Regina Conceição Garcia

Honey bee visitation to sunflower: effects on pollination and plant genotype

Sunflower (Helianthus annuus L.) is an allogamic plant, which needs insects on flowering, especially the honeybees for seed production. Collecting nectar and pollen by honeybees in agricultural crops is essential to apiculture, as well as a better understanding of plant biology. The foraging behavior of Africanized Apis mellifera L. (Hymenoptera, Apidae) and its efficiency of pollination on seed yield of sunflower genotypes (open pollination and restricted pollination) were evaluated. There were peaks of visits by A. mellifera for nectar collection on the 2nd and 3rd flowering days between 7h00 and 8h30. The average density of A. mellifera during increased visitation ranged from 2.27 to 2.94 bees per capitulum. Nectar collecting bees were more frequent (2.28 bees per capitulum) than pollen collecting (0.40 bees per capitulum). On the 3rd flowering day, Helio 360 and Aguara hybrids had higher (p ≤ 0.05) number of bee visits per flower head than the other genotypes. Seed yield was 43 % higher (p ≤ 0.05) from sunflower plants that were visited by pollinator-insects compared with plants restricted to pollinators.

Honey and propolis production, hygiene and defense behaviors of two generations of Africanized honey bees

Phenotypic characters of honeybees, relevant to beekeepers, can be evaluated by studying correlations between them, and the correlated characteristics can be evaluated in the short term to assist in monitoring of annual genetic progress. This work therefore aims to evaluate the production of honey and propolis, the hygiene and defensive behaviours of two generations of Africanized Apis mellifera (Hymenoptera, Apidae), to estimate the correlations between them and their heritability. We used 30 Langstroth beehives in apiaries in Marechal Cândido Rondon, Parana State, Brazil. We used a method of drilling pupae to evaluate hygiene behaviour and the velveteen ball method to test defensive behaviour. We selected ten colonies which had the best honey and propolis production, and which produced F1 queens that were then transferred to beehives at an experimental farm, in order to observe honey and propolis production, hygiene and defence behaviours of their female offspring. The estimated differences for each characteristic between the generations, the correlations between them within each generation and their heritability suggest that selection of colonies based on propolis production was more efficient at maintaining this high production than was selection based on honey production according to the performance of the colonies for this characteristic. The selected behavioural characteristics can be used to enhance performance, but not for improving yield characteristics evaluated.

Implementation of a geographic information system (GIS) for the planning of beekeeping in the west region of Paraná

This study aimed to develop a Geographic Information System (GIS), for storage of information and geographic location of apiaries in eight counties in western Paraná; study the local flora; the land used; and the honey productivity in the harvest of 2010 in two of these areas: Marechal Cândido Rondon and Santa Helena. In order to do so we used the software SPRING, delimiting a radius of action of bees of three kilometers around the apiaries. We interviewed and registered 126 beekeepers with 383 apiaries. By using the images we selected areas with greater and lower overlap of hives in Marechal Cândido Rondon (144 and 44 hives, respectively) and Santa Helena (165 and 40 hives, respectively), in a three kilometers radius, selecting 15 colonies in each area, for the study of the parameters cited. In the multivariate analysis of the grouping, five groups were formed, by their similarity of management, indicating the higher average production in the hives of the most populated area of Santa Helena and lower average production in the most populated of Marechal Cândido Rondon. The grouping of hives, the differences in the production of honey and floristic survey indicated that these differences could be associated with management, floristic and climatic differences recorded in the period of production, in the areas studied.

Pollination of Rapeseed (Brassica napus) by Africanized Honeybees (Hymenoptera: Apidae) on Two Sowing Dates

In this study, performed in the western part of the state of Paraná, Brazil, two self-fertile hybrid commercial rapeseed genotypes were evaluated for yield components and physiological quality using three pollination tests and spanning two sowing dates. The treatments consisted of combinations of two rapeseed genotypes (Hyola 61 and Hyola 433), three pollination tests (uncovered area, covered area without insects and covered area containing a single colony of Africanized Apis mellifera honeybees) and two sowing dates (May 25th, 2011 and June 25th, 2011). The presence of Africanized honeybees during flowering time increased the productivity of the rapeseed. Losses in the productivity of the hybrids caused by weather conditions unfavorable for rapeseed development were mitigated through cross-pollination performed by the Africanized honeybees. Weather conditions may limit the foraging activity of Africanized honeybees, causing decreased cross-pollination by potential pollinators, especially the Africanized A. mellifera honeybee. The rapeseed hybrids respond differently depending on the sowing date, and the short-cycle Hyola 433 hybrid is the most suitable hybrid for sowing under less favorable weather conditions.

Caracterização físico-química de amostras de mel de abelha africanizada dos municípios de Santa Helena e Terra Roxa (PR)

This study aimed to physicochemically characterize the honey samples of Apis mellifera collected in Santa Helena and Terra Roxa counties, located in the western region of Parana State, Brazil. Forty honey samples were collected, 20 in Santa Helena and 20 in Terra Roxa (PR) counties, directly from beekeepers, and were subjected to physico-chemical analyzes of moisture, acidity, pH, ashes, electrical conductivity and color, to verify whether they were in accordance with the existing national legislation (Instruction No. 11), in addition to knowing the physicochemical profile of different sites during the 2008/2009 season. The data were submitted to analysis of variance and F test at 5% significance level. The results showed significant differences (P<0.05) between values of acidity, and the honey samples from Terra Roxa presented a higher value (33.45±7.7 meq.kg-1) than Santa Helena (24 = 53±6.3 meq.kg-1). Most of the analyzed samples were within the specifications prescribed in the legislation for the physico-chemical parameters except for moisture, which despite having presented a significant difference between values obtained from two counties, were above the limits established by the legislation (20%) in eight samples in Santa Helena and seven in Terra Roxa counties, totaling 37.5%. This characteristic may have made the product more susceptible to fermentation, and may have been caused by harvesting immature honey.

Food collection behavior of Apis mellifera and Tetragonisca angustula bees in Brassica napus L. in response to different environmental covariates.

The objective was to evaluate the behavior of Apis mellifera and Tetragonisca angustula bees in pollination tests in Brassica napus at different times of the day, temperature and relative humidity. The experimental design was completely with eight treatments and two pollination tests, repeated in five randomized blocks during seven days of observations for two years, totaling 560 records. During the visits, the following parameters were recorded: collected resources, nectar collection site, time spent on flower, number of flowers visited in one minute, pollen load in the pollen basket and bee contact with anthers and stigma. Data were analyzed using generalized linear models. The number of Africanized and T. angustula bees collecting nectar increased with the passage of time throughout the day and with the decrease of relative humidity. The same was observed for nectar collection in both nectaries. The proportion of bees collecting pollen was higher in the morning hours, as well as when there was an increase in temperature for the two species of bees. Foraging behavior of A. mellifera in B. napus crop favored its pollination, indifferent of which collected floral resource as they came into contact with anthers and stigma. T. angustula bees performed pollination only during pollen collection. Pollination of B. napus was more effective in the warmer hours of the morning, when more of both species of bees carried out pollen collection. Due to its foraging behavior, A. mellifera had greater efficiency for pollination of B. napus; however, the association with T. angustula may potentiate the benefits generated for the crop by cross-pollination.

Phenotypic Correlation and Path Analysis in Sunflower Genotypes and Pollination Influence on Estimates

Eight sunflower genotypes were analyzed to estimate correlation values for nine agronomic traits. Path analysis was used to partition the correlation values into direct and indirect effects on seed yield in two pollination tests (open and restricted pollination). In both tests, there were significant (p<0.05) positive correlation values between seed yield and head diameter, head mass, number and mass of achenes per head and first and last count of germination. There was no correlation (p≥0.05) between seed yield and 1000 seed weight in both pollination tests. Oil content was not correlated (p≥0.05) with seed yield in the open pollination, but it was positively correlated (p<0.05) in restricted plants. The path analysis, in both pollination tests, indicated that head mass had the highest direct effect on seed yield. It can be concluded that the variables head mass and number of seeds per inflorescence (for pollination open) should get due attention in sunflower breeding programs, indirectly contributing to seed yield. In addition, for both pollination tests, the number of seeds per inflorescence has high significant positive correlation to the oil content and may contribute to its increase.