Software for interpolation of vegetative growth of yerba mate plants in 3D

The objective of this work was to build mock-ups of complete yerba mate plants in several stages of development, using the InterpolMate software, and to compute photosynthesis on the interpolated structure. The mock-ups of yerba-mate were first built in the VPlants software for three growth stages. Male and female plants grown in two contrasting environments (monoculture and forest understory) were considered. To model the dynamic 3D architecture of yerba-mate plants during the biennial growth interval between two subsequent prunings, data sets of branch development collected in 38 dates were used. The estimated values obtained from the mock-ups, including leaf photosynthesis and sexual dimorphism, are very close to those observed in the field. However, this similarity was limited to reconstructions that included growth units from original data sets. The modeling of growth dynamics enables the estimation of photosynthesis for the entire yerba mate plant, which is not easily measurable in the field. The InterpolMate software is efficient for building yerba mate mock-ups.

Bacterial spot and early blight biocontrol by epiphytic bacteria in tomato plants

The objective of this work was to evaluate in vitro and in vivo biocontrol of bacterial spot (Xanthomonas vesicatoria) and early blight (Alternaria solani) by the epiphytic bacteria Paenibacillus macerans and Bacillus pumilus. Tomato plants were previously sprayed with epiphytic bacteria, benzalkonium chloride and PBS buffer and, after four days, they were inoculated with A. solani and X. vesicatoria. To determine the phytopathogenic bacteria population, leaflet samples were collected from each treatment every 24 hours, for seven days, and plated on semi-selective medium. The effect of epiphytic bacteria over phytopathogens was performed by the antibiosis test and antagonistic activity measured by inhibition zone diameter. The epiphytic and benzalkonium chloride drastically reduced the severity of early blight and bacterial spot in comparison to the control (PBS). In detached leaflets, the epiphytic bacteria reduced in 70% the number of phytopathogenic bacteria cells in the phylloplane. The antibiosis test showed that the epiphytic bacteria efficiently inhibit the phytopathogens growth. In all the bioassays, the epiphytic bacteria protect tomato plants against the phytopathogens

Performance of 'Oneco' mandarin on six rootstocks in South Brazil

The objective of this work was to assess the effect of six rootstocks on yield, fruit quality, and growth of 'Oneco' mandarin during the first seven harvesting seasons, in Butiá, Rio Grande do Sul State, Brazil. The rootstocks evaluated were: 'Swingle' citrumelo (Citrus paradisi × Poncirus trifoliata), 'Caipira' orange (C. sinensis), 'Troyer' citrange (C. sinensis × P. trifoliata), 'Rangpur' lime (C. limonia), 'Volkamer' lemon (C. volkameriana), and 'Flying Dragon' trifoliata orange (P. trifoliata var. monstrosa). Plants budded onto 'Flying Dragon' had the lowest vegetative development, which indicates the dwarfing characteristics of this rootstock, and had the highest mean production efficiency, despite low yield. Plants grafted on 'Volkamer' lemon and 'Rangpur' lime had the highest alternate bearing. Under the experimental conditions evaluated, the most adequate rootstocks for mandarin 'Oneco' are 'Swingle' citrumelo and 'Troyer' citrange, regarding fruit yield and quality.

In vitro organogenesis from internodal segments of adult sweet orange plants

The objective of this work was to optimize in vitro plant regeneration via organogenesis from tissues of adult 'Hamlin', 'Pêra', and 'Valência' sweet orange plants. Explants were grown in EME culture medium with different concentrations of 6-benzylaminopurine (BAP) and naphthaleneacetic acid (NAA), at 27ºC in the absence of light for 50 days, followed by a 16-hour photoperiod for 20 days. Regeneration was assessed 50 and 70 days after in vitro culture. Organogenesis in cultivars Hamlin and Valência was promoted by EME supplemented with BAP, while NAA showed no apparent effect.

Cover plants with potential use for crop-livestock integrated systems in the Cerrado region

The objective of this work was to evaluate the effects of lignin, hemicellulose, and cellulose concentrations in the decomposition process of cover plant residues with potential use in no-tillage with corn, for crop-livestock integrated system, in the Cerrado region. The experiment was carried out at Embrapa Cerrados, in Planaltina, DF, Brazil in a split plot experimental design. The plots were represented by the plant species and the subplots by harvesting times, with three replicates. The cover plants Urochloa ruziziensis, Canavalia brasiliensis, Cajanus cajan, Pennisetum glaucum, Mucuna aterrima, Raphanus sativus, Sorghum bicolor were evaluated together with spontaneous plants in the fallow. Cover plants with lower lignin concentrations and, consequently, higher residue decomposition such as C. brasiliensis and U. ruziziensis promoted higher corn yield. High concentrations of lignin inhibit plant residue decomposition and this is favorable for the soil cover. Lower concentrations of lignin result in accelerated plant decomposition, more efficient nutrient cycling, and higher corn yield.

'Tommy Atkins' mango trees subjected to high density planting in subhumid tropical climate in northeastern Brazil

The objective of this work was to evaluate the effects of high density planting on 'Tommy Atkins' mango trees cultivated in subhumid warm tropical climate in northeastern Brazil. Treatments consisted of five spacial arrangements of plants (8x5 m, 7x4 m, 6x3 m, 5x2 m and 4x2 m), which resulted in the following plant densities: 250 (control), 357, 555, 1,000 and 1,250 plants per hectare. Plant vegetative and reproductive variables, besides fruit quality parameters, were evaluated at seven and eight years after transplantation to the field. In general, high density planting caused reduction in vegetative and reproductive variables of individual mango trees, but had little influence on fruit quality. Above 555 plants per hectare, a significant decrease was observed in mango tree growth. Furthermore, there were decreases in the percentage of flowering, fruit yield per plant and per area. However, planting density up to 357 plants per hectare, in spite of decreasing plant growth and fruit yield per tree, increases fruit yield per area in 30% in comparison to the control.

Watermelon transformation with Zucchini yellow mosaic virus coat protein gene and comparison with parental cultivar

The objective of this work was to transfer Zucchini yellow mosaic virus coat protein (ZYMV-CP) and neomycin phosphotransferase II (NPT II) genes to the watermelon 'Crimson Sweet'(CS) genome, and to compare the transgenic progenies T1 and T2 with the nontransformed parental cultivar for morphological, pomological, growth and yield characteristics. The ZYMV-CP gene was transferred by Agrobacterium tumefaciens. The presence of the gene in transgenic T0, T1 and T2 plants was determined by polymerase chain reaction, and the results were confirmed by Southern blot. Two experiments were performed, one in the winter-spring and the other in the summer-autumn. In both experiments, the hypocotyl length of transgenic seedlings was significantly higher than that of nontransgenic parental ones. In the second experiment, the differences between transgenic and nontransgenic individuals were significant concerning fruit rind thickness, flesh firmness, fruit peduncle length, size of pistil scar, and a* values for fruit stripe or flesh color. Transferring ZYMV-CP gene to CS genome affected only a few characteristics from the 80 evaluated ones. The changes in rind thickness, flesh firmness and flesh color a* values are favorable, while the increase in the size of pistil scar is undesirable. The transgenic watermelon line having ZYMV-CP gene and the parental cultivar CS are very similar.

Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities

The objective of this work was to evaluate the effect of different drip irrigation regimes and planting densities on the incidence of the leaf miner, Leucoptera coffeella, in arabica coffee plants for one year. The experiment was carried out in 2008, in a complete randomized block design, in a split-plot in time arrangement, with four replicates. The treatments consisted of four drip irrigation regimes - soil water balance, irrigations at 20 and 60 kPa soil tensions, and a nonirrigated treatment -, which were distributed at three plant densities: 2, 500, 5, 000, and 10, 000 plants per hectare. The evaluations were made on a monthly basis between January and December 2008. The highest pest occurrence period was from August to November, a season with low-air relative humidity preceded by a drought period. Irrigated coffee plants showed an incidence of intact mines 2.2 times lower than that of nonirrigated plants. Irrigation and increasing of plant density contribute to the reduction of coffee leaf miner occurrence.

Leaf-cutting ant attack in initial pine plantations and growth of defoliated plants

The objective of this work was to evaluate the natural attack by Acromyrmex crassispinus in initial Pinus taeda plantations without control measures against ants, as well as the effect of defoliation in seedlings of P. taeda. Evaluations of the attack of leaf-cutting ants on P. taeda plantations were done monthly in the first six months, then 9 and 12 months after planting. The percentages of plants that were naturally attacked by ants were registered. The effect of defoliation was evaluated by artificial defoliation, simulating the natural patterns of attack by A. crassispinus on P. taeda seedlings. The natural attack of A. crassispinus was greater during the first months after planting, being more intense in the first 30 days. Artificial defoliation indicated that there were no significant losses in diameter and height in plants with less than 75% defoliation. However, there were significant losses in diameter and height in plants with 100% defoliation, independently of the cut of the apical meristem, and also plant death. The control of leaf-cutting ants in P. taeda plantings, in which A. crassispinus is the most frequent leaf-cutting ant, should be intense only at the beginning of planting, since the most severe attacks occur during this time.

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.

Growth of champa fruit under agroecological conditions of Miraflores, Boyacá, Colombia

The objective of this work was to analyze the growth of champa fruit (Campomanesia lineatifolia) as a function of growing-degree days (GDD) in the municipality of Miraflores, in Boyacá, Colombia. Thirty trees were selected at random, and 100 flowers in full bloom were marked in each tree. From the 26th day after flowering until harvest, 10 samples were taken every 15 days to determine the fruit parameters and growth rate. Temperature was recorded to calculate the GDD. From flowering until harvest, 1,489.1 GDD were accumulated over 145 days. Dry and fresh matter mass of pulp, seed, and total fruit were fitted to a logistic growth model, and three growth stages (S1, S2 and S3) were defined. In the S1, growth was slow, and the relative growth remained nearly stable, whereas the absolute growth rate (AGR) increased slowly. In the S2, maximum growth was observed. In the S3, which corresponds to maturation, dry mass increased gradually, and the AGR decreased, while the fresh pulp and total mass did not cease to increase. The polar and equatorial diameters increased linearly, while the volume followed an exponential model. Champa fruit show a simple sigmoid growth curve.

Transgenic tomato plants expressing the antigen gene PfCP-2.9 of Plasmodium falciparum

The objective of this work was to obtain transgenic tomato plants expressing the PfCP-2.9 protein (a chimera of the antigens MSP1 and AMA1 of Plasmodium falciparum). Cotyledons of seven-day-old tomatoes, cultivar Summers, were transformed via Agrobacterium tumefaciens. Transgenic expression in the T0 plants was verified in the DNA extracted from fruits. PCR analysis was used to test the presence of the gene of interest in the T1 generation. Reverse transcriptase PCR provided evidence of gene expression at the RNA level, and Western blot analysis confirmed the presence of the protein of interest in the T1 plants. This is the first report of successful transformation with the expression of a malaria antigen (PfCP-2.9) in transgenic tomato plants from the T0 and T1 generations.

Defoliation of strawberry mother plants for the production of runner tips

The objective of this work was to determine the sink-source relationships and their effects on the number and growth of runner tips of 'Camino Real' strawberry stock plants. Three types of sources were evaluated: one defoliation at 96 days after planting (DAP), two defoliations at 50 and 96 DAP, and mother plants without defoliation. Four types of sink were accessed: runner tips collected weekly and monthly, four stolons with rooted runner tips in pots, and four freely-grown stolons. A completely randomized experimental design was used in a split-plot arrangement, with four replicates. The source types were placed in the plots, and sink types in the subplots. The number of runner tips, the crown diameter, and the dry matter mass were determined. Number and growth of tips were higher on plants without defoliation, and decreased 44.7% on twice-defoliated mother plants. The two-defoliation management did not reduce runner tip dry matter mass only on plants with rooted stolons, which produced runner tips 50% heavier. Defoliation of mother plants bearing rooting stolons can be used to reduce their growth, without reducing the emission and growth of runner tips.

Pollination requirements of seeded and seedless mini watermelon varieties cultivated under protected environment

The objective of this work was to evaluate the floral biology and pollination requirements of seeded and seedless mini watermelon varieties, and to determine the best varieties to cultivate under protected environment. Three seedless (HA-5106, HA-5158, and HA-5161) and two seeded (Minipol and Polimore) genotypes were tested. Flowers were monitored from the pre-anthesis stage to senescence, and fruit quality was also evaluated. The evaluated treatments were hand-geitonogamous pollination (MG), cross-pollination with pollen from the Polimore variety (MCP), cross-pollination with pollen from the Minipol variety (MCM), and restricted pollination. All varieties had monoecious plants with diclinous flowers, and the stigmas remained receptive throughout anthesis. Fruit set rates of 84.62% (MG), 61.54% (MCP), 48% (MCM), and 0% (restricted) were obtained for seeded varieties, but of 0% (MG), 76.36% (MCP), 82.69% (MCM), and 0% (restricted) for seedless varieties. Fruits did not differ in quality among treatments within each genotype. Therefore, all the studied varieties require a pollination agent and diploid pollen for fruit set to occur, regardless of the donor variety; and Minipol or Polimore with HA-5106 or HA-5158 are the varieties recommended for cultivation in protected environment.

Effect of temperature on percentage of germination of canistel seeds (Pouteria campechiana)

The canistel is a fruit originated in Mexico and Central America, being introduced in Brazil in 1986. The plants present medium size, however it can reach up to 15 meters of height; the leaves measure about 10 to 25 cm; the flowers are complete and small and the fruit presents yellow coloration when ripe, with whitish pulp and sweet flavor. The propagation can be realized by seed or grafting. In view of almost total absence of information about the culture and the possibility to have a commercial cultivation, the present work, was live in which the effect of the temperature was evaluated in the percentage of germination of the seeds. It was checked that the best averages were obtained in temperature of 30ºC and the minor in 15ºC, 20ºC and 40ºC could be considerate the worst of them.