Total Root Number Research Articles

MYB30-INTERACTING E3 LIGASE 1 regulates LONELY GUY 5-mediated cytokinin metabolism to promote drought tolerance in cotton

Abstract Ubiquitination plays important roles in modulating the abiotic stress tolerance of plants. Drought seriously restricts agricultural production, but how ubiquitination participates in regulating drought tolerance remains largely unknown. Here, we identified a drought-inducible gene, MYB30-INTERACTING E3 LIGASE 1 (GhMIEL1), which encodes a RING E3 ubiquitin ligase in cotton (Gossypium hirsutum). GhMIEL1 was strongly induced by polyethylene glycol (PEG-6000) and the phytohormone abscisic acid. Overexpression and knockdown of GhMIEL1 in cotton substantially enhanced and reduced drought tolerance, respectively. GhMIEL1 interacted with the MYB transcription factor GhMYB66 and could ubiquitinate and degrade it in vitro. GhMYB66 directly bound to the LONELY GUY 5 (GhLOG5) promoter, a gene encoding cytokinin riboside 5′-monophosphate phosphoribohydrolase, to repress its transcription. Overexpression of GhMIEL1 and silencing of GhMYB66 altered the homeostasis of cytokinin of plant roots, increased total root length and number of root tips, and enhanced plant drought tolerance. Conversely, silencing GhLOG5 decreased total root length and number of root tips and reduced plant drought tolerance. Our studies reveal that the GhMIEL1-GhMYB66-GhLOG5 module positively regulates drought tolerance in cotton, which deepens our understanding of plant ubiquitination-mediated drought tolerance and provides insights for improving drought tolerance.

ROOT AND MORPHOLOGICAL CHARACTERISTICS OF EUCALYPTUS SEEDLINGS PRODUCED IN BIODEGRADABLE CONTAINERS

The objective of this study was to evaluate the nursery and field development of eucalyptus seedlings produced in biodegradable containers (BC), based on morphological and root characteristics, compared to the conventional method in 55-cm³ tubes. The experiment was conducted in a completely randomized experimental design, using a 3×2 factorial arrangement consisting of three types of containers (55-cm³ tubes; 76-cm³ BC; and 115-cm³ BC) and two eucalyptus clones (CO-1407 and AEC-144). The parameters evaluated in the nursery were: shoot height (SH); stem base diameter (SBD); SH-to-SBD ratio; shoot, root, and total fresh and dry weights; and total number of roots. The parameters evaluated in the field were: SH; SBD; and root distribution. Considering the evaluated characteristics, the use of 115-cm³ BC enabled the development of high-quality seedlings in all evaluation phases. BC-produced seedlings presented better quality and performance in the field. Seedlings produced in 55-cm³ tubes presented lower values for all morphological parameters evaluated in the nursery, as well as in the field up to 120 days after planting.

A simple and efficient non-tissue culture method for genetic transformation of grape immature zygotic embryos via VvBBM overexpression

The process of genetic transformation of grapevine has long been hampered by the inefficiency and complexity of tissue culture-based methods, severely limiting cultivar improvement and functional genome research. In this study, we aimed to develop a novel, non-tissue culture-based method for the genetic transformation of grape immature zygotic embryos without relying on tissue culture. This approach involves the overexpression of the Vitis vinifera BABY BOOM (VvBBM) gene, a key member of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor family, which is known to enhance plant regeneration and transformation efficiency. Using ‘Cabernet Sauvignon’ immature zygotic embryos, we achieved a transformation efficiency of 42.85 % under non-tissue culture conditions, significantly reducing the cycle duration to approximately two months compared to traditional genetic transformation methods. Phenotypic and molecular analyses of the transformed grapevine plants confirmed the integration and overexpression of the VvBBM gene, resulting in improved growth metrics, including increased plant height, root length, and total root number, in a genotype-independent manner. Our results highlight the potential of VvBBM overexpression to circumvent the limitations imposed by tissue culture dependence, providing a rapid, efficient, and scalable alternative to conventional methods. Our study not only provides a practical approach to overcoming the barriers to genetic transformation in grapevine, but also opens new avenues for the application of this technology in the breeding of other economically important crops.

Neighbour-induced changes in root exudation patterns of buckwheat results in altered root architecture of redroot pigweed

Roots are crucial in plant adaptation through the exudation of various compounds which are influenced and modified by environmental factors. Buckwheat root exudate and root system response to neighbouring plants (buckwheat or redroot pigweed) and how these exudates affect redroot pigweed was investigated. Characterising root exudates in plant–plant interactions presents challenges, therefore a split-root system which enabled the application of differential treatments to parts of a single root system and non-destructive sampling was developed. Non-targeted metabolome profiling revealed that neighbour presence and identity induces systemic changes. Buckwheat and redroot pigweed neighbour presence upregulated 64 and 46 metabolites, respectively, with an overlap of only 7 metabolites. Root morphology analysis showed that, while the presence of redroot pigweed decreased the number of root tips in buckwheat, buckwheat decreased total root length and volume, surface area, number of root tips, and forks of redroot pigweed. Treatment with exudates (from the roots of buckwheat and redroot pigweed closely interacting) on redroot pigweed decreased the total root length and number of forks of redroot pigweed seedlings when compared to controls. These findings provide understanding of how plants modify their root exudate composition in the presence of neighbours and how this impacts each other’s root systems.

Early generation clonal selection of sweetpotato (Ipomoea batatas (L.) Lam) using an accelerated breeding scheme

The breeding stages of a clonally propagated crop entails several steps and can take more than five years from hybridisation till cultivar release. The Accelerated Breeding Scheme (ABS) in sweetpotato relies on the use of multiple locations at the early breeding stages to reduce the years required for field evaluation. The aim of the study was to select the best progenies based on the ABS in sweetpotato towards the development of genotypes that combine high protein content with other important agronomic traits. Botanical seeds were generated from crosses between two diverse sets of parents, crossed using a North Carolina II design. F1-progenies (n = 363) were planted in a lattice design at three distinct locations during the 2017/18 planting season. Parameters recorded included pest and disease infestation, storage root traits and yield components, root protein content and nutrient related traits. Nutrient content was determined by near-infrared spectrometry. Analysis of variance and multiple t-distribution test and best test grouping were performed. There were significant differences (p < 0.001) among the genotypes for total number of roots, total root yield, marketable number of roots and marketable yield. The severity of Alternaria blight was significantly higher at Jozini. Forty progenies were selected (12.8% selection pressure) based on agronomic performance. Using the nutrient content results, four promising orange-fleshed clones (NC12-9, NC53-11, NC55-8, NC55-2) and one cream-fleshed clone (NC51-1) were identified with high storage root protein, iron and zinc contents. NC51-1 and NC55-2 produce promising storage root yields. The ABS approach is resource-demanding in the first phase but advances progenies rapidly to the subsequent breeding phases for cultivar release.

Screening of Auxin-like Substances among Synthetic Compounds, Derivatives of Pyridine and Pyrimidine

The effect of known synthetic compounds Ivin (N-oxide-2,6-dimethylpyridine), Methyur (sodium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine), Kamethur (potassium salt of 6-methyl-2-mercapto-4-hydroxypyrimidine) and new synthetic compounds, derivatives of pyrimidine (No. 1 - 7) on the rooting of isolated stem cuttings of haricot bean (Phaseolus vulgaris L.) variety Bilozernaya was studied. The growth regulatory activity of synthetic compounds Ivin, Methyur, Kamethur, and synthetic compounds, derivatives of pyrimidine (No. 1 - 7) was compared with the activity of auxins IAA (1H-indol-3-yl)acetic acid) and NAA (1-naphthylacetic acid). The conducted studies showed that the regulatory effect of synthetic compounds Ivin, Methyur, Kamethur, and synthetic compounds, derivatives of pyridine (No. 1 - 7) on the rooting of isolated stem cuttings of haricot bean was similar to the auxins IAA and NAA. The synthetic compounds Ivin, Methyur, and Kamethur, and synthetic compounds, derivatives of pyrimidine (No. 1, 4, 5, and 7) showed the highest auxin-like activity. The indicators of the total number of roots (pcs) and total length of roots (cm) obtained on isolated stem cuttings of haricot bean immersed in a water solution of synthetic compounds Ivin, Methyur, Kamethur and synthetic compounds, derivatives of pyridine (No. 1, 4, 5 and 7), used at a concentration of 10-7 M, statistically significantly exceeded similar indicators obtained on control isolated stem cuttings of haricot bean immersed in distilled water. The practical use of synthetic compounds Ivin, Methyur, Kamethur, and synthetic compounds, derivatives of pyrimidine (No. 1, 4, 5 and 7) is proposed to improve the vegetative propagation of haricot bean plants (Phaseolus vulgaris L.) and other plant species of the family Fabaceae by stem cuttings.

Plant vegetative propagation plays a considerable role in the regeneration following slash-and-burn agriculture in Caatinga dry forest

Slash-and-burn agriculture is a common practice in dry forests worldwide. Understanding the relative importance of different regeneration mechanisms following this disturbance provides insights into forest regeneration dynamics and resilience. We assessed differences in structural components, the relative contribution of vegetative and sexual reproduction, and the taxonomic composition of woody assemblages among different habitats in a Brazilian Caatinga dry forest after slash-and-burn agriculture. We assessed vegetation parameters (i.e., basal area, height, species richness, and the frequency of each regeneration mechanism) in recently abandoned fields, regenerating forest stands and old-growth forest stands. Overall, trees originates from root suckers accounted for at least 40% of the individuals, stems, and basal areas across the habitats. The structure of regenerating stands was similar to old-growth stands except for species composition, total number of roots, and number of primary roots. The aboveground basal area varied in total values, but not averages, among habitats, indicating a rapid recovery of aboveground biomass after slash-and-burn agriculture. Conversely, recently abandoned fields had higher belowground basal area and basal area of primary roots, revealing that the trees in these habitats emit more roots even with fewer individuals. There was a high degree of species turnover among the habitats, probably due to both species selection by farmers and environmental effects. Nevertheless, the dominant species presented both regeneration mechanisms across the habitats. Our findings thus show that the Caatinga dry forest regeneration considerably relies on the ability of woody plant species to emit root suckers in addition to sexual reproduction, which should be considered for better management practices as slash-and-burn agriculture is and will continue to be practiced.

The effect of live chlorella suspension on the growth and development of grafted seedlings of Cabernet Sauvignon grapes

One of the ways to grow high-quality grafted grape seedlings is to use modern, environmentally friendly biologically active preparations. Today, such preparations include live chlorella suspension. Its use in grape nursery is a new and relevant technological method of growing planting material. The aim of the study was to show the effect of live chlorella suspension on the realization of the biological potential of grapevines, with the subsequent production of high-quality grafted grape seedlings. Field (recording of plant growth and development), laboratory (determination of quantitative and qualitative parameters of plants) and statistical (confirmation of the reliability of the results) research methods were used. The obtained results showed that for soaking rootstock and scion components it is advisable to use the strain Chlorella vulgaris Beijer, dilution 1:5, soaking should be carried out for 72 hours – rootstock components, 18 hours – scion components; for irrigation of grape garden plot it is advisable to use the strain Chlorella vulgaris Beijer. + Ge, dilution 1:5, it was carried out immediately after planting scions and three times during the growing season – in June, July, and August. The use of these strains of live chlorella suspension allowed obtaining a higher yield of standard seedlings from the garden plot, the plants had a well-developed root system and annual growth. Compared to the control, which was water, the total number of roots increased. Plants in these variants were also characterized by increased growth of the aboveground part. Indicators of total and mature growth, which characterize the overall development of grafted grape seedlings, were in the range of 687.1-773.2 cm3 (total growth volume), 337.9-386.6 cm3 (mature growth volume), while 730.1 and 362.6 cm3 , respectively, in the control. The records of the output of standard seedlings from the garden plot also showed the advantage of using a suspension of live chlorella (an increase of 19.0-21.0%) compared to water. The above technological methods allow obtaining high-quality grape seedling products and can be a promising alternative for more sustainable and environmentally friendly agricultural methods

Dissecting the genetic architecture of root-related traits in a grafted wild Vitis berlandieri population for grapevine rootstock breeding

In woody perennial plants, quantitative genetics and association studies remain scarce for root-related traits, due to the time required to obtain mature plants and the complexity of phenotyping. In grapevine, a grafted cultivated plant, most of the rootstocks used are hybrids between American Vitis species (V. rupestris, V. riparia, and V. berlandieri). In this study, we used a wild population of an American Vitis species (V. berlandieri) to analyze the genetic architecture of the root-related traits of rootstocks in a grafted context. We studied a population consisting of 211 genotypes, with one to five replicates each (n = 846 individuals), plus four commercial rootstocks as control genotypes (110R, 5BB, Börner, and SO4). After two independent years of experimentation, the best linear unbiased estimates method revealed root-related traits with a moderate-to-high heritability (0.36–0.82) and coefficient of genetic variation (0.15–0.45). A genome-wide association study was performed with the BLINK model, leading to the detection of 11 QTL associated with four root-related traits (one QTL was associated with the total number of roots, four were associated with the number of small roots (< 1 mm in diameter), two were associated with the number of medium-sized roots (1 mm < diameter < 2 mm), and four were associated with mean diameter) accounting for up to 25.1% of the variance. Three genotypes were found to have better root-related trait performances than the commercial rootstocks and therefore constitute possible new candidates for use in grapevine rootstock breeding programs.

Usage of Machine Learning Algorithms for Establishing an Effective Protocol for the In Vitro Micropropagation Ability of Black Chokeberry (Aronia melanocarpa (Michx.) Elliott)

The primary objective of this research was to ascertain the optimal circumstances for the successful growth of black chokeberry (Aronia melanocarpa (Michx.) Elliott) using tissue culture techniques. Additionally, the study aimed to explore the potential use of machine learning algorithms in this context. The present research investigated a range of in vitro parameters such as total number of roots (TNR), longest root length (LRL), average root length (ARL), number of main roots (NMR), number of siblings (NS), shoot length (SL), shoot diameter (SD), leaf width (LW), and leaf length (LL) for Aronia explants cultivated in different media (Murashige and Skoog (MS) and woody plant medium (WPM)) with different concentrations (0, 0.5, 1, 1.5, and 2 mg L−1) of indole-3-butyric acid (IBA). The study showed that IBA hormone levels may affect WPM properties, affecting the LRL and ARL variables. Aronia explant media treated with 2 mg L−1 IBA had the greatest TNR, NMR, NS, SL, and SD values; 31.67 pieces, 2.37 pieces, 5.25 pieces, 66.60 mm, and 2.59 mm, in that order. However, Aronia explants treated with 1 mg L−1 IBA had the highest LW (9.10 mm) and LL (14.58 mm) values. Finally, Aronia explants containing 0.5 mg L−1 IBA had the greatest LRL (89.10 mm) and ARL (57.57 mm) values. In general, the results observed (TNR, LRL, ARL, NMR, NS, SL, SD, LW, and LL) indicate that Aronia explants exhibit superior growth and development in WPM (25.68 pieces, 68.10 mm, 51.64 mm, 2.17 pieces, 4.33 pieces, 57.95 mm, 2.49 mm, 8.08 mm, and 14.26 mm, respectively) as opposed to MS medium (20.27 pieces, 59.92 mm, 47.25 mm, 1.83 pieces, 3.57 pieces, 49.34 mm, 2.13 mm, 6.99 mm, and 12.21 mm, respectively). In the context of the in vitro culturing of Aronia explants utilizing MS medium and WPM, an analysis of machine learning models revealed that the XGBoost and SVM models perform better than the RF, KNN, and GP models when it comes to making predictions about those variables. In particular, the XGBoost model stood out due to the fact that it had the greatest R-squared value, and showed higher predictive ability in terms of properly forecasting values in comparison to actual outcomes. The findings of a linear regression (LR) analysis were used in order to conduct an efficacy study of the XGBoost model. The LR results especially confirmed the findings for the SD, NS, and NMR variables, whose R-squared values were more than 0.7. This demonstrates the extraordinary accuracy that XGboost has in predicting these particular variables. As a consequence of this, it is anticipated that it will be beneficial to make use of the XGboost model in the dosage optimization and estimation of in vitro parameters in micropropagation studies of the Aronia plant for further scientific investigation.

The caleosin RD20/CLO3 regulates lateral root development in response to abscisic acid and regulates flowering time in conjunction with the caleosin CLO7

The caleosins are encoded by multi-gene families in Arabidopsis thaliana and other plant species. This work investigates the role of two family members, RD20/CLO3 and CLO7, in flowering transition and in root development in response to ABA treatment. Gene expression of the caleosin RD20/CLO3 is induced by ABA in the root tissues and RD20/CLO3 has a negative affect on the total number of lateral roots as well as the length of the lateral roots in response to ABA treatment. The rd20/clo3 mutant has more and longer lateral roots in response to ABA treatment compared to the wild-type, showing that RD20/CLO3 plays a role in the ABA signaling pathway affecting this trait. In contrast, the caleosin CLO7 is not expressed in the roots and does not affect root architecture in response to ABA treatment. The disruption of both RD20/CLO3 and CLO7 together causes a dramatic early-flowering phenotype under long-day conditions, whereas single mutations in these genes do not affect flowering time under these conditions. Both yeast two-hybrid and bimolecular fluorescence complementation showed that both RD20/CLO3 and CLO7 interact with each other and can form homodimers and heterodimers. Taken together, these findings suggest that members of the caleosin gene family play both different and redundant roles in plant development.

Phonemic structure of the root morpheme in the Gothic language (a complex quantitative analysis of lexicographic sources)

The article deals with the problems of the phonemic structure of the root morpheme in Gothic. Using a systematic sampling procedure, the words from a Gothic dictionary were selected to form the register with 382 root morphemes. The study employed a quantitative research with statistical data analysis toinvestigate such characteristics of the Gothic root morpheme as its length in phonemes, distribution, combinability and phonotactics of vowel and consonant phonemes within CV root patterns, their constructive potential and symmetry. The investigation has revealed several fundamental regularities that characterize the Gothic root morpheme organizing on the phonemic level. The results of the study have shown that the Gothic language has roots ranging in length from two to nine phonemes, but four-fifths of the analyzed roots consisted of 3-4 phonemes, the average length of the Gothic root in phonemes is 3.55, the multi-phoneme roots are rare and represented mainly by lexical items of non-Germanic origin. The analysis of the realized canonical forms has shown that the Gothic language system uses only 2% of the theoretically possible forms for the construction of root morphemes at the phonemic level. The vast majority of these roots function as dependent roots, only 5% of them function as independent roots that form complete lexical units. The canonical forms of roots in the Gothic language have different modeling power; the most productive among them are three structural types (CVC, CVCC, CCVC), which form almost four fifths of all roots in the studied array. The phonemic structure of the root morpheme is characterized by a significant consonantal saturation: the initial and final components of most canonical forms are formed by consonants, and the medial ones by vowels. Structures of this type describe almost 90% of the total number of roots in the study sample. It has been proven that the phonemic structure of Gothic roots is characterized by symmetry, with the symmetrically constructed roots being mostly characterized by the mirror type of symmetry.

Improved cassava (Manihot esculenta Crantz) growth and production by application of potassium

Indonesia is the fifth countries in term of cassava production in the world. The biggest cassava area in Indonesia is Lampung. One of the important nutrient fertilizers to improve cassava production is potassium. Consequently, the objective of this study was to evaluate distribution of photoassimilate by determining cassava growth and production under different potassium dosages. Treatment was arranged by factorial (2x3) in randomized complete block design (RCBD) with two reps. The first factor was two cassava clones, UJ3 and UJ5 and the second factor was three potassium (KCl) dosages, 0, 150, and 300 kg/ha. The variables observed in this study were plant height, stem diameter, fresh weight and dry weight of leaf, total root number and swollen root number, distribution of root number, root length, root distribution, and root weight. The result showed that under fertilizer of 300 kg KCl/ha, stem dry weight of UJ3 and UJ5 was not significantly different however root fresh weight of UJ3 seemed higher compared to that of UJ5. It seems that UJ3 cassava clone is more responsive to potassium fertilizer than UJ5 cassava clone.

Analyzing genetic variation for important yield-contributing attributes in genotypes of orange-fleshed sweet potatoes

An experiment was conducted to estimate genetic variability of 47 orange-fleshed sweetpotato(OFSP) genotypes. It was established in two locations(Umudike and Igbariam) in a RCBD fashion with three replications. Data collected were subjected to ANOVA using the software; AGD-R. The results showed that all the characters studied were highly significant (p&lt;0.01) for genotypes. All the traits were significant for location except the vine length, days to 50% flowering and root yield. Most of the characters were also significant for genotypes-location interaction. Significant differences observed among genotypes for most traits indicated the presence of genetic variation among the materials. The genotypic coefficient of variation(GCV) was very high for beta carotene(73.8%) and vitamin A(70.0%). Phenotypic coefficient of variation(PCV) was very high for beta carotene(183.5%), root yield per hectare(151.6%), total root weight per plant(150.6%) and total number of roots per plant(113.5%). The PCV was higher than their corresponding GCV for all the characters studies, indicating that the expression of these characters was influenced by environment. The GCV was consistently higher than PCV in all the traits. The genotypic variance was high for days to 50% flowering(373.16), dry matter(220.30), root girth (140.73), root length (68.10) and root yield per hectar (349.66). The magnitude of VA was consistently larger than that of VD for all the traits suggesting that the additive genetic variance was more important than the dominance genetic variance in the inheritance of most studied traits. All the characters studies had high heritability (&gt;60%). High heritability estimates for those traits indicated a high response to selection

PsPRE1 is a basic helix-loop-helix transcription factor that confers enhanced root growth and tolerance to salt stress in poplar.

The basic helix-loop-helix (bHLH) family of transcription factors is one of the largest and oldest transcription factor families in plants. Members of the bHLH family regulate various growth and metabolic processes in plants. We used quantitative trait locus (QTL) mapping and transcriptome sequencing (RNA-seq) to identify PRE1 as a candidate bHLH transcription factor associated with root dry weight (RDW) in poplar. PRE1 was highly expressed in the roots and xylem, and was responsive to gibberellin, salicylic acid, drought, and salt stress. We cloned the PRE1 homolog from Populus simonii 'Tongliao1', referred to as PsPRE1, and transformed it into 84K poplar (Populus alba × Populus glandulosa). The overexpression of PsPRE1 in 84K poplar increased adventitious root development, fresh weight, total root number, and maximum root length. Poplar lines overexpressing PsPRE1 also exhibited enhanced salt tolerance while retaining a normal growth phenotype in the presence of salt stress. Catalase (CAT) activity in the PsPRE1 overexpression lines was higher than that of the wild-type, which may play a role in detoxifying stress-induced hydrogen peroxide production. An RNA-seq analysis of the PsPRE1 overexpression line revealed several differentially expressed genes (DEGs) involved in or related to auxin-, gibberellin-, and salicylic acid pathways, which indicates that the regulation of root development in poplar by PsPRE1 may involve multiple hormones.

Application of an Improved 2-Dimensional High-Throughput Soybean Root Phenotyping Platform to Identify Novel Genetic Variants Regulating Root Architecture Traits.

Nutrient-efficient root system architecture (RSA) is becoming an important breeding objective for generating crop varieties with improved nutrient and water acquisition efficiency. Genetic variants shaping soybean RSA is key in improving nutrient and water acquisition. Here, we report on the use of an improved 2-dimensional high-throughput root phenotyping platform that minimizes background noise by imaging pouch-grown root systems submerged in water. We also developed a background image cleaning Python pipeline that computationally removes images of small pieces of debris and filter paper fibers, which can be erroneously quantified as root tips. This platform was used to phenotype root traits in 286 soybean lines genotyped with 5.4 million single-nucleotide polymorphisms. There was a substantially higher correlation in manually counted number of root tips with computationally quantified root tips (95% correlation), when the background was cleaned of nonroot materials compared to root images without the background corrected (79%). Improvements in our RSA phenotyping pipeline significantly reduced overestimation of the root traits influenced by the number of root tips. Genome-wide association studies conducted on the root phenotypic data and quantitative gene expression analysis of candidate genes resulted in the identification of 3 putative positive regulators of root system depth, total root length and surface area, and root system volume and surface area of thicker roots (DOF1-like zinc finger transcription factor, protein of unknown function, and C2H2 zinc finger protein). We also identified a putative negative regulator (gibberellin 20 oxidase 3) of the total number of lateral roots.

Genetic variability Analysis for various Yield Contributing Traits in Orange-Fleshed Sweetpotato Genotypes

An experiment was conducted to estimate genetic variability of 47 orange-fleshed sweetpotato (OFSP) genotypes. It was established in two locations (Umudike and Igbariam) in a RCBD fashion with three replications. Data collected were subjected to ANOVA using the software; AGD-R. The results showed that all the characters studied were highly significant (p&lt;0.01) for genotypes. All the traits were significant for location except the vine length, days to 50% flowering and root yield. Most of the characters were also significant for genotypes-location interaction. Significant differences observed among genotypes for most traits indicated the presence of genetic variation among the materials. The genotypic coefficient of variation (GCV) was very high for beta carotene (73.8%) and vitamin A (70.0%). Phenotypic coefficient of variation (PCV) was very high for beta carotene(183.5%), root yield per hectare(151.6%), total root weight per plant(150.6%) and total number of roots per plant(113.5%). The PCV was higher than their corresponding GCV for all the characters studies, indicating that the expression of these characters was influenced by environment. The GCV was consistently higher than PCV in all the traits. The genotypic variance was high for days to 50% flowering (373.16), dry matter (220.30), root girth (140.73), root length (68.10) and root yield per hectare (349.66). The magnitude of VA was consistently larger than that of VD for all the traits suggesting that the additive genetic variance was more important than the dominance genetic variance in the inheritance of most studied traits. All the characters studies had high heritability (&gt;60%). High heritability estimates for those traits indicated a high response to selection.

Vegetative Propagation of Eureka Seedless Lemon (Citrus limon L.Cv Eureka seedless) using Different Types of Stem Cutting and Concentrations of Indole-3-Butyric Acid in Winter

Citrus can be propagated successfully through stem cutting. However, success of the propagation is depends on various internal as well as external factors. The 2*7 factorial Randomized Complete Block Design (RCBD) experiment was conducted at the Institute of Agriculture and Animal Sciences, Paklihawa Campus, Rupandehi, Nepal from 22 November 2019 to 5 March 2020 to assess the interaction effect of types of stem cuttings and indole 3 butyric acid (IBA) concentrations on the vegetative propagation of Eureka seedless lemon in winter. Stem cutting types had two levels: hardwood and semi-hardwood cutting and IBA concentrations had seven different level i.e control, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, and 5000 ppm respectively forming overall 14 treatments and three replications. Statistically, significant interaction effects were seen in root parameters. The highest total number of the root(18.00) were found in hardwood cuttings treated with 4000 ppm and lowest total number of roots(1.66) was found in semi-hardwood cuttings treated with 0 ppm of IBA. A statistically significant interaction effect was not found in most of the shoot parameters. However, maximum sprouting (93.33%), the average number of shoots (4.67), average length of the shoot (7.86), and minimum days for first sprouting (30.67 days) were found in hard wood cuttings treated with 4000 ppm IBA. Considering different root and shoot parameters, hardwood cuttings treated with 4000 ppm performed best for root and shoot development. Thus, hardwood cuttings treated with 4000 ppm IBA can be appropriate method for easy and early propagation of eureka seedless lemon.

Oxidative stress protection and growth promotion activity of Pseudomonas mercuritolerans sp. nov., in forage plants under mercury abiotic stress conditions.

SAICEUPSMT strain was isolated from soils in the mining district of Almadén (Ciudad Real, Spain), subjected to a high concentration of mercury. Using the plant model of lupinus, the strain was inoculated into the rhizosphere of the plant in a soil characterized by a high concentration of mercury (1,710 ppm) from an abandoned dump in the mining district of Almadén (Ciudad Real, Spain). As a control, a soil with a minimum natural concentration of mercury, from a surrounding area, was used. Under greenhouse conditions, the effect that the inoculum of the SAICEUPSMT strain had on the antioxidant capacity of the plant was studied, through the quantification of the enzymatic activity catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), and glutathione reductase (GR). Likewise, the capacity of the plant to bioaccumulate mercury in the presence of the inoculum was studied, as well as the effect on the biometric parameters total weight (g), shoot weight (g), root weight (g), shoot length (cm), root length (cm), total number of leaves (N), and total number of secondary roots (No). Finally, in view of the results, the SAICEUPSMT strain was identified from the phenotypic and genotypic point of view (housekeeping genes and complete genome sequencing). The inoculum with the SAICEUPSMT strain in the presence of mercury produced a significant reduction in the enzymatic response to oxidative stress (CAT, APX, and SOD). It can be considered that the strain exerts a phytoprotective effect on the plant. This led to a significant increase in the biometric parameters total plant weight, root weight and the number of leaves under mercury stress, compared to the control without abiotic stress. When analyzing the mercury content of the plant with and without bacterial inoculum, it was found that the incorporation of the SAICEUPSMT strain significantly reduced the uptake of mercury by the plant, while favoring its development in terms of biomass. Given the positive impact of the SAICEUPSMT strain on the integral development of the plant, it was identified, proving to be a Gram negative bacillus, in vitro producer of siderophores, auxins and molecules that inhibit stress precursors. The most represented fatty acids were C16:0 (33.29%), characteristic aggregate 3 (22.80%) comprising C16:1 ω7c and C16: 1ω6c, characteristic aggregate 8 (13.66%) comprising C18:1 ω7c, and C18: 1 cycle ω6c and C 17:0 (11.42%). From the genotypic point of view, the initial identification of the strain based on the 16S rRNA gene sequence classified it as Pseudomonas iranensis. However, genome-wide analysis showed that average nucleotide identity (ANI, 95.47%), DNA-DNA in silico hybridization (dDDH, 61.9%), average amino acid identity (AAI, 97.13%), TETRA (0.99%) and intergenic distance (0.04) values were below the established thresholds for differentiation. The results of the genomic analysis together with the differences in the phenotypic characteristics and the phylogenetic and chemotaxonomic analysis support the proposal of the SAICEUPSMT strain as the type strain of a new species for which the name Pseudomonas mercuritolerans sp. is proposed. No virulence genes or transmissible resistance mechanisms have been identified, which reveals its safety for agronomic uses, under mercury stress conditions.

Viabilidade da visão computacional no melhoramento genético na produção de raízes de batata-doce

ABSTRACT The improvement of sweet potato is a costly job due to the large number of characteristics to be analyzed for the selection of the best genotypes, making it necessary to adopt new technologies, such as the use of images, associated with the phenotyping process. The objective of this research was to develop a methodology for the phenotyping of the root production aiming genetic improvement of half-sib sweet potato progenies through computational analysis of images and to compare its performance to the traditional methodology of evaluation. Sixteen half-sib sweet potato families in a randomized block design with 4 replications were evaluated. At plant level, the weight per root and the total number of roots were evaluated. The images were acquired in a “studio” made of mdf with a digital camera model Canon PowerShotSX400 IS, under artificial lighting. The evaluations were carried out using the R software, where a second-degree polynomial regression model was fitted to predict the root weight (in grams) and the genetic values and expected gains were obtained. It was possible to predict the root weight at plant and plot level, obtaining high coefficients of determination between the predicted and observed weight. Computer vision allowed the prediction of root weight, maintaining the genotype ranking and consequently the similarity between the expected gains with the selection. Thus, the use of images is an efficient tool for sweet potato genetic improvement programs, assisting in the crop phenotyping process.