Interactions Between Environment and Genetic Diversity in Perennial Grass Phenology: A Review of Processes at Plant Scale and Modeling

In perennial grasses, the reproductive development consists of major phenological stages which highly determine the seasonal variations of grassland biomass production in terms of quantity and quality. The reproductive development is regulated by climatic conditions through complex interactions subjected to high genetic diversity. Understanding these interactions and their impact on plant development and growth is essential to optimize grassland management and identify the potential consequences of climate change. Here, we review the main stages of reproductive development, from floral induction to heading, i.e., spike emergence, considering the effect of the environmental conditions and the genetic diversity observed in perennial grasses. We first describe the determinants and consequences of reproductive development at individual tiller scale before examining the interactions between plant tillers and their impact on grassland perenniality. Then, we review the available grassland models through their ability to account for the complexity of reproductive development and genetic × environmental interactions. This review shows that (1) The reproductive development of perennial grasses is characterized by a large intraspecific diversity which has the same order of magnitude as the diversity observed between species or environmental conditions. (2) The reproductive development is determined by complex interactions between the processes of floral induction and morphogenesis of the tiller. (3) The perenniality of a plant is dependent on the reproductive behavior of each tiller. (4) Published models only partly explain the complex interactions between morphogenesis and climate on reproductive development. (5) Introducing more explicitly the underlying processes involved in reproductive development in models would improve our ability to anticipate grassland behavior in future growth conditions.

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Calibration of LgrassFlo, a new model of perennial grass phenology in response to temperature and photoperiod.

10.5194/egusphere-egu21-12430 ◽

2021 ◽

Author(s):

Simon Rouet ◽

Jean-Louis Durand ◽

Didier Combes ◽

Abraham Escobar-Gutierrez ◽

Romain Barillot

Keyword(s):

Genetic Diversity ◽

Plant Architecture ◽

Floral Induction ◽

Perennial Grass ◽

Heading Date ◽

Reproductive Development ◽

Perennial Grasses ◽

Floral Transition ◽

New Model ◽

Primary Induction

In perennial grasses, the reproductive development encompasses several phenological events, such as apex induction, floral transition, heading and flowering, that deeply affect biomass production, forage quality and plant perenniality. Despite the importance of perennial grasses in agricultural systems and natural ecosystems, we still lack accurate models predicting the reproductive development and its consequences on plant growth and grassland management. Most of available models implements a fixed scheduling of the reproductive development expressed either in thermal time or in calendar time. The progressive completion of floral induction and the effects of environmental factors are generally poorly described. In addition, the vegetative and reproductive developments are represented as independent and successive phases. In the present work, we introduce the new model LgrassFlo, which simulates the reproductive development of perennial grasses in interaction with plant vegetative development and considering the effects of environmental conditions on floral induction.LgrassFlo simulates the canopy as the dynamics of a collection of individual plants, each being composed of one or more tillers. The 3D description of leaf growth and tillering is based on a functional-structural plant model of perennial ryegrass (Lgrass). We developed a new model of floral induction describing the progression of the primary and secondary induction of each apex of the plant according to (i) the daily temperature, (ii) photoperiod and (iii) plant architecture. This model was coupled to Lgrass, the model ensemble being called LgrassFlo. During apex induction, LgrassFlo accounts for an increase in the rates of leaf primordia initiation and leaf elongation. After floral transition, we assume that the apex only initiates spikelet primordia and that internodes start to elongate. LgrassFlo simulates the date of floral transition, the final number of leaves and the heading date based on a 3D representation of plant architecture.A specific experiment was carried out in order to calibrate LgrassFlo on data describing the vegetative and reproductive development of three Lolium perenne cultivars contrasted for their precocity and exposed to four inductive conditions in growth chambers. The first three conditions consisted in a period allowing for primary induction (low temperature &#8211; short day) followed by a period allowing for secondary induction (high temperature &#8211; long day), the two periods being spaced by a non-inductive period (high temperature - short day) of 0, 3 or 6 weeks. In the fourth condition, plants were not exposed to conditions allowing for the primary induction. A set of vegetative and reproductive parameters were estimated for each individual plant of the experiment. The parameter values were independent of the experimental treatment but showed a large genetic diversity both between and within varieties. Using this calibration, LgrassFlo satisfactorily predicted the observed diversity in final leaf number and heading date.The present model is a step forward towards a better prediction of perennial grass phenology in actual and future climatic conditions. In this respect, the model is being currently used to simulate the observed genetic diversity in the heading date of several Lolium perenne cultivars grown in contrasted temperate climates over the last 15 years.

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Genetic Diversity and Structure of Latvian Tilia cordata Populations

Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. ◽

10.2478/prolas-2021-0039 ◽

2021 ◽

Vol 75 (4) ◽

pp. 261-267

Author(s):

Dainis Edgars Ruņģis ◽

Baiba Krivmane

Keyword(s):

Genetic Diversity ◽

Microsatellite Markers ◽

Vegetative Reproduction ◽

Growth Conditions ◽

Climatic Conditions ◽

Tilia Cordata ◽

High Genetic Diversity ◽

Genetic Diversity And Structure ◽

Broadleaf Tree ◽

Broadleaf Species

Abstract Changing climatic conditions are transforming the ecological and silvicultural roles of broadleaf tree species in northern Europe. Small-leaved lime (Tilia cordata Mill.) is distributed throughout most of Europe, and is a common broadleaf species in Latvia. This species can tolerate a broad range of environmental and ecological conditions, including temperature, water availability, and soil types. The aim of this study was to assess the genetic diversity and differentiation of Latvian T. cordata populations using nuclear microsatellite markers developed for Tilia platyphyllos. After testing of 15 microsatellite markers, Latvian T. cordata samples were genotyped at 14 micro-satellite loci. Latvian T. cordata populations had high genetic diversity, and were not overly isolated from each other, with moderate gene flow between populations. No highly differentiated populations were identified. Vegetative reproduction was identified in most analysed populations, and almost one-third of analysed individuals are of clonal origin. T. cordata has high timber production potential under the current climatic and growth conditions in Latvia, and therefore this species has potential for use in forestry, as well as playing a significant role in maintaining biodiversity and other ecosystem services.

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Aggressiveness Changes in Populations of Didymella pinodes over Winter and Spring Pea Cropping Seasons

Applied and Environmental Microbiology ◽

10.1128/aem.00480-16 ◽

2016 ◽

Vol 82 (14) ◽

pp. 4330-4339 ◽

Cited By ~ 5

Author(s):

G. Laloi ◽

J. Montarry ◽

M. Guibert ◽

D. Andrivon ◽

D. Michot ◽

...

Keyword(s):

Genetic Diversity ◽

Ascochyta Blight ◽

Growing Season ◽

Climatic Conditions ◽

Single Population ◽

High Genetic Diversity ◽

Content Type ◽

Didymella Pinodes ◽

Pathogenicity Tests ◽

Cropping Seasons

ABSTRACTAscochyta blight, caused by the necrotrophic ascomyceteDidymella pinodes, is responsible for severe losses in winter and spring pea crops. Despite different climatic conditions, epidemics on winter and spring crops are due to a single population ofD. pinodes, suggesting gene flow either between the two crops or from reservoir sources during the cropping season. This should lead to similar pathogenicity characteristics in isolates sampled from the two crops. However, these hypotheses have never been formally tested. We therefore sampled a total of 520D. pinodesstrains throughout a growing season from winter and spring pea plots (WP and SP, respectively) and from winter and spring trap plants (TWP and TSP). Amplified fragment length polymorphism (AFLP) markers revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic. These results support the idea that alloinoculum contributes to the carryover of epidemics between winter and spring crops and that the most aggressive isolates are selected as an epidemic progresses.IMPORTANCEAscochyta blight, caused byDidymella pinodes, is responsible for severe losses in pea crops. While previous studies have shown that ascochyta blight epidemics on winter and spring crops are due to a single population ofD. pinodes, suggesting that isolates from the two crops present similar pathogenicity characteristics, that hypothesis have never been tested. Genetic analysis of subpopulations sampled throughout a growing season from winter and spring pea plots revealed high genetic diversity within subpopulations, whereas pathogenicity tests showed that mean aggressiveness increases over the course of an epidemic.

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Browsing herbivores improve the state and functioning of savannas: a model assessment of alternative land use strategies

10.22541/au.162682707.72443437/v1 ◽

2021 ◽

Author(s):

Katja Irob ◽

Niels Blaum ◽

Selina Baldauf ◽

Leon Kerger ◽

Angelina Kanduvarisa ◽

...

Keyword(s):

Land Use ◽

Perennial Grass ◽

Climatic Conditions ◽

Perennial Grasses ◽

Unexpected Result ◽

Model Assessment ◽

Grass Cover ◽

Livestock Farming ◽

Erosion Risk ◽

Feeding Regimes

Changing climatic conditions and unsustainable land use are perceived as major threats to savannas worldwide. In the past, land use in African savannas was dominated by livestock-farming as one of the major economic products, which led to degraded, shrub encroached pastures in many regions. One response to this widespread degradation is a shift from land use dominated by cattle to strategies characterized by animal compositions with more mixed feeding regimes and higher browser proportions. However, the consequences for ecosystem properties and processes remain so far largely unclear. We used the ecohydrological, spatially explicit savanna model EcoHyD to assess the impacts of two contrasting, herbivore-related land use strategies on a Namibian savannah: grazing versus browsing herbivores. We varied the densities of grazers and browsers and determined the resulting composition and diversity of the plant community, total vegetation cover, soil moisture and water use by plants. Our results show that properties making plants less attractive to herbivores were best adapted to different densities of grazing (cattle) or browsing (pure browsing wildlife) animals. Also, properties leading to a competitive advantage under limited water availability were among the dominant ones. Overall, the results are in line with our expectations: we found heavy shrub encroachment with a loss of the perennial grass matrix under high stocking rates of cattle. A novel and unexpected result was that regardless of the density of browsers, grass cover and plant functional diversity were significantly higher in wildlife scenarios. This increased grass cover, but also the higher total cover improved water uptake by plants. We conclude that in contrast to grazers, browsers even in high densities do not lead to ecosystem degradation, but rather sustain a diverse vegetation with high cover of perennial grasses over a long time, implying also a lower erosion risk and higher provision of ecosystem services.

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Macropods, feral goats, sheep and cattle. 2. Equivalency in what and where they eat

The Rangeland Journal ◽

10.1071/rj19059 ◽

2019 ◽

Vol 41 (6) ◽

pp. 519 ◽

Cited By ~ 2

Author(s):

Lester Pahl

Keyword(s):

Diet Composition ◽

Perennial Grass ◽

Climatic Conditions ◽

Perennial Grasses ◽

The Other ◽

Green Leaf ◽

Wide Range ◽

Annual Grasses

The extent to which sheep, cattle, feral goats, red kangaroos, western grey kangaroos, euros and eastern grey kangaroos are equivalent in their use of the Australian southern rangelands is partly dependent on the extent to which their diets and foraging areas overlap. These herbivores all eat large amounts of green annual grasses, ephemeral forbs and the green leaf of perennial grasses when they are available. Overlap in use of these forages by all seven herbivores is concurrent and high. As the abundance of these preferred forages declines, sheep, cattle and feral goats consume increasing amounts of mature perennial grasses and chenopod and non-chenopod perennial forbs. Red kangaroos and western grey kangaroos continue to graze mature perennial grasses longer than sheep, cattle and feral goats, and only switch to perennial forbs when the quantity and quality of perennial grasses are poor. Consequently, overlap in use of perennial forbs by sheep, cattle, feral goats, red kangaroos and western grey kangaroos is sequential and moderately high. When palatable perennial forbs are eaten out, the diets of all herbivores except feral goats comprise predominantly dry perennial grass, and overlap is again concurrent and high. In comparison, feral goats have higher preferences for the browse of a wide range of shrubs and trees, and switch to these much earlier than the other herbivores. When perennial grasses and perennial forbs become scarce, sheep, feral goats and cattle browse large shrubs and trees, and overlap is sequential and high. If climatic conditions remain dry, then red and western grey kangaroos will also browse large shrubs and trees, but overlap between them, sheep, cattle and goats is sequential and low. In contrast to the other herbivores, the diets of euros and eastern grey kangaroos are comprised predominantly of perennial grasses, regardless of climatic conditions. As for diet composition, concurrent overlap in foraging distributions of sheep, cattle, feral goats and the four species of macropods is often low. However, over periods of several months to two or three years, as climatic conditions change, overlap in foraging distributions is sequential and high. While equivalency in what and where these herbivores eat is not quantifiable, it appears to be high overall. This is particularly so for perennial grass, which is the dominant forage for herbivores in the southern rangelands.

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GENETIC DIVERSITY OF BROILER CHICKEN BRANDS RAISED IN ARID AND SEMI-ARID ZONES OF NORTHERN NIGERIA USING MITOCHONDRIAL DNA

FUDMA Journal of Sciences ◽

10.33003/fjs-2021-0502-650 ◽

2021 ◽

Vol 5 (2) ◽

pp. 456-461

Author(s):

A. Y. Abdullahi ◽

M. Nasir ◽

A. G. Khalee ◽

R. M. Ashiru ◽

H. M. Zango ◽

...

Keyword(s):

Genetic Diversity ◽

Mitochondrial Dna ◽

Rural Areas ◽

Dna Analysis ◽

Haplotype Diversity ◽

Climatic Conditions ◽

Arid Zones ◽

High Genetic Diversity ◽

Hot Dry Season ◽

Semi Arid

A sector of broiler production is growing very fast to meet the high demand of meat in Nigeria. However, high mortality rates among the broilers especially during the hot dry season in arid and semi-arid zones is worrisome. There is a need for molecular genetics study that could aid in management, conservation and sustainable exploitation of this species. To evaluate the genetic diversity of broilers raised in these regions, a total of forty-six broilers were randomly sampled from eight different brands (Agrited, Amo, Chi, Fol-hope, Obasanjo, Olam, Yammfy and Zatech) for mitochondrial DNA analysis. Four haplotypes were detected among all the samples used that belong to the four strains. The sequences of mitochondrial regions revealed high haplotype diversity (0.78600) and low nucleotide diversity (0.00286). Lower genetic diversity observed may increase the chances of rapid disease infection and distribution during any disease outbreak. Introduction of new strains of broilers with high genetic diversity is highly recommended. Future study should be conducted on the performance of these strains during the extremely hot temperature period in arid and semi-arid zones of Nigeria. This is to provide reliable information for the sake of local broiler farmer’s benefit who invests largely on this sector. The study will also help the geneticists from these brands to develop a strain that could survive and perform excellently under severe climatic conditions of the rural areas of arid and semi-arid zones of Nigeria

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Statistical analysis of genetic diversity using faba bean landraces database

Agricultural Science and Technology ◽

10.15547/ast.2020.03.033 ◽

2020 ◽

Vol 12 (3) ◽

pp. 211-215

Author(s):

N. Velcheva ◽

S. Petrova

Keyword(s):

Genetic Diversity ◽

Cluster Analysis ◽

Faba Bean ◽

Plant Genetic Resources ◽

Sustainable Use ◽

Climatic Conditions ◽

Ex Situ ◽

Breeding Value ◽

High Genetic Diversity ◽

Breeding Programs

Abstract. Evaluation of genetic diversity among landraces could be an invaluable aid related to the sustainable use of ex situ collections. Statistical methods are currently available for analysis of databases from investigation of stored germplasm. Faba bean (Vicia faba L.) is a self-pollinating with high percentage of foreign pollination legume crop with a great importance for food and forage due to its high protein content as well as the important role in soil fertility and nitrogen fixation. The local populations are well adapted to specific agro-climatic conditions in the growing areas and are a rich initial material for the breeding programs. The purpose of this study is to establish the genetic diversity of 21 Bulgarian faba bean landraces by important traits in order to review the current potential of conserved germplasm for its sustainable use. All genotypes, included in the study, are collected from expeditions in the country, recorded in the National Register for Plant Genetic Resources and long term stored at the National Genebank. They are characterized according to the International Faba Bean Descriptors. The cluster analysis results show a high genetic diversity in the collection and the variability of each studied trait is presented. The factor analysis, which complements the cluster analysis, gives a reason to group the genotypes with their features into groups that have a breeding value. Genetic diversity in the studied collection has been identified and some of the landraces could be included in future breeding programs.

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Germination rates of old and fresh seeds and their implications on invasiveness of the ornamental Canary Islands date palm (Phoenix canariensis)

European Journal of Ecology ◽

10.17161/eurojecol.v6i2.13474 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Dirk HR Spennemann ◽

Melissa Pike ◽

Wayne Robinson

Keyword(s):

Experimental Data ◽

Genetic Diversity ◽

Environmental Factors ◽

Canary Islands ◽

Environmental Conditions ◽

Seasonal Variations ◽

Date Palm ◽

Present Stage ◽

High Genetic Diversity ◽

Phoenix Canariensis

In many countries, Canary Islands Date Palms (Phoenix canariensis) have escaped their horticulturally managed settings and have commenced to colonise surrounding natural bushland. While dispersed by various vectors, both birds and canids such as foxes, fluctuating environmental conditions may inhibit germination in the season of deposition. The potential of old, previous season’s seeds to germinate when conditions turn favourable has direct implications on the plant’s ability to establish viable, colonising populations. Nothing is known about the ability of older, previous season’s seeds to successfully germinate. Based in experimental data, this paper shows that that the seeds of Phoenix canariensis exhibit both substantial inter-specimen and inter-seasonal variations in their germination potential. The observed variability is caused by the high genetic diversity inherent in a given palm population, as well as by range of environmental factors. At the present stage it is impossible to separate these two. Directions for further research are outlined.

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