Influence of different cultivars on oil quality and chemical characteristics of avocado fruit

The objective of this paper was to determine the chemical composition of the avocado fruit of cultivars Fortuna, Collinson, and Barker and to carry out a detailed analysis of the fatty acid composition of the pulp, seed, and peel oils. The saturated fatty acid (SFA) of the pulp oils accounted for around 22.3, 29.4, and 41.3% of the total fatty acids in the Fortuna, Collinson and Barker cultivars, respectively, and these values indicate better quality of pulp oil of Fortuna and Collinson cultivars than that of the Barker cultivar. There was very little variation in the content monounsaturated fatty acids of the peel oils between the cultivars. However, the seed oil of the Collinson cultivar was the best since it contained the lowest (30.8% of total fatty acids) content of SFA, but it had very high concentrations of 9,12-octadecadienoic (23.9 to 29.4% of total fatty acids) and 9,12,15-octadecatrienoic (9.9 to 18.3% of total fatty acids) acids.

Growth and maturation of pequi fruit of the Brazilian cerrado

The objective of this study was to characterize the development of pequi fruit (Caryocar brasiliense) of the Brazilian cerrado. It takes 84 days (12 weeks) for pequi to develop with the onset of flowering in September and early fruit set in January. Pequi fruit showed a simple sigmoid growth curve, and its growth was characterized based on fresh mass and longitudinal and transverse diameters. The contents of titratable acidity, soluble solids, β-carotene, and vitamin C increased during fruit growth, reaching their maximum values at the 12th week (84 days) after anthesis. Pequi is a fruit with an extremely high respiratory activity; its respiratory rate decreased during its development. Pequi fruit has been classified as a non-climacteric fruit due to the decrease of both respiration and ethylene production rates during maturation and ripening.

Influence of temperate grass seed rotation systems on weed seed soil bank composition

Due to changing cropping practices in perennial grass seed crops in western Oregon, USA, alternative rotation systems are being considered to reduce weed infestations. Information is generally lacking regarding the effects of alternative agronomic operations and herbicide inputs on soil weed seed bank composition during this transition. Six crop rotation systems were imposed in 1992 on a field that had historically produced monoculture perennial ryegrass (Lolium perenne L.) seeds. Each system plot was 20 x 30 m, arranged in a randomized complete block design, replicated four times. Twenty to thirty soil cores were sampled in June 1997 from each plot. The weed species composition of the cores was determined by successive greenhouse grow-out assays. In addition to seed density, heterogeneity indices for species evenness, richness, and diversity were determined. The most abundant species were Juncus bufonius L. and Poa annua L. Changes in seed bank composition were due to the different herbicides used for the rotation crop components. Compared to the other rotation systems, no-tillage, spring-planted wheat (Triticum aestivum L.) and oat (Avena sativa L.) reduced overall weed seed density and richness, but did not affect weed species evenness or diversity. When meadowfoam (Limnanthes alba Hartweg ex Benth.) succeeded wheat in rotation, weed species richness was unaffected, but evenness and diversity were reduced, compared to the other rotation systems. For meadowfoam in sequence after white clover (Trifolium repens L.), crop establishment method (no-tillage and conventional tillage) had no effect on weed seed species density, evenness, or diversity.

Chilling requirement for seed germination and phenological observations on peach cultivars

In subtropical climate areas, the models and methods proposed to evaluate the chilling requirement of temperate fruit crops often do not provide satisfactory results, thus calling for the development of alternative techniques. The aim of this study was to evaluate the correlations between some phonological traits and chilling requirement for seed germination of 18 peach cultivars and one nectarine cultivar. Two experiments were installed separately for the correlation studies. In experiment 1, the phenological traits were observed in the field, while in experiment 2, the chilling requirement for 50 and 100% seed germination of each cultivar was assessed. The number of days for beginning of bloom (r = 0.70**, 0.61**) and full bloom (r = 0.72**, 0.76**) were both significantly correlated with the number of chilling units for 50% and 100% germination of seeds. The number of days for beginning of budding and dormancy break were both significantly correlated with the number of chilling units for 50% and 100% germination (r = 0.48*, 0.50*, respectively). However, the same significant effect for these phenological traits was not found between chilling units and 50% germination of seeds, as well as between chilling units and harvest dates.

Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae)

Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera, Tephritidae). Studies on Ceratitis capitata, a world fruit pest, can aid the implementation of control programs by determining the plants with higher vulnerability to attacks and plants able to sustain their population in areas of fly distribution. The objective of the present study was to evaluate the influence of eight tropical fruits on the following biological and behavioral parameters of C. capitata: emergence percentage, life cycle duration, adult size, egg production, longevity, fecundity, egg viability, and oviposition acceptance. The fruits tested were: acerola (Malpighia glabra L.), cashew (Anacardium occidentale L.), star fruit (Averrhoa carambola L.), guava (Psidium guajava L.), soursop (Annona muricata L.), yellow mombin (Spondias mombin L.), Malay apple (Syzygium malaccense L.), and umbu (Spondias tuberosa L.). The biological parameters were obtained by rearing the recently hatched larvae on each of the fruit kinds. Acceptance of fruits for oviposition experiment was assessed using no-choice tests, as couples were exposed to two pieces of the same fruit. The best performances were obtained with guava, soursop, and star fruit. Larvae reared on cashew and acerola fruits had regular performances. No adults emerged from yellow mombin, Malay apple, or umbu. Fruit species did not affect adult longevity, female fecundity, or egg viability. Guava, soursop, and acerola were preferred for oviposition, followed by star fruit, Malay apple, cashew, and yellow mombin. Oviposition did not occur on umbu. In general, fruits with better larval development were also more accepted for oviposition.

Simultaneous selection in progenies of yellow passion fruit using selection indices

This study aimed to evaluate the efficiency of simultaneous selection (selection indices) using estimated genetic gains in yellow passion fruit and to make a comparison between the methodologies of Mulamba & Mock and Elston. The study was conducted with 26 sib progenies of yellow passion fruit for intrinsic production characteristics including fruit number, fruit mass, fruit length and diameter, and for the fruit characteristics skin thickness, soluble solids and acidity. Two methodologies were applied: first, in the joint analysis of fruit characteristics and of intrinsic production characteristics in a single phase of selection; and second, in the analysis in two phases, in which priority was given to the intrinsic production characteristics in the first phase, and later, in the second phase, the best fruit characteristics were chosen among the progenies of the first phase. The analysis of variance was applied to the data to detect genetic variability among progenies. The Elston's selection indice was unable to provide distribution of genetic gains consistent with the purposes of the study, as it selected a single progeny of passion fruit. However, the index based on the sum of ranks of Mulamba & Mock was more suitable, as it provided a balanced distribution of gains, selecting a larger number of progenies. The methodology of selection using indices is advantageous in passion fruit, since it contributes to higher genetic gains for all the traits evaluated, and the selection in a single phase was proved efficient for progeny selection.

Shifts in composition of avian communities related to temperate-grassland afforestation in southeastern South America

Afforestation of temperate grasslands with fast-growing trees for industrial pulpwood production is spreading in South America. Despite high afforestation rates resulting from governmental policies that stimulate pulpwood production in grasslands of southern Brazil and Uruguay, the impact of this activity on biodiversity remains to be properly assessed. We used an Impact-Reference study design to evaluate how grassland afforestation affects the composition of grassland bird assemblages. We sampled eucalyptus plantations and neighboring natural grasslands in southern Brazil from 2006-2009, and relied on nested sampling and analysis to separate the effects of afforestation from the natural variability of grasslands. We recorded a significant difference in composition between assemblages from grasslands and tree plantations. Species adapted to open, treeless areas tended to be negatively affected in relation to edge or forest birds in eucalyptus plantations. Afforestation is systematically replacing the bird assemblage of hilltop grasslands by a collection of common edge and forest species that occur in nearby riverine and hillside forests. Although most grassland birds negatively affected by tree plantations are common and widespread, observed and predicted afforestation rates in southeastern South America may result in regional population reductions in the near future.

Thevetia peruviana (Family: Apocynaceae) in the control of slug and snail pests

An aqueous extract prepared from Kernels of the fruit of Thevetia peruviana (Pers.) Schumann (Family : Apocynaceae) was found under experimental conditions, to be toxic ti the slug Laevicaulis alte (Férussac) and the snail Achatina fulica Bowdich, the important agrihorticultural pests of Indo-Pacific countries. Concentrations as low as 1% (w/v) killed all the slugs exposed in less than 981.00 (± SD 22.76) min, and 2% of the extract killed 100% of the slugs L. alte and 50%, 50% and 30% of the snail A. fulica in between 92.34 (± SD 6.63) - 321.33 (± SD 4.14) and 271.20 (± SD 17.54) - 298.26 (± SD 16.69) min respectively. The most effective concentration of the extract was 20%; it killed 100% of exposed slugs and snails within a short time (40-50 and 90-1440 min respectively) when the extract was exposed on the soil in experimental trays or when it was applied to potato slices offered as food to the gastropods.

Postharvest mechanical damage affects fruit quality of 'Montenegrina' and 'Rainha' tangerines

The objective of this work was to evaluate the visual and chemical quality of tangerines after mechanical damage by impacts. The tangerine cultivars Montenegrina and Rainha were submitted to different degrees of impact and evaluated for decay and oleocellosis, loss of fresh weight, total soluble solids, total titratable acidity and ascorbic acid degradation, as well as for epicarp color changes. Experiments with three replicates and experimental units of six fruit for each cultivar were done in a completely randomized design. Impact produced qualitative internal and minor external changes on tangerines. The main modifications produced by impact on the fruit were losses of citric acid and soluble solids, which increased the solid:acid ratio, and losses of ascorbic acid. 'Montenegrina' tangerines are more susceptible to internal quality damage than 'Rainha'.

Gene expression profile during coffee fruit development and identification of candidate markers for phenological stages

The objective of this work was to identify genes that could be used as suitable markers for molecular recognition of phenological stages during coffee (Coffea arabica) fruit development. Four cultivars were evaluated as to their differential expression of genes associated to fruit development and maturation processes. Gene expression was characterized by both semi-quantitative and quantitative RT-PCR, in fruit harvested at seven different developmental stages, during three different seasons. No size polymorphisms or differential expression were observed among the cultivars for the evaluated genes; however, distinct expression profiles along fruit development were determined for each gene. Four out of the 28 evaluated genes exhibited a regular expression profile in all cultivars and harvest seasons, and, therefore, they were validated as candidate phenological markers of coffee fruit. The gene α-galactosidase can be used as a marker of green stage, caffeine synthase as a marker of transition to green and yellowish-green stages, and isocitrate lyase and ethylene receptor 3 as markers of late maturation.

Sensitivity of yellow passion fruit to ultraviolet-B radiation

The objective of this work was to evaluate the effects of UV-B radiation on the vegetative growth and on the gas exchange characteristics of passion fruit plants (Passiflora edulis) grown in greenhouse. The average unweighted UV-B radiation near the apex of the plants was 8 W m-2 for the UV-B treatment (high UV-B), and 0.8 W m-2 for the control plants (low UV-B). Plants were irradiated with UV-B for 7 hours per day, centered on solar noon, during 16 days. High UV-B radiation resulted in lower shoot dry matter accumulation per plant. The content of UV-B absorbing compounds and anthocyanins was increased in the plants exposed to high UV-B radiation, when compared with the control. UV-B radiation did not affect stomatal conductance or transpiration rate, but reduced photosynthesis and instantaneous water-use efficiency, and increased intercellular CO2 concentration. The accumulation of UV-B-absorbing compounds and anthocyanins did not effectively shield plants from supplementary UV-B radiation, since the growth and photosynthetic processes were significantly reduced.

Effect of preharvest spraying with thidiazuron on fruit quality and maturity of apples

Apple trees, cultivars Gala and Fuji, were sprayed at full bloom with thidiazuron (TDZ) at the doses of 0, 5, 10, or 20 g (a.i.) ha-1 and fruit were assessed for quality and maturity. In both cultivars, the increase of TDZ dose had detrimental effects on fruit quality, causing a reduction of fruit red surface and an increase of percentage of fruit that was asymmetrical and with calyx-end rot. TDZ caused an increment of calyx-end aperture that might have increased calyx-end rot. TDZ increased density and the length : diameter (L : D) ratio of the fruit. The number of viable seeds was not affected by TDZ. TDZ resulted in a substantial delay of fruit maturity in 'Gala' but not in 'Fuji'. TDZ also reduced soluble solids content (SSC) in 'Gala' and reduced titratable acidity in both cultivars.

The avocado fruit borer, Stenoma catenifer (wals.) (Lepidoptera: elachistidae): egg and damage distribution and parasitism

The avocado fruit borer, Stenoma catenifer (Wals.) has been a limiting factor in growing avocados over the last years in many Brazilian states. This is a result of the lack of safe and feasible management practices to minimize the fruit borer damage. The aim of this study was to obtain information on the pest biology and ecology as well as on the role of natural enemies to define strategies to control the pest. Samples were taken biweekly and consisted of 20 fruits collected randomly (10 from the upper half and 10 from the lower half of the plant) in ten plants, cv. Margarida, in a commercial avocado grove in Arapongas and Cambé regions, PR, from October/2001 to September/2002. Laboratory determinations of the percentage of damaged fruit per plant region, location and number of bored fruit sites, and the number and location of the fruit borer eggs, including parasitized ones, were performed. The results showed that S. catenifer preferred to oviposit and attack fruits located on the upper half of the trees. The majority of the eggs were laid on the fruit pedicel whereas the damage was mainly located on the lower half of the fruits. Trichogrammatids were the most constant and abundant parasitoids found in both localities throughout the study period.

Estimates of genetic parameters for fruit yield and quality in custard apple progenies

Apparently, there are no custard apple cultivars defined for the northeastern region of Brazil. The establishment of breeding programs aimed at the selection of types from productive locations for later cloning is desirable. This work's objective was to evaluate the yield (during the first three crops) and quality (first crop) of fruits from 20 half-sibling custard apple tree progenies, selected from home orchards. An additional objective was to estimate genetic parameters for the traits evaluated. A micro sprinkling-irrigated experiment was conducted in Mossoró-RN, Brazil, as random blocks with five replications. In characteristics evaluated for periods longer than a year (diameter, height and mean weight of fruits, number of fruits ha-1 and fruit yield (kg ha-1), and a split-plot design was adopted, with progenies considered as plots and annual cropping seasons as subplots. The best progenies in terms of fruit yield (A3 and A4) are not necessarily the best for fruit dimensions and fruit mean weight (A2, FE4, JG1, JG2, SM1, SM7, and SM8). These progenies show great potential to be used in future studies on crosses or on vegetative propagation. In this regard, progeny JG2 should be highlighted as promising in terms of yield and fruit size. The progenies are not different with regard to percentages (in relation to mean fruit mass) of pericarp, endocarp, seeds, and receptacle, in the fruit, and fruit volume, number of seeds/fruit, and total soluble solids content in the fruit pulp, but progeny FE4 presents higher total titratable acidity in the fruit pulp. Narrow-sense heritability estimates were relatively high for all characteristics in which there was variability between progenies, with higher values for number of fruits ha-1 (80 %) and fruit yield (78 %). Relatively high coefficients of genotypic variation (around 20%) were observed for number of fruits ha-1 and fruit yield, with lower values for the other characteristics. There were positive genotypic and phenotypic correlations between fruit diameter (FD) and fruit height, FD and mean fruit weight, and number of fruits ha-1 and fruit yield.

Passiflora edulis Sims: the correct taxonomic way to cite the yellow passion fruit (and of others colors)

Passiflora edulis, the passion fruit native from Brazil, has several common names (such as sour passion fruit, yellow passion fruit, black passion fruit, and purple passion fruit), and presents a wide variability with the different rind colors of its fruits, which are very easy to notice. However, in 1932, Otto Degener suggested that the yellow passion fruit had its origin in Australia through breeding, calling it P. edulis forma flavicarpa, and that it could be distinguished by the color of the fruit, the deeper shade of purple of the corona, and the presence of glands on the sepals. These distinctions do not support themselves, for the glands are common to the species (although they may be absent), and the corona has a wide range of colors, regardless of the color of the fruit. A more critical ingredient is the fact that the external coloration of the fruit is a character of complex inheritance and is not dominant, thus displaying a number of intermediate colors, making it difficult to identify the extreme colors. For the correct scientific naming of agricultural plants, the International Code of Botanical Nomenclature must be used in conjunction with the International Code of Nomenclature for Cultivated Plants, with the selections with significant agronomic characteristics recognized and named cultivars. In accordance with the international convention promoted by the UPOV, of which Brazil is a signatory, several colors (light yellow, yellow, orange yellow, pink red, red, red purple, green purple, purple, and dark purple) can be recognized in order to adequately characterize passion fruit cultivars within the species P. edulis. At taxonomic level, Passiflora edulis Sims must be used for any plant and color of sour passion fruits, in combination with a cultivar name for the selected materials.