Interactive Effects Of Genotype Research Articles

Growth enhancement and extenuation of drought stress in maize inoculated with multifaceted ACC deaminase producing rhizobacteria

IntroductionMaize is a major staple cereal crop grown and consumed globally. However, due to climate change, extreme heat and drought stresses are greatly affecting its production especially in sub-Saharan Africa. The use of a bio-based approach to mitigate drought stress is therefore suggested using plant growth-promoting rhizobacteria (PGPR).MethodsThis study investigated the abilities of 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing PGPR Pseudomonas sp. MRBP4, Pseudomonas sp. MRBP13 and Bacillus sp. MRBP10 isolated from maize rhizosphere soil, to ameliorate the effect of drought stress in maize genotypes MR44 and S0/8/W/I137TNW//CML550 under two water regimes; mild drought stress (50% FC) and well-watered conditions (100% FC). The rhizobacterial strains were identified by 16S rRNA sequencing and biochemical tests, and evaluated for plant growth-promoting and abiotic stress tolerance traits.Results and discussionThe synergistic effect of the bacterial strains had a highly significant (p < 0.001) effect on the total soluble sugar, soil moisture content and relative water content, which were enhanced under water-stress in the inoculated plants. Relative water content was significantly highest (p < 0.001) in maize plants co-inoculated with Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 (60.55%). Total chlorophyll content was significantly enhanced in maize seedlings sole inoculated with Pseudomonas sp. MRBP4, Pseudomonas sp. MRBP13, and co-inoculated with Pseudomonas sp. MRBP13 + Bacillus sp. MRBP10 by 15.91%, 14.99% and 15.75% respectively, over the un-inoculated control. Soil moisture content increased by 28.67% and 30.71% compared to the un-inoculated control when plants were inoculated with Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 and Pseudomonas sp. MRBP4 + Bacillus sp. MRBP10 respectively. The interactive effect of genotype × bacteria significantly enhanced biomass production. Leaf area was highest in maize plants co-inoculated with Pseudomonas sp. MRBP4 + Pseudomonas sp. MRBP13 (212.45 ± 0.87 cm2) under drought stress. Treatment of maize seeds with Pseudomonas sp. MRBP 4 + Pseudomonas sp. MRBP13 + Bacillus sp. MRBP10 significantly increased the root length (10.32 ± 0.48 cm) which enhanced survival of the maize seedlings. Bioinoculation of maize seeds with these strains could boost maize production cultivated in arid regions.

HIV Transgenic Rats Demonstrate Superior Task Acquisition and Intact Reversal Learning in the Within-Session Probabilistic Reversal Learning Task.

The HIV transgenic (HIVtg) rat is a commonly used animal model of chronic HIV infection that exhibits a wide range of cognitive deficits. To date, relatively little work has been conducted on these rats' capacity for reversal learning, an assay of executive function and cognitive flexibility used in humans. The present study sought todetermine the impact of HIV genotype on probabilistic reversal learning, effortful motivation, and spontaneous locomotion/exploration in rats. Male (n = 8) and female (n = 8) HIVtg rats and wildtype (WT) controlswere utilized. Cognitive flexibility was assessed via the Probabilistic Reversal Learning Task (PRLT), which reinforced responses to two stimuli on differential probabilistic schedules that periodically reversed. Effortful motivation and locomotor/exploratory behavior were assessed via the Progressive Ratio Breakpoint Task (PRBT) and the Behavioral Pattern Monitor (BPM), respectively. Regardless of sex, HIVtg rats required fewer trials to ascertain initial PRLT reward schedules than WT rats, and completed the same number of reversals. Secondary behaviors suggested that HIVtg PRLT performance was facilitated by a speed-accuracy tradeoff strategy. No main or interactive effects of genotype were observed in the PRBT or BPM. Relative to WT controls, HIVtg rats exhibited superior probabilistic reinforcement learning. Reversal learning was unaffected by HIV genotype, as was effortful motivation and exploratory behavior. These findings contrast with previous characterizations of the HIVtg rat, thus indicating a nuanced cognitive profile that is dependent upon suchtask specifications as within- versus between-session assessment and probabilistic versus deterministic reward schedules.

Responses of photosynthesis and P/Fe traits to P application in soybean under stress of low Fe.

We examined the effects of phosphorus (P) levels on photosynthetic and P/Fe traits of soybean under the stress of low Fe and their genotypic differences, to provide a theoretical basis for rational application of P and Fe fertilizer. Six P-efficient and six P-inefficient soybean varieties screened in the early stage were used as experimental materials. Four treatments of P:Fe ratio were set, including 0:30, 30:30, 150:30 and 300:30 (μmol·L-1). We measured chlorophyll fluorescence traits and P-Fe utilization efficiency in soybean. A stepwise regression equation was established with seed weight per plant. Pathway analysis was performed, with the response of P-efficient and P-inefficient soybean genotypes to different P:Fe treatments being comprehensively evaluated by factor scores. The results showed significant main and interactive effects of genotype and P:Fe on the relative electron transfer rate of photosystem Ⅱ (ETR) at beginning of flowering stage (R1), the proportion of the energy absorbed by photosystem Ⅱ dissipated into heat (NPQ) at R1 stage, and proportion of energy absorbed by photosystem Ⅱ devoted to the photochemical reaction (qL) at R1 stage. Results of canonical correlation analysis showed a negative correlation between P utilization efficiency of seed at full maturity stage (R8) and photosynthetic rate at R1 stage of P-efficient genotypes. Seed Fe utilization efficiency of P-inefficient genotypes at R8 stage was positively correlated with NPQ at R1 stage, but negatively correlated with qL at R1 stage. The actual photochemical efficiency of PSⅡ (ΦPSⅡ) at R1 stage was negatively correlated with P-efficient genotypes, but positively correlated with P-inefficient genotypes, which indicated that ΦPSⅡ at R1 stage was an important indicator for identifying soybean genotypes with different P efficiency under stress of low Fe. The comprehensive performance of P-efficient soybean genotypes decreased first and then increased with P level, while P-inefficient soybean genotypes increased first and then decreased. The inflection point of both genotypes appeared in P:Fe of 30:30. Thus, P:Fe ratio of 30:30 could be used as a threshold to identify soybean genotypes with different P efficiency under stress of low Fe. In conclusion, P fertilizer application should be equal to or greater than 1:1 (P:Fe) when planting P-efficient soybean genotypes in low Fe area, while P fertilizer application should not exceed 1:1 (P:Fe) when planting P-inefficient soybean genotypes.

Exploring long-term variety performance trials to improve environment-specific genotype × management recommendations: A case-study for winter wheat

• We used long-term wheat variety performance trials to evaluate G, E, and M effects. • Sub-region accounted for 46 % of the yield variability across all environments. • Management practices accounted for 44–77 % of yield variability within sub-regions. • Yield variability of 1–8 % was due to genotype within sub-regions. • Management practices and genotype traits improving yield varied by sub-region. The complex and interactive effects of genotype (G), environment (E), and management (M) can be a barrier to the development of sound agronomic recommendations. We hypothesize that long-term variety performance trials (VPT) can be used to understand these effects and improve regional recommendations. Our objective was to explore long-term VPT data to improve management and variety-selection recommendations using winter wheat ( Triticum aestivum L.) in the U.S. central Great Plains as a case-study. Data of grain yield, variety, and trial management were collected from 748 wheat VPT conducted in the states of Colorado, Kansas, and Oklahoma over nineteen harvest years (2000–2018) and 92 locations, resulting in 97,996 yield observations. Using 30-yr cumulative annual precipitation and growing degrees days, we partitioned the study region into 11 contiguous sub-regions, which we refer to as growing adaptation regions (GAR). We used variance component analysis, gradient boosted trees, and conditional inference trees to explore the management and variety trait effects within each GAR. For the variety trait analysis, the VPT dataset was reduced to account for varieties for which 17 agronomic traits and 11 disease/insect reaction ratings were available (65,264 yield observations). GAR accounted for 46 % of the total variation in grain yield, M for 32 %, residuals (including interactions) for 13 %, year for 7 %, and G for 2 %. Conditional inference trees identified interactions among management practices and their effects on yield within each GAR. For instance, water regime was the most important practice influencing wheat yield in the semi-arid western portion of the study region, followed by sowing date and fungicide. In dryland trials, there was typically an interaction between fungicide, sowing date, and tillage system, depending on GAR. Other management practices (e.g. dual-purpose management, crop rotation, and tillage practice) also significantly affected yield, depending on GAR. The main variety trait associated with increased yields depended on region and management combination. For instance, drought tolerance was the most important trait in dryland trials while stripe rust tolerance was more relevant in irrigated trials in the semi-arid region. In this research, we demonstrated an approach that uses widely available long-term VPT data to improve management and variety selection recommendations and can be used in other regions and crops for which long-term VPT data are available.

Interactive effects of genotype, seasonality and extraction method on chemical compositions and yield of essential oil from rosemary (Rosmarinus officinalis L.)

Rosemary is an important crop for industrial production of essential oil. However, there is a significant effect of the genetic variation and the production process on the essential oil composition. Therefore, the present study was aimed at elucidating the effect of season and processing method on essential oil composition using the volatile structure of rosemary germplasm that was cultivated at the Newe Ya'ar research center for 30 years. Analysis of the essential oil composition of thirty-three germplasm identified four chemical groups: a '1,8-cineole' type, a 'verbenone' type, a 'camphor' type, and a 'α-pinene' type. Application of fractional factorial analysis of variance to the data indicated interactions of volatile by germplasm, volatile by method (hydro-distillation or solvent extraction), and volatile by season (summer 2017 or winter 2018), but not for germplasm by method, germplasm by season or method by season. This suggests that the germplasm was seasonally stable. Yet, the interaction between volatile by method pointed out that more camphor and 1,8-cineole were obtained by distillation, whereas more α-pinene was obtained by solvent extraction. Using four germplasm that were selected as chemo-type representatives for comparing hydro-distillation by Clevenger modified apparatus and steam-distillation, α-pinene was identified as a minor component in the hydrosol, whereas 1,8-cineole, camphor, borneol and verbenone were major components in the hydrosol. The outcome of the study reflects the importance of evaluating the effects of environment, genetic and processing methods on essential oil composition for accurate industrial breeding and production of essential oils.

Interactive Effects of Genotype and Nitrogen on the Phenology and Yield Determination of Okra [Abelmoschus esculentus (L.)

Limited studies have been conducted to assess key yield-determining processes and their inter-relationships in okra under both nitrogen (N) poor as well as optimum growing environments on a set of contrasting genotypes. Therefore, in this study, we analyze the yield formation in two diverse genotypes of okra (Sabz Pari ‘SP’ and Arka Anamika ‘AA’) across seven contrasting N environments (0–300 kg ha−1) and to determine effects of genetic (G), environmental (E) and their interaction (G × E) on a set of traits relevant to vegetative growth, onset of reproductive cycle, pod characteristics, and yield. The effects of G, E, and G × E were significant for majority of traits. Ranking of genotypes changed across the environments for most of the traits indicating a cross-over type G × E interactions. Majority of traits showed differential response to varied N availability. Mean values of plant height, canopy diameter, leaves plant−1, leaf area plant−1, stem girth, internodes plant−1, length of internode, pod length, pod diameter, and pod yield enhanced with rising N (50–300 kg ha−1). However, pod fresh weight and number of pods plant−1 declined with N availability above 150 kg ha−1. The onset of first flowering delayed with decline in N availability and vice versa. Late maturing genotype AA indicated a better yield potential across N environments by producing 50.96% more yield over early maturing genotype SP. There existed significant inter-relationships among most of the traits. Four traits including leaf area plant−1, pod diameter, pod fresh weight and number of pods plant−1 explained most of the variance (97.4%) in pod yield. It was concluded that gain in these parameters may lead to an increase in pod yield. Our approach could be useful in developing an indirect selection criterion for yield improvement in okra and could provide a theoretical framework for breeding programmes in developing an ideal genotype.

Interactive Effects of Genotype and Molybdenum Supply on Yield and Overall Fruit Quality of Tomato.

Molybdenum (Mo) is an essential trace element for plant growth, development, and production. However, there is little known about the function and effects of molybdenum in tomato plants. The present study assessed the influences of different Mo concentrations on four tomato F1 hybrids (“Bybal” F1, “Tyty” F1, “Paride” F1, and “Ornela” F1) grown using a soilless system with different Mo levels [0.0, 0.5 (standard NS), 2.0, and 4.0 μmol L−1, respectively]. The crop yield, plant vigor, fruit skin color, TA, fruit water content as well as the accumulation of SSC, and some antioxidant compounds such as lycopene, polyphenols and ascorbic acid were evaluated. The minerals concentration, including nitrogen (N), Mo, iron (Fe), and copper (Cu), were measured in tomato fruits. Results revealed that tomato plants grown with 2.0 μmol Mo L−1 compared to plants grown with 0.5 μmol Mo L−1 incurred a significant increase of total yield by 21.7%, marketable yield by 9.1%, aboveground biomass by 16.7%, plant height at 50 DAT by 6.5%, polyphenol content by 3.5%, ascorbic acid by 1.0%, SSC by 3.5%, N fruit content by 24.8%, Mo fruit content by 20.0%, and Fe fruit content by 60.5%. However, the Mo concentration did not significantly influence the average fruit weight, b* fruit skin color coordinate and TA. Furthermore, tomato fruits from plants grown with 2.0 μmol Mo L−1 showed a lower Cu fruit content (16.1%) than fruits from plants grown with 0.5 μmol Mo L−1 (standard NS). Consequently, our study highlights the different behavior of the tomato genotypes tested when subjected to different levels of Mo concentration in the nutrient solution. Nevertheless, taking all in consideration our results clearly suggest that a Mo fertilization of 2.0 μmol Mo L−1 effectively enhance crop performance and overall fruit quality of tomato.

Genetic down-regulation of gibberellin results in semi-dwarf poplar but few non-target effects on chemical resistance and tolerance to defoliation

Plant stature can be strongly modified via regulation of endogenous levels and signalling of the plant hormone gibberellin (GA). Down-regulation of GA can produce semi-dwarf tree varieties with improved qualities such as reduced susceptibility to wind damage, enhanced root growth and more compact cultivation. However, these modifications may have unintended, non-target consequences for defence against herbivores, via either of two mechanisms: (i) reduced biomass production may cause trade-offs with chemical resistance traits, as predicted by the growth-differentiation balance hypothesis, and (ii) altered biomass allocation to either roots or photosynthetic tissues may affect regrowth potential and thus tolerance to defoliation. We studied GA down-regulated (GE) and non-transgenic wild-type hybrid poplar (Populus alba × P. tremula) in an outdoor, aboveground common garden and defoliated half of all replicate trees to simulate defoliation. We then quantified the independent and interactive effects of genotype and defoliation on growth and chemical resistance-related traits, including phenolic glycosides (PGs), condensed tannin and nitrogen. We also calculated tolerance to defoliation as the differential in relative growth between undefoliated and defoliated trees. Our results indicate that two of the four GA down-regulated genotypes had significantly reduced stem height, basal diameter, volume (d²h), total biomass and increased allocation to leaves relative to the wild type. One of those two genotypes also had reduced allocation to roots. One and sometimes both of these same two genotypes also had at least 20% lower levels of condensed tannins and PGs and similar increases in lignin and nitrogen. Tolerance, as calculated by the differential in relative growth between undefoliated and defoliated trees, was similar among all experimental genotypes. However, two GE genotypes flushed fewer leaves in response to defoliation relative to the wild type. Our results indicate that GA down-regulation strongly alters biomass production and allocation in poplar but does not necessarily compromise the ability of these trees to tolerate damage. However, some of the modifications we observed do have the potential to alter non-target resistance traits over time, and warrant further research, especially under plantation conditions.

Interactive effects of genotype x environment on the live weight of GIFT Nile tilapias.

In this paper, the existence of a genotype x environment interaction for the average daily weight in GIFT Nile tilapia (Oreochromis niloticus) in different regions in the state of Paraná (Brazil) was analyzed. The heritability results were high in the uni-characteristic analysis: 0.71, 0.72 and 0.67 for the cities of Palotina (PL), Floriano (FL) and Diamond North (DN), respectively. Genetic correlations estimated in bivariate analyzes were weak with values between 0.12 for PL-FL, 0.06 for PL and 0.23 for DN-FL-DN. The Spearman correlation values were low, which indicated a change in ranking in the selection of animals in different environments in the study. There was heterogeneity in the phenotypic variance among the three regions and heterogeneity in the residual variance between PL and DN. The direct genetic gain was greater for the region with a DN value gain of 198.24 g/generation, followed by FL (98.73 g/generation) and finally PL (98.73 g/generation). The indirect genetic gains were lower than 0.37 and greater than 0.02 g/generation. The evidence of the genotype x environment interaction was verified, which indicated the phenotypic heterogeneity of the variances among the three regions, weak genetic correlation and modified rankings in the different environments.

Interactive effects of genotype and food quality on consumer growth rate and elemental content.

Consumer body stoichiometry is a key trait that links organismal physiology to population and ecosystem-level dynamics. However, as elemental composition has traditionally been considered to be constrained within a species, the ecological and evolutionary factors shaping consumer elemental composition have not been clearly resolved. To this end, we examined the causes and extent of variation in the body phosphorus (P) content and the expression of P-linked traits, mass specific growth rate (MSGR), and P use efficiency (PUE) of the keystone aquatic consumer Daphnia using lake surveys and common garden experiments. While daphnid body %P was relatively constrained in field assemblages sampled across an environmental P gradient, unique genotypes isolated from these lakes showed highly variable phenotypic responses when raised across dietary P gradients in the laboratory. Specifically, we observed substantial inter- and intra-specific variation and differences in daphnid responses within and among our study lakes. While variation in Daphnia body %P was mostly due to plastic phenotypic changes, we documented considerable genetic differences in daphnid MSGR and PUE, and relationships between MSGR and body P content were highly variable among genotypes. Overall, our study found that consumer responses to food quality may differ considerably among genotypes and that relationships between organismal life-history traits and body stoichiometry may be strongly influenced by genetic and environmental variation in natural assemblages.

Interactive effects of genotype and N/S-supply on glucosinolates and glucosinolate breakdown products in Chinese cabbage (Brassica rapa L. ssp. pekinensis)

Chinese cabbage is rich in glucosinolates (GLS) and their breakdown products, mainly isothiocyanates (ITC), which are assumed to be human health-promoting compounds. Sulphur and nitrogen have been shown to influence concentrations and patterns of both. Little is known as to whether the effect of varying sulphur and nitrogen nutrition on glucosinolate and isothiocyanate content is influenced by the genotype. Therefore, two cultivars of Brassica rapa L. ssp. pekinensis were grown with increasing S (0.0, 0.3, and 0.6 g pot-1) and N (1 and 2 g pot-1) supply. Results show that total GLS concentration increased with higher N and S application, but ratios between individual GLS compounds remained unchanged. High N supply reduced the concentration of GLS, especially of the aliphatic ones, while the indole and aromatic GLS exhibited statistically insignificant responses to increasing N and S application. The profile of breakdown products was dominated by epithionitriles, followed by ITCs and nitriles. The ITCs were substantially reduced in response to increasing N and decreasing S supply. This was not observed for nitriles. Overall, GLS pattern were primarily influenced by the genetic background of the cultivar and less influenced by differential nutrition. Results show that selection of the cultivar is of utmost importance when glucosinolates and their breakdown products shall be increased by fertilization. The online version of this article (doi: 10.5073/JABFQ.2016.089.036) contains supplementary files .

Genotype variation in bark texture drives lichen community assembly across multiple environments.

A major goal of community genetics is to understand the influence of genetic variation within a species on ecological communities. Although well-documented for some organisms, additional research is necessary to understand the relative and interactive effects of genotype and environment on biodiversity, identify mechanisms through which tree genotype influences communities, and connect this emerging field with existing themes in ecology. We employ an underutilized but ecologically significant group of organisms, epiphytic bark lichens, to understand the relative importance of Populus angustifolia (narrowleaf cottonwood) genotype and environment on associated organisms within the context of community assembly and host ontogeny. Several key findings emerged. (1) In a single common garden, tree genotype explained 18-33% and 51% of the variation in lichen community variables and rough bark cover, respectively. (2) Across replicated common gardens, tree genotype affected lichen species richness, total lichen cover, lichen species composition, and rough bark cover, whereas environment only influenced composition and there were no genotype by environment interactions. (3) Rough bark cover was positively correlated with total lichen cover and richness, and was associated with a shift in species composition; these patterns occurred with variation in rough bark cover among tree genotypes of the same age in common gardens and with increasing rough bark cover along a -40 year tree age gradient in a natural riparian stand. (4) In a common garden, 20-year-old parent trees with smooth bark had poorly developed lichen communities, similar to their 10-year-old ramets (root suckers) growing in close proximity, while parent trees with high rough bark cover had more developed communities than their ramets. These findings indicate that epiphytic lichens are influenced by host genotype, an effect that is robust across divergent environments. Furthermore, the response to tree genotype is likely the result of genetic variation in the timing of the ontogenetic shift from smooth to rough bark allowing communities on some genotypes to assemble faster than those on other genotypes. Organisms outside the typical sphere of community genetics, such as lichens, can help address critical issues and connect plant genotype effects to long-established streams of biological research, such as ontogeny and community assembly.

The effect of drought stress on the traits related to the Remobilization of wheat genotype in the cold region of Ardabil

To evaluate storage and Remobilization ability photosynthetic material in 10 variant of wheat and bread, a pilot randomized complete block design was done under optimal conditions and with drought stress at the end of 2012 in the field of Islamic Azad University, Ardabil branch. Characteristics of the amount of Remobilization of material and storage from stem to grain, contribution amount of stem reserves to the grain yield, transfer efficiency of carbohydrates from stem to seed and special weight of stem were measured at physiological maturity. The results of combined variance analysis showed that the effect of the environment (drought), genotypes and interactive effect of genotype on all of the traits showed significant differences at 0.1 levels that implies to the large impact of environment on these characteristics. Results showed that Remobilization amount of stem reserves in stressed environment is significantly more than its favorable environment. Only two types of 10 types had greater efficiency in the transference of carbohydrates in stressed condition. So we can conclude that Remobilization of material in optimal moisture condition plays important role in the grain yield. Contribution amount of stem reserves in stressed condition was variant from %7.3 in cultivar type to %28.75 by Trakya type. In terms of transfer efficiency of carbohydrates Azar-2 figure easy the lowest.

The interaction of early life experiences with COMT val158met affects anxiety sensitivity

The pathogenesis of anxiety disorders is considered to be multifactorial with a complex interaction of genetic factors and individual environmental factors. Therefore, the aim of this study was to examine gene-by-environment interactions of the genes coding for catechol-O-methyltransferase (COMT) and monoamine oxidase A (MAOA) with life events on measures related to anxiety. A sample of healthy subjects (N = 782; thereof 531 women; mean age M = 24.79, SD = 6.02) was genotyped for COMT rs4680 and MAOA-uVNTR (upstream variable number of tandem repeats), and was assessed for childhood adversities [Childhood Trauma Questionnaire (CTQ)], anxiety sensitivity [Anxiety Sensitivity Index (ASI)] and anxious apprehension [Penn State Worry Questionnaire (PSWQ)]. Main and interaction effects of genotype, environment and gender on measures related to anxiety were assessed by means of regression analyses. Association analysis showed no main gene effect on either questionnaire score. A significant interactive effect of childhood adversities and COMT genotype was observed: Homozygosity for the low-active met allele and high CTQ scores was associated with a significant increment of explained ASI variance [R(2) = 0.040, false discovery rate (FDR) corrected P = 0.04]. A borderline interactive effect with respect to MAOA-uVNTR was restricted to the male subgroup. Carriers of the low-active MAOA allele who reported more aversive experiences in childhood exhibited a trend for enhanced anxious apprehension (R(2) = 0.077, FDR corrected P = 0.10). Early aversive life experiences therefore might increase the vulnerability to anxiety disorders in the presence of homozygosity for the COMT 158met allele or low-active MAOA-uVNTR alleles.

COMT and ALDH2 polymorphisms moderate associations of implicit drinking motives with alcohol use.

Dual process models of addiction emphasize the importance of implicit (automatic) cognitive processes in the development and maintenance of substance use behavior. Although genetic influences are presumed to be relevant for dual process models, few studies have evaluated this possibility. The current study examined two polymorphisms with functional significance for alcohol use behavior (COMT Val158Met and ALDH2*2) in relation to automatic alcohol cognitions and tested additive and interactive effects of genotype and implicit cognitions on drinking behavior. Participants were college students (n = 69) who completed Implicit Association Tasks (IATs) designed to assess two classes of automatic drinking motives (enhancement motives and coping motives). Genetic factors did not show direct associations with IAT measures; however, COMT and ALDH2 moderated associations of implicit coping motives with drinking outcomes. Interaction effects indicated that associations of implicit motives with drinking outcomes were strongest in the context of genetic variants associated with relatively higher risk for alcohol use (COMT Met and ALDH2*1). Associations of genotype with drinking behavior were observed for ALDH2 but not COMT. These findings are consistent with the possibility that genetic risk or protective factors could potentiate or mitigate the influence of reflexive cognitive processes on drinking behavior, providing support for the evaluation of genetic influences in the context of dual process models of addiction.

Interaction effect among maternal environment, maternal investment and progeny genotype on life history traits inCallosobruchus chinensis

Summary1. Transgenerational effects, genetic or non‐genetic, affect population dynamics and the evolution of life‐history traits. Besides genetic components, the size of gametes (eggs and seeds), simultaneously a parental and progeny character, can mediate environmental condition experienced by a parent. In both animals and arthropods, mothers are known to reduce their egg mass depending on their malcondition.2. Progeny may also modify their life history traits to increase their own fitness when constrained by maternal investment, which may eventually nullify transgenerational effects on population dynamics and evolution. Such fitness modification by the progeny under new environmental conditions requires phenotypic plasticity interacting with egg mass. We hypothesize that different selective environments should produce inter‐population genetic diversification of the response to maternal investment on each egg, which would be detected as a paternal genotype × environment × previous (i.e. maternal) environment (G × E × preE) interaction in progeny fitness.3. To evaluate the contribution of maternal non‐genetic resource and the genetic component separately, we used an inbred‐isofemale‐line approach to eliminate the influence of the genetic correlation between egg mass and other life history traits, in the adzuki bean beetle,Callosobruchus chinensis. The females were reared at either high or low densities to generate variability in egg resources. To test the additive or interactive effect of genotype, non‐genetic egg resources, and maternal environment on the life history traits of the progeny, they were crossed with males from laboratory and wild strains that had been subjected to different levels of population density.4. The G × E × preE interaction effect was detected on the correlation structure between egg mass and development time: In the offspring of mothers reared at low density, the negative correlation between egg mass and development time was higher with lab strain fathers, whereas in the offspring of mothers reared at high density, the negative correlation was higher with the wild strain fathers.5. Our results indicate a genetic difference in the response of development time but not of adult mass to environmental variation in egg mass. Such density‐dependent enhancement of maternal effects may destabilize population dynamics and accelerate evolution.

The association between dopamine D4 receptor exon III polymorphism and intensity of PTSD symptoms among flood survivors

Thanks to the development of molecular genetics methods it is now possible to look for the genes which may contribute to posttraumatic stress disorder (PTSD). Polymorphism located in exon III of dopamine receptor type 4 (DRD4) gene was related to maladaptive stress responses as well as temperament traits related to PTSD. This study analyzed the association between the variable number tandem repeat (VNTR) DRD4 exon III polymorphism and intensity of PTSD symptoms in 107 (57 women and 50 men) survivors of a flood aged 14–62. Intensity of PTSD symptoms was measured using PTSD-F and PTSD-C questionnaires. Multivariate analysis of covariance (MANCOVA) was conducted to test the main and interactive effects of genotype and level of trauma exposure. Participants with at least one copy of the DRD4 long allele (seven or eight repetitions) had more intense PTSD symptoms on the Avoidance/Numbing scale (Cohen's f = .22) and the Total Scale (Cohen's f = .2) of the PTSD-F than participants who did not have these alleles in genotype. The results must be treated with caution, however, due to methodological restrictions and they need to be replicated on a larger sample.

Bread from composite cassava–wheat flour. II: Effect of cassava genotype and nitrogen fertilizer on bread quality

There is an increasing interest in the use of cassava roots for food and industrial purposes especially in the baking industry in Nigeria. Development of some cassava mosaic disease (CMD) resistant clones and application of inorganic fertilizers are principal strategies targeted in the country to boost and sustain cassava root production and utilization. A study was conducted to determine the effect of cassava genotype and field application of nitrogen fertilizer on some physical properties of bread from composite cassava–wheat (CCW) flour. Five CMD cassava clones were planted in a randomized complete block design with two level of fertilizer treatments (0 and 160 kg nitrogen/ha) with two replications while harvesting was done 12 months after planting. Composite flour was produced at a ratio of 10/90 (cassava/wheat flour, w/w). The oven spring, specific volume, crumb texture (softness) and crumb moisture of loaves ranged from −0.57 to 0.63 cm, 4.37 to 6.85 cm3/g, 18.4 to 29.4 mm and 31.40% to 34.70%, respectively. The crust’s tristimulus color parameters L∗, a∗, b∗ and brownness index also ranged from 54 to 67, 9 to 15, 22 to 29, and 57 to 83, respectively. These values differed significantly from each other at p < 0.01. Out of all these loaf properties, crumb texture was the most affected by the main and interactive effects of cassava genotype and fertilizer application (p < 0.001) while loaf weight was only affected by their interactive effects (p < 0.05). Digital image analysis of the bread crumb showed that the total number of cells, number of small cells and total cell area of the bread crumb ranged from about 22 to 27 cm−3, 20 to 25 cm−3 and 12% to 29%, respectively. The distribution of large cells and total cell area occupied in the crumb were principally determined by the genotypic difference (p < 0.05) in the cassava roots. The main effect of fertilizer application significantly affected the distribution of small cells, total number of cell and the cell area (p < 0.05). However, the interactive effects of genotype and fertilizer application was more significant (p < 0.01) on the crumb cell characteristics. The study indicated that optimal quality of CCW bread loaf could be attained by appropriate selection of cassava genotype and fertilizer application.

Competition‐ and resource‐mediated tradeoffs between growth and defensive chemistry in trembling aspen (Populus tremuloides)

Costs of defense are thought to maintain genetic variations in the expression of defense within plant populations. As with many plant species, aspen exhibits considerable variation in allocation to secondary metabolites. This study examined the independent and interactive effects of genotype, soil fertility and belowground competition on defensive chemistry and growth in trembling aspen (Populus tremuloides). Four aspen genotypes were grown with high and low soil fertility, and with and without root competition. Physiological, morphological and allocational determinants of growth were measured to identify growth-defense tradeoffs. Nutrient limitation and competition decreased growth, leaf mass ratio, leaf nitrogen concentration and photosynthesis, and increased root : shoot ratio and leaf condensed tannin concentrations. The competition treatment also resulted in increased leaf phenolic glycoside (PG) concentrations. Aspen growth was negatively correlated with PG concentrations under low fertility with competition. The relationship between growth and its major determinants was also negatively related to foliar condensed tannins expressed as a proportion of tree mass, indicating an additional indirect cost of allocation to secondary metabolites.

Interactive effects of genotype, environment, and ontogeny on resistance of cucumber (Cucumis sativus) to the generalist herbivore, Spodoptera exigua.

Host-plant genotype, environment, and ontogeny all play a role in determining plant resistance to herbivory, yet little is known about the nature of the interactions among these factors. We investigated resistance of cucumber plants Cucumis sativus to the generalist herbivore Spodoptera exigua in a manipulative experiment involving three factors. In particular, we tested the effects of bitter (cucurbitacins present) vs. sweet (cucurbitacins absent) plants (genotype), with or without previous herbivory (environment), and cotyledons vs. true leaves (ontogeny). Contrary to our expectations, S. exigua growth was 54% higher on bitter plants than on sweet plants; growth was 63% higher, however, on undamaged plants compared to damaged plants, and 59% higher on true leaves compared to cotyledons. Moreover, all two-way interaction terms between genotype, environment, and ontogeny were significant. For example, S. exigua performance was higher on bitter than on sweet plants; however, this effect was strongly influenced by whether the tissue consumed was a cotyledon or true leaf and also whether it had been previously damaged. An examination of leaf nutritional chemistry revealed that some of our results could be explained by genotypic, environmental, and ontogenic differences in foliar nitrogen content. In contrast, the cucurbitacin content of plants did not appear to affect caterpillar growth. Our results provide evidence for the importance of interactions between genotype, environment, and ontogeny in determining herbivory and illustrate the value of manipulative experiments in revealing the complexities of these interactions.