Season Interaction Research Articles

Disentangling the Mechanisms Shaping the Prokaryotic Communities in a Eutrophic Bay.

ABSTRACTEutrophication occurring in coastal bays is prominent in impacting local ecosystem structure and functioning. To understand how coastal bay ecosystem function responds to eutrophication, comprehending the ecological processes associated with microbial community assembly is critical. However, quantifying the contribution of ecological processes to the assembly of prokaryotic communities is still limited in eutrophic waters. Moreover, the influence of these ecological processes on microbial interactions is poorly understood. Here, we examined the assembly processes and co-occurrence patterns of prokaryotic communities in a eutrophic bay using 156 surface seawater samples collected over 12 months. The variation of prokaryotic community compositions (PCCs) could be mainly explained by environmental factors, of which temperature was the most important. Under high environmental heterogeneity conditions in low-temperature seasons, heterogeneous selection was the major assembly process, resulting in high β-diversity and more tightly connected co-occurrence networks. When environmental heterogeneity decreased in high-temperature seasons, drift took over, leading to decline in β-diversity and network associations. Microeukaryotes were found to be important biological factors affecting PCCs. Our results first disentangled the contribution of drift and microbial interactions to the large unexplained variation of prokaryotic communities in eutrophic waters. Furthermore, a new conceptual model linking microbial interactions to ecological processes was proposed under different environmental heterogeneity. Overall, our study sheds new light on the relationship between assembly processes and co-occurrence of prokaryotic communities in eutrophic waters.IMPORTANCE A growing number of studies have examined roles of microbial community assembly in modulating community composition. However, the relationships between community assembly and microbial interactions are not fully understood and rarely tested, especially in eutrophic waters. In this study, we built a conceptual model that links seasonal microbial interactions to ecological processes, which has not been reported before. The model showed that heterogeneous selection plays an important role in driving community assembly during low-temperature seasons, resulting in higher β-diversity and more tightly connected networks. In contrast, drift became a dominant force during high-temperature seasons, leading to declines in the β-diversity and network associations. This model could function as a new framework to predict how prokaryotic communities respond to intensified eutrophication induced by climate change in coastal environment.

Evaluation of Kenyan wheat (Triticum aestivum L.) cultivars for rust resistance, yield and yield components

Stem rust (Puccinia graminis f. sp. tritici) is an important fungal disease of wheat (Triticum aestivum) due to its ability to cause severe yield losses on susceptible cultivars grown under conducive conditions. The objective of this study was to evaluate 81 Kenyan wheat cultivars for yield, agronomic traits and resistance to rust. A 3-season field experiment was conducted in a 9 × 9 partially balanced lattice design at KALRO, Njoro (0˚ 20’S and 35˚ 56’E) under stem rust (Sr) and yellow rust (Yr) pressure. The results from this study showed that effects due to season, cultivar and cultivar × season interaction were significant (p≤0.001) for number of kernels spike-1, Area Under Disease Progress Curve for stem rust (AUDPC_SR), Area Under Disease Progress Curve for yellow rust (AUDPC_YR), yield, 1000-kernel weight (TKW), biomass and days to heading. Principal component analysis showed AUDPC was the most effective disease parameter for determining rust resistance and biplot analysis identified cultivars K. Fahari, K. Kingbird, K. Songbird and K. Pelican with desirable traits for yield, TKW, biomass and kernels spike -1. Stem rust contributed to the highest in reduction of yield and TKW accounting for 12.87% and 21.95% variation, respectively while Yr contributed the most to biomass reduction accounting for 25.65% variation. From this study, cultivars Bounty, Lenana, and K. Leopard which produced high yield, low AUDPC_SR and AUDPC_YR values ranging from 3.5- 32.2 and 15.6-80.4, respectively can be used as valuable genetic stocks for improvement of rust resistance in wheat cultivars in Kenya

Assessment of rhizome yield of local Indonesian turmeric (Curcuma longa L.) during two growing seasons

Abstract. Aulia R, Maulana H, Filio YL, Shafira NA, Anindita PA, Suganda T, Concibido V, Karuniawan A. 2022. Assessment of rhizome yield of local Indonesian turmeric (Curcuma longa L.) during two growing seasons. Biodiversitas 23: 2534-2543. In Indonesia, rhizome yield evaluation across diverse growing seasons is very useful for selecting turmeric genotypes that have the potential to be developed into commercial varieties. Evaluation using multiple measurements has high accuracy. This study aimed to select turmeric genotypes based on differences in agro-morphological traits, identify genotypes by season interactions (GEIs), and select stable and high-yielding turmeric during two seasons. The study was conducted for two growing seasons (Planting Season 1 in January - October 2019 and Planting Season 2 in January - October 2020) using an augmented design. Cluster analysis based on agro-morphological traits was used to select turmeric genotypes based on their proximity. A combined analysis of variance (ANOVA) was used to estimate the effect of GEIs on rhizome yield and yield attributes. Rhizome yield evaluation was analyzed using parametric and nonparametric measurements. The results showed that twenty-five turmeric genotypes were selected based on agro-morphological differences. GEIs caused the variation of rhizome yield with a contribution of 34.88%, and yield attributes of 7.04% for weight per plant (WPP), 10.97% for rhizome width (RW), 11.95% for Petiole length (PL), 47.25% for lamina length (LL), and 25.44% for lamina width (LW). The results of parametric and nonparametric measurements selected six genotypes of turmeric into ideal groups, namely G4 (CL-12), G6 (CL-20), G9 (CL-30), G12 (CL-37), G22 (CL-82), and G26 (Cek 1). They can be developed as superior local commodities and used as breeding materials for turmeric plants in the future.

Aflatoxin contamination in dairy feed during wet and dry seasons in selected rural areas of Sidama zone in Southern Ethiopia

This study was conducted in the southern region of Ethiopia. The objectives were to assess the occurrence and level of aflatoxin B1 contamination in dairy cow feeds. The analytical technique used was Enzyme-linked immunosorbent assay(ELISA). Two-way ANOVA was used to analyze +the season and location interaction effect. Laboratory analysis showed that 81.2% of the feed samples had a detectable level of AFB1 within the range of 0.067-29.69 µg/kg and with an average of 7.91±5.83 µg/kg. From the positive samples, 52.5 and 4.58% of the feed sample were above EU (5 µg/kg) and USA (20 µg/kg) limits for dairy cattle feed respectively. Average AFB1 concentration during the dry season (8.74± 5.6 µg/kg) is significantly higher (P<0.05) than wet season (7.02± 5.86 µg/kg). This result implies that sustainable good practices should be maintained for all feed harvesting, storage, and feeding practices by feed producers and dairy farmers regarding aflatoxin contamination.

Physiological, blood-biochemical and behavioural changes of Ghoongroo pigs in seasonal heat stress of a hot-humid tropical environment.

The present study investigated the effect of seasonal heat stress on the physiological, behavioural and blood bio-chemical profile of adult Ghoongroo pigs (1.5-2years of age) of different physiological groups. Thirty Ghoongroo pigs (10 boars, 10 non-pregnant sows and 10 pregnant sows) were allotted to individual pens. The study continued for 1year covering three main seasons, i.e. summer (March-June), rainy (July-October) and winter (November-February) season. Temperature humidity index was significantly (P < 0.05) higher in summer (83.2 ± 0.47) followed by rainy (68.5 ± 1.13) and winter (66.8 ± 0.67) seasons, which indicated that pigs were exposed to heat stress during summer. Rectal temperature and pulse rate were not affected by group × season interaction but were affected by group (P = 0.002) and season (P < 0.001), which were usually greater during summer than during winter and in boars than in pregnant sows. Respiration rate was affected by group × season interaction (P = 0.002), which was greater in boars than in non-pregnant and pregnant sows during summer and rainy season but was similar in winter among the groups. Total erythrocytes, leucocytes counts, and cortisol levels were influenced by group (P < 0.001), season (P < 0.001) and group × season interaction (P < 0.001), which increased in summer compared with winter. Sodium and potassium concentrations in serum were not affected by group and group × season interaction but were affected by season (P < 0.001), which were lower in summer than in winter. All behaviour activities (standing, resting and roaming time, urination, fighting and drinking frequency) were affected by group (P < 0.001), season (P < 0.001) and group ×season interaction (P < 0.001), except eating time that was only influenced by season. The present study suggested that Ghoongroo pigs experienced heat stress during summer, which was reflected in physiological, blood-biochemical and behavioural alterations.

Integrating historical observations alters projections of eastern North American spruce–fir habitat under climate change

AbstractSpruce–fir (Picea–Abies) forests of the North American Acadian Forest Region are at risk of disappearing from the northeastern United States and Canada due to climate change. Species distribution models (SDMs) have been used to predict changes in this critical transitional ecosystem in the past, but none have addressed how seasonal patterns of temperature and precipitation interact to influence tree species abundance. Inferences have also been limited by contemporary inventory data that could not fully characterize species ranges because they either, (1) only sampled species occurrence after large‐scale human disturbance and settlement, or (2) did not span critical geopolitical boundaries (e.g., the US–Canadian border) that intersect the focal species' range(s). Here, we built new SDM models to better assess the bioclimatic distribution of four spruce–fir species and to test the importance of seasonal climate interactions. We compiled an extensive database of tree occurrence and abundance from recent (~1955–2012) and historical time periods (1623–1869) to model current species distributions and to predict how these might change under future climate. We found that including historical tree data in our SDMs revealed previously unrecognized suitable habitat along the southern edge of species' contemporary ranges. Random forest models predicted occurrence with high accuracy (area under receiver operator curve &gt;0.98), and the seasonal climate variables that emerged as most important for these cold‐adapted species all included interactions that reflected sensitivity to colder temperatures, and preferences for wet weather concentrated in the winter months. Under moderate climate warming (representative concentration pathway 6.0), the northeastern United States retained additional suitable habitat when historical data were included through 2060 for three of the four species: red spruce (Picea rubens), black spruce (Picea mariana), and balsam fir (Abies balsamea), while white spruce (Picea glauca) habitat contracted into Canada. In contrast, future predictions from models that used contemporary data alone forecast extirpation for all four species from the northeastern United States. Overall, these findings highlight that prediction of species ranges in transitional ecosystems that span geopolitical boundaries and gradients of intense land use are improved when historical data and seasonal climate interactions of both temperature and precipitation variables are incorporated.

Feedlot pens with greenhouse roofs improve beef cattle performance in temperate weather.

Muddy pens can negatively affect welfare and performance of feedlot beef cattle. In some regions with temperate weather, plastic greenhouse covers, above the entire pens are used to fatten cattle in a clean and dry environment. The objective of this research was to investigate effects of greenhouse roofed pens on beef cattle feedlot performance in temperate weather. Data were collected from a feedlot located in Central Mexico between 2016 and 2019. The study included 1,062 closeouts of pens with 68,305 crossbred bulls fed in pens with or without a greenhouse roof. Feeding ranged from 82 to 210 d, depending on the initial weight of cattle, which ranged from 255 to 511 kg. For each pen, average daily dry matter intake (DMI; kg of DMI·animal−1·d−1), average daily gain (ADG, kg·animal−1·d−1), and feed efficiency (G:F, ADG/DMI) were measured. Factorial analyses were performed to test the interaction and main effects of initial weight grouping (light, medium, and heavy), roof, and season as fixed effects, and year as a random effect. None of the three-way interactions were significant (P > 0.51). There was no initial weight grouping × roof interactions for DMI and ADG (P > 0.31). There was (P = 0.03) an initial weight grouping × roof interaction for G:F, as pens of all initial weight groups had greater (P < 0.01) G:F in pens with greenhouse roof than its counterpart in pens without greenhouse roof, but the advantage was greater for pens with light cattle (0.178 vs. 0.166; P < 0.01). There was no initial weight grouping × season interactions for all variables (P > 0.39). There was no roof × season interaction for DMI (P = 0.47), but there were interactions for ADG and G:F (P < 0.01). The ADG was not different (P > 0.13) during summer and autumn based on the roofing system, but pens with greenhouse roofs had greater ADG during spring (1.70 vs. 1.61) and winter (1.68 vs. 1.64; P ≤ 0.01). The G:F was greater (P < 0.01) in all seasons for pens with a greenhouse roof, with the most prominent advantage during spring (0.173 vs. 0.160). There were main effects for cattle initial weight grouping and roof for all variables (P < 0.01). Season affected DMI and G:F (P < 0.01). Pens with greenhouse roofs had decreased DMI (9.70 vs. 9.86), greater ADG (1.67 vs. 1.63), and increased G:F (0.173 vs. 0.166) compared to pens without greenhouse roofs (P < 0.01). Pens with greenhouse roofs in feedlots located in temperate regions positively affect beef cattle performance.

Edaphic Response and Behavior of Agricultural Soils to Mechanical Perturbation in Tillage

Mechanical perturbation constrains edaphic functionality of arable soils in tillage. Seasonal soil tool interactions disrupt the pristine bio-physio-mechanical characteristics of agricultural soils and crop-oriented ecological functions. They interfere with the natural balancing of nutrient cycles, soil carbon, and diverse organic matter that supports soil ecosystem interactions with crop rooting. We review soil working in tillage, associated mechanistic perturbations, and the edaphic response of affected soil properties towards cropping characteristics and behavior as soil working tools evolve. This is to further credit or discredit the global transition to minimum and no-till systems with a more specific characterization to soil properties and edaphic crop-oriented goals of soil tooling. Research has shown that improvement in adoption of conservation tillage is trying to characterize tilled soils with edaphic states of native soil agroecosystems rendering promising strategies to revive overworked soils under the changing climate. Soil can proliferate without disturbance whilst generation of new ecologically rich soil structures develops under more natural conditions. Researchers have argued that crops adapted to the altered physio-mechanical properties of cultivated soils can be developed and domesticated, especially under already impedance induced, mechanically risked, degraded soils. Interestingly edaphic response of soils under no-till soil working appeared less favorable in humid climates and more significant under arid regions. We recommend further studies to elucidate the association between soil health state, soil disturbance, cropping performance, and yield under evolving soil working tools, a perspective that will be useful in guiding the establishment of future soils for future crops.

Duck hunter activity, success, and satisfaction on public hunting areas

AbstractBecause hunting disturbance can influence local distribution of ducks and their availability to hunters, managers often limit access to hunting areas to improve hunting success and satisfaction. Few studies have quantified the effectiveness of public area access restrictions on duck hunter activity, harvest, or hunters' satisfaction with their hunting experience. We used a cross‐over design over 6 consecutive hunting seasons (2008–2009 through 2013–2014) on State Wildlife Areas (SWAs) in northeastern Colorado, USA, to compare the effects of restricted hunting access regulations and regulations without these restrictions on duck hunter activity, harvest success, harvest levels, and satisfaction. We also considered effects of SWA types, duck abundance, temperature, precipitation, use of equipment by duck hunting parties, and, for hunter satisfaction, hunting success, hunting parties' satisfaction with ducks seen, habitat conditions, crowding from other hunters, and SWA regulations. The number of days when duck hunters had access to restricted properties was about half that on unrestricted properties, and unrestricted properties were used by about twice as many duck hunting parties, but the mean number of hunting parties per available hunting day and mean party size were similar under the 2 types of regulations. Most (56%) duck hunting parties did not bag any ducks; hunting success (harvest of ≥1 duck by a hunting party) was best explained by a model that included a regulation type × hunting season interaction, a SWA type × month interaction, hunter density the previous day, an index of hunter investment (number of decoys used and whether dogs and calls were used), and temperature. Successful hunting parties harvested 1.92 ± 1.60 (SD) ducks/hunter/day (range = 0.1–7.0); the best model predicting the number of ducks harvested per hunter in successful parties included a regulation type × hunting season interaction, a SWA type × month interaction, hunter density the previous day, an index of hunter investment, temperature, and precipitation. Overall satisfaction of duck hunting parties with a day's hunt averaged 3.62 ± 1.20 based on a rank scale of 1 (very unsatisfied) to 5 (very satisfied), and was best explained by a model that included hunting party success; hunter investment; temperature; and satisfaction with duck numbers, habitat conditions, hunting regulations, and crowding. While greatly reducing days available for hunting, access restrictions were associated with improved chances of hunting parties successfully harvesting ≥1 duck in 5 of 6 hunting seasons, and substantially greater numbers of ducks harvested by hunters in successful parties in 1 of 6 hunting seasons. Restrictions did not have a strong direct effect on hunting parties' satisfaction with a day's hunt. Uncontrolled factors, including weather and use of equipment by hunters, had important influences on hunter success, harvest, and satisfaction. Managers should carefully assess hunting activity, hunter expectations and desires, and hunting area characteristics when considering access restrictions on public hunting areas.

Ammi Analysis in Rice (Oryza sativa L.) Germplasm

Seventy genotypes of rice were evaluated under three seasons. Additive main effects and multiplicative interaction (AMMI) model was applied to ascertain extent of genotype ´ into season interaction (GSI) and also the stability of rice genotypes over three seasons. Significant difference was observed by AMMI analysis among the 70 genotypes as well as seasons. The sum of the first principal component accounted to 87.04% of the GSI. In the present inquiry, the genotypes viz., G26 (484.45 mg), G17 (474.78 mg) and G31 (377.87 mg) registered with high mean per day productivity and coupled with higher PCA scores. The aforementioned genotypes are exclusively suitable for favourable seasons. The genotypes G7 and G11, were nearer to the center point axes. They were influenced with the seasons. These genotypes had maximum per day productivity as well as stability and hence suitable for different seasons.

The Adrenal Cortisol Response to Increasing Ambient Temperature in Polar Bears (Ursus maritimus).

Simple SummaryHuman-caused climate change is proceeding rapidly and providing challenges to wildlife species, especially those adapted to colder temperatures. We investigated the cortisol response of polar bears to increasing ambient temperatures to improve our knowledge of the physiology of this Arctic species with the goal of informing management in zoos and in the wild. In adult polar bears temperatures above 20 °C were associated with an increase in the hormone cortisol to accommodate increased thermoregulatory demands. This temperature threshold was surprisingly high for an Arctic-adapted species. Zoos can provide sufficient housing options to prevent overheating in polar bears exposed to warmer temperatures but our results are concerning for wild polar bears. The number of days reaching 20 °C in the Arctic has increased significantly over the past 30 years and the associated increase in thermoregulatory costs add to the physiological burden many wild polar bears are already facing with the loss of sea ice hunting opportunities. We recommend that the management of polar bears in the wild and under human care be adapted to reflect the increased cortisol concentrations associated with thermoregulatory challenges in warmer temperatures.Our objective was to identify the upper ambient temperature threshold that triggers an increase in cortisol in response to increased thermoregulatory demands in polar bears. The results reported here include endocrine data collected over two years from 25 polar bears housed in 11 accredited zoological institutions across North America. The effects of ambient temperature, sex, age group (juvenile, adult, elderly), breeding season and humidity on fecal cortisol metabolite (FCM) concentrations (N = 8439 samples) were evaluated using linear mixed models. Ambient temperatures were placed into five different categories: <5 °C, 6–10 °C, 11–15 °C, 16–20 °C, and >20 °C. Ambient temperature and humidity had a significant (p < 0.05) effect on FCM concentrations with significant (p < 0.05) interactions of sex, age and breeding season. Once biotic factors were accounted for, there was a significant (p < 0.05) increase in FCM concentrations associated with ambient temperatures above 20 °C in adult polar bears. The implications of these findings for the management of both zoo and wild polar bears are discussed.

Noise attenuation varies by interactions of land cover and season in an urban/peri-urban landscape.

Anthropogenic noise is increasing worldwide because of growing human populations, transportation, and resource extraction. This excessive noise negatively impacts humans and wildlife. To mitigate noise pollution, the use of vegetation in urban planning is becoming increasingly common. However, noise attenuation can be influenced by poorly understood differences in land cover and seasonality that exist across complex urban and peri-urban environments. We compared the noise attenuation capacity of sites typifying dominant land covers in southern Ontario, Canada (forest, tallgrass prairie, and agriculture) across three seasons (summer, fall, and winter). We found that total noise attenuation was affected by a complex interaction of both site and season across low (250 Hz), mid (500 Hz), and high (1000 Hz) frequency sound. Seasonal changes in vegetation density varied between sites and seemed to play only a partial role in total noise attenuation. While forest, trees, and shrubs continue to be effective for managing noise pollution, our results suggest that other types of land cover can also be useful (e.g., tallgrass prairie). With growing interest in the potential noise attenuating capabilities of vegetation, we recommend further consideration of the seasonal variation in attenuation that can occur across the diverse land covers of urban and peri-urban environments.

Efficacy of rhizobia strains on growth and chemical composition of cancer bush (Sutherlandia frutescens)

ABSTRACT Cancer bush (Sutherlandia frutescens), which is facing extinction, can be conserved through cultivation using best agricultural practices that include nodulation with effective rhizobia bacteria. The objective of the study was to compare the efficacy of commercial and native nodulation bacteria on productivity of S. frutescens over two seasons. Seasonal interaction on productivity variables was not significant (P < 0.05), with pooled data (n = 75) subjected to analysis of variance. Treatments had a significant effects on plant variables, contributing from 58 to 91% in total treatment variation (TTV) of the variables. Relative to untreated control, commercial strains significantly increased plant variables from 31 to 44%, whereas wild strains increased the variables from 17 to 195%. Similarly, both commercial and native strains significantly increased nitrogen, protein and symbiotic efficiency, with magnitudes of native strains being significantly higher than those of commercial strains. Treatments had no significant effects on K and protein in leaf tissues of S. frutescens. In conclusion, the native strains as investigated in the current study have the potential for use in the husbandry of cancer bush.

Seasonal Differences in Structural and Genetic Control of Digestibility in Perennial Ryegrass.

Perennial ryegrass is an important forage crop in dairy farming, either for grazing or haying purposes. To further optimise the forage use, this study focused on understanding forage digestibility in the two most important cuts of perennial ryegrass, the spring cut at heading and the autumn cut. In a highly diverse collection of 592 Lolium perenne genotypes, the organic matter digestibility (OMD) and underlying traits such as cell wall digestibility (NDFD) and cell wall components (cellulose, hemicellulose, and lignin) were investigated for 2 years. A high genotype × season interaction was found for OMD and NDFD, indicating differences in genetic control of these forage quality traits in spring versus autumn. OMD could be explained by both the quantity of cell wall content (NDF) and the quality of the cell wall content (NDFD). The variability in NDFD in spring was mainly explained by differences in hemicellulose. A 1% increase of the hemicellulose content in the cell wall (HC.NDF) resulted in an increase of 0.81% of NDFD. In autumn, it was mainly explained by the lignin content in the cell wall (ADL.NDF). A 0.1% decrease of ADL.NDF resulted in an increase of 0.41% of NDFD. The seasonal traits were highly heritable and showed a higher variation in autumn versus spring, indicating the potential to select for forage quality in the autumn cut. In a candidate gene association mapping approach, in which 503 genes involved in cell wall biogenesis, plant architecture, and phytohormone biosynthesis and signalling, identified significant quantitative trait loci (QTLs) which could explain from 29 to 52% of the phenotypic variance in the forage quality traits OMD and NDFD, with small effects of each marker taken individually (ranging from 1 to 7%). No identical QTLs were identified between seasons, but within a season, some QTLs were in common between digestibility traits and cell wall composition traits confirming the importance of hemicellulose concentration for spring digestibility and lignin concentration in NDF for autumn digestibility.

Analysis of Kenya’s Atmospheric Moisture Sources and Sinks

Abstract Achievement of the United Nations Sustainable Development Goals (SDGs) is contingent on understanding the potential interactions among human and natural systems. In Kenya, the goal of conserving and expanding forest cover to achieve SDG 15 “Life on Land” may be related to other SDGs because it plays a role in regulating some aspects of Kenyan precipitation. We present a 40-yr analysis of the sources of precipitation in Kenya and the fate of the evaporation that arises from within Kenya. Using MERRA-2 climate reanalysis and the Water Accounting Model 2 layers, we examine the annual and seasonal changes in moisture sources and sinks. We find that most of Kenya’s precipitation originates as oceanic evaporation but that 10% of its precipitation originates as evaporation within Kenya. This internal recycling is concentrated in the mountainous and forested Kenyan highlands, with some locations recycling more than 15% of evaporation to Kenyan precipitation. We also find that 75% of Kenyan evaporation falls as precipitation elsewhere over land, including 10% in Kenya, 25% in the Democratic Republic of the Congo, and around 5% falling in Tanzania and Uganda. Further, we find a positive relationship between increasing rates of moisture recycling and fractional forest cover within Kenya. By beginning to understand both the seasonal and biophysical interactions taking place, we may begin to understand the types of leverage points that exist for integrated atmospheric water cycle management. These findings have broader implications for disentangling environmental management and conservation and have relevance for large-scale discussions about sustainable development.

Location and seasonal effects on sugarcane smut and implications for resistance breeding in South Africa

Smut, Sporisorium scitamineum (Syd.) (formerly Ustilago scitamineum), is a major disease of sugarcane causing cane yield losses of 0.25 to 0.75% for every 1% of infected stools. Breeding resistant cultivars is part of integrated smut management. The objective of this study was to determine the effects of locations and seasons on smut infection genotype in irrigated sugarcane breeding trials. Data for smut-infected stools and smut whips collected from early and late season trials at Pongola (NPG) and Mpumalanga research stations (MP) were analysed using linear mixed models. There were significant (p < 0.001) location, season, location by season, genotype, genotype by location, genotype by season and genotype by location by season interaction effects for infected stools and whips. Broad sense heritability in late season trials averaged 0.89 compared to 0.61 in early season, while that for MP (0.79) was higher than for NPG (0.69) indicating higher selection efficiency for smut resistance in late season MP trials. Genotypes had significantly (p < 0.001) higher infected stools and whips at MP than at NPG and in late than early season trials. Smut-screening using MP late season trials will increase efficiency of breeding for smut resistance in South Africa.

Mega-environment analysis of maize breeding data from Brazil

The development and recommendation of single cross maize hybrids (SH) to be used in extensive land areas (mega-environments), and in different crop seasons requires many experiments under numerous environmental conditions. The question we asked is if the data from these multi-environment experiments are sufficient to identify the best hybrid combinations. The aim of this study was to critically analyze the phenotype data of experiments of yield, established by a large seed producing company, under a high level of imbalance. Data from evaluation of 2770 SH were used from experiments conducted over four years, involving the first and second crop seasons, in 50 locations of different years and regions of Brazil. Different types of analysis were carried out and genetic and non-genetic components were estimated, with emphasis on the different interactions of the SH with the environments. Results showed that the coincidence of common hybrids in these experiments is normally small. The estimates of the correlations between of the hybrids coinciding in the environments two by two is of low magnitude. The hybrid × crop season interaction was always expressive; however, the interactions of hybrids and other environmental variables were also important. Under these conditions, alternatives were discussed for making with the information obtained from the experiments, can be more efficient on the process to obtain new hybrids by companies.

Complex tourism and season interactions contribute to disparate physiologies in an endangered rock iguana.

To promote survival and fitness, organisms use a suite of physiological systems to respond to both predictable and unpredictable changes in the environment. These physiological responses are also influenced by changes in life history state. The continued activation of physiological systems stemming from persistent environmental perturbations enable animals to cope with these challenges but may over time lead to significant effects on the health of wildlife. In the present study, we tested how varying environmental perturbations driven by tourism and associated supplemental feeding affects the energetics, corticosterone and immunity of six discrete populations of the northern Bahamian rock iguana (Cyclura cychlura inornata and Cyclura cychlura figginsi). We studied populations within and outside the reproductive season and quantified tourist numbers during sample collection. Specifically, we measured clutch size, body condition, plasma energy metabolites, reactive oxygen species, baseline corticosterone concentrations and immune function of male and female iguanas from each population to address whether (i) disparate physiologies are emerging across a gradient of tourism and feeding, (ii) both subspecies respond similarly and (iii) responses vary with season/reproductive condition. We found significant effects of tourism level, season and their interaction on the physiology of both C. c. inornata and C. c. figginsi, supporting the idea that tourism is leading to the divergence of phenotypes. Specifically, we found elevated plasma energy metabolites, oxidative stress and a measure of innate immunity (bactericidal ability), but reduced corticosterone concentrations with increasing tourism in both subspecies of rock iguanas. These physiological metrics differ according to the level of tourism in both subspecies and persist across seasons despite variation with natural seasonal and reproductive changes. These findings suggest that anthropogenic disturbance results in disparate physiologies in northern Bahamian rock iguanas.

Spatial and seasonal distribution of Ostracoda in a lagoonal environment along the northeastern coast of India: Implications to assess coastal ecology and paleoenvironment

Variable seasonal interaction of both fresh and marine waters in lagoon ecosystems generally creates salinity gradients, which significantly impact the microhabitat of the benthos. This study assessed the spatial-seasonal abundance and diversity of ostracods along the salinity gradient of Chilika Lagoon (India) by seasonally collecting substrate sediment from twenty-two fixed stations along with the environmental parameters of lagoon-bottom water in Asia's largest brackish water lagoon. The samples were analyzed for living and dead ostracod species abundance, diversity and correlated with environmental parameters. The river mouth proximal region having sandy silt substrate under low energy conditions and high total organic carbon, had a higher abundance of low salinity tolerant ostracod species. The interior region of the lagoon showed a high abundance and diversity of variable salinity tolerant brackish water species, with a high proportion of dead specimens. In the region proximal to the sea mouth that is influenced by high energy conditions and sandy substrate, ostracod abundance and diversity are low, and only a few very high salinity tolerant ostracod species are found. Canonical correspondence analysis in addition to environmental preferences of living ostracod species and articulated valve abundance suggest environment-specific ostracod assemblages, consistent with the traditional use of ostracod species as a proxy to reconstruct paleo coastal ecology and paleoenvironment.

Thyroid hormone levels in Tortoises (Testudo spp.) depending on Season and Sex

Thyroid hormones and the factors influencing them are rarely studied in tortoises. This study therefore aimed to calculate reference intervals (RI) for specific species, sexes, and seasons for thyroid hormones and iodine levels in blood of four adult Mediterranean tortoise species and to evaluate possible correlations between thyroid hormones, serum iodine, plasma protein and increased liver and kidney values. Thyroid hormones (total tetraiodothyronine [tT4], free tetraiodothyronine [fT4], total triiodothyronine [tT3], and free triiodothyronine [fT3]) were measured in plasma from adult, healthy Hermann´s (Testudo hermanni, n = 255), spur-thighed (Testudo graeca, n = 89), marginated (Testudo marginata, n = 72), and Russian tortoises (Testudo horsfieldii, n = 30). Species, sex and season specific variations were determined by Bayesian information criterion (BIC) and correlations between plasma thyroid hormones, protein, iodine and increased liver/kidney values were evaluated by Spearman’s rank correlation test. Total T4 did not reveal any species, sex, or seasonal differences (RI 0.102 to 0.455 µg/dL), while seasonal differences were found for fT4 (RI spring 0.624 to 9.012; summer 0.379 to 5.476; fall 0.376 to 5.426 pmol/L). The tT3 levels differed significantly depending on species, season, and the interaction of species x season. Seasonal differences were also found for fT3 and iodine. Several significant (p &amp;lt; 0.05) correlations were detected between the tested analytes, especially positive correlations between tT4 and fT4. These results provide a tool for the evaluation of thyroid hormone levels in Mediterranean tortoises and indicate the influence of season on the thyroid in these animals.