Response Traits Research Articles

Transgenerational Plasticity Enhances the Tolerance of Duckweed (Lemna minor) to Stress from Exudates of Microcystis aeruginosa

Transgenerational plasticity (TGP) refers to the influence of ancestral environmental signals on offspring’s traits across generations. While evidence of TGP in plants is growing, its role in plant adaptation over successive generations remains unclear, particularly in floating plants facing fluctuating environments. Duckweed (Lemna minor), a common ecological remediation material, often coexists with the harmful bloom-forming cyanobacterium Microcystis aeruginosa, which releases a highly toxic exudate mixture (MaE) during its growth. In this study, we investigate the TGP of duckweed and its adaptive role under stress from MaE during the bloom-forming process. We found that exposure to MaE induces significant phenotypic plasticity in duckweed, manifested by alterations in morphological, physiological, and transcriptomic profiles. Specifically, MaE exposure significantly affected duckweed, promoting growth at low concentrations but inhibiting it at high concentrations, affecting traits like biomass, frond number, total frond area, and photosynthetic efficiency. Additionally, the activities of antioxidant enzymes, together with the levels of proline, soluble sugars, and proteins, are elevated with increasing MaE concentrations. These plastic changes are largely retained through asexual reproductive cycles, persisting for several generations even under MaE-free conditions. We identified 619 genes that maintain a ‘transcriptional memory’, some of which correlate with the TGP-linked alterations in morphological and physiological traits in response to MaE stress. Notably, progeny from MaE-exposed lineages demonstrate enhanced fitness when re-exposed to MaE. These results enhance our comprehension of the adaptive significance of TGP in plants and suggest feasible approaches for utilizing duckweed’s TGP in the bioremediation of detrimental algal blooms.

Unveiling early-stage responses of sensitive traits to water stress in tropical maize: a characterization study of a public panel

Unveiling early-stage responses of sensitive traits to water stress in tropical maize: a characterization study of a public panel

The role of lag phases between real-term marine heatwaves in the trait responses of two macrophyte species

The role of lag phases between real-term marine heatwaves in the trait responses of two macrophyte species

A high-throughput approach for quantifying turgor loss point in grapevine

Quantifying drought tolerance in crops is critical for agriculture management under environmental change, and drought response traits in grape vine have long been the focus of viticultural research. Turgor loss point (πtlp) is gaining attention as an indicator of drought tolerance in plants, though estimating πtlp often requires the construction and analysis of pressure-volume (P-V) curves which are very time consuming. While P-V curves remain a valuable tool for assessing πtlp and related traits, there is considerable interest in developing high-throughput methods for rapidly estimating πtlp, especially in the context of crop screening. We tested the ability of a dewpoint hygrometer to quantify variation in πtlp across and within 12 clones of grape vine (Vitis vinifera subsp. vinifera) and one wild relative (Vitis riparia), and compared these results to those derived from P-V curves. At the leaf-level, methodology explained only 4–5% of the variation in πtlp while clone/species identity accounted for 39% of the variation, indicating that both methods are sensitive to detecting intraspecific πtlp variation in grape vine. Also at the leaf level, πtlp measured using a dewpoint hygrometer approximated πtlp values (r2 = 0.254) and conserved πtlp rankings from P-V curves (Spearman’s ρ = 0.459). While the leaf-level datasets differed statistically from one another (paired t-test p = 0.01), average difference in πtlp for a given pair of leaves was small (0.1 ± 0.2 MPa (s.d.)). At the species/clone level, estimates of πtlp measured by the two methods were also statistically correlated (r2 = 0.304), did not deviate statistically from a 1:1 relationship, and conserved πtlp rankings across clones (Spearman’s ρ = 0.692). The dewpoint hygrometer (taking ∼ 10–15 min on average per measurement) captures fine-scale intraspecific variation in πtlp, with results that approximate those from P-V curves (taking 2–3 h on average per measurement). The dewpoint hygrometer represents a viable method for rapidly estimating intraspecific variation in πtlp, and potentially greatly increasing replication when estimating this drought tolerance trait in grape vine and other crops.

Ecological diversification of sea catfishes is accompanied by genome-wide signatures of positive selection

Habitat transitions have shaped the evolutionary trajectory of many clades. Sea catfishes (Ariidae) have repeatedly undergone ecological transitions, including colonizing freshwaters from marine environments, leading to an adaptive radiation in Australia and New Guinea alongside non-radiating freshwater lineages elsewhere. Here, we generate and analyze one long-read reference genome and 66 short-read whole genome assemblies, in conjunction with genomic data for 54 additional species. We investigate how three major ecological transitions have shaped genomic variation among ariids over their ~ 50 million-year evolutionary history. Our results show that relatively younger freshwater lineages exhibit a higher incidence of positive selection than their more ancient marine counterparts. They also display a larger disparity in body shapes, a trend that correlates with a heightened occurrence of positive selection on genes associated with body size and elongation. Although positive selection in the Australia and New Guinea radiation does not stand out compared to non-radiating lineages overall, selection across the prolactin gene family during the marine-to-freshwater transition suggests that strong osmoregulatory adaptations may have facilitated their colonization and radiation. Our findings underscore the significant role of selection in shaping the genome and organismal traits in response to habitat shifts across macroevolutionary scales.

Weak integration allows novel fin shapes and spurs locomotor diversity in reef fishes.

In complex functional systems composed of many traits, selection for specialized function can induce trait evolution by acting directly on individual components within the system, or indirectly through networks of trait integration. However, strong integration can also hinder diversification into regions of trait space that are not aligned with axes of covariation among traits. As a result, non-independence among traits may limit capacity for functional expansion. We explore this dynamic in the evolution of fin shapes in 106 species from 38 families of coral reef fishes, a polyphyletic assemblage that shows exceptional diversity in locomotor function. Despite strong shared developmental pathways and expectations of a strong match between form and function, we find that species that share swimming mode show substantial disparity in fin shape, and preferred swimming mode is a poor predictor of fin shape. The evolution of fin shape is weakly integrated across the four functionally dominant fins in swimming (the pectoral, caudal, dorsal, and anal fins) and integration is weakened as derived swimming modes evolve. The weak integration among fins in the ancestral locomotor condition provides a primary axis of diversification while allowing for substantial off-axis diversification via independent trait responses to selection. However, the evolution of novel locomotor modes coincides with a loss of integrated axes of covariation among fins. Our study highlights the need for additional work on the functional consequences of fin shape in fishes and impact of evolutionary integration on functions other than locomotion.

Dietary energy level and β2-adrenergic agonist supplementation on growth performance, dietary energy, carcass traits, and visceral mass of hairy lambs

Context The beta-agonist zilpaterol (ZH) is a feed additive that improves growth performance via protein accretion during the finishing phase of ruminant fattening. However, evaluating the possible interaction between ZH and nutrients of the diet has received limited attention. Aims We investigated the changes in growth performance and carcass traits in response to ZH supplementation of hairy lambs fed finishing diets with different energy concentration. Methods Forty-eight Pelibuey × Katahdin crossbred male lambs (43.8 ± 6.3 kg) were used in a 34-day feeding trial to evaluate the interaction between diet energy density [8.37 (LE) and 8.79 (HE) MJ of net energy for maintenance (NEm) per kilogram of diet] and zilpaterol hydrochloride supplementation (ZH, dosed at 0 or 6 mg ZH/kg) on growth performance, carcass traits, and visceral mass. All diets contained 14.5% crude protein (CP). Key results There was no interaction of energy level and ZH in any of the variables evaluated. HE increased average daily gain (ADG) and gain efficiency (GF) without affecting the observed-to-expected dietary NE. Zilpaterol supplementation increased ADG, GF, and observed-to-expected dietary NE. Both HE and ZH increased carcass weight. HE increased carcass fat, whereas ZH decreased it. HE increased dressing percentage. ZH increased longissimus muscle area, the muscle:fat ratio in the shoulder, and leg whole-cut proportion. Visceral mass was not affected by energy level. ZH decreased visceral fat. Conclusions Increasing diet energy from 8.37 to 8.79 MJ NEm/kg enhanced growth performance and carcass traits but did not improve dietary energy utilization. Supplemental ZH enhanced growth performance, dietary-energy utilization and carcass traits of lambs. Implications ZH supplementation is a tool to enhance growth performance by improving protein accretion and reducing carcass fat. Response to ZH supplementation is independent of the differences in energy density of finishing diets.

Response of some Vegetative Traits of Red Roomy Grapevines to Paclobutrazol Treatments

Response of some Vegetative Traits of Red Roomy Grapevines to Paclobutrazol Treatments

Trait responses, nonconsumptive effects, and the physiological basis of Helicoverpa armigera to bat predation risk.

Predation reduces the population density of prey, affecting its fitness and population dynamics. Few studies have connected trait changes with fitness consequences in prey and the molecular basis and metabolic mechanisms of such changes in bat-insect systems. This study focuses on the responses of Helicoverpa armigera to different predation risks, focusing on echolocating bats and their calls. Substantial modifications were observed in the nocturnal and diurnal activities of H. armigera under predation risk, with enhanced evasion behaviors. Accelerated development and decreased fitness were observed under predation risks. Transcriptomic and metabolomic analyses indicated that exposure to bats induced the upregulation of amino acid metabolism- and antioxidant pathway-related genes, reflecting shifts in resource utilization in response to oxidative stress. Exposure to bat predation risks enhanced the activity of DNA damage repair pathways and suppressed energy metabolism, contributing to the observed trait changes and fitness decreases. The current results underscore the complex adaptive strategies that prey species evolve in response to predation risk, enhancing our understanding of the predator-prey dynamic and offering valuable insights for innovative and ecologically informed pest management strategies.

Genotype-by-environment interaction in Dutch elm disease resistance

Dutch elm disease (DED) is a devastating forest disease. Recently, the deployment of native resistant cultivars has prompted initiatives of elm reintroduction in Europe and North America. It is known that DED resistance varies with the tree genotype and is influenced by climatic factors. However, genotype-by-environment interactions in DED resistance remain largely unexplored. In this work, we examined whether there is genetic variation in DED resistance plasticity and the roles of tree growth, phenology and anatomical traits in plastic responses. We established two experimental plots with 12 Ulmus minor genotypes in two environmentally contrasting locations in Spain: Madrid, under an inland continental climate, and Valencia, under a coastal Mediterranean climate. We monitored growth and phenology detecting high plasticity in both traits. In the inland plot, genotypes were taller and showed a more synchronized phenology than in the coast. A first DED-pathogen inoculation was carried out 45 days after the average flushing date in each location, after which trees exhibited more symptoms inland. A second inoculation was carried out by dividing the coastal plot trees into early and late flushing trees and inoculating each group at 45 days after its average flushing date. Therein, susceptibility rose to a level close to the inland plot. In both inoculations, we detected a significant genotype-by-location interaction in DED resistance. The xylem anatomy revealed high plasticity and a significant genotype-by-location interaction in most traits. In the coastal trial, trees formed narrower vessels and stored more starch before inoculation. The synchrony of leaf phenology, higher growth rate, lower starch reserves and higher structural vulnerability of earlywood to DED possibly favored susceptibility in the inland plot. The varying responses of genotypes in phenology, growth and anatomy at both locations were likely related to the differences in DED resistance, which can have important consequences for elm reintroduction.

Above and belowground functional trait response to biochar addition in seedlings of six tropical dry forest tree species

Above and belowground functional trait response to biochar addition in seedlings of six tropical dry forest tree species

Unlocking the role of novel primary/di-amine oxidases in crop improvement: Tissue specificity leads to specific roles connected to abiotic stress, hormone responses and sensing nitrogen

Genetic improvements of solanaceous crops for quality and stress responsive traits are needed because of the central role vegetables and fruits have in providing nutrients to human diets. Copper amine oxidase (CuAO) encoding genes involved in metabolism of primary/di-amine nitrogenous compounds, play a role in balancing internal nitrogen (N) pools especially when external N supply fluctuates during growth, development and environmental stresses. In the present study, we investigated the occurrence, molecular evolution and possible role(s) of these unknown genes in tomato crops. Multiple genome-wide bioinformatics approaches led to the identification of eight bona fide CuAO genes (SlCuAO1–SlCuAO8) in the tomato genome with gene numbers like those in Arabidopsis and rice indicating their conserved functional relevance with a tandemly duplicated SlCuAO6-SlCuAO7 pair at chr.9. A conserved intron-exon size and phase distribution for SlCuAO2, 3, 4 pairs are similar to a recently identified single duckweed SpCuAO1 orthologue gene indicating its evolutionary conservation. Synteny analysis showed their closest association to Arabidopsis and but not with rice. Transcriptome data indicated that gene expression for about six genes (SlCuAO1, 2, 3, 4, 6, 7) is root specific, fruit specific for SlCuAO5 and flower specific for SlCuAO8 thus indicating amine oxidation is variable across tissues with a prominance in the root tissue. The majority of CuAO genes are negatively regulated by methyl jasmonate. Positive regulation, however, involves CuAO3/8. Transcript analysis of the ethylene-deficient transgenic lines indicated that ethylene is required for activation of SlCuAO4. CuAO4 and CuAO5 exhibited most significant tissues-independent gene expression responses across various nitrogen regimes. Drought, heat and N stress identified CuAO5 as an overlapping highly expressed gene that corroborates with putrescine accumulation for free and conjugated forms with an opposite abundance of bound forms. Taken together our study highlights new insights into the roles of copper amine oxidation genes and identifies CuAO5 as a multiple stress induced gene that can be used in genetic improvement programs for combining heat, drought and nitrogen use efficiency related traits.

Plant virus community structuring is shaped by habitat heterogeneity and traits for host plant resource utilisation.

Host plants provide resources critical to viruses and the spatial structuring of plant communities affects the niches available for colonisation and disease emergence. However, large gaps remain in the understanding of mechanisms that govern plant-virus disease ecology across heterogeneous plant assemblages. We combine high-throughput sequencing, network, and metacommunity approaches to test whether habitat heterogeneity in plant community composition corresponded with virus resource utilisation traits of transmission mode and host range. A majority of viruses exhibited habitat specificity, with communities connected by key generalist viruses and potential host reservoirs. There was an association between habitat heterogeneity and virus community structuring, and between virus community structuring and resource utilisation traits of host range and transmission. The relationship between virus species distributions and virus trait responses to habitat heterogeneity was scale-dependent, being stronger at finer (site) than larger (habitat) spatial scales. Results indicate that habitat heterogeneity has a part in plant virus community assembly, and virus community structuring corresponds to virus trait responses that vary with the scale of observation. Distinctions in virus communities caused by plant resource compartmentalisation can be used to track trait responses of viruses to hosts important in forecasting disease emergence.

Responses of Local and Non-Local Tropical Plant Seedling Functional Traits to Simulated Drought

Responses of Local and Non-Local Tropical Plant Seedling Functional Traits to Simulated Drought

Vegetation cover in outdoor enclosures reduces feather pecking in farm-reared red-legged partridges (Alectoris rufa)

Feather pecking is a major problem in intensively reared birds, leading to welfare issues, chronic stress and economic losses. Despite the ample literature on how to improve the living conditions in the poultry industry, very little attention has been paid to gamebird species. The red-legged partridge (Alectoris rufa) plays a crucial role in the ecosystems of the Iberian Peninsula and also holds significant socio-economic importance in rural areas, as it is the primary species for small game hunting. Our aim was to experimentally test whether improved housing conditions with abundant natural vegetation cover reduce feather pecking and enhance body condition and growth in red-legged partridges. For two years, we compared the degree of feather pecking in red-legged partridges raised in two types of enclosures: a) in the absence of vegetation and b) with abundant natural vegetation. We also took morphometric measures (body weight and tarsus length) of the birds. We found that feather pecking varied both according to vegetation cover and bird age. Chicks aged between 42 and 67 days old exhibited a higher degree of feather pecking than adults. Vegetation cover reduced feather pecking in adults in one of the years of study and in chicks in the other. Additionally, we also found partial support that the presence of vegetation can improve body condition, as during one year, chicks raised in enclosures with vegetation were marginally heavier than those raised without vegetation. These findings suggest that the presence of vegetation might be a contributing factor in mitigating the development of abnormal behaviours in captive red-legged partridges. Future studies are necessary to evaluate what additional measures can be implemented to enhance the effectiveness of a vegetation enriched environment. Additionally, future studies should aim to investigate the effects vegetation cover in aviaries on other parameters relevant to the welfare of these birds, such as the physiological stress response and other specific behavioural traits.

Trait‐mediated indirect effect involving a chain of learning in agroecosystems

AbstractAn increase in predation risk triggers a trait response of prey, which alters the interactions between the prey and other species, ultimately affecting other species in the ecosystem. Such predator‐driven trait‐mediated indirect effects (TMIEs) may have been shaped by long‐term evolutionary processes involving the organisms involved, but learning may also be important, especially in contemporary ecosystems experiencing repeated biological invasions. The apple snail Pomacea canaliculata is an important introduced pest of rice, Oryza sativa. Recently, the carrion crow Corvus corone has been found to prey on this species only in some areas, suggesting that learning is involved in this predation. In addition, apple snails can learn to escape from predators and exhibit predator‐specific responses. Thus, the “chain of learning” by the crow and the snail may shape novel TMIEs in the rice ecosystem. We conducted field and mesocosm experiments to test this hypothesis. In the field experiment, we simulated predation by crows in rice fields and investigated the behavior of apple snails. The snails exhibited escape behaviors in response to the simulated predation, and both the proportion of individuals showing the escape response and the degree of escape response were greater in fields with predation by crows than those without predation. In the mesocosm experiment, apple snails from fields with and without predation by crows were separately introduced into mesocosms simulating rice fields, and the behaviors of the snails and the number of remaining rice plants were recorded for 16 days at three levels of predation risk (daily, every 4 days, or no predation). Both the presence/absence of predation in the collection fields and simulated predation affected the escape responses of the snails. Moreover, damage to rice was more severe in mesocosms containing snails from fields without predation than those containing snails from fields with predation. These results suggest that the “chain of learning” causes TMIEs in agroecosystems.

Hypothalamic-pituitary-adrenal axis plasticity across life-history stages of a free-living subtropical finch, Amandava amandava amandava.

The alterations of phenotypic traits (morphology, endocrine physiology, and behavior) in response to predictable environmental cues across life-history stages in seasonally breeding birds enable successful culmination of reproduction. The present study elucidated the plasticity of the hypothalamic-pituitary-adrenal (HPA) axis in a subtropical free-living finch, Amandava amandava amandava, and suggests the crucial role of the baseline corticosterone (CORT) to coordinate energetic readiness across life-history stages. Birds were captured monthly from an area (25.1337° N 82.5644° E) in Uttar Pradesh, India, from June 2014 to May 2015. Only male birds were included in this study corresponding to different life-history stages (6/life-history stage; 2/month): pre-breeding (June-August), breeding (September-November), post-breeding (December-February), and quiescent phases (March-May). The pituitary expression of adrenocorticotropic hormone (ACTH), adrenal interrenal cell morphometry, and plasma level of the CORT showed varied patterns across life-history stages. The density and immunointensity of the ACTH-immunoreactive corticotropes and the interrenal cell number increased along with the significant plasma CORT elevation during the breeding cycle (both pre-breeding and breeding phases). CORT might facilitate the energy demand for the display of sexual behavior (nest-building, courtship), testicular recrudescence, and foraging of food for offspring during the breeding cycle. On the contrary, plasma CORT decrease in the post-breeding and quiescent phases might enable the bird to molt avoiding the protein catabolic effect of the hormone. Given the complexity involved in the study of baseline CORT in free-living birds, more studies are needed to better understand the crucial role of the HPA axis in the modulation of life-history stages in this and other subtropical avian species.

Functional traits as an indicator of urbanization impact on the scorpion assemblage in Neotropical forest

Currently, natural forests face significant loss of vegetation cover linked to habitat loss due to urban expansion. Therefore, we investigated the effects of changes in different land uses and land cover at the landscape scale resulting from the urbanization process on the functional traits of the body of scorpions in the Brazilian Atlantic Forest. In 10 forest fragments in Paulista, Pernambuco, we observed that forest cover had a statistically significant negative relationship with the average functional body traits of the scorpion assemblage. Distinct functional body traits were associated with the conditions of the surrounding landscape. Forest units with lower forest cover harbored species with higher average functional body traits, indicating adaptation to the urban scenario. Conversely, in areas with greater forest cover, species with smaller functional body traits predominated, suggesting habitat sensitivity and dependence on less disturbed environments. Our results indicate that scorpions may be indicators of changes in functional body traits due to land use change. These findings highlight significant implications for biodiversity conservation in the Atlantic Forest in the face of urban expansion, emphasizing the role of scorpions as key indicators of changes in functional body traits in response to the altered landscape.

Effects of the Prenatal Maternal Health Status on Calf Disease Prevalences and Respective Genetic Parameter Estimates in German Holstein Cattle.

The aim of the present study was to infer phenotypic responses and genetic parameters of the F1 calf diseases diarrhoea (DIAR) and pneumonia (PNEU) in dependency of the prenatal maternal health status (PMHS) of the dam and of the herd-calving year. The PMHS considered diagnoses for the cow disease mastitis (MAST) and claw disorders (CD) during gestation of F0 dams. Furthermore, 305-d milk production traits of F1 offspring from either healthy or diseased dam groups were compared. The study comprised 20,045 female calves (F1 = generation 1) and their corresponding dams (F0 = parental generation 0), kept in 41 large-scale herds. All F1 calves were from their dams' 2nd parity, implying that all dam (maternal) diseases were recorded during the first lactation and dry period of the dams. The F1 calves were phenotyped for DIAR up to 30 days post-partum, and for PNEU up to 180 days of age. At least one entry for the respective disease implied a score = 1 = sick, otherwise, a score = 0 = healthy, was assigned. Production records of the 10,129 F1 cows comprised 305-d records in first lactation for milk yield (MY), protein yield (PY) and fat yield (FY). Linear and generalised linear mixed models were applied to infer phenotypic responses of F1 traits in dependency of the PMHS for CD and MAST. A diagnosis for MAST or CD in F0 cows during gestation was significantly (p ≤ 0.05) associated with an increased prevalence for DIAR and PNEU, with pairwise differences of least-squares-means between calves from healthy and diseased cow groups up to 3.61%. The effects of PMHS on 305-d production traits in offspring were non-significant (p > 0.05). In bivariate genetic analyses, DIAR and PNEU were defined as different traits according to the PMHS, i.e., DIAR-MASThealthy and DIAR-MASTdiseased, DIAR-CDhealthy and DIAR-CDdiseased, PNEU-MASThealthy and PNEU-MASTdiseased, and PNEU-CDhealthy and PNEU-CDdiseased. The direct heritabilities for DIAR and PNEU were quite similar in the healthy and respective diseased dam group. Slightly larger direct heritabilities in the diseased dam groups were due to increased genetic variances. Maternal heritabilities were quite stable and smaller than the direct heritabilities. In random regression models, genetic parameters for DIAR and PNEU were estimated along the continuous herd-calving-year prevalence scale, considering a prevalence for MAST and CD (based on the 20,045 dam records plus 16,193 herd contemporary records) in the range from 0% to 30%. Direct heritabilities for PNEU were quite stable along the herd-calving-year gradient for MAST and CD. For DIAR, we observed stronger estimate fluctuations, especially increasing direct heritabilities in dependency of the herd-calving-year prevalence for MAST from 0.13 (at a MAST prevalence of 0%) to 0.30 (at a MAST prevalence of 30%). Consequently, obvious genotype x herd-calving-year PMHS interactions were observed for DIAR on the prenatal MAST scale, with a minimal correlation of 0.48 between direct genetic effects at 0% MAST prevalence and at 30% MAST prevalence. The correlations between direct genetic and maternal genetic effects were antagonistic at all herd-calving-year prevalence levels, displaying strongest fluctuations for "DIAR-MAST." The genotype x herd-calving-year PMHS interactions for DIAR suggest consideration of specific sires according to the herd health status for CD and for MAST.

Adding gastrointestinal parasite resistance to the breeding objective in hair sheep: initial steps.

The U.S. Maternal Hair index was designed by the National Sheep Improvement Program (NSIP) to increase total weight of lamb weaned per ewe lambing (TW). Producers are interested in adding gastrointestinal nematode (GIN) resistance to this breeding objective since parasitism causes substantial economic losses. The NSIP provides producers with estimated breeding values (EBV) for post-weaning fecal egg count (PFEC), an indicator of GIN resistance. Our objective was to gauge the effects of including PFEC as another selection criterion and goal trait. Selection index theory was used to construct 11 indexes. First was a benchmark index with TW as the goal. Weaning weight, and number of lambs born and weaned, were selection criteria. An index was then designed with PFEC added as a selection criterion. In 9 more indices, PFEC was also included as a goal trait, where the economic value of TW was scaled relative to that of PFEC. PFEC received a scaled economic value of -1 with that of TW increasing from +1 to +5 at +0.5 increments. Selection criteria were modelled as EBV or phenotypes. Annual genetic responses in goal traits were predicted. The top 3% of males and 26% of females were selected. Breeding values and phenotypes were simulated for 200 lambs by Cholesky decomposition and used to generate index scores, with 100 replicates run. Concordances with the animals selected in the benchmark scenario were determined. Using EBV as selection criteria, TW increased by 1.46kg/yr in the benchmark scenario. However, unfavorably, PFEC increased by 2.24%/yr. When using phenotypic criteria, TW increased by 0.52kg/yr and PFEC by 0.28%/yr. Once added as a goal trait, PFEC decreased regardless of the scaled economic value of TW. However, responses in TW were also reduced, although less so as its scaled economic value increased. A scaled economic value of +3 for TW appeared reasonable over other choices with 79% of the emphasis placed on TW in the breeding objective. With EBV as selection criteria, PFEC declined by 7.96%/yr with 98% of the response in TW retained. Also, on average, 64% of males and 80% of females were chosen in common with the benchmark. With phenotypic selection criteria, PFEC declined by 5.13%/yr and 94% of the response in TW was retained; 61% of males and 80% of females were chosen in common with the benchmark. Implementing an index with scaled economic values of +3 for TW and -1 for PFEC would balance gains in TW with reductions in PFEC.