Role of healthy nursery plants in orange yield during eight years of Citrus Variegated Chlorosis epidemics

The production and commercialization of citrus seedlings inspected and produced in protected screen-houses has become mandatory in Sao Paulo State, Brazil since January 2003. This law was intended to avoid the dispersion of Citrus Variegated Chlorosis (CVC), disease caused by Xylella fastidiosa. Our objective was to compare the yield over 8 years of `Natal` sweet orange trees grafted onto Rangpur lime obtained from healthy nursery plants and from plants artificially inoculated with X. fastidiosa. Yield was evaluated in an orchard planted in February 1999 with two treatments: (i) trees from healthy nursery plant, and (ii) trees from plants artificially inoculated with X. fastidiosa. The mean yield was 21% higher in trees from healthy nursery plants, as compared to trees from inoculated nursery plants. This difference represents a gain of approximately 203 boxes of 40.8 kg each, considering a planting density of 550 plants per hectare. (C) 2011 Elsevier B.V. All rights reserved.

Identification of microsatellites markers associated with yield components and quality parameters in sugarcane

Marker assisted selection depends on the identification of tightly linked association between marker and the trait of interest. In the present work, functional (EST-SSRs) and genomic (gSSRs) microsatellite markers were used to detect putative QTLs for sugarcane yield components (stalk number, diameter and height) and as well as for quality parameters (Brix, Pol and fibre) in plant cane. The mapping population (200 individuals) was derived from a bi-parental cross (IACSP95-3018 x IACSP93-3046) from the IAC Sugarcane Breeding Program. As the map is under construction, single marker trait association analysis based on the likelihood ratio test was undertaken to detect the QTLs. Of the 215 single dose markers evaluated (1:1 and 3:1), 90 (42%) were associated with putative QTLs involving 43 microsatellite primers (18 gSSRs and 25 EST-SSRs). For the yield components, 41 marker/trait associations were found: 20 for height, 6 for diameter and 15 for stalk number. An EST-SSRs marker with homology to non-phototropic hypocotyls 4 (NPH4) protein was associated with a putative QTL with positive effect for diameter as also with a negative effect for stalk number. In relation to the quality parameters, 18 marker trait associations were found for Brix, 19 for Pol, and 12 for fibre. For fibre, 58% of the QTLs detected showed a negative effect on this trait. Some makers associated with QTLs with a negative effect for fibre showed a positive effect for Pol, reflecting the negative correlation generally observed between these traits.

Analysis of genomic and functional RFLP derived markers associated with sucrose content, fiber and yield QTLs in a sugarcane (Saccharum spp.) commercial cross

Expressed sequence tags derived markers have a great potential to be used in functional map construction and QTL tagging. In the present work, sugarcane genomic probes and expressed sequence tags having homology to genes, mostly involved in carbohydrate metabolism were used in RFLP assays to identify putative QTLs as well as their epistatic interactions for fiber content, cane yield, pol and tones of sugar per hectare, at two crop cycles in a progeny derived from a bi-parental cross of sugarcane elite materials. A hundred and twenty marker trait associations were found, of which 26 at both crop cycle and 32 only at first ratoon cane. A sucrose synthase derived marker was associated with a putative QTL having a high negative effect on cane yield and also with a QTL having a positive effect on Pol at both crop cycles. Fifty digenic epistatic marker interactions were identified for the four traits evaluated. Of these, only two were observed at both crop cycles.

An integrated molecular map of yellow passion fruit based on simultaneous maximum-likelihood estimation of linkage and linkage phases

The development of genetic maps for auto-incompatible species, such as the yellow passion fruit (Passiflora edulis Sims f.flavicarpa Deg.) is restricted due to the unfeasibility of obtaining traditional mapping populations based on inbred lines. For this reason, yellow passion fruit linkage maps were generally constructed using a strategy known as two-way pseudo-testeross, based on monoparental dominant markers segregating in a 1:1 fashion. Due to the lack of information from these markers in one of the parents, two individual (parental) maps were obtained. However, integration of these maps is essential, and biparental markers can be used for such an operation. The objective of our study was to construct an integrated molecular map for a full-sib population of yellow passion fruit combining different loci configuration generated from amplified fragment length polymorphisms (AFLPs) and microsatellite markers and using a novel approach based on simultaneous maximum-likelihood estimation of linkage and linkage phases, specially designed for outcrossing species. Of the total number of loci, approximate to 76%, 21%, 0.7%, and 2.3% did segregate in 1:1, 3:1, 1:2:1, and 1:1:1:1 ratios, respectively. Ten linkage groups (LGs) were established with a logarithm of the odds (LOD) score >= 5.0 assuming a recombination fraction : <= 0.35. On average, 24 markers were assigned per LG, representing a total map length of 1687 cM, with a marker density of 6.9 cM. No markers were placed as accessories on the map as was done with previously constructed individual maps.

Genetic Diversity and a PCR-Based Method for Xanthomonas axonopodis Detection in Passion Fruit

Xanthomonas axonopodis pv. passiflorae causes bacterial spot in passion fruit. It attacks the purple and yellow passion fruit as well as the sweet passion fruit. The diversity of 87 isolates of pv. passiflorae collected from across 22 fruit orchards in Brazil was evaluated using molecular profiles and statistical procedures, including an unweighted pair-group method with arithmetical averages-based dendrogram, analysis of molecular variance (AMOVA), and an assigning test that provides information on genetic structure at the population level. Isolates from another eight pathovars were included in the molecular analyses and all were shown to have a distinct repetitive sequence-based polymerase chain reaction profile. Amplified fragment length polymorphism technique revealed considerable diversity among isolates of pv. passiflorae, and AMOVA showed that most of the variance (49.4%) was due to differences between localities. Cluster analysis revealed that most genotypic clusters were homogeneous and that variance was associated primarily with geographic origin. The disease adversely affects fruit production and may kill infected plants. A method for rapid diagnosis of the pathogen, even before the disease symptoms become evident, has value for producers. Here, a set of primers (Xapas) was designed by exploiting a single-nucleotide polymorphism between the sequences of the intergenic 16S-23S rRNA spacer region of the pathovars. Xapas was shown to effectively detect all pv. passiflorae isolates and is recommended for disease diagnosis in passion fruit orchards.

Ethylene action blockade and cold storage affect ripening of `Golden` papaya fruit

The purpose of this work was to evaluate the effects of ethylene action blockade and cold storage on the ripening of `Golden` papaya fruit. Papayas harvested at maturity stage 1 (up to 15% yellow skin) were evaluated. Half of the fruits, whether treated or not treated with 100 nL L(-1) of 1-methylcyclopropene (1-MCP), were stored at 23A degrees C, while the other half were stored at 11A degrees C for 20 days prior to being stored at 23A degrees C. Non-refrigerated fruits receiving 1-MCP application presented a reduction in respiratory activity, ethylene production, skin color development and pectinmethylesterase activity. Even with a gradual increase in ethylene production at 23A degrees C, fruits treated with 1-MCP maintained a high firmness, but presented a loss of green skin color. Cold storage caused a decrease in ethylene production when fruits were transferred to 23A degrees C. The results suggest that pulp softening is more dependent on ethylene than skin color development, and that some processes responsible for loss of firmness do not depend on ethylene.

Seed development, yield and quality of two palm species growing in different tropical forest types in SE Brazil: implications for ecological restoration

Natural forest remnants have been set as seed production fields to supply seeds of native tree species for tropical forest restoration, but the effect of different forest types on seed production has not been accessed to date for palm species. In this work, we studied seed development, yield, and quality of two palm species in different tropical forest types in SE Brazil. Seed production of palmiteiro (Euterpe edulis) and queen-palm (Syagrus romanzoffiana), which are largely used in restoration efforts due to their importance for vertebrate frugivores, were studied in natural remnants of Atlantic Rainforest, Restinga Forest, Seasonally Dry Forest, and Cerrado Forest. We studied seed development, yield, size, and germination of seed lots produced in some of these forest types, including seeds harvested in 2008, 2009, and both years. Seed yield and quality, as well as seed dry mass in 2009, were higher for palmiteiro seeds produced in the Atlantic Rainforest, while queen-palm seeds produced at the Restinga Forest showed the higher mass and yield, but the lowest physiological potential. Consequently, these natural differences of seed yield and quality have to be taken into account for establishing standards for seed commercialization and analysis, seed pricing, and seedling production in forest nurseries.

Nitrogen and potassium fertilization affect apple fruit quality in southern Brazil

Nitrogen (N) and potassium (K) are usually found in higher concentrations than other macronutrients in apple (Malus x domestica Borkh) fruits and are most frequently associated with changes in fruit quality. The aim of this article was to evaluate the effects of N and K fertilization on some fruit quality attributes of Fuji apple. The experiment was conducted at Sao Joaquim, State of Santa Catarina, Brazil, during 2004 and 2005. A factorial design was used with N and K annual fertilizer rates (0, 50, 100, and 200 kg ha(-1) of N and K2O) replicated in three orchards. Fifteen days prior to harvest, three fruit samples were collected from each treatment and site. One sample was used for total soluble solid content (TSS), titratable acidity, pulp firmness, and fruit color parameter analyses, and the other samples were refrigerated in a conventional atmosphere for 3 and 6 months for subsequent determination of fruit quality. Nitrogen fertilization negatively affected fruit color, flesh firmness, and TSS content. These same variables were positively affected by K fertilization, except for flesh firmness.

Parametric correlation functions to model the structure of permanent environmental (co)variances in milk yield random regression models

The objective of the present study was to estimate milk yield genetic parameters applying random regression models and parametric correlation functions combined with a variance function to model animal permanent environmental effects. A total of 152,145 test-day milk yields from 7,317 first lactations of Holstein cows belonging to herds located in the southeastern region of Brazil were analyzed. Test-day milk yields were divided into 44 weekly classes of days in milk. Contemporary groups were defined by herd-test-day comprising a total of 2,539 classes. The model included direct additive genetic, permanent environmental, and residual random effects. The following fixed effects were considered: contemporary group, age of cow at calving (linear and quadratic regressions), and the population average lactation curve modeled by fourth-order orthogonal Legendre polynomial. Additive genetic effects were modeled by random regression on orthogonal Legendre polynomials of days in milk, whereas permanent environmental effects were estimated using a stationary or nonstationary parametric correlation function combined with a variance function of different orders. The structure of residual variances was modeled using a step function containing 6 variance classes. The genetic parameter estimates obtained with the model using a stationary correlation function associated with a variance function to model permanent environmental effects were similar to those obtained with models employing orthogonal Legendre polynomials for the same effect. A model using a sixth-order polynomial for additive effects and a stationary parametric correlation function associated with a seventh-order variance function to model permanent environmental effects would be sufficient for data fitting.

Random regression models to estimate test-day milk yield genetic parameters Holstein cows in Southeastern Brazil

A total of 152,145 weekly test-day milk yield records from 7317 first lactations of Holstein cows distributed in 93 herds in southeastern Brazil were analyzed. Test-day milk yields were classified into 44 weekly classes of DIM. The contemporary groups were defined as herd-year-week of test-day. The model included direct additive genetic, permanent environmental and residual effects as random and fixed effects of contemporary group and age of cow at calving as covariable, linear and quadratic effects. Mean trends were modeled by a cubic regression on orthogonal polynomials of DIM. Additive genetic and permanent environmental random effects were estimated by random regression on orthogonal Legendre polynomials. Residual variances were modeled using third to seventh-order variance functions or a step function with 1, 6,13,17 and 44 variance classes. Results from Akaike`s and Schwarz`s Bayesian information criterion suggested that a model considering a 7th-order Legendre polynomial for additive effect, a 12th-order polynomial for permanent environment effect and a step function with 6 classes for residual variances, fitted best. However, a parsimonious model, with a 6th-order Legendre polynomial for additive effects and a 7th-order polynomial for permanent environmental effects, yielded very similar genetic parameter estimates. (C) 2008 Elsevier B.V. All rights reserved.

Milk yield, milk composition, eating behavior, and lamb performance of ewes fed diets containing soybean hulls replacing coastcross (Cynodon species) hay

The objective of this experiment was to evaluate the effects of replacing coastcross hay NDF by soybean hull (SH) NDF on the lactation performance and eating behavior of ewes and also on the performance of their lambs. Fifty-six Santa Ines lactating ewes (56.1 +/- 6.8 kg of initial BW; mean +/- SD) were penned individually and used in a randomized complete block design with 14 blocks and 4 treatments. Diets were formulated to provide similar concentrations of NDF (56%) and CP (16%). The SH NDF replaced 33 (SH33), 67 (SH67), or 100% (SH100) of the NDF contributed by coastcross hay in a 70% forage-based diet (SH0), resulting in SH inclusion rates of 0, 25, 54, and 85% of the dietary DM. Once a week, from the second to the eighth week of lactation (weaning time), ewes were separated from their lambs, stimulated by a 6-IU i.v. oxytocin injection, and hand milked to empty the udder. After 3 h, milk production was obtained after the same procedure. Quadratic effect for milk production (142.4, 179.8, 212.6, and 202.9 g/3 h) and cubic effect for DMI (2.27, 2.69, 3.25, and 3.00 kg/d) were observed as SH inclusion increased from 0 to 85% of the dietary DM. Milk fat (7.59, 7.86, 7.59, and 7.74%), protein (4.53, 4.43, 4.40, and 4.55%), and total solids (18.24, 18.54, 18.39, and 18.64%) did not differ among the 70% forage-based diet and diets with SH NDF replacing 33, 67, or 100% of the NDF. A linear increase in lactose concentration was observed with SH inclusion. Ewe BW gain during the trial showed a cubic response (0.37, 0.03, 4.80, and 2.80 kg) with SH inclusion. The preweaning ADG of lambs increased linearly, and ADG of lambs after weaning decreased linearly with SH inclusion. Final BW of lambs (2 wk after weaning) did not differ among treatments. Eating behavior observations were conducted with 44 ewes. The same facilities, experimental design, dietary treatments, and feeding management were used. Observations were visually recorded every 5 min for a 24-h period when ewes were 46 +/- 6.8 d in milk. Eating time (min/d, min/g of DMI, and min/g of NDF intake) and time expended in rumination and chewing activities (min/g of DMI and min/g of NDF intake) decreased linearly with the addition of SH in the diets. The inclusion of SH improved DMI and milk production, also reflecting on the BW of lambs at weaning. Milk performance was not affected when SH NDF replaced 100% of hay NDF.

Outcrossing rate in sweet passion fruit based on molecular markers

P>Yellow and sweet passion fruit are insect-pollinated species native to the tropics. Fruits are used commercially for human consumption worldwide. The yellow passion fruit is an outcrossing species with self-incompatible flowers. However, the reproductive system of the sweet passion fruit (Passiflora alata) has not been well elucidated. The objective of this work was to characterize aspects of the mating system in the sweet passion fruit using random amplified polymorphic DNA (RAPD) and microsatellite markers, particularly the rate of outcrossing in P. alata progenies. A multilocus outcrossing rate of t(m) = 0.994 was determined from RAPD and t(m) = 0.940 from microsatellites, supporting P. alata as an outcrossing species. The fixation indices of the maternal generation (F(m)) were -0.200 and 0.071 with RAPD and microsatellite loci, respectively, indicating the absence of inbreeding in the maternal generation. The paternity correlation (r(p)) varied from -0.008 with RAPD markers to 0.208 with microsatellite markers, suggesting a low probability of finding full sibs within the progenies. The results demonstrated that all progenies assessed in this study were derived from outcrossing.

SOYBEAN YIELD COMPONENTS IN DIFFERENT SOWING PERIODS IN THE WESTERN OF STATE OF BAHIA

Yield is closely linked to the plant yield components and depend directly of the genotype interaction with the environment. Essays were installed in the experimental field of the Bahia Foundation in the Maria Gabriela farm in the county of Sao Desiderio - BA in the year 2006-2007. The aim of this work was to evaluate yield components of five soybean cultivars with different maturation cycles indicated for the Western Region of Bahia in different sowing periods. The experimental design was in random blocks in 4 x 5 factorial scheme (four sowing periods: Ep1 first - 11/29/2006, Ep2 second - 12/14/2006, Ep3 third - 12/28/2007, Ep4 fourth - 01/12/2007 and five cultivars: M-SOY 8411, BRS Corisco, BRS 263 [Diferente], BRS Barreiras e M-SOY 9350) with four repetitions. The following characteristics were evaluated: total number of pods per plant, total number of beans per plant, mass of 1000 beans and yield. Plant yield components, total number of pods per plant, total number of beans per plant, mass of 1000 beans, reduced with sowing delay and showed compensation effect between cultivars and sowing periods. Late sowing Ep3 (28/12/2006) and Ep4 (12/01/2007) were not favourable to raise yield of soybean in the Western Region of Bahia.

Yield, Potassium Uptake, and Use Efficiency in Upland Rice Genotypes

Potassium (K) is an essential nutrient for higher plants. Information on K uptake and use efficiency of upland rice under Brazilian conditions is limited. A greenhouse experiment was conducted with the objective to evaluate influence of K on yield, K uptake, and use efficiency of six upland rice genotypes grown on Brazilian Oxisol. The K rate used was zero (natural soil level) and 200 mg K kg-1 of soil. Shoot dry weight and grain yield were significantly influenced by K level and genotype treatments. However, K x genotype interactions were not significant, indicating similar responses of genotypes at two K levels for shoot dry weight and grain yield. Genotypes produced grain yield in the order of BRS Primavera BRA 01596 BRSMG Curinga BRS 032033 BRS Bonanca BRA 02582. Potassium concentration in shoot was about sixfold greater compared to grain, across two K levels and six genotypes. However, K utilization efficiency ratio (KUER) (mg shoot or grain yield / mg K uptake in shoot or root) was about 6.5 times greater in grain compared to shoot, across two K level and six genotypes. Potassium uptake in shoot and grain and KUER were significantly and positively associated with grain yield. Soil calcium (Ca), K, base saturation, acidity saturation, Ca saturation, K saturation, Ca/K ratio, and magnesium (Mg)/K ratio were significantly influenced by K application rate.

Growth-active gibberellins overcome the very slow shoot growth of Hancornia speciosa, an important fruit tree from the Brazilian ""Cerrado""

Shoot elongation of Hancornia speciosa, an endangered tree from the Brazilian savannah ""Cerrado"", is very slow, thus limiting nursery production of plants. Gibberellins (GAs) A(1), A(3), and A(5), and two inhibitors of GA biosynthesis, trinexapac-ethyl and ancymidol were applied to shoots of Hancornia seedlings. GA(1) and GA(3) significantly stimulated shoot elongation, while GA(5) had no significant effect. Trinexapac-ethyl and ancymidol, both at 100 A mu g per seedling, inhibited shoot elongation up to 45 days after treatment, though the effect was statistically significant only for ancymidol. Somewhat surprisingly, exogenous GA(3) more effectively stimulated shoot elongation in SD-grown plants, than in LD-grown plants. The results from exogenous application of GAs and inhibitors of GA biosynthesis imply that Hancornia shoot growth is controlled by GAs, and that level of endogenous growth-active GAs is likely to be the limiting factor for shoot elongation in Hancornia. Application of GAs thus offer a practical method for nursery production of Hancornia seedlings for outplanting into the field.