Significant Effect Of Genotype Research Articles

Genotype by year interaction for selected traits in sweet maize (Zea maize L.) hybrids using AMMI model

This study investigated genotype × environment interactions for the stability of expression of four productivity traits (cobs yield, cobs I class trade share, lend of cobs and fulfilment of cobs) of sweet maize hybrids (Zea mays L.). The additive main effects and multiplicative interaction (AMMI) model was employed to assess genotype × environment interaction. AMMI stability value was used to evaluate both stability and genotype. The genotype selection index was calculated for each hybrid, incorporating both the average trait value and the stability index. Ten sweet maize hybrids were evaluated: Golda, GSS 1453, GSS 3071, GSS 5829, GSS 8529, Overland, Noa, Shinerock, Sindon, and Tessa. Trials were ran conducted over four vegetative seasons at a single location in the Wielkopolska region using replicated field experiments. The AMMI model revealed significant genotypic and environmental effects for all analyzed traits. Based on their superior stability and favorable average trait values, both the Golda cultivar and the GSS 3071 hybrid are recommended for further breeding program inclusion.

Unraveling genotype-by-environment interaction in maize using cutting edge statistical tools: Innovative empirical selection for increased yield stability

By prioritizing high yields in ideal conditions, traditional breeding might miss out that genotypes with superior yield and stability. Thus,this study seeks to identify stable genotypes that offer more predictable and reliable yields; under both stress and resourceful environments, leading to not only greater food security but financial stability as well. Incorporating both fixed (AMMI&GGI) and random effects models (BLUP & MTSI), not only leveraged theoretical but also empirical comparisons-weakness of each model is covered by all 4 models-to select elites hybrids Maize. Furthermore, a multi-environment trial assessed 41 hybrids across 4 research stations in 2 winter seasons using RCB design. Likewise, compiled cutting-edge statistical methods for GEI analyses from the “metan” package (R-Software), selected hybrids with consistent performance with meticulous analysis. AMMI(Additive Main effects and Multiplicative Interaction)analysis revealed that of significant (p ≤ 0.05) effects of genotype, environment, & genotype-environment interaction (GEI), explaining yield variance with interaction effects were captured by 3 interaction principal components (IPCs). Moreover,GEI graphics of AMMI biplots elucidates four hybrids(MRM-4062, Super-22, PAC-744, and Gen-4118) with high yield stability and above-average performance. Additionally, eight hybrids (4118, 4558, 5454, NMH1258, PAC 746, PAC 745 Gold, and SUPER 9090) exhibited superior yield, regardless of their stability. Nepalgunj exhibited the lowest GEI value. Conversely, Rampur displayed an above-average GEI, indicating a strong ability to modulate varieties performance. Besides this, GGE biplot revealed two potential mega-environments based on yield similarities. Nine high-yielding hybrids (SUPPER 6768, SUPPER 9396, PAC750, MBS5622, PAC745 Gold, MRM4065, NMH8392, Gen-4118, and Gen-4558) were identified as vertex hybrids, signifying their superior performance across wide environments. Even supposing, mixed effects model, both the best linear unbiased prediction (BLUP) weighted with average absolute score standardized by yields (WAASBY) models, Gen-4118 ranked highest in terms of average yield, followed by NMH-8392, TMH2858, and others, and Multi-Trait Stability Index (MTSI) identified SUPPER-9090 as the most stable and high-yielding genotype, followed by NMH4040, Super-22, Gen-4118, MBS-1144, and NMH1255. In a nutshell, Gen-4118, Super-9090, MRM-4062, NMH1258, NMH-8392, TMH2858, PAC 746, PAC 745 Gold emerge as the highest-yielding and most consistently high-performinghybrids, offering promise for commercial farming across diverse environments. Clearly,this study has potential to mitigate risks for farmers (economic burden, crop failure) and bolster food security/climate resilience. What's more, it paves the way for future research on cold tolerance genes for even greater crop improvement.

The Role of Collagen VIII in the Aging Mouse Kidney.

The gradual loss of kidney function due to increasing age is accompanied by structural changes such as fibrosis of the tissue. The underlying molecular mechanisms are complex, but not yet fully understood. Non-fibrillar collagen type VIII (COL8) could be a potential factor in the fibrosis processes of the aging kidney. A pathophysiological significance of COL8 has already been demonstrated in the context of diabetic kidney disease, with studies showing that it directly influences both the development and progression of renal fibrosis occurring. The aim of this study was to investigate whether COL8 impacts age-related micro-anatomical and functional changes in a mouse model. The kidneys of wild-type (Col8-wt) and COL8-knockout (Col8-ko) mice of different age and sex were characterized with regard to the expression of molecular fibrosis markers, the development of nephrosclerosis and renal function. The age-dependent regulation of COL8 mRNA expression in the wild-type revealed sex-dependent effects that were not observed with collagen IV (COL4). Histochemical staining and protein analysis of profibrotic cytokines TGF-β1 (transforming growth factor) and CTGF (connective tissue growth factor) in mouse kidneys showed significant age effects as well as interactions of the factors age, sex and Col8 genotype. There were also significant age and Col8 genotype effects in the renal function data analyzed by urinary cystatin C. In summary, the present study shows, for the first time, that COL8 is regulated in an age- and sex-dependent manner in the mouse kidney and that the expression of COL8 influences the severity of age-induced renal fibrosis and function.

Combining ability of Egyptian cotton (Gossypium barbadense L.) reveals genetic potential for improved yield and fiber quality

BackgroundAs the most widely cultivated fiber crop, cotton production depends on hybridization to unlock the yield potential of current varieties. A deep understanding of genetic dissection is crucial for the cultivation of enhanced hybrid plants with desired traits, such as high yield and fine fiber quality. In this study, the general combining ability (GCA) and specific combining ability (SCA) of yield and fiber quality of nine cotton parents (six lines and three testers) and eighteen F1 crosses produced using a line × tester mating design were analyzed.ResultsThe results revealed significant effects of genotypes, parents, crosses, and interactions between parents and crosses for most of the studied traits. Moreover, the effects of both additive and non-additive gene actions played a notably significant role in the inheritance of most of the yield and fiber quality attributes. The F1 hybrids of (Giza 90 × Aust) × Giza 86, Uzbekistan 1 × Giza 97, and Giza 96 × Giza 97 demonstrated superior performance due to their favorable integration of high yield attributes and premium fiber quality characteristics. Path analysis revealed that lint yield has the highest positive direct effect on seed cotton yield, while lint percentage showed the highest negative direct effect on seed cotton yield. Principal component analysis identified specific parents and hybrids associated with higher cotton yield, fiber quality, and other agronomic traits.ConclusionThis study provides insights into identifying potential single- and three-way cross hybrids with superior cotton yield and fiber quality characteristics, laying a foundation for future research on improving fiber quality in cotton.

Identification of superior genotypes for leaf architecture traits in Sorghum bicolor through GGE biplot analysis

Context Well-organised leaf architecture produces compact canopies and allows for greater sunlight penetration, higher photosynthetic rates, and thus greater yields. Breeding for enhanced leaf architecture of sorghum (Sorghum bicolor L.), a key food source in semi-arid regions, benefits its overall production. Aims The study focuses on selecting useful genotypes with excellent leaf architecture for grain sorghum improvement. Methods In total, 185 sorghum genotypes were subjected to multi-environment trials. Leaf flagging-point length, leaf length, leaf width, leaf angle and leaf orientation value (LOV) were characterised under field conditions. Genotype + genotype × environment interaction (GGE) biplot analysis was used to identify the most stable genotypes with the highest LOV. Key results Statistical analysis showed significant effects of genotype × environment interaction (P < 0.001), and high broad-sense heritability for the traits. Correlation analysis demonstrated negative correlations (P < 0.001) between LOV and its components. Singular value decomposition of LOVs in the first two principal components explained 89.19% of the total variation. GGE biplot analysis identified G55 as the ideotype with the highest and most stable LOV. Conclusions Leaf architecture optimisation should be given greater attention. This study has identified a genotype with optimal and stable leaf architecture, laying the foundation for improvement in breeding to increase overall yields of sorghum. Implications Genotype G55 can be utilised as a parent with other parents that display economically important characteristics in breeding programs to produce offspring that can be planted densely to increase population yields. Genotypes identified with loose leaf architecture are useful in dissecting genes controlling leaf architecture by crossing with G55 to construct genetic mapping populations.

Assessment of stability for some yield components in wheat under different fertilizations on saline soil

Salt-affected soils constrain wheat production in many countries. It is estimated that more than 831 million hectares (Mha) are salt affected globally, with 10 Mha of cultivated land lost annually. Salinity adversely affects wheat grain yield and grain quality traits. Wheat genotypes show wide variation for salinity stress tolerance. The main objective of this study was to evaluate the performance and stability of spike traits in 14 winter wheat varieties with different origin, in order to identify the varieties that can exploit the growing conditions of saline soils. The wheat material was tested in nine environments as a combination of three years and three fertilization treatments (urea, calcium nitrate, ammonium nitrate), using a split-plot design with three replications. At maturity plant height, spike length, grains number per spike, and spike yield were determined. The significant effect of genotype × environment interaction on the phenotypic expression of different traits indicates differential response of the genotypes across the testing environments, thus offering the possibility of identifying some genotypes of interest. The Romanian varieties ‘Alex’ and ‘Glosa’ present the highest productivity of spike associated with an average stability, being specifically adapted to favourable rainfall conditions, achieving above-average yields in less favourable conditions. The varieties ‘Cerere’, ‘Genesi’, ‘Alex’ and ‘Glosa’ can be selected for crossing and included in wheat breeding programs for the development of stable cultivars adapted to saline soils.

A comprehensive analysis of APOE genotype effects on human brain structure in the UK Biobank

Alzheimer’s disease (AD) risk is increased in carriers of the apolipoprotein E (APOE) ε4 allele and decreased in ε2 allele carriers compared with the ε3ε3 genotype. The aim of this study was to determine whether: the APOE genotype affects brain grey (GM) or white matter (WM) structure; and if differences exist, the age when they become apparent and whether there are differential effects by sex. We used cross-sectional magnetic resonance imaging data from ~43,000 (28,494 after pre-processing) white British cognitively healthy participants (7,446 APOE ε4 carriers) aged 45–80 years from the UK Biobank cohort and investigated image-derived phenotypes (IDPs). We observed no statistically significant effects of APOE genotype on GM structure volumes or median T2* in subcortical structures, a measure related to iron content. The volume of white matter hyperintensities differed significantly between APOE genotype groups with higher volumes in APOE ε4ε4 (effect size 0.14 standard deviations [SD]) and ε3ε4 carriers (effect size 0.04 SD) but no differences in ε2 carriers compared with ε3ε3 carriers. WM integrity measures in the dorsal (mean diffusivity [MD]) and ventral cingulum (MD and intracellular volume fraction), posterior thalamic radiation (MD and isotropic volume fraction) and sagittal stratum (MD) indicated lower integrity in APOE ε4ε4 carriers (effect sizes around 0.2–0.3 SD) and ε3ε4 (effect sizes around 0.05 SD) carriers but no differences in ε2 carriers compared with the APOE ε3ε3 genotype. Effects did not differ between men and women. APOE ε4 homozygotes had lower WM integrity specifically at older ages with a steeper decline of WM integrity from the age of 60 that corresponds to around 5 years greater “brain age”. APOE genotype affects various white matters measures, which might be indicative of preclinical AD processes. This hypothesis can be assessed in future when clinical outcomes become available.

Soil and seed both influence bacterial diversity in the microbiome of the Cannabis sativa seedling endosphere.

Phytobiomes have a significant impact on plant health. The microbiome of Cannabis sativa is particularly interesting both because of renewed interest in this crop and because it is commercially propagated in two different ways (i.e. clonally and by seed). Angiosperms obtain a founding population of seed-borne endophytes from their seed-bearing parent. This study examines the influence of both seed and soil-derived bacteria on the endospheres of cannabis seedlings of both hemp- and drug-types. A multi-factorial metagenomic study was conducted with three cannabis genotypes and two soil sources, which were tested both before and after autoclave sterilization. Seedlings were grown on soil, then rinsed and surface-sterilized, and 16S rDNA amplicons from seedling endophytes were sequenced, taxonomically classified, and used to estimate alpha- and beta-diversity in Qiime2. The statistical significance of differences in seedling microbiomes across treatments was tested, and PiCRUST2 was used to infer the functional relevance of these differences. Soil was found to have a profound effect on the alpha-diversity, beta-diversity, relative abundance, and functional genes of endophytic bacteria in germinating cannabis seedlings. Additionally, there was a significant effect of cannabis genotype on beta diversity, especially when genotypes were grown in sterilized soil. Gammaproteobacteria and Bacilli were the two most abundant taxa and were found in all genotypes and soil types, including sterilized soil. The results indicated that a component of cannabis seedling endosphere microbiomes is seed-derived and conserved across the environments tested. Functional prediction of seedling endophytes using piCRUST suggested a number of important functions of seed-borne endophytes in cannabis including nutrient and amino acid cycling, hormone regulation, and as precursors to antibiotics. This study suggested both seed and soil play a critical role in shaping the microbiome of germinating cannabis seedlings.

CD38 genetic variation is associated with increased personal distress to an emotional stimulus

Genetic variation in CD38—a putative oxytocin pathway gene—has been linked to higher oxytocin levels, empathy, and sensitive parenting, but also to more negative interpersonal outcomes (e.g., alienation from friends and family, poorer romantic relationship quality). To reconcile these seemingly contradictory findings, we drew upon the idea that CD38 variation may heighten social-emotional sensitivity and, consequently, make individuals prone to negative emotions in distressing interpersonal situations. To test this hypothesis, we performed a secondary analysis of a dataset including participants’ (n = 171; 94 females) empathic concern (“sympathetic”) and distress-related (“anxious”) responses to an emotional video. Distress responses were higher for the CD38 rs3796863 AA/AC group vs. the CC group (p = 0.03, η2 = 0.027); however, there was no significant effect of genotype for empathic concern responses to the video or for indices of trait empathy. These findings provide preliminary evidence that, in the face of an interpersonal stressor, CD38 genetic variation may predict more self-focused, aversive emotional reactions. More broadly, this finding highlights the need to adopt a more nuanced perspective in which the influence of oxytocin system variation (assessed by oxytocin-related genetic variation) should be considered in light of the social context.

Deciphering G × E Interaction of Photo-insensitive Horsegram [Macrotyloma uniflorum (Lam.) Verdc.] Mutants using AMMI and GGE Biplot Models

Background: Photosensitivity in horsegram restricts horizontal expansion in its cultivable area. Using induced mutagenesis, photo-insensitive mutants of a popular variety PAIYUR 2 were evolved. Methods: The mutants were experimented with across seasons and locations. All the experiments were conducted in the randomized block design with five replications. The AMMI and GGE biplot models were employed to tag the best-yielding and stable genotype(s). Result: The ANOVA indicated significant effects of genotypes (G), environments (E) and their combined genotype × environment interaction (G × E) for all the experimental traits implying a large range of variation. The interaction effect in AMMI has been partitioned into several principal components. Of the six Principal Components (PC), the first PC explained the major variation. It is 60.20% for the number of clusters per plant, 99.60% for days to fifty percent flowering, 92.57% for the number of pods per cluster, 96.63% for the number of pods per plant, 99.66% for days to maturity and 96.34% for yield per hectare. AMMI and GGE biplot analyses helped to identify the best performing and stable photo-insensitive mutants TNAU-HG-DM-001 and TNAU-HG-DM-004 for further exploitation.

GENETIC VARIATION AND HERITABILITY ESTIMATES IN CHICKPEA SEEDLING TRAITS: IMPLICATIONS FOR BREEDING PROGRAMS

Chickpea, also known as Bengal gram, Channa, or garbanzo bean, is a vital pulse crop that offers wholesome food to the growing population. Originating from modern-day southeast Turkey and Syria, chickpea germplasm is abundant in Ethiopia, serving as a secondary centre of genetic diversity for various dietary legumes. Two main varieties are desi and Kabuli. A study at the University of Punjab Lahore found significant genetic variations in chickpea seedlings, with high genetic components and a broad-sense heritability of 87.04%. Root length showed a significant genotypic effect, with a PCV of 16.39% and a larger GCV than SL. The root-to-seedling length ratio showed a significant genotypic variance, with a heritability estimate of 69.98% and a genetic advance of 5.740%. Seedling biomass did not show significant genotypic variation. Leaf characteristics showed substantial genotypic differences, indicating extensive genetic heterogeneity. The correlation matrix showed substantial correlations between seven qualities in chickpea seedlings, suggesting genetic and physiological links between the qualities. These findings can inform breeding efforts, improve breeding programs, and generate new varieties with improved features.

Genotype by environment and genotype by yield*trait interactions in sugar beet: analyzing yield stability and determining key traits association

The genotype by environment interaction significantly influences plant yield, making it imperative to understand its nature for the creation of breeding programs to enhance crop production. However, this is not the only obstacle in the yield improvement process. Breeders also face the significant challenge of unfavorable and negative correlations among key traits. In this study, the stability of root yield and white sugar yield, and the association between the key traits of root yield, sugar content, nitrogen, sodium, and potassium were examined in 20 sugar beet genotypes. The study was conducted using a randomized complete block design with four replications over two consecutive years across five locations. The combined analysis of variance results revealed significant main effects of year, location, and genotype on both root yield and white sugar yield. Notably, two-way and three-way interactions between these main effects on root yield and white sugar yield resulted in a significant difference. The additive main effect and multiplicative interaction analysis revealed that the first five interaction principal components significantly impacted both the root yield and white sugar yield. The linear mixed model results for root yield and white sugar yield indicated that the genotype effect and the genotype by environment interaction were significant. The weighted average absolute scores of the best linear unbiased predictions biplot demonstrated that genotypes 20, 4, 7, 2, 16, 3, 6, 1, 14, and 15 were superior in terms of root yield. For white sugar yield, genotypes 4, 16, 3, 7, 5, 1, 10, 20, 2, and 6 stood out. These genotypes were not only stable but also had a yield value higher than the total average. All key traits, which include sugar content, sodium, potassium, and alpha amino nitrogen, demonstrated a negative correlation with root yield. Based on the genotype by yield*trait analysis results, genotypes 20, 19, and 16 demonstrated optimal performance when considering the combination of root yield with sugar content, sodium, alpha amino nitrogen, and potassium. The multi-trait stability study, genotype 13 ranked first, and genotypes 10, 8, and 9 were identified as the most ideal stable genotypes across all traits. According to the multi-trait stability index, genotype 13 emerged as the top-ranking genotype. Additionally, genotypes 10, 8, and 9 were recognized as the most stable genotypes.

Effect of Feeding Selected Strains of Conserved Breed Hens with Diets Containing Legumes on Egg Quality and Content and Activity of Lysozyme

Abstract The aim of the study was to evaluate the effect of replacing soybean meals with legume grains in diets on laying performance of hens and egg quality, with particular emphasis on egg lysozyme content. The study included 4 breeds/strains of laying hens included in the conservation programme in Poland, i.e.: Green-legged Partridge (Z-11), Yellow-legged Partridge (Ż-33), Rhode Island Red (R-11), and Leghorn (H-22). At 41–56 weeks of age, the hens of each strain were divided into two groups: I (control) − fed ad libitum with a standard diet based soybean meal, and II (experimental) − fed ad libitum with a diet that contained beans, peas and lupins instead of soybean meal. At 56 weeks of age, 32 eggs were taken at random from each group of hens and each strain, which were subjected to quality assessment. The results of the study confirm the possibility of feeding the above-mentioned hens with diets in which soybeans were replaced with 28% of faba bean, pea, and yellow lupin grains without a significant effect on laying performance, but with a change in some egg quality characteristics. In groups of hens fed a diet without soybean, a decrease in egg and albumen weight, albumen and yolk pH values, and an increase in yolk yellowness were recorded, as well as an increase in Haugh units and air cell height and shell porosity. There was a significant effect of genotype and diet and simultaneously of both factors on the content and activity of lysozyme in the thin and thick albumen. In the experimental groups, the average content and activity of lysozyme in the thin albumen decreased and in the thick albumen increased. Regardless of diet, statistically significant variation in egg internal quality and egg shell quality between hen strains was shown, as well as a correlation between the content and activity of lysozyme in eggs and shell colour.

Avaliação precoce da interação genótipo x safras na cultura da mandioca sob déficit hídrico

ABSTRACT The aim of this study was to evaluate the effect of genotype x harvest interactions on different agronomic traits, the genetic correlation between traits in early selection under water stress, and early selection in cassava. 25 cassava genotypes were evaluated in a randomized block experimental design with four replications. The variables root weight (RW), root number per plant (RN), root diameter (RD), root length (RL), root dry matter content (DMC), stem number per plant (SN), plant height (PH), stem diameter (SD), mite severity (MS), and harvest index (HI) were evaluated under water stress conditions in two harvests. Broad-sense heritability (h²), realized heritability ( ( h R 2 )), and the index of coincidence (IC) were estimated. Accuracy estimates ranged from 0.62 for RL to 0.86 for DMC. A significant genotype effect was identified on all traits, except for RW, RL and SD. Significant genotype x harvest interactions occurred for the variables SN, PH, SD, and HI. (h²) estimates ranged from 0.27 for RL to 0.79 for SN. The estimates of the index of coincidence ranged from 100% to 25%. A positive correlation was observed between all variables under study, except for MS, RN and SN, and the other traits. The genotypes showed similar performance in the two harvests for most variables, except for SN, PH, SD, and HI.

Caracterização do germoplasma de soja com aptidão ao consumo humano no Uruguai

Abstract Soybean (Glycine max (L.) Merrill) is a crop of world economic importance; and its grain constitutes a significant source of protein and carbohydrates for human consumption. This work aimed to characterize soybean genotypes available in Uruguay for human consumption regarding protein quantity and quality, carbohydrate composition and oil content in relation to yield, both in genetically modified and conventional genotypes. In this study, 13 genotypes grown in three different environments (two locations, two years), a conventional set (22 genotypes) and a genetically modified set (36 genotypes), grown in a single environment were subject to study. The traits measured were yield, total protein, oil content, soluble protein, glycinin (11S), conglycinin (7S), the 11S/7S ratio, soluble carbohydrates, sucrose and total raffinose family oligosaccharides (RFOs). A significant environmental and genotype effect was detected for most of the parameters. The interaction between genotype and environment was significant for total protein, oil content and sucrose. Soluble protein and the 11S fraction were only affected by environment; soluble carbohydrates and the 7S fraction were only affected by genotype. It was possible to identify genotypes with good characteristics for human consumption (high total protein, sucrose, ratio 11S/7S and low oligosaccharides) across environments, both genetically modified and conventional genotypes. Variability was found among the genotypes available in Uruguay in the parameters studied.

Physiological, agro-morphological, and germination responses of a worldwide chickpea (Cicer arietinum) collection subjected to drought stress by applying polyethylene glycol (PEG) on germinating seeds and by exposure plants to water restriction at the vegetative stage

Given that agriculture uses considerable quantities of water to meet food requirements, the scarcity of rainfall and the drying up of water tables could compromise agricultural production. Faced with the urgency of a world undergoing demographic change and a current agro-climatic trend marked by low rainfall at the vegetative stage, the sustainability of chickpea production requires new varieties with resilience and adaptation to climatic change. The aim of this study is the selection genotypes that are tolerant to early drought stress and able to avoid terminal drought. To this end, a collection of 159 genotypes was evaluated, using an augmented-RCBD (Randomized Complete Block Designs), in two experiments (drought stress by water restriction and stress imposition by Polyethylene glycol (PEG) application) simulating the effect of drought. Our results show significant genetic variability and a fairly significant genotype effect in both trials. We noted an interesting positive correlation between germination percentage in the presence of PEG and pod and seed production under water stress at the vegetative stage, and these same traits showed strong heritability. 16 genotypes had a germination percentage ≥50% in the 20% PEG treatment. In addition, 18 Desi and 4 Kabuli genotypes performed well in both trials, with good germination percentage, pod and seed production, good canopy coverage, better normalized difference vegetation index, and low to medium wilting. It would therefore make sense to exploit these genotypes in hybridization programs for the creation of pure drought-tolerant lines, and also to evaluate them in different arid and semi-arid regions over several years.

Evaluation of rapeseed (Brassica napus L.) genotypes for tolerance to PEG (polyethylene glycol) induced drought at germination and early seedling growth

Rapeseed (Brassica napus L.) is an important oilseed crop well adapted to Mediterranean area. However, increasing drought, due to climate change, impairs its growth and development, mainly when this stress occurs early during germination. This study carried out in vitro conditions aimed to investigate the effect of water deficit on seed germination and seedling growth traits in 12 genotypes to select the most drought-tolerant ones. Drought conditions were created using polyethylene glycol 6000 to induce three osmotic potential levels, namely −0.7 MPa for moderate stress, −0.9 MPa for intermediate stress, and −1.1 MPa for severe stress. Germination percentage (GP), germination rate (GR), mean germination time (MGT), root length (RL), shoot length (SL), root-to-shoot ratio (RSR), seedling vigor index (SVI), shoot elongation rate (SER), and root elongation rate (RER) were measured/calculated. ANOVA and PCA were performed to analyze the data gathered. Results showed a significant effect of genotype, drought, and drought × genotype interaction on all studied parameters. Under severe drought conditions, overall values of GP, GR, RL, SL, SER, RER, and SVI decreased by 87.15 %, 53.29 %, 9.33 %, 4.73 %, 78 %, 82 %, and 96 %, respectively, while those of MGT and RSR increased by 56 % and 76 %, respectively, when compared to unstressed conditions. However, the genotypes studied reacted differently to the three levels of water stress. Based on PCA results, RL, RER, and GP proved to be the most discriminating of drought-tolerant genotypes. Overall, higher drought tolerance was associated with higher values in RL, SL, and SVI. Accordingly, the variety ‘Nap10’ and, to a lesser extent, ‘Baraka’ and ‘Nap9’ exhibited higher drought tolerance than the rest of genotypes, which makes them potential cultivars for dry areas. However, further studies in real field conditions are needed to confirm their tolerance to drought occurring at germination as well as during other stages, mainly flowering.

Does FOXO3 longevity genotype explain the conflicting data on late‐life hypertension and risk of Alzheimer’s disease?

AbstractBackgroundThe association of late‐life hypertension (LHTN) with Alzheimer’s disease (AD) remains controversial. We hypothesize that FOXO3 longevity‐associated genotype modulates the association between LHTN and incident AD.MethodSubjects were 2,688 American men of Japanese ancestry (baseline age: 77.0 ± 4.1 years, range 71‐93 years) from the Kuakini Honolulu Heart Program. Status was known for FOXO3 rs2802292 genotype, LHTN at baseline, and diagnosis of incident dementia over 21 years follow‐up. Association of FOXO3 genotype with LHTN and incident all‐cause dementia, vascular dementia (VD) and Alzheimer’s disease was assessed using Cox regression.ResultDuring the follow‐up, 725 men were diagnosed with all‐cause dementia, 513 with AD and 104 with VD. A multivariable Cox model, adjusting for age, education, APOE‐ε4 and cardiovascular risk factors, showed LHTN increased VD risk (HR = 1.71, 95%CI = 1.08–2.71, p = 0.022), but not AD risk. We found no significant protective effect of FOXO3 longevity genotype, nor of LHTN, on all‐cause dementia and AD at the population level. However, in a full Cox model adjusting for age, education, APOE‐ε4 and other cardiovascular risk factors, there was a significant interaction effect of LHTN and FOXO3 longevity genotype on incident AD (ß = –0.52, p = 0.0061). In men with FOXO3 rs2802292 longevity genotype (TG/GG), LHTN showed protection against AD (HR = 0.72; 95% CI = 0.55–0.95, p = 0.021). In men with FOXO3 rs2802292 non‐longevity genotype (TT), LHTN had no protective effect (HR = 1.16; 95% CI = 0.90‐1.51, p = 0.25).DiscussionSince the effect of LHTN on AD incidence differed according to FOXO3 genotype, the overall effect, namely, a weighted average effect of LHTN on AD across different FOXO3 genotypes, would be moving towards the null (i.e., HR = 1). This would explain why most studies have found no significant association between LHTN and AD. One exception is the Ibadan study, in which all participants were African American. African Americans have the highest proportion (94%) of FOXO3 rs2802292 longevity genotype (TG/GG) in all races, and the strongest effect of LHTN in protecting against AD (RR = 0.33).ConclusionThis longitudinal study found that FOXO3 genotype modulates the effect of late‐life hypertension on incident AD, thus explaining the conflicting data on late‐life hypertension and Alzheimer’s disease.

The effects of ApoE e4 genotype on plasma p‐tau181 concentrations on clinically diagnosed Alzheimer’s disease (AD) compared to controls

AbstractBackgroundThe association between ApoE e4, a powerful genetic risk factor for AD, and beta‐amyloid (Aβ) pathology has been reported, but the evidence for the correlation with tau pathology is not as clear. The current study examined the relationship between ApoE e4 allele and plasma concentrations of p‐tau181 in patients with clinically diagnosed AD compared with an age‐matched controls with normal cognitive function.MethodWe examined 302 EDTA plasma samples of patients assessed at the UBC Hospital Clinic for Alzheimer’s disease. The cohort was clinically characterized as controls (n = 59) if no significant cognitive impairment was found, and AD (n = 243) if they fulfilled the NIA‐AA criteria (McKhann 2011). The plasma ptau‐181 levels were measured using an ADx‐developed p‐tau181‐specific Simoa assay. ApoE genotyping was performed on extracted DNA from blood samples. We examined the association of presence of ApoE e4 allele and plasma p‐tau181 concentrations using two‐by‐two ANOVA using SPSS 29.ResultThe plasma concentrations of p‐tau181 in AD who are ApoE e4 carriers (75.4 pg/ml) were slightly higher than but not significantly different from in AD non‐ ApoE4 carriers (70.1 pg/ml) (p = 0.64). The plasma levels of ptau‐181 in control cases with and without the ApoE allele were 24.8 and 24 pg/ml respectively (p = 1.000). There was no statistical significant interaction between the effects of AD and ApoE e4 carrier status on plasma p‐tau181 (F (1, 298) = 0.21, p = 0.65, ηp2 = 0.001).ConclusionWhile the plasma p‐tau181 concentrations were significantly higher in AD groups compared to controls (p<0.001) it was no significant effect of ApoE e4 genotype on the levels of plasma p‐tau181 in the control or AD groups (p = 0.94, p = 0.21). This suggests that the ApoE e4 carrier status does not affect plasma p‐tau181 concentrations significantly, independent of the AD clinical status.

Genotypic differences in water deficit effects on leaf and crown traits in mature field-grown cocoa

Cocoa trees are highly sensitive to water stress but these negative effects may differ genetically and may be mitigated by potassium (K) application. We studied these effects on six-year-old adult trees, five genotypes produced by somatic-embryogenesis, and one by cross pollination (Hybrid), grown under sub-optimal field conditions in central Côte d'Ivoire. Trees were subjected to two soil water treatments (with or without dry season irrigation) and two K fertilization levels (with and without K). We assessed interactive effects of treatments on several leaf and crown traits: sap flux density (SF), leaf water potential (LWP), stomatal conductance (Gs), leaf size (LS), specific leaf area (SLA), leaf water content (LWC), leaf area index (LAI), light interception, litterfall and a visual index of whole-plant water stress (WSI). Mixed-effects model results revealed that withholding irrigation negatively affected SF, LWP, Gs, LS, SLA, LAI and light capture and increased WSI scores. Potassium application did not significantly mitigate the negative effects of withholding irrigation. A significant effect of genotype was observed for most of the monitored leaf physiological, morphological and crown traits. Furthermore, we found significant, positive interactions between genotype and irrigation for SF, LWP, leaf area, LS, SLA, LWC, LAI and intercepted light, suggesting that the differences in observed responses to drought conditions are genotype-specific. These results provide insights into the acclimation strategies of cocoa and genetic variation therein, and can be used to select drought-tolerant genotypes.