Variation In Growth Response Research Articles

The Interactive Effects of Nutrient Density and Breed on Growth Performance and Gut Microbiota in Broilers.

This study investigated whether variations in growth response to low nutrient density across breeds are linked to microbiota regulation. Arbor Acres (AA) and Beijing-You (BY) were fed high- (HN) and low-nutrient (LN) diets from day (d) 0 to d42. Body weight, feed intake, and intestinal measurements were recorded, and microbiota from the ileum and cecum were analyzed on d7, d21, and d42. Results showed that AA broilers had greater growth performance with a lower feed conversion ratio (FCR) and greater average daily gain (ADG) than BY chickens. The LN diet negatively affected AA broiler growth due to impaired intestinal development, while BY chickens compensated by increasing feed intake. Microbiota composition was primarily affected by breed than by nutrient density, with AA broilers having more beneficial bacteria and BY chickens having more short-chain fatty acid (SCFA)-producing bacteria. The LN diets reduced anti-inflammatory bacteria such as Shuttleworthia and Eisenbergiella in the cecum on d7. By d21, LN diets decreased Lactobacillus and increased proinflammatory Marvinbryantia, potentially impairing growth. However, LN diets enriched SCFA-producing bacteria like Ruminococcaceae_UCG.013, Eisenbergiella, and Tyzzerella in BY chickens and Faecalitalea in AA broilers by d21, which may benefit gut health. By d42, LN diets reduced genera linked to intestinal permeability and fat deposition, including Ruminococcus_torques_group, Romboutsia, Erysipelatoclostridium, and Oscillibacter. Additionally, LN diets enriched Christensenellaceae_R-7_group in AA broilers, associated with intestinal barrier integrity, and increased anti-inflammatory bacteria Alistipes and Barnesiella in AA broilers and BY chickens, respectively, by d42. Overall, AA broilers were more susceptible to reduced nutrient density due to impaired intestinal development, while BY chickens adapted better by increasing feed intake. The microbiota responses to low nutrient density varied over time, potentially negatively affecting gut health in the early stage and growth in the middle stage but possibly improving lipid deposition and gut health in the middle and late stages.

Combined Effects of Fishing and Environment on the Growth of Larimichthys polyactis in Coastal Regions of China

In fisheries’ stock assessments, the concept of “growth plasticity”—the ability of organisms to modulate their growth rates in response to environmental conditions—has gained attention in recent years. Historically, the impacts of fishing activities and environmental fluctuations were considered separately, while their combined effects have recently come into focus. This study collected 834 adult small yellow croakers (Larimichthys polyactis) from the northern Yellow Sea, the central Yellow Sea, the southern Yellow Sea, and the northern East Sea by trawling during 2020–2021. Using otolith increments as a proxy for annual somatic growth, the study reconstructed otolith chronologies during 2015–2020 for these four stocks. The results of the mixed-effects modeling suggested that temperature during spawning and previous overwintering seasons had comparable importance for the annual growth of small yellow croakers, with higher temperature promoting growth. The growth of small yellow croakers was also found to be correlated with ENSO events, with a lag of 1 to 2 years. A further investigation into combined effects revealed that higher fishing pressure might inhibit the small yellow croaker’s response to favorable environmental conditions. Furthermore, considering the potential differences in growth plasticity among stocks, an analysis was conducted on the spatial variations in growth response to these factors. The analysis revealed that, compared to the stocks in the Yellow Sea, the stock from the East China Sea could exhibit higher growth, superior adaptability to temperature, and a distinctive response to fishing pressure. In conclusion, the present study, while primarily focusing on temperature, preliminarily analyzed the combined effects of fishing and environment and underscored the differences in growth plasticity between stocks in the Yellow Sea and the East China Sea. Despite the limited factors analyzed in this study, it suggests a direction for future studies, highlighting the necessity to include more environmental factors, and even population factors (e.g., the biomass of preys), for a more comprehensive understanding of the combined effects. Based on the observed differences between the two potential subpopulations, this study also provides new insights for the management of the small yellow croaker based on metapopulation dynamics.

PSLBI-21 Interactive effects of dietary betaine supplementation and soybean hulls inclusion on growth performance and carcass composition of young growing pigs

Abstract Growing barrow pigs [n = 24; Large White x Landrace x Duroc; 29.51 ± 3.24 kg initial body weight (BW)] were assigned to 4 treatments in a 2 x 2 factorial design to evaluate the synergistic effects of dietary levels of betaine (BET; 0 and 0.1%) and soybean hulls (SBH; 0 and 15%) on growth performance and carcass composition. Pigs were blocked by initial BW and housed in individual pens with ad libitum access to feed and water for a 28-d feeding period. Pigs were weighed and feed intake was recorded at 14-d intervals. Real-time ultrasonic (RTU) measurements of the 10th-rib longissimus dorsi muscle area (LMA) and off-midline backfat thickness (BF) were obtained initially and on d 28 for all pigs. Prediction equations were used to estimate total fat tissue (TOFAT) and fat-free total lean (FFTOLN) from the measurements. All data were analyzed using the MIXED procedure of the SAS software. Growth performance data were analyzed as repeated measures on time and carcass data were analyzed as single measures with the respective baseline values used as covariate in the statistical model. There were no SBH x BET interactions for growth response variables. Pig growth was not affected by dietary BET supplementation. During the first 14 d of the study, pigs fed 15% SBH had decreased average daily gain (ADG; P = 0.01), average daily feed intake (ADFI; P = 0.02), and feed efficiency [gain:fee; (G:F;P = 0.04)] when compared with pigs fed diets without SBH. From d 15 to 28, dietary addition of 15% SBH reduced ADFI (P = 0.01), whereas no significant effects on the other growth performance variables were observed. Overall, when compared with pigs fed diets without SBH, pigs fed diets with 15% SBH had reduced feed intake (P = 0.01) and ADG (P = 0.04), which resulted in lighter pigs (P = 0.03) at the completion of the feeding trial. A SBH x BET interaction (P = 0.04) was observed for LMA, with decreased values (P < 0.05) detected for BET-supplemented pigs only when SBH was not included in the diet. No additional carcass composition traits were altered by BET supplementation. Including 15% SBH to the diet decreased BF (P = 0.05) and TOFAT (P = 0.04) in growing pigs. Neither BET supplementation nor SBH inclusion affected FFTOLN. In conclusion, adding supplemental BET to diets with SBH did not synergistically alter nutrient partitioning of young growing pigs. Although no beneficial effects of BET supplementation on growth and carcass composition traits were observed, feeding pigs diets containing 15% SBH resulted in slower growth rates with less fat deposition.

Suitability of maize crop residue fermented by Pleurotus ostreatus as feed for edible crickets: growth performance, micronutrient content, and iron bioavailability.

Small-scale farming of edible insects could help combat public health challenges such as protein energy malnutrition and anemia, but reliable low-cost feeds for insects are needed. In resource-limited contexts, where grains such as maize are prohibitively costly for use as insect feed, the feasibility of insect farming may depend on finding alternatives. Here, we explore the potential to modify plentiful maize crop residue with edible mushroom mycelium to generate a low-cost feed adjunct for the farmed two-spotted cricket, Gryllus bimaculatus. Mushroom farming, like insect agriculture, is versatile; it can yield nutritious food while increasing system circularity by utilizing lignocellulosic residues from row crops as inputs. Pleurotus ostreatus, is an edible basidiomycete capable of being cultivated on corn stover (Zea mays). Mushroom harvest results in abundant "spent" substrate, which we investigated as a candidate feed ingredient. We created six cricket feeds containing fermented Pleurotus substrate plus an unfermented control, measuring cricket mass, mortality, and maturation weekly to evaluate cricket growth performance impacts of both fungal fermentation duration and mushroom formation. Pasteurized corn stover was inoculated with P. ostreatus mycelium and fermented for 0, 2, 3, 4, or 8 weeks. Some 4 and 8-week substrates were induced to produce mushrooms through manipulations of temperature, humidity, and light conditions. Dried fermented stover (40%) was added to a 1:1 corn/soy grain mix and fed to crickets ad libitum for 44 days. The unfermented control group showed higher survivorship compared to several fermented diets. Control group mass yield was higher for 2 out of 6 fermented diets. Little variation in cricket iron content was observed via ICP-spectrometry across feeds, averaging 2.46 mg/100 g. To determine bioavailability, we conducted in vitro Caco-2 human colon epithelial cell absorption assays, showing that iron in crickets fed fruiting-induced substrates was more bioavailable than in unfruited groups. Despite more bioavailable iron in crickets reared on post-fruiting substrates, we conclude that Pleurotus-fermented stover is an unsuitable feed ingredient for G. bimaculatus due to high mortality, variability in growth responses within treatments, and low mass yield.

Varying growth response of Central European tree species to the extraordinary drought period of 2018 – 2020

Droughts have intensified in Central Europe and will likely become a major driver of forest ecosystem change in the future. Regional studies are needed to understand drought impacts on forests and to provide guidance for adaptive management. In this study, we have investigated the effects of an extraordinary drought period in 2018 – 2020 on tree growth in the State of Bavaria (Germany). We (i) assessed overall changes in tree growth compared to pre-drought conditions, (ii) mapped the spatial configuration of drought and its impact on growth across ecoregions, (iii) quantified the standardized drought effect for the most abundant tree species, and (iv) analyzed the inter- and intraspecific variability in growth responses to drought.Covering a large environmental gradient, we compared 3,462 tree basal area growth records at 200 inventory plots with the pre-drought period of 2006 – 2017. We analyzed drought impacts on tree growth using nonparametric randomization tests and linear quantile mixed models (LQMMs).Median annual tree growth declined by 41.3% during drought. Decreases in growth were statistically significant for 13 out of 20 species. Growth reductions were most distinct in northwestern ecoregions of Bavaria. After controlling for other covariates of tree growth, the most abundant conifers, Picea abies [Karst.] and Pinus sylvestris [L.], were overall more susceptible than the common broadleaves, Fagus sylvatica [L.], Quercus robur [L.], and Quercus petraea [Matt.]. Yet, all species exhibited a high intraspecific variation in drought response.Altering tree species composition is a key strategy to adapt forest ecosystems. Our study reveals high potential to mitigate future drought impacts by admixing P. abies- and P. sylvestris-dominated forests with more drought-adapted broadleaved tree species. In addition, the high intraspecific variability in drought susceptibility indicates potential to promote provenances or individuals with low drought sensitivity to reduce the local loss of tree species.

Intraspecific variation in growth response to drought stress across geographic locations and genetic groups in Coffea canephora.

Uganda lies within the drier end of the natural distribution range of Coffea canephora and contains unexplored genetic material that could be drought-adapted and useful for developing climate-resilient varieties. Using water treatment: (i) ample and (ii) restricted-water, the response of 148 genotypes were studied comprising wild, feral and cultivated C. canephora. Biomass allocation, standing leaf area and leaf area growth data were collected. Linear mixed effect models and PCA were used to the analyze effect of water treatment on genotypes from different: (i) cultivation status, (ii) genetic groups and (iii) locations. We also assessed the relationship between drought tolerance for relative growth rate in leaf area (RGRA), total number of leaves (TNL), total leaf area (TLA) and total leaf dry weight (TLDW) of genotypes at final harvest. Restricted-water reduced RGRA across genetic groups (3.2-32.5%) and locations (7.1-36.7%) but not cultivation status. For TNL, TLA and TLDW, genotypes that performed well in ample-water performed worse under restricted-water, indicating growth-tolerance trade-off. Drought tolerance in RGRA and TNL were negatively correlated with wetness index suggesting some degree of adaptation to local climate. Findings indicate a growth-tolerance trade-off within this tropical tree species and drought tolerance of Uganda's C. canephora is somewhat associated with local climate.

8 Impact of Increasing Level of Milk Production on Cow and Calf Performance in the Nebraska Sandhills

Abstract Selection for increased milk production across the United States has resulted in variable cow and calf productivity responses. The calf growth response variability may be due to the relationship between calf milk and forage intake, which nursing and grazing behavior may help explain. The objectives of this study were to determine the impact of increasing level of milk production on cow body weight (BW), body condition score (BCS), reproductive performance, calf growth, nursing, and grazing behaviors in the Nebraska Sandhills. In a 2-yr study, data were collected on 118 mature crossbred cow-calf pairs from March- and May-calving herds. On approximately 30, 60, 90, 120, and 210 d postpartum, individual cow 24-h milk yield was estimated through weigh-suckle-weigh techniques. Cow BW and BCS were collected 14 d prior to calving, weekly from d 30 through breeding, and at weaning. Calf BW was recorded at each milking. Calf nursing and grazing behaviors were determined during 3-wk periods at EARLY (65.4 ± 10.0 d) and LATE (162 ± 22.3 d) lactation using high frequency (1 hz) global positioning system (GPS) data collected with neck collars. Milk area under the curve values were calculated to determine total milk production during lactation for each cow and all response variables were analyzed using linear regression analysis. Cow BW, BW change, and reproductive performance were not (P > 0.12) associated with total milk production, except for a tendency (P = 0.09) for lower BW at breeding with increased milk production. At weaning, cow BCS was negatively associated (P = 0.02) with increasing milk production but was not associated at any other physiological stage. Calf percent of time spent grazing was not affected (P = 0.33) by increasing dam milk production. However, percent of time nursing exhibited a tendency (P = 0.10) to decrease with increasing dam milk production. Pre-weaning calf BW was positively associated (P < 0.01) with increased milk production at each weigh date. A positive association of calf average daily gain (ADG) with increasing dam milk production was observed (P < 0.04) from birth to age 120 d with only a tendency (P = 0.09) for a positive association observed from age 120 d to weaning. However, steer ADG in the finishing phase was not associated (P = 0.63) with level of dam milk production. In this study and environmental conditions, increasing milk production had a positive increase in calf growth during the pre-weaning phase without any negative impact reproduction.

INVITRO-PLANT REGENERATION FROM MATURED SEED EXPLANT OF LOCAL AND IMPROVED RICE (ORYZA SATIVA L.) VARIETIES

Plant tissue cultures of crops are carried out to produce more crops within a short period of time and as well to overcome the demands of food by the fast growing population. Numerous concerns have been centered towards indica rice, for a reason the study aimed at assessing the growth and if possible yield performance of some local rice varieties using invitro plant regeneration method. The study was conducted to observe the regeneration potential and also to establish a suitable in vitro plantlet regeneration protocol from mature seed explant of four rice varieties viz local rice Variety (Maizabuwa and Mai kwalli) and improved rice variety (Nerica and Faro 44). Maizabuwa was the only variety that successfully regenerated by proliferating shoot and root from the rice seed explant while Faro 44, had root development in the MS media under in-vitro condition. After transplanting, only Maizabuwa successfully germinated from the soil and plantlet growth was observed. No variations was observed in growth responses (plant height (cm), number of tillers, number of leaves and leaf area (cm2)) between in-vitro and soil regenerated (potted in soil) Maizabuwa and Faro 44 rice varieties, whereas variation in growth responses measured between the four varieties of rice directly potted in soil media was observed. Soil potted plants showed some significant differences in growth where Maizabuwa and Nerica varieties indicated to contribute to such variation. The study indicate that seeds of Maizabuwa local rice variety can be suggested to farmers if interested in large scale farming as the variety has shown observable tolerance to in-vitro regeneration and as well potted soil media conditions.

Cotton waste‐derived biochar and compost improve early growth and AMF association in cotton

AbstractImproving the sustainability of cotton (Gossypium hirusutum L.) production can be achieved by returning organic matter and nutrients to degraded soils. Amendment with biochar prepared from locally available feedstocks has been suggested as a pathway to sustainability. A greenhouse study collaboratively conducted by Malian and Texas A&M investigators evaluated the effect of biochar prepared from two feedstocks readily available in northwestern Africa: cotton field residue and rice (Oryza sativa L.) hulls, on cotton plants grown to 6 wk. A composted municipal biosolid was included for comparison with the more carbon (C)‐stable biochars. Four soils of contrasting properties were included in the study. Plant growth response variables were all affected by soil type (p < .0001). Shoot height was improved by biochars and composts in all soils. Root mass was improved by amendment only in the soil with the greatest clay content. Nitrogen (N) uptake was significantly depressed, and phosphorus (P) uptake was increased under biochar and compost amendment in the most coarsely textured soil. No effect on N and P uptake was observed in the soil with the greatest clay content. Ridge regression analysis showed that arbuscular mycorrhizal fungi (AMF) root colonization was positively related to the P content of the amendments (1.41*Pamend), negatively related to soil P (–0.49*Psoil) and positively related to both soil pH (2.15*pH) and clay content (1.130*clay%). Results indicate that degraded soils may be restored through amendment with biochar created from locally available feedstock to improve sustainability of cotton production. Soil properties will determine the degree of benefit.

The intraspecific variation of functional traits modulates drought resilience of European beech and pubescent oak

Abstract A higher frequency and intensity of droughts will impair forest productivity. Therefore, improving our understanding of which factors enhance tree growth resilience against drought has become a crucial issue, but we lack information at the intraspecific level. In this study, we investigate the role played by climatic conditions and tree characteristics in the growth response to severe droughts in two deciduous Fagaceae species near their southern distribution limit: the temperate European beech Fagus sylvatica and the Mediterranean pubescent oak Quercus pubescens. The study area is located in Catalonia, NE Spain, where 149 trees were cored covering the water availability gradient of the species in the region. In addition, tree size (diameter and height) and an ensemble of stem, leaf and hydraulic traits were collected for each tree. Growth responses to extreme droughts during the period 1980–2015 were assessed using resilience indicators based on residual basal area increment series predicted by a model including growing season water balance. Although resistance was unrelated to drought intensity, higher water availability improved recovery and reduced drought legacy effects. Taller trees showed higher resilience against drought, which could be explained by the relationship between the variation in tree height and functional traits, such as leaf nitrogen concentration, leaf turgor loss point and resistance to xylem embolism. For both species, trees with lower cavitation resistance, higher leaf nitrogen concentration and tighter stomatal regulation (suggested by less negative turgor loss point and carbon isotope composition) displayed better performance during and after severe droughts. Both species showed a progressive decrease in resilience and increase in legacy effects. Synthesis. This study highlights the relevance of analysing intraspecific variation of functional traits involved in tree water and carbon balance to improve our understanding of the resilience and variability of growth responses to drought within species.

Population structure and the influence of microenvironment and genetic similarity on individual growth at Alaskan white spruce treelines

Knowledge on the adaptation of trees to rapid environmental changes is essential to preserve forests and their ecosystem services under climate change. Treeline populations are particularly suitable for studying adaptation processes in trees, as environmental stress together with reduced gene flow can enhance local adaptation. We investigated white spruce (Picea glauca) populations in Alaska on one moisture-limited and two cold-limited treeline sites with a paired plot design of one forest and one treeline population each, resulting in six plots. Additionally, one forest plot in the middle of the distribution range complements the study design. We combined spatial, climatic and dendrochronological data with neutral genetic marker of 2203 trees to investigate population genetic structure and drivers of tree growth. We used several individual-based approaches including random slope mixed-effects models to test the influence of genetic similarity and microenvironment on growth performance. A high degree of genetic diversity was found within each of the seven plots associated with high rates of gene flow. We discovered a low genetic differentiation between the three sites which was better explained by geographic distances than by environmental differences, indicating genetic drift as the main driver of population differentiation. Our findings indicated that microenvironmental features had an overall larger influence on growth performances than genetic similarity among individuals. The effects of climate on growth differed between sites but were smaller than the effect of tree size. Overall, our results suggest that the high genetic diversity of white spruce may result in a wider range of phenotypes which enhances the efficiency of selection when the species is facing rapid climatic changes. In addition, the large intra-individual variability in growth responses may indicate the high phenotypic plasticity of white spruce which can buffer short-term environmental changes and, thus, allow enduring the present changing climate conditions.

Impacts of recurrent dry and wet years alter long‐term tree growth trajectories

Abstract Climate extremes, such as abnormally dry and wet conditions, generate abrupt shifts in tree growth, a situation which is expected to increase under predicted climate conditions. Thus, it is crucial to understand factors determining short‐ and long‐term tree performance in response to higher frequency and intensity of climate extremes. We evaluated how three successive droughts and wet years influenced short‐ and long‐term growth of six dominant Iberian tree species. Within species variation in growth response to repeated dry and wet years was evaluated as a function of individual traits related to resource and water use (diameter at breast height [DBH], wood density [WD] and specific leaf area [SLA]) and tree‐to‐tree competition across climatically contrasted populations. Furthermore, we assessed how short‐term accumulated impacts of the repeated dry and wet years influenced long‐term growth performance. All species showed strong short‐term growth decreases and enhancements due to repeated dry and wet years. However, patterns of accumulated growth decreases (AcGD) and enhancements (AcGE) across climatically contrasting populations were species‐specific. Furthermore, individual trait data were weakly associated with either AcGD or AcGE and the few relevant associations were found for conifers. Intraspecific variations in tree growth responses to repeated climates extremes were large, and not explained by intraspecific variability in SLA and WD. Accumulated impacts of repeated dry and wet years were related to long‐term growth trends, showing how the recurrence of climate extremes can determine growth trajectories. The relationships of AcGD and AcGE with long‐term growth trends were more common in conifers species. Synthesis. Repeated climate extremes do not only cause short‐term growth reductions and enhancements but also determine long‐term tree growth trajectories. This result shows how repeated droughts can lead to growth decline. Conifers were more susceptible to the accumulated effects of extreme weather events indicating that in the future, more intense and frequent climate extremes will alter growth performance in forests dominated by these species.

Dissecting the Genotypic Variation of Growth Responses to Far-Red Radiation in Tomato.

The recent development of light-emitting diodes (LEDs) and their application in modern horticulture stimulated studies demonstrating that additional far-red (FR) radiation (700–800 nm) increases plant dry mass. This effect of FR has been explained by improved photosynthesis and/or plant architecture. However, the genotypic variation in this response is largely unknown. Here, we aim to explore and explain the genotypic variation in growth responses to additional FR. We expected the genotypic variation in the responses of plant dry mass to additional FR. Further, we hypothesized that a significant improvement of both net assimilation rate (NAR) and leaf area ratio (LAR) is responsible for a strong dry mass increase under additional FR, while some genotypes respond only marginally or even negatively in NAR or LAR under FR, thus resulting in a weak FR effect on plant dry mass. To test these hypotheses, we grew 33 different tomato genotypes for 21 days with 0, 25, or 100 μmol m–2 s–1 of FR added to a common white + red LED background lighting of 150 μmol m–2 s–1. Genotypes responded similarly with respect to plant height, stem dry mass, and shoot:root ratio; i.e., they all increased with increasing FR. However, the response of total plant dry mass varied among genotypes. We categorized the genotypes into three groups (strongly, moderately, and weakly responding groups) based on their relative response in total plant dry mass to FR. Growth component analysis revealed that the strongly responding genotypes increased strongly in NAR rather than LAR. The weakly responding genotypes, however, showed a substantial increase in LAR but not NAR. The increase in LAR was due to the increase in specific leaf area. Leaf mass fraction, which is the other component of LAR, decreased with FR and did not differ between groups. In conclusion, tomato genotypes that increased strongly in NAR in response to FR were able to achieve a more substantial increase in dry mass than did other genotypes. This is the first study to explain the differences in growth responses of a large number of tomato genotypes toward FR in their light environment.

Variation in Growth Response of Coastal Dune-Building Grass Species Ammophila Arenaria and Leymus Arenarius to Sand Burial

AbstractAmmophila arenaria and Leymus arenarius are dune-building grass species native to European seacoasts. The present study aimed to compare growth responses to the sand burial of A. arenaria and L. arenarius from coastal habitats of the Baltic Sea, when the intensity of sand accretion was relatively low under controlled conditions. Plants were grown from seeds collected from natural coastal habitats, transplanted into individual containers, buried in the sand at different depths in the rapid shoot elongation stage, and further cultivated (11 or 9 weeks) in an automated greenhouse. Burial in sand significantly stimulated the growth of shoots of A. arenaria, the effect was earlier at high burial intensities (46 and 60%) and was evident ten days after the start of treatment. Both shoot and root dry mass increased for plants buried at 13%; however, increased burial depth (37, 46 and 60%) resulted in a significant increase in root biomass. In comparison, shoot biomass decreased significantly at the highest burial intensity (60%). For L. arenarius, there was no direct dependence of shoot elongation rate on burial depth. There was a tendency for increased elongation growth and biomass allocation to leaf sheaths despite a decrease in total shoot mass. Most strikingly, root biomass decreased with sand burial in parallel with increased burial depth up to 21% intensity. In conclusion, although both grass species showed a positive shoot growth response to moderate sand burial intensity, differences in individual responses at the morphological and physiological level indicate the existence of different genetically based adaptation strategies.

Dissecting the Genetic Regulation of Yeast Growth Plasticity in Response to Environmental Changes.

Variable individual responses to environmental changes, such as phenotype plasticity, are heritable, with some genotypes being robust and others plastic. This variation for plasticity contributes to variance in complex traits as genotype-by-environment interactions (G × E). However, the genetic basis of this variability in responses to the same external stimuli is still largely unknown. In an earlier study of a large haploid segregant yeast population, genotype-by-genotype-by-environment interactions were found to make important contributions to the release of genetic variation in growth responses to alterations of the growth medium. Here, we explore the genetic basis for heritable variation of different measures of phenotype plasticity in the same dataset. We found that the central loci in the environmentally dependent epistatic networks were associated with overall measures of plasticity, while the specific measures of plasticity identified a more diverse set of loci. Based on this, a rapid one-dimensional genome-wide association (GWA) approach to overall plasticity is proposed as a strategy to efficiently identify key epistatic loci contributing to the phenotype plasticity. The study thus provided both analytical strategies and a deeper understanding of the complex genetic regulation of phenotype plasticity in yeast growth.

Clonal Variation in Growth Response of Populus deltoides Bartr. to Nitrogen Fertilization Under Nursery Conditions

Populus deltoides, an extensively planted poplar in Jammu and Kashmir and is one of the ten most prominent tree species grown in the State. A strapping clone x fertilizerinteraction was observed fordiameter, height and biomass. Growth response of six male clones of this species to three levels ofnitrogen (50, 75 and100 kg ha 1 ) was evaluated in nursery for two years to produce healthy and vigorous nursery stock. While application of N- fertilizer @ 75 kg ha 1 recorded maximum height, diameter, number of branches plant', numberofleaves plant', leafarea plant', internodal length and total biomass (fresh and dry) plant', the application of 100 kg N ha ' was observed to exert toxic effects and reduced the growth performance. In terms ofefficient utilization ofNitrogen fertilizer (NUE), the application of 50 kg N ha ' yield maximum biomass p er unit of N- used by the plant. The male clones have recently received a lot of attention due to the increasing cotton mince produced by female clones in Kashmir valley. In currentscenario male clones are the betterperspective to replace the female ones without compromising the economy generated by this species.

SAT-096 Response to RHGH Therapy in Children with Isolated Short Stature with or Without an Identified Genetic Cause

Introduction: Children with isolated (former known as idiopathic) short stature (ISS) have been treated with rhGH with a variable response. Objectives: To evaluate the short-term response to rhGH therapy in children with ISS with or without a genetic diagnosis. Methods: We analyzed retrospectively the growth rate and height SDS change in the first year of rhGH treatment according to the presence or absence of defects in genes that regulate growth plate. The decision to start rhGH treatment was based on clinical features and the genetic results were obtained during the follow-up. Patients were enrolled in several previous genetic studies using gene candidate approach or multigene sequencing analysis. Results: A total of 51 prepubertal children (36 boys) with ISS were treated with rhGH. Thirteen of these children start puberty during the treatment and three of them were concomitant treated with GnRH analog. Basal characteristics of these children were 7.7 ± 3.2 years of age, height SDS -2.5 ± 0.8; sitting height/height (SH/H) SDS 1.2 ± 1.4; BMI SDS 0 ± 1.0 and mild delay of bone age (-1.6 ± 1.3 y). The mean target height SDS was -1.2 ± 0.9y, 18 (35%) of these children have at least one parent with height SDS < -2 and 3 (6%) both parents are short. Consanguinity was present in 3 (6%) cases. Among this cohort, fifteen children had pathogenic or likely pathogenic allele variants in genes that regulate growth plate: IHH (n = 4), SHOX (n = 9) and NPR2 (n = 2). Seven (47%) of these variants were inherited from a short stature parent. Children with or without an identified genetic cause have similar age and height SDS at the start of the treatment. A higher BMI and SH/H SDS were observed in children with genetic defects than in those without (BMI SDS 0.5 ± 1.1 vs. -0.15 ± 0.9, p = 0.02; SH/H SDS 2.0 ± 1.4 vs. 0.9 ± 1.3, p = 0.006). Additionally, children with genetic defects had a less marked bone age delay (-1.0 ± 1.3 vs. -1.9 ± 1.2; p = 0.02). Both groups were treated with similar rhGH dose (50 μg/kg/day). Patients with and without an identified genetic cause had similar improvement in growth velocity during the first year of therapy: 4.8 ± 1.6 to 8.9 ± 1.7 cm/y for patients with molecular diagnosis vs. 4.6 ± 1.2 to 8.5 ± 2.3 cm/y for those without. This resulted in similar height SDS change during this period for both groups (0.6 ± 0.3 vs. 0.6 ± 0.5 SDS for children with or without a genetic cause, respectively). Age at the start of treatment was the main variable that explains growth response variability during this first year (r2 = 0.17, p = 0.009). Conclusion: The presence or absence of an identified genetic cause, involving genes that regulate growth plate, did not significantly influence the short-term growth response to rhGH therapy of children with ISS. Long-term follow-up is still needed to assess the final height of these children and possibly to assess whether there is a different growth rate related to each known affected gene.

Field Inoculation of Bread Wheat with Rhizophagus irregularis under Organic Farming: Variability in Growth Response and Nutritional Uptake of Eleven Old Genotypes and A Modern Variety

Arbuscular mycorrhizal fungi (AMF) promote crop growth and yield by increasing N and P uptake and disease resistance, but the role of field AMF inoculation on the uptake of micronutrients, such as Fe and Zn, and accumulation in plant edible portions is still not clarified. Therefore, we studied the effect of field inoculation with Rhizophagus irregularis in an organic system on 11 old genotypes and a modern variety of bread wheat. Inoculation increased root colonization, root biomass and shoot Zn concentration at early stage and grain Fe concentration at harvest, while it did not modify yield. Genotypes widely varied for shoot Zn concentration at early stage, and for plant height, grain yield, Zn and protein concentration at harvest. Inoculation differentially modified root AMF community of the genotypes Autonomia B, Frassineto and Bologna. A higher abundance of Rhizophagus sp., putatively corresponding to the inoculated isolate, was only proved in Frassineto. The increase of plant growth and grain Zn content in Frassineto is likely linked to the higher R. irregularis abundance. The AMF role in increasing micronutrient uptake in grain was proved. This supports the introduction of inoculation in cereal farming, if the variable response of wheat genotypes to inoculation is considered.

Variability in growth responses of non-O157 EHEC isolates in leafy vegetables, sprouted seeds and soil extracts occurs at the isolate level.

Foods of plant origin are recognised as a major source of foodborne pathogens, in particular for Shigatoxigenic Escherichia coli (STEC). Most work for STEC and plant-based fresh produce has focused on the most prevalent outbreak serogroup, O157. However, non-O157 STEC is an emerging hazard, and as such it is important to characterise aspects within this group that reflect their ability to colonise alternative hosts and habitats relevant to horticultural production. Growth kinetics were quantified for a diverse set of clinical enterohaemorrhagic E. coli isolates in extracts made from different tissues of spinach, lettuce or sprouted seeds, or from soil, to represent association with ready-to-eat fresh produce production. For leafy vegetables, spinach apoplast supported the fastest rates of growth and lettuce root extracts generated the slowest growth rates. Growth rates were similar for the majority of isolates in fenugreek or alfalfa sprouted seed extracts. Monosaccharides were the major driver of bacterial growth. No correlations were found for growth rates between different serotypes or for Shigatoxin gene carriage. Thus, growth rates varied in a plant-dependent and isolate-dependent manner, for all plant or soil extracts tested, indicative of isolate-specific differences in metabolic flexibility. These findings are relevant for risk assessment of non-O157 STEC.

Pertumbuhan Beberapa Bentuk Potongan Pangkal Setek Tanaman Mawar (Rosa sp.) Akibat Cara Aplikasi Zat Pengatur Tumbuh Root-Up

The research aims to study the growth of rose cuttings due to the shape of the base of cuttings and the way of Root-up application. The experiment was carried out in Screen House in Pasirbanteng, Hegarmanah Village, Jatinangor District. Sumedang Regency. The experiment was conducted from March to August 2015. The methode based on Randomized Block Design consisting of two factors. The first factor is the Root-up (W) application method which consists of 3 factor levels, namely without root up (w1), powder (w2), and paste (w3). The second factor is Form Cutting (S) consisting of 3 levels of treatment, is the oblique sliced (s1), taper sliced (s2), and flat sliced (s3). The factors composed of nine combinations of treatments, each of which was repeated 3 times. The results show that was not the interaction between the shape of cuttings and Root-up applications on the growth response variables of cutting rose plants, is number of shoots, length of shoots, root length, number of roots, and root volume. The oblique sliced and tapered slice form the base and of the cutting shave the best effect on the length of shoots of rose plants cutting