Commercial Clones Research Articles

Abstract 6008: Antibody validation for clinical pharmacodynamic assay reveals cross-reactivity of commercial DNMT3B clones

Abstract Cooperativity between the maintenance DNA methyltransferase, DNMT1, and de novo methyltransferases, DNMT3A and 3B, is essential for proper maintenance and integrity of the methylome, and deregulation of these enzymes and associated transcriptional silencing of multiple genes has been shown in many types of cancer. Two DNA methyltransferase inhibitors are currently in clinical use with several others undergoing clinical evaluation, and the pharmacodynamic response of DNMT enzymes is a crucial aspect of understanding therapeutic effects in preclinical studies and clinical trials. Vigorous fit-for-purpose validation of research-grade reagents and the application of effective quality control testing procedures to assess lot-to-lot variability (and reject unacceptable lots) are essential to assure robust and reproducible pharmacodynamic assay performance. During the antibody validation process for the DNMT3B enzyme target, two commercial monoclonal antibody clones were found to exhibit significant cross-reactivity to another cellular protein and inappropriate subcellular localization via immunohistochemistry (IHC), including diffuse cytoplasmic staining and significant staining in a DNMT3B knock out (KO) cell line. Two other commercial monoclonal antibody clones showed the expected nuclear expression in the HCT116 parental cell line and lack of staining in the DNMT KO cells. Further evaluation via western blot revealed that the cross-reacting antibodies detected a band of the approximate expected molecular weight (MW) of DNMT3B but of a protein that was expressed equivalently in the parental and DNMT3B KO cell line pair, whereas the two other antibody clones only detected a significant band of correct MW in the parental but not the KO cell line. These results suggest that some commercial antibody clones are binding to a protein other than DNMT3B and that they are unsuitable for use with IHC and western blot to evaluate subcellular localization and expression levels of DNMT3B protein. We presume that these non-specific antibody clones were chosen for commercial development based on target screening via Western blot that did not include evaluation of a validated DNMT3B knock out cell line, as is not uncommon for research-grade antibody clones. This data highlights the critical importance of thorough fit-for-purpose validation and quality control for crucial reagents used for pharmacodynamic biomarker studies. Funded by NCI Contract No HHSN261200800001E Citation Format: Gabriel J. Benton, Manisha Mohandoss, James H. Doroshow, Ralph E. Parchment, Katherine V. Ferry-Galow. Antibody validation for clinical pharmacodynamic assay reveals cross-reactivity of commercial DNMT3B clones. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6008.

Abstract 6630: Flow cytometry immunophenotyping using commercial antibodies to maximize detection of PD-1 in immuno-oncology (I-O) clinical studies with anti-PD-1 check point inhibitors

Abstract Precision for Medicine’s translational biomarker expertise supports global clinical trials with flow cytometry. A biomarker strategy which includes flow cytometry to generate pharmacokinetic/pharmacodynamic (PK/PD) models for rational design of dose escalation and expansion of clinical studies, may need to consider concomitant drugs for checkpoint inhibition like Pembrolizumab. Precision has optimized the use of commercial anti-PD-1 and anti-IgG4 reagents to detect both free PD-1 and/or Pembro-bound PD-1 when patients are on study with a new molecular entity as either a monotherapy or in combination with concomitant checkpoint inhibitors. For I-O studies conventional efficacy endpoints combined with flow biomarker driven surrogate endpoints enhance therapeutic decisions for determining mechanism of action and biological response when incorporated in early-phase clinical studies. Precision developed and qualified a flow immunophenotyping assay to quantify PD-1 on CD4+ and CD8+ T cells using a commercial PD-1 clone (PD1.3.1.3) and an anti-IgG4. This enabled detection of both free and drug bound PD-1 receptor. We compared detection of PD-1 in PHA stimulated healthy donors treated with saturating Pembrolizumab or no drug treatment. There was not a significant difference observed in PD-1 quantification in the presence or absence of Pembrolizumab, which demonstrated that our approach was able to accurately measure total PD-1 whether free or bound. As Pembrolizumab was titrated from the saturating concentration there was a dose-dependent decrease in detection of PD-1. We have used this assay to detect PD-1 with several new I-O therapies that combined standard anti-PD-1 checkpoint inhibitors, and in these clinical studies for advanced and rare solid tumor indications, we observed an average of 20-40% increase in PD-1 compared to no drug treatment. Immuno-oncology clinical trials which incorporate checkpoint inhibitors like either PD-1 or PD-L1, the availability of commercial reagents are key considerations to detect these receptors when designing a sensitive, selective, and accurate biomarker assay. Citation Format: Venkat Mohanram, Ming Yang, Angelina Bisconte, Deborah Phippard. Flow cytometry immunophenotyping using commercial antibodies to maximize detection of PD-1 in immuno-oncology (I-O) clinical studies with anti-PD-1 check point inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6630.

Viability of Deficit Irrigation Pre-Exposure in Adapting Robusta Coffee to Drought Stress

Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat tolerance were identified as: 14.KR7.2, 25.X1.1, 35.KR5.5, 36.KR5.6, 41.KR7.5, 46.KR6.4, 47.KR6.5, 291.X1.3, 318.X1.3, and 15.KR7.3. This is the first prospect into the potential of C. canephora half-sibs’ diversity as an unbound source of genetic variation for abiotic stress tolerance breeding.

Evaluation of In Vitro Efficacy of Commercial Fungicides Against Alternaria Alternata Isolates Causing Leaf Spot on Populus Deltoides

Poplar is the one of the domesticated forest trees in India and has better synergy with agriculture system than forestry operations. Populus deltoides have shown great promise in north-western part of India. Many a times, single clone of poplars have been propagated extensively. Ninety per cent of the total planted poplar comprises of clones G-48, WSL-22, WSL-39, Udai, WSL-32, Wimco81 and S7C15 in the states of Punjab, Haryana, Uttarakhand and Uttar Pradesh. High incidence of Alternaria leaf spot was noticed on different commercial clones of P. deltoides (G-48, Udai, WSL-22 and WSL-39) during surveys in poplar nurseries (2009-11). The most common method of managing plant diseases is use of fungicides. In vitro efficacy of two fungicides, namely, propiconazole (systemic) and chlorothalonil (non-systemic) was tested against Alternaria alternata isolates using poisoned food technique. It was observed that propiconazole was more effective in suppressing the growth of the fungus than chlorothalonil as cent per cent inhibition was achieved for all the isolates at 40ppm. On the other hand, cent per cent inhibition of growth was achieved for only four isolates, no. A15, A24, A41 and A47 at highest concentration of 400ppm of chlorothalonil. The study indicated that propiconazole proved to be effective at a very low concentration of 40ppm against A. alternata under in vitro conditions.

Expression of Three Clones of PD-L1 in Lung Cancer: A Single-center Experience.

Programmed cell death ligand 1 (PD-L1) is an immune checkpoint protein involved in immune evasion of malignant tumors. Confirmation of PD-L1 expression in non-small cell lung cancer (NSCLC) is necessary for the determination of immunotherapy using immune checkpoint inhibitors (ICIs). PDL-1 expression is currently analyzed by immunohistochemistry and is the only available biomarker that can guide the treatment of NSCLC using ICIs. The present study was conducted to compare the expression of three different commercial clones of PD-L1 in order for immunohistochemistry (IHC) for these clones to become more reliable for surgical pathologists. This study examined the expression of PD-L1 in 76 cases of resected lung cancer using IHC. Three clones were examined: SP263, SP142, and 22C3PharmDx, which are commercially approved for quantifying PD-L1 expression in lung cancer. Of the 76 patients whose samples were evaluated for PD-L1 using the IHC 22C3pharmDx assay, 19 (25.0%) had a tumor proportion score (TPS) of ≥50% and 41 (53.9%) had a PD-L1 TPS of ≥1%. Furthermore, using the SP263, 48.7% had a TPS of ≥1% and 18.4% of >50%. The SP142 assay was used to evaluate tumor cells (TCs) and immune cells (ICs). Twenty (26.3%) cases were positive for TCs and 25 (32.9%) were reactive for ICs. These three commercial PD-L1 clones are comparable for detecting primary targets for anti-tumor immunotherapies. Careful evaluation by a pathologist is necessary to minimize misinterpretation errors.

Insights into Long-Term Acclimation Strategies of Grapevines (Vitis vinifera L.) in Response to Multi-Decadal Cyclical Drought

Changing climatic conditions across Australia’s viticulture regions is placing increasing pressure on resources such as water and energy for irrigation. Therefore, there is a pressing need to identify superior drought tolerant grapevine clones by exploring the extensive genetic diversity of early European clones in old vineyards. Previously, in a field trial, we identified drought-tolerant (DT) dry-farmed Cabernet Sauvignon clones that had higher intrinsic water use efficiency (WUEi) under prolonged soil moisture deficiency compared to drought-sensitive (DS) clones. To investigate whether the field-grown clones have been primed and confer the drought-tolerant phenotypes to their subsequent vegetative progenies, we evaluated the drought responses of DT and DS progenies under two sequential drought events in a glasshouse alongside progenies of commercial clones. The DT clonal progenies exhibited improved gas exchange, photosynthetic performance and WUEi under recurrent drought events relative to DS clonal progenies. Concentration of a natural priming agent, γ-amino butyric acid (GABA), was significantly higher in DT progenies relative to other progenies under drought. Although DT and commercial clones displayed similar drought acclimation responses, their underlying hydraulic, stomatal and photosynthetic regulatory mechanisms were quite distinct. Our study provides fundamental insights into potential intergenerational priming mechanisms in grapevine.

Screening and QTLs detection for drought factor index trait in rubber (Hevea brasiliensis Müll. Arg.)

Climate change has an impact. Droughts will become more common in the future and as a result is the drop of rubber production. Drought tolerant rubber genotypes, may reduce drought risk, could be discovered by selection of germplasm and crossing progenies. As perennial plant, conventional rubber selection of rubber needs long time. Molecular detection such as QTL (precise and fast detection) for screening to get drought tolerant rubber genotypes is very important to be conducted. A variable widely used to screen stress tolerance genotypes is Performance Index (PI). Measurement of PI in normal, moderate, and severe drought stress enables the calculation of the Drought Factor Index (DFI). DFI as an integrative parameter for drought tolerance trait provides simple and robust method to quantify the tolerance ability of plants to withstand drought condition. This research is the first application of DFI to select drought-tolerant rubber genotypes and to identify QTLs related to DFI. This research aimed to select candidate drought-tolerant genotypes from the biparental population PB 260 × SP 217 as well as to identify QTLs related to DFI variable. One hundred and thirty-two genotypes and four control commercial clones, namely PB 260, SP 217, GT1, and RRIM 600 have been successfully screened using DFI variable. Normal, moderate, and severe drought stresses were calibrated for each plant by monitoring the fraction of transpirable soil water (FTSW). Due to the skewed distribution of DFI data that was generated in the phenotyping step, the Kruskal-Wallis non-parametric test was used to test the significance of each QTLs using MapQTL version 6 software. From this research, it can be concluded that DFI can be used as a parameter for selection of drought tolerant rubber clones. Based on DFI calculation, the top ten high DFI genotypes/clones were genotype number 34, 206, 056, 007, 205, 225, 066, 235, 109, and clone RRIM 600. Furthermore, the most significant detection of QTL for DFI variables was found in locus g5TA2155, located at 0.553 cM in LG5. It indicated that this locus contained genes controlling DFI trait. • Climate change results in prolonged dry season that impacts on the drops of rubber yield. • Drought Factor Index was calculated for one hundred and thirty-two genotypes from the PB 260 x SP 217 population • The genotypes with a high Drought Factor Index were selected as candidate drought-tolerant rubber genotypes. • Furthermore, the QTLs for Drought Factor Index were also determined. • Identification of genetic markers on genes underlying QTL enable Marker Assisted Selection for drought tolerance

Germplasm characterization of half‐sib families from seminal matricies of Coffea canephora

AbstractThe genetic diversity of Coffea canephora Pierre ex A. Froehner present in old seminal crops must be characterized because it represents a source of genetic variability for breeding programs. In this study, the genetic diversity of 388 half‐sib families of C. canephora, collected from Espírito Santo, Brazil, were assessed for their phenotypic traits. The data were obtained in a trial planted in April 2018 with five commercial clones as controls. Vegetative development was evaluated based on plant height, stem diameter, and average height and diameter growth rates. Abiotic (drought) and biotic (rust, leaf miner, and mealybug) stresses were evaluated by a rating scale. The phenotypic variability of the population was detected for all traits, and divergent clusters of families were identified. Negative correlations indicated that adverse conditions hampered the early development of the coffee plants. Groups of families should be investigated for breeding programs according to adequate development even under stressful conditions. These results show the importance of preserving the germplasm of old crops in the south of Espírito Santo as a source of genetic resources for coffee breeding programs. This valuable resource should be maintained and conserved as a strategy to guarantee the sustainability of coffee production.

Characterization of a new set of monoclonal β-amyloid antibodies

β-Amyloid (Aβ) deposition is a commonly studied neuropathology in the human brain, occurring as compact and diffuse parenchymal plaques, cerebral amyloid angiopathy (CAA), and meningeal/subpial amyloidosis. Compact plaques associated with dystrophic neurites generally referred to as neuritic plaques, are a pathological hallmark of Alzheimer's disease (AD). We evaluated three recently developed monoclonal mouse antibodies against Aβ (A1, A2 and A3) using appropriate tissue samples and assay controls in the present study. In immunohistochemistry, antibodies A1, A2 and A3 displayed all forms of cerebral Aβ deposition in a range of dilutions in cryostat and paraffin sections. These labeled profiles appeared morphologically comparable to that visualized by two commercial Aβ antibody clones, 6E10 and D12B2. In immune-dot blotting assays, antibodies A1, A2 and A3 at highly diluted concentrations detected an increase of Aβ in neocortical lysates of AD samples compared to control. Moreover, these antibodies clearly labeled Aβ pathology in brain sections of three commonly used transgenic mouse models of AD, namely, APP/PS1 mice, 5XFAD mice, and 3XTg-AD mice. Taken together, these monoclonal mouse anti-Aβ antibodies can serve as new experimental tools for basic, translational, and diagnostic research into aging and AD-related cerebral Aβ neuropathology in both human and experimental animal brains.

Variation in Growth, Wood Basic Density and Fiber Characters in Selected Clones of Acacia auriculiformis A. Cunn. Ex benth

The study aimed to screen and shortlist superior Acacia auriculiformis clones for desirable growth and wood properties. Twenty clones stem volume, wood basic density and fibre characters were studied at age of four. Significant variations were recorded in tree volume and wood properties among the clones, the stem volume of the clones was ranging from 0.022 to 0.073 m3 and the maximum tree volume was noticed in clones IFGTBAA 7 and followed by IFGTBAA 27 and 18, the studied clones average stem volume was 0.039 m3. The average wood basic density of the clones was 469 kg/m3 and this trait was ranging from 406 to 509 kg/m3. The screened A. auriculiormis clones average fibre length was ranging from 785.4 µm to 1140.6 µm and a maximum fibre length above 1000 µm was recorded in clones IFGTBAA 18, 23, 26 and 62. The average Runkel Ratio of all the clones was 0.91 and it was ranging from 0.7 to 1.1. There was no significant positive correlation noticed between growth, wood basic density and fibre properties except stem volume and fibre lumen diameter. Hence, it was decided to select superior clones, IFGTB 7,18,20,23 and 27 based on combined traits of Stem Volume, Wood Basic Density and Fibre Length to establish large scale commercial pulp wood plantations and clones which were having higher density and fibre properties had scope to utilize as parents in A. auriculiformis improvement programme to enhance tree volume and wood quality.

Evaluation of Models for Utilization in Genomic Prediction of Agronomic Traits in the Louisiana Sugarcane Breeding Program

Sugarcane (Saccharum spp.) is an important perennial grass crop for both sugar and biofuel industries. The Louisiana sugarcane breeding program is focused on improving sugar yield by incrementally increasing genetic gain. With the advancement in genotyping and (highthroughput) phenotyping techniques, genomic selection is a promising marker-assisted breeding tool. In this study, we assessed ridge regression best linear unbiased prediction (rrBLUP) and various Bayesian models to evaluate genomic prediction accuracy using a 10-fold cross validation on 95 commercial and elite parental clones from the Louisiana sugarcane breeding program. Datasets (individual and pooled in various combinations) were constructed based on soil type (light—Commerce silty loam, heavy—Sharkey clay) and crop (plant cane, ratoon). A total of 3906 SNPs were used to predict the genomic estimated breeding values (GEBVs) of the clones for sucrose content and cane and sugar yield. Prediction accuracy was estimated by both Spearman’s rank correlation and Pearson’s correlation between phenotypic breeding values and GEBVs. All traits showed significant variation with moderate (42% for sucrose content) to high (85% for cane and sugar yield) heritability. Prediction accuracy based on rank correlation was high (0.47–0.80 for sucrose content; 0.61–0.69 for cane yield, and 0.56–0.72 for sugar yield) in all cross-effect prediction models where soil and crop types were considered as fixed effects. In general, Bayesian models demonstrated a higher correlation than rrBLUP. The Pearson’s correlation without soil and crop type as fixed effects was lower with no clear pattern among the models. The results demonstrate the potential implementation of genomic prediction in the Louisiana sugarcane variety development program.

Phosphorus Shortage Induces an Increase in Root Exudation in Fifteen Eucalypts Species

A significant proportion of the carbon fixed by plants is transported to the roots and exuded to the rhizosphere. Exudates may have important roles in the rhizosphere, such as desorbing labile phosphorus (P) or mobilizing manganese (Mn) and other metal cations. This study evaluated the root exudation profiles of seedlings of 15 eucalypt species in response to a P shortage and if the ability to exude organic compounds was related to P and Mn accumulation in the shoots. The plants were grown on sand and were irrigated with nutrient solutions containing either sufficient P (500 µM) or low P (25 µM). Organic acids (OA), amino acids/polyamines, and phenolics were analyzed in the root exudates by UPLC-MS/MS. Plants with a low P level had low leaf P contents and growth reduction. A P shortage induced the exudation of the three groups of metabolites analyzed at higher levels than sufficient P availability. Despite that, the composition pattern of root exudates was similar among species under low or sufficient P concentrations. Citric and isocitric acids were the major OAs found in the exudates, followed by oxalic, malic, and succinic acids. Among the amino acids/polyamines identified, putrescine was the most abundant in all species, followed by glycine. Cinnamic acid was the predominant phenolic in the root exudates. Our results indicate that P limitation induces a conserved response genetic mechanism in eucalypts. Such results can be further investigated to adapt commercial clones to soils with low P availability.

Physicochemical analysis of Ugandan tea (Camellia sinensis) germplasm reveals potential commercial green and black tea varieties

ABSTRACT Tea (Camellia sinensis L.) is an important beverage consumed worldwide. In Uganda, it is the second-largest and highly prioritized export crop after coffee and provides the much-needed jobs to more than 800,000 people. Despite its importance in the country, the crop has received very limited research attention for its improvement and optimal utilization. This study was aimed at characterizing existing tea germplasm in Uganda to inform future breeding initiatives for market-preferred tea varieties. Fifty-eight advanced tea clones were randomly selected from the tea germplasm conserved at Uganda’s Tea Research Center in Rwebitaba and analyzed in the laboratory for eight physicochemical descriptors. Hierarchical cluster analysis performed on the 58 clones using Cluster-R package revealed four main clusters, indicating the existence of variation for physicochemical parameters within tested germplasm. This variation can be exploited to select among and/or improve the studied germplasm genetically for quality. High fermentation rate, which is one of the key indicators for good-quality black teas, revealed 15 fast-fermenter tea clones. Clone “UTR12/12” was identified as the most rapid fermenter, fully fermenting within 30 min, which implies a good clone for black tea. The clone also had the highest polyphenol content (26.7%), higher than the high-quality clone “UTR6/8” (control). Other tea clones whose polyphenol content was within the range of the control black tea clone were: “UTR144/10” (20.9%) and ‘UTR144/17, (20.66%). The identified promising black tea clones can be advanced to multi-location trials for further evaluation and selection for eventual variety release as commercial black-tea clones.

Sucrose-Specific Genic Microsatellites to Analyse the Genetic Structure Among the Commercial Hybrids and Clones of Interspecific and Intergeneric Origin in Saccharum Complex

Sucrose-Specific Genic Microsatellites to Analyse the Genetic Structure Among the Commercial Hybrids and Clones of Interspecific and Intergeneric Origin in Saccharum Complex

Changes in the Composition of Flavonols and Organic Acids during Ripening for Three cv. Sauvignon Blanc Clones Grown in a Cool-Climate Valley

The influence of the geographical location and clone type on the contents of flavonols and organic acids of Sauvignon blanc grapes over the ripening process was investigated. The assay was carried out on three commercial clones of cv. Sauvignon blanc (Clone 242, Clone 107, and Clone 1-Davis) grown in two zones (referred to as low and high zones) in Casablanca Valley, Chile. The low zone is closer to the Pacific Ocean (i.e., 20 km away) than the high zone (which is 37 km away). Clear differences in the contents of total phenols, flavonols and organic acids of the grapes were observed during ripening. All the clones grown in the low zone exhibited a higher titratable acidity than those grown in the high zone. An analysis of the flavonol contents of the grape skins showed differences among clones associated with the geographical zone of cultivation. There was no difference in the tartaric acid concentration among clone types; however, a higher tartaric acid concentration was found in clones grown in the low zone than those grown in the high zone for all clone types. Similar results were found for the malic acid concentration. A discriminant analysis showed that the chemical analysis for the contents of total phenols, flavonols and organic acids influenced the classification based on the clone type. The results showed that grapes of different qualities can be grown in two geographical subunits into the larger area of Casablanca Valley.

Genetic Variability and Combining Abilities for Earliness to Nut Yield and Nut Weight in Selected Cashew (Anacardium Occidentale L.) Clones

ABSTRACT Introduction of exotic clones into the pedigree of commercial cashew clones could constitute a viable strategy to overcome the current low early nut yield and nut weight of the crop in West Africa. The aim of this study was to assess the combining abilities of Beninese, Brazilian and Ghanaian clones for early nut yield and nut weight. Twelve F1 hybrids were evaluated in the field for five traits such as stem diameter increment, canopy spread, nut yield, nut weight and cropping efficiency. Significant difference (p ≤ .01) was observed for most of the traits. Nut weight varied from 5.3 to 10.1 g/year, whilst nut yield ranged from 666.1 to 872.8 kg/ha/year among the top five crosses in the third to fifth year after planting. The Beninese (BE) progenies were comparable to the Ghanaian (SG) progenies for early nut yield but inferior to the Ghanaian and Brazilian (A) progenies for nut weight. Pearson correlation coefficient estimate (r = 0.74; p ≤ .01) suggest that, selecting for canopy spread in the north-south direction might improve early nut yield. GCA effects were more important than SCA effects. Narrow-sense heritability was moderate and exceeded 50% for all the traits. BE203 and SG224 showed positive GCA for early nut yield, whereas A2 and SG273 showed positive GCA for nut weight. Our study suggest that the Brazilian, Beninese and Ghanaian clones had different merits as potential parents for early nut yield and nut weight and could constitute a suitable genetic resource for improving cashew productivity.

Inbred progeny of tall fescue infected with Epichloë fungal endophyte have a high defence compound content and no depression in seed set

ABSTRACT Substantial evidence is available on the capacity of particular strains of Epichloë fungal endophyte to remove the barriers of self‐pollination in host grasses. We hypothesized that this might open up new methods to obtain inbred lines for specific turf hybrids and genetic studies. In the present study, we evaluated the first generation of self‐pollination derived plants of endophyte infected clones (EIS1) from putative genotypes 75B+ and 75C+ and those from the first generation of self‐pollination in six commercial tall fescue clones plus their hybrids with 75B− and 75C− for growth, seed yield and polyphenolic content as an index for biosynthesis of defence compounds under field conditions. The results showed that EIS1 had high hyphal density within leaf sheaths and higher growth and seed‐related traits in at least one genotype. There were higher amounts of flavonoid and phenolic compounds (up to twofold) in both genotypes than in their hybrid counterparts and endophyte‐free progeny. Selected genotypes within EIS1 contained significantly more chlorogenic acid, p‐coumaric acid and rutin than the best non‐infected genotypes. We conclude that phenotypic selection of individuals from the S1 population is feasible for improving fitness and stress resistance in novel inbred lines of tall fescue for development of new turf cultivars with the desired ecophysiological traits.

Long‐term quantification of leaf‐cutting ant damage in willow forestations in the lower delta of the Paraná River, Argentina

Abstract Leaf‐cutting ants are major pests of Neotropics forest plantations. The lower delta of the Paraná River contains the main Argentine Salicaceae production, strongly attacked by Acromyrmex lundii and Acromyrmex ambiguus. Nevertheless, there is no damage quantification in willow plantations attributed to leaf‐cutting ant species. In an area without leaf‐cutting ant control, we installed 15 blocks with eight willow stakes each: four clones × two treatments; with and without leaf‐cutting ant exclusion. We used two traditional (Americano, Nigra 4) and two new (Géminis, Yaguareté) commercial clones. During 2014–2018, we measured the damaged foliage, height and diameter of each tree. Foliage was damaged intensely during the first 2 years. After 1537 days, the loss in height and diameter was greater in Americano (70%), followed by Géminis (50%–60%), Yaguareté (40%–50%) and Nigra 4 (45%–40%). Stake survival with exclusion was greater (>80%) than stakes without exclusion (<50%). Total loss of wood volume was 93% for Americano, followed by Géminis (77%), Yaguareté (66%) and Nigra 4 (51%). Although the new clones were heavily attacked, they produced two to three times more wood volume than Americano; replacing Americano with the new clones would help to reduce leaf‐cutting ants impact on plantations and pesticides released into the environment.

Genetic variability of conilon coffee population from cultivar ‘ES8152’ based on morphoagronomic variables

This study aimed to analyze the genetic variability of Coffea canephora population with 190 genotypes from cultivar ‘ES8152’, based on morphoagronomic characteristics and vegetation index, to identify the most important characteristics for genetic divergence and compare them with commercial clones. The experiment was installed, in 2019, at the Bananal do Norte Experimental Farm/INCAPER, Cachoeiro de Itapemirim, ES, Brazil. The experiment was carried out in Federer’s augmented block design with three blocks, four common treatments (commercial clones A1, LB1, V8 and V12) and 190 regular treatments, genotypes from the seed production field of the conilon coffee cultivar ‘ES8152’. At 24 months of age 14 morphoagronomic characteristics and vegetation index were evaluated. Descriptive analysis of the data, the estimation of the Standardized Euclidean Distance (ED) followed by the grouping by the methods of Tocher, UPGMA and principal coordinates, in addition to the relative importance of the characters estimated by the Singh methodology were performed. The most distant genotypes were 62 and 83 (ED=2.620) and the closest were 42 and 160 (ED=0.208). Genotype 83 stood out as the most distant among the others. The optimization and hierarchical groupings allowed the identification of genotypes 15, 81, 107 and 184 as similar to commercial clones. The discard analysis of variables recommended the elimination of the vegetation index and average internode length of the next diversity analysis. Principal coordinate analysis found phenotypic similarity of the genotypes 30, 81, 115, 141 and 163 with the clone V12, of the genotype 119 with the clone A1 and genotype 17 with clone LB1. The study, of morphoagronomic characters, allowed to detection the genetic diversity existing in the materials evaluated, indicating those with phenotypic similarity with the commercial clones, being possible the early identification of promisinggenotypes, agronomically superior, to start a breeding program for clonal selection, recurrent selection and controlled crosses to maximize heterosis. Key words: Coffea canephora; pre-breeding; genetic diversity; clusters.

Genetic structure and diversity in wild and breeding populations of Eucalyptus urophylla

Abstract Eucalyptus urophylla S.T. Blake is a species of great commercial importance, especially in tropical regions, and it is the main eucalypts species cultivated in Brazil. This study evaluated the genetic diversity among and within seven populations of E. urophylla and estimated the genetic distance between individuals to draw inferences about the genetic structure between and within the sampled populations. For that, 19 microsatellite markers were genotyped in 254 individuals originating from four wild populations, introduced in Brazil, two breeding populations, and one population consisting of commercial clones. The wild populations of E. urophylla introduced in Brazil have high genetic similarity and the few generations of breeding have already generated significant differences in population structure between improved and wild populations. As expected, breeding populations are closer to commercial clones than wild populations. However, compared to wild populations, breeding populations exhibit greater genetic diversity as they originated from a mixture of provenances. The population formed by clones was the only one that showed a negative Wright fixation index, that is, heterozygosity was higher than expected for a population in Hardy-Weinberg equilibrium.