nitrogen increased in fruit. The decrease in polyphenols induced a significant decrease in the oxidative stability of the oil and its bitterness. Tocopherol content, on the contrary, increased with nitrogen application, mainly by an increase in α-tocopherol, the main component in the olive oil. No effect was found on pigment content, particularly carotenoid and chlorophyllic pigments, neither on fatty acid composition.

Free access