Half-sib Lines Research Articles

Varijabilnost i diskriminacijska moć anatomskih parametara kod linija polusrodnika juglans regia podrijetlom iz prirodnih sastojina u Đerdapskoj klisuri, Srbija u rasadničkim uvjetima

This paper presents analysis of anatomical parameters of leaves in Juglans regia half-sib lines from natural stands in Đerdap Gorge in Serbia. Thirty-five half-sib lines were examined, designated according to the number of their mother trees from R1-R35. Twenty measured and derived anatomical parameters were examined, describing stomatal and leaf blade cross-section traits. According to Hierarchical analysis of variance, variation of the majority of characters describing stomatal properties were significantly affected by effect of half-sib lines. The effect of variation between plants within half-sib lines was significant for all examined stomatal traits. However, in cross-section characters, the effect of differences between half-sib lines was significant only for thickness of spongy mesophyll (SL). The discrimination model with seven selected traits achieved 60.5% of correct allocation, while the correct allocation of the model with all 20 examined traits was 81.6%. According to the results of stepwise discriminant analysis, the most powerful trait in discrimination of these half-sib lines were stomatal aperture width/stomatal aperture length ratio (Wb/La) and stomatal aperture length/ stomata guard cell length ratio (La/LA). Presented results strongly support implementation of stomatal and cross-section leaf traits in further studies that would deal with description of variability of Juglans regia.

Assessment of the phenotypic diversity of wild cherry (Prunus avium L.) populations and halfsib lines by multivariate statistical analyses

Abstract Wild cherry (Prunus avium L.) is a multi-purpose tree species with great ecological and economic importance for European forestry. Evaluating this species phenotypic diversity and quantitative traits characterization is of great importance to define its genetic resources conservation and breeding strategies. In this work, variations of physiological, biochemical, anatomical and morphological traits of one-year-old wild cherry seedlings were evaluated within and among populations to distinguish and characterize their phenotypic portfolio. We observed significant differences at the intra- and inter-population levels considering both biochemical and physiological leaf traits, whereas differences in morphological and anatomical traits were found to be significant only among half-sib lines within populations (i.e. intra-population level). With a multivariate approach, we explored the inter-population specificity and found out that the tiered approach spanning from organ morphology, across physiological scale, to the biochemical level gave out enough power to discriminate between different populations, and their acquisition and resource-use strategies. Moreover, stepwise discriminative analysis showed that radical scavenger capacity against 2,2’-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS•+) and water-use efficiency contributed to discrimination of studied populations to the largest extend. Lastly, our study highlights the robustness of certain functional traits, such as ABTS•+, water-use efficiency, net photosynthesis, total flavonoid content, width of stomata guard cell, and stomatal aperture length, which could be considered as a proxy to discriminate between wild cherry populations and assess phenotypic diversity.

Varijabilnost svojstava sadnica kitnjaka (Quercus petraea (Matt.) Liebl) sa Područja PIO "Avala"

The research of the variability within the population based on morphometric characteristics of seedlings had been conducted to preserve the available gene pool of the Sessile oak population located in the Area of Outstanding Natural Landscape (AONL) "Avala" and the controlled use of the genetic resources. Fifty best-quality trees based on the phenotypic characteristics, the carriers of the Sessile oak (Quercus petraea (Matt.) Liebl) reproductive material production were selected at the population level. Approximately 3 kg of apparently healthy and undamaged acorns were collected from each tree, separated by mother trees, and used for seedling production in the nursery under uniform environmental conditions. The root collar diameter and the height of the randomly selected 50 seedlings per half-sib line were measured at the end of the first growing season, and the sturdiness quotient was calculated based on the measured values. The obtained mean values of the morphometric characteristics indicate a high variability among the tested genotypes. This is also confirmed by the analysis of variance which determined statistically significant differences between the analyzed half-sib lines for all observed morphometric characteristics. The obtained results represent a good starting point for future research on breeding, long-term preservation, and improvement of the ecological adaptability and evolutionary potential of the Sessile oak population by applying adequate in-situ and ex-situ conservation measures. Based on the research results, it can be recommended to use this important species for reintroduction in optimal microclimatic conditions, as well as for the selection of the best individuals for reintroduction.

Variability of morphological parameters of one- and two-year-old seedlings of different sessile oak half-sib lines

This research aimed to determine the variability of the part of the sessile oak gene pool from the area of the Natural Monument ?Kosutnjak Forest? at the level of one- and two-year-old seedlings, in the progeny test established in the nursery of the Faculty of Forestry. The research was conducted with one-year-old and two-year-old seedlings of 10 half-sib lines of the sessile oak. The heights and root collar diameters were measured, and the survival of the seedlings at the end of the second growth period, as well as the annual height and diameter growth, were determined. The results of descriptive statistics, one-way analysis of variance and Fisher?s least significant differences test, as well as multivariate analyzes - cluster and analysis of the main components were also presented in the research. The obtained results indicate a satisfactory level of genetic variability, which represents a good starting point for the realization of ex situ conservation of part of the gene pool, by establishing a field trial in the area of Kosutnjak and/or by introducing seedlings in smaller or larger groups to this area. In this way, part of the gene pool of the starting population, represented by seedlings of different half-sib lines, is permanently preserved, the number of the starting population increases, and conditions are created for continuous scientific and research work.

Genetic differentiation in functional traits among wild cherry (Prunus avium L.) half-sib lines

Understanding intra-specific variation in leaf functional traits is one of the key requirements for the evaluation of species adaptive capacity to ongoing climate change, as well as for designing long-term breeding and conservation strategies. Hence, data of 19 functional traits describing plant physiology, antioxidant properties, anatomy and morphology were determined on 1-year-old seedlings of wild cherry (Prunus avium L.) half-sib lines. The variability within and among half-sib lines, as well as the estimation of multi-trait association, were examined using analysis of variance (ANOVA) followed by Tukey's honestly significant difference test and multivariate analyses: principal component analysis (PCA), canonical discriminant analysis (CDA) and stepwise discriminant analysis (SDA). Pearson’s correlation coefficient was used to evaluate linear correlation between the study parameters. The results of the ANOVA showed the presence of statistically significant differences (P < 0.01) among half-sib lines for all study traits. The differences within half-sib lines, observed through the contribution of the examined sources of variation to the total variance (%), had higher impact on total variation in the majority of the examined traits. Pearson’s correlation analysis and PCA showed strong relationships between gas exchange in plants and leaf size and stomatal density, as well as between leaf biomass accumulation, intercellular CO2 concentration and parameters related to antioxidant capacity of plants. Likewise, the results of SDA indicate that transpiration and stomatal conductance contributed to the largest extent, to the discrimination of the wild cherry half-sib lines. In addition, PCA and CDA showed separation of the wild cherry half-sib lines along the first principal component and first canonical variable with regards to humidity of their original sites. Multiple adaptive differences between the wild cherry half-sib lines indicate high potential of the species to adapt rapidly to climate change. The existence of substantial genetic variability among the wild cherry half-sib lines highlights their potential as genetic resources for reforestation purposes and breeding programmes.

The growth of one-year-old narrow-leaved ash seedlings is strongly related to the leaf area parameters

The leaf area of plant leave scan be considered as an indicator of the plant growth conditions, and its variability is usually associated with adaptation and response to the changing environment. The aim of this study is to investigate the relation of the leaf area parameters on growth of the narrow-leaved ash 1+0 seedlings from the nursery trial and determining variability between the 18 half-sib lines. The seedlings were obtained from seeds collected from 18 maternal trees found in the area of the special nature reserve Upper Danube Region. Ten randomly selected 1+0 seedlings per half-sib line were selected for further study, and all leaves per seedling were collected, herbarized and scanned. The leaf area of each leaf (LACL) was measured using an open-source image processing program – ImageJ, and the total leaf area per seedling (TLA) was calculated. Also, the number of leaves per plant (NCL) as well as the number of leaflets within each imparipinnate compound leaf (NLCL) were counted. The results showed that differences between studied attributes were statistically significant among 18 selected half-sib lines (p &lt; 0.05). The most variable parameter was the total leaf area per seedling (TLA; CV=68.98%), which is strongly correlated to the leaf area per each leaf (LACL; r=0.95) and the number of leaflets (NLCL; r=0.94). In this study, we confirmed that leaf parameters were highly correlated to the growth of one-year-old Fraxinus angustifolia seedlings.

The Role of Population and Half-Sib Family on Driving Suitable Functional Traits for Quercus suber L. Forest Restoration

Research Highlights: Seedlings of different Quercus suber L. populations and half-sib families differ in their response to multiple stressors, which may have consequences on the future distribution of this Mediterranean species. Background and Objectives: Global change will likely increase the frequency and severity of drought in drylands. Plant species’ distributions will largely depend on their ability to respond to the combined effect of drought and other environmental stressors. Genetic diversity in morpho-functional traits are key components of this response. Yet, information on the response to multiple stresses is scarce for many iconic species. The present study assessed the variability in the response of populations and half-sib families of a Mediterranean acidophilous tree, cork oak, to drought and changes in soil conditions. Materials and Methods: We sampled acorns of half-sib families from two cork oak populations genetically introgressed with the alkaline-tolerant species Quercus ilex L., and from a non-introgressed cork oak population located in its core habitat. We germinated the acorns and subjected seedlings to contrasted levels of water availability and additions of calcium and magnesium carbonate, and assessed their morpho-physiological response. Results: Response to drought and soil chemistry composition differed between populations and families. For some traits, introgressed populations responded similarly to drought than the non-introgressed population. Conversely, the response to soil chemistry was not clearly related to introgression. When considering half-sib families within populations, the population effect diminished, which revealed the importance of intra-population variation. However, relevant traits for water scarcity adaptations, such as specific leaf area and root:shoot ratio, remained significantly different at the population level, which highlights the relevance of these traits for management. Conclusions: Our study shows that the adaptive management and restoration of cork oak forests should consider not only geographic provenances, but also half-sib lines within populations.

Half-Sib Lines of Pedunculate Oak (Quercus robur L.) Respond Differently to Drought Through Biometrical, Anatomical and Physiological Traits

Quercus robur L. is one of the most valued tree species of deciduous temperate forests. However, in the last decade, serious oak declines and loss of adaptation plasticity have been reported throughout Europe as a consequence of drought. Therefore, the aim of the present study was to define the adaptation potential of five Q. robur half-sib lines from the UNESCO Biosphere Reserve Mura-Drava-Danube to drought, using physiological, anatomical and biometrical traits. Half-sib lines that exhibited drought tolerance had particular suites of trait expression regarding biometrical traits (seedling height, root length, root to shoot ratio of dry mass and specific leaf area), leaf stomatal traits (stomatal density per mm2, stomata guard cell length and width, stomatal aperture length and width) and leaf structural traits (adaxial epidermis thickness, palisade parenchyma thickness, spongy parenchyma thickness, lamina thickness). All of the observed parameters of chlorophyll a fluorescence were shown to be good indicators of short-term and severe drought. For the selection of drought-tolerant half-sib lines, all studied chlorophyll a fluorescence parameters associated with the heat dissipation of light energy (coefficient of non-photochemical quenching, quantum yield of regulated energy dissipation, Stern-Volmer type non-photochemical fluorescence quenching) and one parameter related to photochemical dissipation of light energy (effective quantum yield (efficiency) of PS II photochemistry) were proven to be suitable. On the other hand, the coefficient of photochemical quenching, coefficient of photochemical fluorescence quenching assuming interconnected photosystem II antennae and electron transport rate were not suitable for distinguishing the different responses of the studied half-sib lines under drought. The importance of results of the present study is in the selection of drought-tolerant Q. robur half-sib lines for future reforestation programs, particularly in protected areas with sensitive forest management and restricted activities for mitigation of the adverse effects of climate changes.

Constitution of Composite Cross Maize (Zea mays L.) Populations Selected for the Semi-Arid Environment of South Madagascar

In many African countries, such as Madagascar, a large part of the population is currently estimated to be undernourished, and self-subsistence agriculture represents the primary source of food available for the family. Smallholder farmers cultivate crops with limited agricultural input and use old landraces or obsolete hybrid varieties, with a total country-wide production that is far from being able to sustain the national food demand. In this study, we have developed two maize composite cross populations (CCPs) of different kernel colors, through a selection process among 30 half-sib lines, chosen both for their agronomic performance and their environmental adaptability to a Malagasy farm context. The best half-sib lines, identified through field tests, were clustered as a parental group for open-pollinated crosses. The new CCP created, after two years of seed multiplication in an open field, showed promising yields compared with the hybrids, parental varieties, and local landraces, with average values of 2.7 t/ha for the white CCP and 3.5 t/ha for the yellow one. The seeds produced were then distributed among 15 local farmers to begin a participatory breeding program. Our approach represents an innovative step to improve and stabilize maize yields, employing populations adapted to the cultivation environment and able to cope with different stresses, thereby helping farmers’ life conditions.

The use of physiological, biochemical and morpho-anatomical traits in tree breeding for improved water-use efficiency of Quercus robur L.

Aim of study: In the present paper the nature and level of co-dependence between leaf functional traits and intrinsic water-use efficiency (WUEi) were studied in one-year-old Quercus robur L. seedlings, grown in a common garden experiment under moderate drought conditions. The study was established to identify those traits that might potentially be utilized to improve leaf-level WUEi, and therefore be used in breeding programmes to enhance drought adaptation of Q. robur.Area of study: The study was carried out at the common garden site within the UNESCO Biosphere Reserve Mura-Drava-Danube.Material and methods: The study involved one-year-old seedlings of eight half-sib lines of Q. robur. Eighteen leaf parameters were analyzed; i.e. physiological, biochemical, morphological and anatomical. The data were processed using multivariate statistical methods: a) principal component analysis, b) stepwise regression analysis, and c) path coefficient analysis.Main results: The results showed that leaf stomata traits, particularly stomatal density (SD), and leaf dry mass per unit leaf area (LMA) were the most important traits, closely associated with WUEi. Stomatal density achieved the highest score on PC1 (0.825), in which WUEi had the highest loading (0.920), as well. SD was also included first in stepwise regression model.Research highlights: These results demonstrate that under moderate water stress WUEi in Q. robur half-sib lines were mainly the result of the plants’ structural acclimation to surrounding environmental conditions. Keywords: Quercus robur L.; half-sib line; intrinsic water-use efficiency; leaf functional traits.

The impact of drought on the physiological characteristics of half-sib lines of Turkey oak (Quercus cerris L.)

Two half-sib lines of Turkey oak (Quercus cerris L.) (C1 and C2) were subjected to different treatments in semi-controlled conditions: optimal soil moisture - control (K), drought followed by recovery after the restoration of the optimal soil moisture (T1) and the treatment of constant drought (T2). Changes in the physiological parameters related to the process of photosynthesis were examined in correlation with the applied treatments. Treatment T2 was influenced to a significant reduction in the intensity of photosynthesis, stomatal conductance and instantaneous water use efficiency, as well as to a significant increase in the intercellular CO2 concentration in both half-sib lines. In relation to control, treatment T2 did not lead to a significant variation in the maximum photochemical efficiency in the examined half-sib lines. In treatment T1, the second half-sib line (C2) showed better ability to recover the intensity of photosynthesis and stomatal conductance after re-watering, while using the same treatment before recovery, water was used more efficiently compared to the first half-sib line (C1). The results of the study indicate specific adaptive predispositions of the examined half-sib lines in relation to drought stress and recovery.

The effect of half-sib lines on morphological attributes of one-year old Fraxinus angustifolia seedlings

Aiming to produce forest reproductive material at the family level, we tested quality of twenty Fraxinus angustifolia Vahl half-sib lines in the nursery experiment. We measured height (HT) and root collar diameter (DIA) of one-year old seedlings, and we monitored germination rate and mortality during the first growing season. Seeds of 20 half-sib lines originating from Sombor area (north Serbia) were sown in seedbed on autumn 2016. The seed dormancy was not broken in all seeds equally, resulting with un-uniform germination over a two months period. All measured attributes shows a statistically significant differences, indicating a strong effect of genetic control. The highest average and DIA were measured in half-sib line 7 (22.62 cm; 5.79 mm, respectively). The lowest average DIA was measured in half-sib lines 18 (2.85 mm) and 19 (2.94 mm), which can be result of growing density effect (104 seedlings m-2 for line 18 and 126 seedlings m-2 for line 19, compared to 40 seedlings m-2 for line 7). The correlation between DIA and HT is strong and positive (R=0.90). Due to its morphological superiority, half-sib line 7 could be recommended for mass production of Fraxinus angustifolia seedlings at the family level.&#x0D; Keywords: Height; Root Collar Diameter; Seedlings Quality; Narrow leaved ash

THE IMPORTANCE OF WOODY PLANT INTRODUCTION FOR FOREST TREES IMPROVEMENT

The history of woody plant introduction is closely linked with that of transportationand the European exploration of the planet (16th–19th centuries). Each colonialpower established major botanical gardens and experimental stations in variousparts of the world. By the 20th century, the purpose of introductions shifted fromfood plants to timber and other species yielding non-agricultural products. Finally,during the latter part of the 20th century the importance of ornamental speciesincreased dramatically, especially to the more developed and wealthier regions.Over the past two centuries many species have started to spread in their introducedranges. Until relatively recently the majority of introduced woody species havebeen highly beneficial, if not essential, to humanity’s development, but now everincreasingnumbers of species are becoming detrimental to the maintenance of theearth’s biodiversity and to the well-being of human societies. Throughout the 19thand specially in 20th century the large-scale planting of trees for timber productionhas been one of the main reasons for the introductions of a large number of species,especially conifers e.g. Pinus, Picea. Pseudotsuga and Poplars and Willowsspecies. By using methods of mass and individual selection and by establishing ofprovenances tests, as well as by half and full sib lines of selected exotics test trees,genetical potential productivity and adaptability of introduced species have beentested in numerous experimental plots in areas where introduced have been done.This paper attempts to unravel the relationships between humans and woody plantsby looking at the changes in the introduction of species, the way they are perceivedby different human groups and the impact these non native species have on foresttrees improvement and other human activities.

NORWAY SPRUCE (Picea abies (L.) Karst.) SEEDLINGS SURVIVAL IN PROGENY TEST “DRINIĆ”

This paper presents the results of survival in progeny tests in the Republic of Srpska (Bosnia and Herzegovina).Four progeny tests of Norway spruce on sites: Drinić, Derventa, Nevesine and Srebrenica wereestablished on the territory of the Republic of Srpska in 2009. These progeny tests consist of six populations:Han Pijesak 1 and 2, Foča, Potoci, Olovo and Kneževo. The total number of half-sib lines was 36.In this paper, the data collected during 2014 were analyzed and they refer to the survival of Norwayspruce seedlings in the progeny test in Drinić. The data were processed in order to determine whichpopulations and half-sib lines are best adapted to ecological conditions of Drinić area.The results indicate a significant variability of survival among the tested populations and half-sib lines.They also indicate a higher adaptability of population originating from geographically more distantprovenances from progeny test, in comparison with closer populations. The results can be used for thepurpose of transferring the spruce reproductive material from Bosnia and Herzegovina to Drinić area,as well as the sites which are characterized by similar ecological conditions.

Adaptive plasticity and epigenetic variation in response to warming in an Alpine plant.

Environmentally induced phenotypic plasticity may be a critical component of response to changing environments. We examined local differentiation and adaptive phenotypic plasticity in response to elevated temperature in half-sib lines collected across an elevation gradient for the alpine herb, Wahlenbergia ceracea. Using Amplified Fragment Length Polymorphism (AFLP), we found low but significant genetic differentiation between low- and high-elevation seedlings, and seedlings originating from low elevations grew faster and showed stronger temperature responses (more plasticity) than those from medium and high elevations. Furthermore, plasticity was more often adaptive for plants of low-elevation origin and maladaptive for plants of high elevation. With methylation sensitive-AFLP (MS-AFLP), we revealed an increase in epigenetic variation in response to temperature in low-elevation seedlings. Although we did not find significant direct correlations between MS-AFLP loci and phenotypes, our results demonstrate that adaptive plasticity in temperature response to warming varies over fine spatial scales and suggest the involvement of epigenetic mechanisms in this response.

Intra-and inter-provenance variability of Ostrya carpinifolia Scop. seedlings

Hop Hornbeam (Ostrya carpinifolia Scop.) seedlings from 45 half-sib lines, from three provenances were analyzed. Intra-population variability between half-sib lines was found for morphological attributes of two-year seedlings. In this sense, maternal (seed) trees with the greatest potential for the production of reproductive material may be selected. Interpopulation variability between provenances was found for morphological and physiological attributes, except for the height and dry mass of the two-year seedlings. The influence of half-sib lines and provenances on the concentration of the studied nutrients should be further examined in a larger number of samples. Despite its large potential, Hop Hornbeam is not used for afforestation in Serbia. In those terms, we should work to change attitudes in the selection of the common types of reforestation species.

Usefulness of multiparental populations of maize (Zea mays L.) for genome-based prediction.

The efficiency of marker-assisted prediction of phenotypes has been studied intensively for different types of plant breeding populations. However, one remaining question is how to incorporate and counterbalance information from biparental and multiparental populations into model training for genome-wide prediction. To address this question, we evaluated testcross performance of 1652 doubled-haploid maize (Zea mays L.) lines that were genotyped with 56,110 single nucleotide polymorphism markers and phenotyped for five agronomic traits in four to six European environments. The lines are arranged in two diverse half-sib panels representing two major European heterotic germplasm pools. The data set contains 10 related biparental dent families and 11 related biparental flint families generated from crosses of maize lines important for European maize breeding. With this new data set we analyzed genome-based best linear unbiased prediction in different validation schemes and compositions of estimation and test sets. Further, we theoretically and empirically investigated marker linkage phases across multiparental populations. In general, predictive abilities similar to or higher than those within biparental families could be achieved by combining several half-sib families in the estimation set. For the majority of families, 375 half-sib lines in the estimation set were sufficient to reach the same predictive performance of biomass yield as an estimation set of 50 full-sib lines. In contrast, prediction across heterotic pools was not possible for most cases. Our findings are important for experimental design in genome-based prediction as they provide guidelines for the genetic structure and required sample size of data sets used for model training.

Analysis of inter-line variability of bald cypress (Taxodium distichum L. rich.) juvenile seedlings using morphometric markers

In this paper are presented results of the analysis of inter-line variability of morphometric characters of Bald cypress juvenile seedlings at the level of 20 half-sib lines. Obtained results contribute to better understanding of relationship of analyzed characters, as well as the influence of analyzed characters to the differentiation of half-sib lines. Based on these results, differences were observed in the values of the analyzed characters for each half-sib line individually. The determined values of seedlings? size indicate good genetic and adaptive potential of this species, which can be considered as a starting point for the mass production of quality planting material and its use in Serbia.

Fungal endophyte (Epichloë festucae) alters the nutrient content of Festuca rubra regardless of water availability.

Festuca rubra plants maintain associations with the vertically transmitted fungal endophyte Epichloë festucae. A high prevalence of infected host plants in semiarid grasslands suggests that this association could be mutualistic. We investigated if the Epichloë-endophyte affects the growth and nutrient content of F. rubra plants subjected to drought. Endophyte-infected (E+) and non-infected (E−) plants of two half-sib lines (PEN and RAB) were subjected to three water availability treatments. Shoot and root biomass, nutrient content, proline, phenolic compounds and fungal alkaloids were measured after the treatments. The effect of the endophyte on shoot and root biomass and dead leaves depended on the plant line. In the PEN line, E+ plants had a greater S:R ratio than E-, but the opposite occurred in RAB. In both plant lines and all water treatments, endophyte-infected plants had greater concentrations of N, P and Zn in shoots and Ca, Mg and Zn in roots than E- plants. On average, E+ plants contained in their shoots more P (62%), Zn (58%) and N (19%) than E- plants. While the proline in shoots increased in response to water stress, the endophyte did not affect this response. A multivariate analysis showed that endophyte status and plant line impose stronger differences in the performance of the plants than the water stress treatments. Furthermore, differences between PEN and RAB lines seemed to be greater in E- than in E+ plants, suggesting that E+ plants of both lines are more similar than those of their non-infected version. This is probably due to the endophyte producing a similar effect in both plant lines, such as the increase in N, P and Zn in shoots. The remarkable effect of the endophyte in the nutrient balance of the plants could help to explain the high prevalence of infected plants in natural grasslands.

Germination response of endophyticFestuca rubraseeds in the presence of arsenic

Epichloë fungal endophytes colonize the intercellular space of aerial organs of their plant hosts without causing symptoms. These symbionts are known to improve the performance of their host grasses in some situations of biotic and abiotic stress, leading to the suggestion that they can be used to improve grass tolerance to contaminants. The grass Festuca rubra is a host of the endophyte Epichloë festucae. We used two half-sib lines of F. rubra, each line composed of infected (E+) or endophyte-free (E−) seeds, to study the effect of varying levels of arsenic (6, 12, 25, and 50 mg L−1), and of the endophyte in seed germination and radicle growth. The results showed that seed germination was not significantly affected by arsenic (As) levels lower than 25 mg L−1, indicating that this grass has a relatively high tolerance of As at the germination stage. The decrease in germination observed at 25 and 50 mg L−1 was due to increased seed mortality and to the reversible inhibition of the germination of viable seeds caused by As. The presence of the endophyte did not change the germination response to arsenic of one line, but affected negatively the germination of the other line. In contrast to the process of germination, radicles of E+ seeds of both lines were longer than those of endophyte-free seeds. The results of this work indicate that Epichloë endophytes can affect the performance of some F. rubra genotypes when As is present in the soil.