Distribution, abundance and seasonality of scale insects in sugarcane crops in the state of São Paulo

In the state of São Paulo, the main sugarcane producing region of the world, two species of scale insects have frequently occurred, Aclerda takahashii (Kuwana, 1932) (Hemiptera: Aclerdidae) and Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae). To map the distribution and abundance of these species, 17 sugarcane producing fields, distributed in six mesoregions in São Paulo, were evaluated in August 2017 and, January, February, June and July 2018 during the ripening phase. The study on the seasonality of these species, by the presence or absence of the scale insects during the phenological cycle of the plant, was conducted between August 2017 and July 2018 in two sugarcane producing fields in the municipality of Jaboticabal, São Paulo, Brazil. The presence of S. sacchari was found in all the analyzed locations, and A. takahashii in twelve. Both scale insects showed significant difference of infestation in the node’s region of the stems during the ripening phase in one of the studied locations. The aclerdid presented significant difference by infestation in one site during the ripening phase of the plant. The pseudococcid infested a greater number of nodes in the following phases of development; vegetative, grand growth and ripening in both studied areas, but it was in one site during the ripening phase that presented the greatest difference. Although the pink sugarcane mealybug was more abundant than A. takahashii in both studies, there were no patterns of relationships between the numbers of individuals to geographical locations and temperature.

In vitro propagation of select tomatillo (Physalis ixocarpa Brot. ex Horm.) plant families

The objective was to propagate select Physalis ixocarpa plants in vitro, acclimatize them and describe their phenological cycle. The in vitro response of stem apices was evaluated in families from the Tecozautla 04, Manzano Tepetlixpa and Morado San Miguel varieties. The apices were cultured in a medium containing Murashige and Skoog inorganic salts (100 %), supplemented with 0.4 mg·L-1 thiamine, 60 mg·L-1 L-cysteine, 100 mg·L-1 myo-inositol, 0.5 mg·L-1 nicotinic acid, 0.5 mg·L-1 pantothenic acid, 3 % sucrose and 7 g·L-1 agar, without growth regulators and the pH adjusted to 5.7 ± 0.1. in vitro rooting was done for 30 days, with 16 h of light at 3,000 μmol∙m-2∙s-1. The variables evaluated in vitro were seedling height, vigor, callus presence, root length, and number of leaves, roots, stems and buds. Plants produced in vitro were acclimatized and transplanted in greenhouses to follow their phenological cycle. The variables evaluated in acclimatization and phenological cycle were plant height and number of leaves, buds, flowers and set fruits. A completely randomized design was used for the in vitro evaluation, and randomized complete blocks for the greenhouse. The families with the best morphogenic responses in vitro were Tecozautla 04 and Manzano, and in phenological development they presented greater plant height. In acclimatization, survival was 100 % in all clones. in vitro responses, acclimatization and phenology depended on the variety and families.

Characterizing bracken fern phenological cycle using time series data derived from Sentinel-2 satellite sensor

Bracken fern is an invasive plant that has caused serious disturbances in many ecosystems due to its ability to encroach into new areas swiftly. Adequate knowledge of the phenological cycle of bracken fern is required to serve as an important tool in formulating management plans to control the spread of the fern. This study aimed to characterize the phenological cycle of bracken fern using NDVI and EVI2 time series data derived from Sentinel-2 sensor. The TIMESAT program was used for removing low quality data values, model fitting and for extracting bracken fern phenological metrics. The Sentinel-2 satellite-derived phenological metrics were compared with the corresponding bracken fern phenological events observed on the ground. Findings from our study revealed that bracken fern phenological metrics estimated from satellite data were in close agreement with ground observed phenological events with R2 values ranging from 0.53–0.85 (p < 0.05). Although they are comparable, our study shows that NDVI and EVI2 differ in their ability to track the phenological cycle of bracken fern. Overall, EVI2 performed better in estimating bracken fern phenological metrics as it related more to ground observed phenological events compared to NDVI. The key phenological metrics extracted in this study are critical for improving the precision in the controlling of the spread of bracken fern as well as in implementing active protection strategies against the invasion of highly susceptible rangelands.

Locally adapted oak populations along an elevation gradient display different molecular strategies to regulate bud phenology.

Research conducted: With the ongoing global warming, there are serious concerns about the persistence of locally adapted populations. Indeed, with the raising of temperature, the phenological cycle of tree species may be strongly affected since higher winter temperatures may have a negative impact on endodormancy release if chilling requirements are not fulfilled during winter and late frost in spring may expose trees if buds flush too early. Thus, Environmental gradients (showing continuous variations of environmental conditions) constitute a design of choice to analyze the effect of winter dormancy in locally adapted population. Methods: In the present study, we used an elevation gradient in the Pyrenees to explore the gene expression network involved in dormancy regulation in natural populations of sessile oak locally adapted to temperature. Terminal buds were harvested during dormancy induction and release at different elevations. Then, gene expression was quantified using RNAseq and we used a likelihood ratio test to identify genes displaying significant dormancy, elevation or dormancy-by-elevation interaction effects. Key results: Our results highlight molecular processes in locally adapted populations along this elevation cline, and made it possible to identify key dormancy-by-elevation responsive genes revealing that locally adapted populations have evolved distinct molecular strategies to adapt their bud phenology in response to environmental variation (i.e. temperature).

Pinus Pollen Emission Patterns in Different Bioclimatic Areas of the Iberian Peninsula

Background: In the Northern Hemisphere, pine forests predominate due to their natural distribution and silvicultural importance. Pinus tree species are large pollen producers. Nowadays, the context of climate change influences their distribution, abundance, growth and productivity. The objectives of the study were to assess the patterns of the Pinus flowering behavior regarding their pollen presence in the atmosphere and intensity in different bioclimatic areas of the Iberian Peninsula during recent years. Methods: The survey was carried out in three different biogeographic zones of Spain: Vigo (Eurosiberian region) and Ourense (transition area between the Eurosiberian and Mediterranean areas) located in northwest Spain and Toledo (Mediterranean area) placed in the center of the Iberian Peninsula. Airborne pollen was collected with volumetric traps in each study area from 1995 to 2019. Results: Pinus pollen showed a marked single pollination period during late March in the Eurosiberian region and April in the transition zone between the Eurosiberian and the Mediterranean area. Two different peaks with lower pollen intensity were detected during the pollen season in Toledo (Mediterranean area), the first during late March and the second from the end of May to the beginning of June. The trends detected revealed changes in the timing of the phenological cycle, such us longer pollen seasons and later end dates of the Main Pollen Season (MPS) in some cases. The mean Annual Pollen Integral (API) in the Eurosiberian area (Vigo) and transition zone (Ourense) was similar, with about 4400 pollen grains. In the Mediterranean area (Toledo), a lower API amount of 1618 pollen grains was recorded. A trend towards an increase of 126 and 80 pollen grains per year in the airborne pine load was detected in the transition and Mediterranean areas studied, respectively. Conclusions: The rates of the annual integral Pinus pollen percentage with respect to the total pollen of forest species in the atmosphere of the areas studied showed a decreasing percentage trend during the last years.

Cerium (Ce) Affects the Phenological Cycle and the Quality of Tulip (Tulipa gesneriana L.)

Objective: To study the effect of Ce applied in a nutrient solution during the productive cycle, on the duration of the phases of the phenological cycle of tulip cv. Jan van Nes. Design/Methodology/Approach: Commercial bulbs (caliber 12+) were planted under shade cloth conditions during the autumn-winter period. The levels of Ce used were 5, 15 and 15 µM from CeCl3 7H2O; Ce was applied in the nutrient solution from the first day of the sowing, apart from the control without its application. Results: The different concentrations of Ce bulb sprouting. The low concentration of Ce (5 ?M) promoted the early formation of floral buds and their coloration. Hence, the application of 5 ?M Ce advances flowering of the tulip without exhibiting changes in the period of time to reach senescence. When 25 ?M Ce were applied, the opposite effects were observed. The duration of the flower was not significantly affected by the treatments. Study Limitations/Implications: This study was made only in one cultivar of tulip. Findings/Conclusions: The application of 5 µM of Ce had a positive effect in the tulip cycle, by stimulating bulb sprouting, the formation of the floral bud, the coloration, and the advance of the flowering cycle

Flowering phenology in alpine grassland strongly responds to shifts in snowmelt but weakly to summer drought

Alpine plants complete their seasonal phenological cycle during two to three snow-free months. Under climate change, snowmelt advances and the risk of summer droughts increases. Yet, photoperiodism may prevent alpine plants from benefiting from an earlier start of the growing season. To identify the drivers of flowering phenology in the seven main species of an alpine grassland, we experimentally shifted the snowmelt date through snow manipulations, and excluded precipitation during summer. With “time-to-event” models, we analysed the beginning of main flowering with respect to temperature sums, time after snowmelt, and calendar day (photoperiod). We identified two phenology types: four species tracking snowmelt dates directly or with a certain lag set by temperature sums, including the dominant sedge Carex curvula, Anthoxanthum alpinum Helictotrichon versicolor, and Trifolium alpinum, and three species tracking photoperiod: Geum montanum, Leontodon helveticus and Potentilla aurea. Photoperiodism did not act as daylength threshold but rather modulated the thermal sums at flowering. Hence, photoperiod delayed flowering after earlier snowmelt. The grass A. alpinum was the only one of seven species that clearly responded to drought by earlier and longer flowering. The remarkably high importance of snowmelt dates for both phenology types suggests an earlier onset of flowering in a warmer climate, particularly for non-photoperiod-sensitive species, with an increasing risk for freezing damages and potential disruptions of biotic interactions in the most frequent type of alpine grassland across the Alps. Consequentially, the distinct microclimate and species-specific responses to photoperiod challenge temperature-only based projections of climate warming effects on alpine plant species.

Caracterização morfoagronômica de raças locais de Zea mays L. em sistema agroecológico de produção

The objective of this study was to verify if Landrace maize compared to conventional hybrid corn differ in cycle and morphoagronomic traits when grown in agroecological system. The experiment was conducted at the Center for Agricultural Research at the Passo Fundo University, in a randomized block design with five replications, three Landraces of Creole maize (“Cabo roxo”, “Aztequinha” and “FrancoBrazileiro”) and hybrid maize. conventional (22s18 - Sementes Sempre). The fertilizer inputs were made with organic compost and Efficient Microorganisms (MS). Spontaneous species population, phenological cycle, stem diameter, ear and grain characteristics and yield per hectare were evaluated. The treatments did not differ significantly in the evaluation of the cycle in days presenting statistical difference only in plant height at the end of the cycle, where the Landrace “Cabo roxo” presented height of 209,9 cm. Regarding plant and ear characterization, the treatments differed significantly only in the evaluation of grain weight per ear, where the conventional hybrid reached 170,4 g. Thus, it was found that there is little significant difference between the local breeds and the conventional hybrid in the agroecological production system using mulch mass.