Significant Levels Of Genetic Variation Research Articles

Assessment of Breeding Potential of Taro (Colocasia esculenta L.) Genotypes Using D2 Analysis under Hill Zone of Karnataka

Using Mahalanobis D2 statistics, the genetic diversity of 20 genotypes of taro for 21 characteristics was assessed as part of a breeding work to increase production potential. Five clusters were formed from the genotypes, indicating a significant level of genetic variation in the material being studied. With eight genotypes, Cluster I was the largest, followed by Cluster II with seven, and Cluster III with three. Each of the solitary clusters IV and V has a single genotype. The clusters that exhibit the greatest number of genotypes are indicative of limited genetic diversity. The intra-cluster distance was highest in cluster III and lowest in clusters IV and V. Clusters I and V have the highest inter-cluster distance, followed by II and V. These clusters could potentially be used as prospective genotypes for a hybridization programme. Tuber yield/plot (13%) showed the largest contribution to the overall divergence, followed by Corm yield/plant (12.20%) and Tuber yield/plant (11.43%). The finding that clusters V and III showed high cluster means for plant height, number of leaves per plant, leaf breadth, leaf area, leaf area index, tuber yield per plant, tuber yield per plot, and estimated tuber yield is noteworthy. These clusters can be effectively used in hybridization programmes to obtain desired transgressive segregants.

Genetic Diversity of Cowpea Parental Lines Assembled for Breeding in Uganda

Cowpea is a grain legume that is commonly grown in Sub-Saharan Africa (SSA) for a variety of uses including food, feed, and soil fertility enhancement through nitrogen fixation. Genetic improvement in cowpea can be accomplished by creating breeding populations from high-performing but genetically diverse parental lines. The goal of this study was to use single nucleotide polymorphic markers (SNPs) to estimate genetic diversity and population stratification among cowpea parental genotypes from five countries. A total of 2,746 SNP markers were used to analyze 62 cowpea genotypes that differed in key characteristics. Only 55% of the SNP markers were polymorphic across the 62 genotypes and met the selection requirement. The gene diversity varied from 0.52 to 0.57 with an average of 0.55, while the polymorphic information content ranged from 0.46 to 0.51 with an average of 0.49, showing that the cowpea parental lines are genetically diverse. The analysis of molecular variance (AMOVA) found high significant (p < 0.001) variation among genotypes and non-significant variation across genotypes depending on country of origin. The cluster analysis for the 62 genotypes using the unweighted pair group procedure with arithmetic mean approach divided the genotypes into two distinct groups. Genotypes from the same geographical regions tended to cluster together and there was a significant level of genetic variation among genotypes from Uganda and Nigeria. The SNP markers utilized in this study were effective at distinguishing genotypes and may be used to estimate the diversity in the cowpea core collection. The genetic diversity in this collection is important for future development of improved varieties of cowpea in Uganda.

A New Aculodes Species (Prostigmata: Eriophyidae) Described from an Invasive Weed by Morphological, Morphometric and DNA Barcode Analyses.

Simple SummaryNatural enemies of cheatgrass, an invasive plant in the western USA that is associated with recent increases in destructive wildfires, were sought as part of a classical biological control program targeting that plant. A population of mites was discovered infesting cheatgrass plants in central Bulgaria and determined to be a new species using morphological, morphometric analysis (i.e., measurement of specific body parts) and DNA barcoding (i.e., comparison of DNA sequences in genes shared by all mite species). Without these modern analytical tools, this mite would probably have been considered as the same species as another mite that infests other plants. This new mite species will now be tested to determine if it is suitable for importation and release in the USA as a biological control agent of cheatgrass.A new species of eriophyoid mite, Aculodes marcelli sp. nov., was discovered on cheatgrass, Anisantha tectorum (L.) Nevski (syn. Bromus tectorum L.), an annual grass that is native to Eurasia and Northern Africa. This grass was introduced to North America near the end of the 19th century and now is widespread and associated with the observed increases in the size, frequency, and intensity of wildfires in western N. America. In this paper, A. marcelli sp. nov., is morphologically described and illustrated. Compared with other Aculodes spp., it differs based on morphology and the sequence of the mitochondrial cytochrome oxidase gene, subunit I (MT-CO1). Results of morphometric analysis showed clear differentiation between A. marcelli sp. nov., and the most similar congener, A. altamurgiensis from Taeniatherum caput-medusae. Analysis of MT-CO1 sequence divergence revealed significant levels of genetic variation (17.7%) and supported the results from the morphometric analysis; therefore, it is determined that they are two different species. Aculodes marcelli sp. nov., is a new candidate agent for classical biological control of A. tectorum.

Characterization of carnation (Dianthus caryophyllus L.) genotypes and gamma irradiated mutants using RAPD, ISSR and SSR markers

Carnation genotypes and mutants developed using gamma irradiations were characterized using PCR based DNA markers (RAPD, ISSR and SSR) for designing future breeding strategies. RAPD markers showed 70.00 to 94.74 percent polymorphism among the genotypes and mutants whereas, for ISSR and SSR markers 83.33 to 94.44 and 66.67 to 87.50 percent polymorphism was recorded, signifying variability among different genotypes tested. UPGMA based analysis of cluster separated carnation genotypes and mutants into two discrete groups. RAPD, ISSR and SSR markers were subjected for comparative analysis like effective multiplex ratio, marker index, polymorphic information content, resolving power and gene flow wherein, highest EMR (13.00), MI (5.33) and Rp (70) values were found for ISSRs and maximum PIC value (0.63), gene flow (3.33) were found for SSR. The results clearly indicated the reproducibility of SSRs and their ability to detect variability among the genotypes and mutants. Significant level of genetic variation was depicted by AMOVA which suggested the usefulness of studies in carnation breeding and unique bands obtained could be utilized for varietal identification.

Polygenic adaptation of rosette growth in Arabidopsis thaliana

The rate at which plants grow is a major functional trait in plant ecology. However, little is known about its evolution in natural populations. Here, we investigate evolutionary and environmental factors shaping variation in the growth rate of Arabidopsis thaliana. We used plant diameter as a proxy to monitor plant growth over time in environments that mimicked latitudinal differences in the intensity of natural light radiation, across a set of 278 genotypes sampled within four broad regions, including an outgroup set of genotypes from China. A field experiment conducted under natural conditions confirmed the ecological relevance of the observed variation. All genotypes markedly expanded their rosette diameter when the light supply was decreased, demonstrating that environmental plasticity is a predominant source of variation to adapt plant size to prevailing light conditions. Yet, we detected significant levels of genetic variation both in growth rate and growth plasticity. Genome-wide association studies revealed that only 2 single nucleotide polymorphisms associate with genetic variation for growth above Bonferroni confidence levels. However, marginally associated variants were significantly enriched among genes with an annotated role in growth and stress reactions. Polygenic scores computed from marginally associated variants confirmed the polygenic basis of growth variation. For both light regimes, phenotypic divergence between the most distantly related population (China) and the various regions in Europe is smaller than the variation observed within Europe, indicating that the evolution of growth rate is likely to be constrained by stabilizing selection. We observed that Spanish genotypes, however, reach a significantly larger size than Northern European genotypes. Tests of adaptive divergence and analysis of the individual burden of deleterious mutations reveal that adaptive processes have played a more important role in shaping regional differences in rosette growth than maladaptive evolution.

Genetic characterization of farmed and wild populations of African catfish (Clarias gariepinus Burchell, 1822) using the random amplified polymorphic marker

The genetic characterization of Clarias gariepinus was conducted in this study. Thirty (30) C. gariepinus specimens were collected, fifteen (15) each from the wild and farms in northeastern Nigeria for their genetic relatedness and diversity using the RAPD markers. DNA extraction from the blood sample was performed using the Gene Jet Genomic DNA Purification Kit. Five primers were used in employing PCR and amplified 402 RAPD bands from the four strains of Clarias gariepinus. Three hundred and six (76.12%) bands were polymorphic while 86 (21.39%) were monomorphic. The percentage of polymorphism obtained from farmed and wild populations ranged from 58 (47.3%) to 69 (75.9%), respectively. The polymorphic bands per loci within the populations ranged from 67.9% to 82.0%. The mean numbers of inbreeding coefficient (FIS) were 0.083 and 0.053 in the farmed and wild populations. Gene diversity values within farmed and wild populations (Ht) were 0.4522 and 0.4018. The mean genetic differentiation (FST) ranged between (0.203) in the farmed and 0.129 in the wild populations. The analysis of molecular variance revealed that there was 96% of genetic variance within the population and 4% among the population. The genetic identity and distance of four populations were 0.9490 and 0.1038, respectively. The phylogenetic measure has shown that the four strains were divided into two clusters at approximately 0.089 similarity levels. The result indicated a significant level of genetic variation and minimal dendrogram separation in Clarias gariepinus in northeastern Nigeria. Conclusively, this information will be a useful tool for the genetic and breeding program of Clarias gariepinus.

Adaptation in response to environmental unpredictability.

Understanding how organisms adaptively respond to environmental fluctuations is a fundamental question in evolutionary biology. The Mediterranean region typically exhibits levels of environmental unpredictability that vary greatly in habitats over small geographical scales. In cyclically parthenogenetic rotifers, clonal proliferation occurs along with occasional bouts of sex. These bouts contribute to the production of diapausing eggs, which allows survival between growing seasons. Here, we studied two diapause-related traits in rotifers using clones from nine Brachionus plicatilis natural populations that vary in the degree of environmental unpredictability. We tested the hypothesis that the level of environmental unpredictability is directly related to the propensity for sex and inversely related to the hatching fraction of diapausing eggs. We found significant levels of genetic variation within populations for both traits. Interestingly, a positive correlation between pond unpredictability-quantified in a previous study from satellite imagery-and the propensity for sex was found. This correlation suggests a conservative, bet-hedging strategy that provides protection against unexpectedly short growing seasons. By contrast, the hatching fraction of diapausing eggs was not related to the level of environmental predictability. Our results highlight the ability of rotifer populations to locally adapt to time-varying environments, providing an evolutionarily relevant step forward in relating life-history traits to a quantitative measure of environmental unpredictability.

GENETIC DIVERSITY OF NATURAL POPULATIONS OF Moringa peregrina IN EGYPT

The genetic diversity of two populations of Moringa peregrina in South Sinai was performed by inter-simple sequence repeat markers (ISSR) using ten primers. The investigation was carried out as a primary step towards developing effective conservation strategies for the protection of Moringa peregrina germplasm. The aim of this study was to assess the genetic diversity within and among twenty individuals of Moringa peregrina collected from two populations in Wadi Zaghra and Wadi Feiran, South Sinai. The ISSR marker analysis showed a significant level of genetic variation within and among the populations, reached 95.45% of polymorphism. Cluster analysis was performed to construct a dendrogram using UPGMA. The dendrogram clustered the individuals into two major clusters, the first one for Wadi Zaghra individuals (about 78% polymorphism) and the second one for Wadi Feiran individuals (about 75% polymorphism). The obtained results indicate the high genetic diversity between the individuals of Moringa peregrina in South Sinai.

Genetic diversity of common carp (Cyprinus carpio L.) strains breed in Poland based on microsatellite, AFLP, and mtDNA genotype data

The common carp (Cyprinus carpio L.) has a long-standing history in Polish pond aquaculture, which has given rise to a great number of local breeds, strains and hatchery populations. They are well adapted to their local conditions, play an important role for fisherman's livelihoods and embody valuable genetics for future breeding programs. Proper maintenance of animal genetic resources (AnGR) requires an appropriate strategy based upon the precise knowledge of their genetic structure. This study genetically characterizes 20 common carp strains breed in Poland alongside with wild carp from Onuma Lake in Japan. We study three different types of genetic markers including the 963 AFLP markers, a set of 11 microsatellite loci (STR) and DNA sequences of the mitochondrial control region (D-loop). Bayesian clustering analysis of microsatellite loci divided the studied strains into 17 distinct clusters. Using population assignment test 92.4% of carp individuals were correctly assigned to their strain of origin. Microsatellite and AFLP marker analysis have shown the moderate but significant level of genetic variation between strains (AMOVA 23% and 18.2% respectively). AFLP and STR analysis of genetic distances gave equivalent values and were positively correlated with high values of the Mantel test (r=0.553, n=20, p=0.001). Only two mtDNA haplotypes (H5 and H2) were detected in all studied carp strains with H2 being the most prevalent.This is the first comprehensive genetic research of common carp strains breed in Poland which provided crucial data for the national conservation strategy. This study means that this resource can now be placed within the context of similar studies worldwide allowing the further improvement and breeding work.

ISSR Marker Based Population Genetic Study of Melocanna baccifera (Roxb.) Kurz: A Commercially Important Bamboo of Manipur, North-East India.

Melocanna baccifera (Roxb.) Kurz is an economically important bamboo of North-East India experiencing population depletion in its natural habitats. Genetic variation studies were conducted in 7 populations sampled from 5 districts of Manipur using ISSR molecular markers. The investigation was carried out as a primary step towards developing effective conservation strategies for the protection of bamboo germplasm. ISSR marker analysis showed significant level of genetic variation within the populations as revealed by moderately high average values of Nei's genetic diversity (H 0.1639), Shannon's diversity index (I 0.2563), percentage of polymorphic bands (PPB 59.18), total genetic variation (Ht 0.1961), and genetic diversity within population (Hs 0.1639). The study also divulged a high genetic variation at species level with Shannon's diversity index (I), Nei's genetic diversity (H), and percentage of polymorphic band (PPB%) recorded at 0.3218, 0.1939, and 88.37, respectively. Genetic differentiation among the populations (Gst) was merely 19.42% leaving 80.58% of genetic variation exhibited within the populations. The low genetic diversity between populations was consistent with AMOVA. The low genetic differentiation among populations coupled with existence of significantly high genetic diversity at species level indicated the urgent necessity of preserving and protecting all the existing natural bamboo populations in the region.

Identification of Highly Variable Supernumerary Chromosome Segments in an Asexual Pathogen.

Supernumerary chromosome segments are known to harbor different transposons from their essential counterparts. The aim of this study was to investigate the role of transposons in the origin and evolution of supernumerary segments in the asexual fungal pathogen Fusarium virguliforme. We compared the genomes of 11 isolates comprising six Fusarium species that cause soybean sudden death syndrome (SDS) or bean root rot (BRR), and identified significant levels of genetic variation in A+T-rich repeat blocks of the essential chromosomes and in A+T-neutral regions of the supernumerary segments. The A+T-rich repeat blocks in the essential chromosomes were highly variable between F. virguliforme and non-F. virguliforme isolates, but were scarcely variable between F. virguliforme isolates. The A+T-neutral regions in the supernumerary segments, however, were highly variable between F. virguliforme isolates, with a statistically significant number (21 standard deviations above the mean) of single nucleotide polymorphisms (SNPs). And supernumerary sequence types and rearrangement patterns of some F. virguliforme isolates were present in an isolate of F. cuneirostrum but not in the other F. virguliforme isolates. The most variable and highly expressed region in the supernumerary segments contained an active DNA transposon that was a most conserved match between F. virguliforme and the unrelated fungus Tolypocladium inflatum. This transposon was absent from two of the F. virguliforme isolates. Furthermore, transposons in the supernumerary segments of some F. virguliforme isolates were present in non-F. virguliforme isolates, but were absent from the other F. virguliforme isolates. Two supernumerary P450 enzymes were 43% and 57% identical to their essential counterparts. This study has raised the possibility that transposons generate genetic variation in supernumerary chromosome segments by frequent horizontal transfer within and between closely related species.

English

This study assessed the genetic diversity and differentiation in sweetpotato accessions in Ghana to guide selection for genetic improvement on beta-carotene, dry matter and sugar contents to promote increased utilization. One hundred and fifteen sweetpotato accessions from four different sources, which were the International Potato Centre (CIP) collection, local collection from farmers&rsquo; field, local improved varieties, and local and exotic collections from the National Agricultural Research Programmes were studied using 40 agro-morphological and physico-chemical traits, and 25 SSR markers. Variability was obtained for 13 agro-morphological traits and all the physico-chemical traits. Significant genetic diversity indicates existence of a high degree of agro-morphological and physicochemical variation. Within Group variation (97%) accounted for most of the diversity indicating a broad genetic base. The divergence indicates that breeders can form different populations with significant levels of genetic variation to exploit heterosis and improvement of populations. A strong negative relationship was found for sugar content and dry matter content and indicates a possible development of non-sweet high dry matter sweetpotato varieties. However, developing non-sweet, high dry matter and high beta-carotene sweetpotato varieties could be challenging due to the strong negative association between dry matter content and beta-carotene content, and the positive association existing between beta-carotene and sugar content. This study has in addition confirmed the breeding potential of sweetpotato accessions in Ghana and the probability of providing useful genetic variation for the development of farmer preferred cultivars. &nbsp; Key words: Analysis of Molecular Variance (AMOVA), diversity, end-user, simple sequence repeats (SSR) markers, Sweetpotato, traits.

Genetic diversity and population structure of an Italian landrace of runner bean (Phaseolus coccineus L.): inferences for its safeguard and on-farm conservation

The landraces are considered important sources of valuable germplasm for breeding activities to face climatic changes as well as to satisfy the requirement of new varieties for marginal areas. Runner bean (Phaseolus coccineus L.) is one of the most cultivated Phaseolus species worldwide, but few studies have been addressed to assess the genetic diversity and structure within and among landrace populations. In the present study, 20 different populations of a runner bean landrace from Central Italy named "Fagiolone," together with 41 accessions from Italy and Mesoamerica, were evaluated by using 14 nuclear SSRs to establish its genetic structure and distinctiveness. Results indicated that "Fagiolone" landrace can be considered as a dynamic evolving open-pollinated population that shows a significant level of genetic variation, mostly detected within populations, and the presence of two main genetic groups, of which one distinguished from other Italian runner bean landraces. Results highlighted also a relevant importance of farmers' management practices able to influence the genetic structure of this landrace, in particular the seed exchanges and selection, and the past introduction in cultivation of landraces/cultivars similar to seed morphology, but genetically rather far from "Fagiolone." The most suitable on-farm strategies for seed collection, conservation and multiplication will be defined based on our results, as a model for threatened populations of other allogamous crop species. STRUCTURE and phylogenetic analyses indicated that Mesoamerican accessions and Italian landraces belong to two distinct gene pools confirming the hypothesis that Europe could be considered a secondary diversification center for P. coccineus.

Assessment of intraspecific genetic variation between three morphotypes of Cissus quadrangularis using CCMP markers

The objective of the current study was to assess and establish intraspecific variation between three morphotypes of Cissus quadrangularis using ten Consensus Chloroplast Microsatellite Primers. Significant level of genetic variation was detected between the three morphotypes. Sequence analysis of the CCMP PCR fragment showed the high degree of similarity to the chloroplast genome sequences of other Vitaceae members indicating that these regions are highly conserved.Plant Tissue Cult. &amp; Biotech. 24(2): 205-212, 2014 (December)

Molecular characterization of madras red sheep using microsatellite markers

Genetic diversity of Madras Red sheep was investigated by microsatellite markers recommended by FAO. All the loci studied were highly informative and polymorphic. The number of observed alleles (Na) detected ranged from 3 to14, with an overall mean of 7.00±2.81. The mean effective number of alleles was (Ne) 4.42±2.12. The overall means for observed (Ho) and expected (He) heterozygosity were 0.65±0.25 and 0.73±0.16, respectively. The mean polymorphism information content (PIC) value was 0.6704 which ranged from 0.2170 to 0.8215. The within breed estimate (FIS) indicated heterozygosity shortage of 0.07. The Hardy-Weinberg equilibrium (HWE) test revealed that 76% (19/25)) loci deviated from equilibrium. Shannon's information index (I) was sufficiently high with a mean of 1.5578. The study revealed that even a breed with significant level of genetic variation needs proper genetic management for improvement and conservation.

Genetic Differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) Populations on Cultivated Cowpea and Wild Host Plants: Implications for Insect Resistance Management and Biological Control Strategies

Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a polyphagous insect pest that feeds on a variety of leguminous plants in the tropics and subtropics. The contribution of host-associated genetic variation on population structure was investigated using analysis of mitochondrial cytochrome oxidase 1 (cox1) sequence and microsatellite marker data from M. vitrata collected from cultivated cowpea (Vigna unguiculata L. Walp.), and alternative host plants Pueraria phaseoloides (Roxb.) Benth. var. javanica (Benth.) Baker, Loncocarpus sericeus (Poir), and Tephrosia candida (Roxb.). Analyses of microsatellite data revealed a significant global FST estimate of 0.05 (P≤0.001). The program STRUCTURE estimated 2 genotypic clusters (co-ancestries) on the four host plants across 3 geographic locations, but little geographic variation was predicted among genotypes from different geographic locations using analysis of molecular variance (AMOVA; among group variation −0.68%) or F-statistics (F ST Loc = −0.01; P = 0.62). These results were corroborated by mitochondrial haplotype data (φSTLoc = 0.05; P = 0.92). In contrast, genotypes obtained from different host plants showed low but significant levels of genetic variation (F ST Host = 0.04; P = 0.01), which accounted for 4.08% of the total genetic variation, but was not congruent with mitochondrial haplotype analyses (φSTHost = 0.06; P = 0.27). Variation among host plants at a location and host plants among locations showed no consistent evidence for M. vitrata population subdivision. These results suggest that host plants do not significantly influence the genetic structure of M. vitrata, and this has implications for biocontrol agent releases as well as insecticide resistance management (IRM) for M. vitrata in West Africa.

Genetic Structure of Pelagic and Littoral Cichlid Fishes from Lake Victoria

The approximately 700 species of cichlids found in Lake Victoria in East Africa are thought to have evolved over a short period of time, and they represent one of the largest known examples of adaptive radiation. To understand the processes that are driving this spectacular radiation, we must determine the present genetic structure of these species and elucidate how this structure relates to the ecological conditions that caused their adaptation. We analyzed the genetic structure of two pelagic and seven littoral species sampled from the southeast area of Lake Victoria using sequences from the mtDNA control region and 12 microsatellite loci as markers. Using a Bayesian model-based clustering method to analyze the microsatellite data, we separated these nine species into four groups: one group composed of pelagic species and another three groups composed mainly of rocky-shore species. Furthermore, we found significant levels of genetic variation between species within each group at both marker loci using analysis of molecular variance (AMOVA), although the nine species often shared mtDNA haplotypes. We also found significant levels of genetic variation between populations within species. These results suggest that initial groupings, some of which appear to have been related to habitat differences, as well as divergence between species within groups took place among the cichlid species of Lake Victoria.

Evaluation of Genetic Relationship between Trigonella-Melilotus complex Using CCMP Markers

&#x0D; &#x0D; &#x0D; To distinguish the taxa at the specific and varietal levels a range of DNA fingerprinting techniques are being employed. The objective of the current study was to establish the genetic correlation between the Trigonella-Melilotus complex i.e. M. indica, M. alba and Trigonella polyceratia using ten Consensus Chloroplast Microsatellite Primers (CCMPs). The polymorphism between the two genera indicated that they are intimately related and symbolize novel incongruity. Owing to less significant level of genetic variation, detected through CCMP, the differences between the two genera could be accredited to gene mutation or inconsequential chromosomal alterations.&#x0D; &#x0D; &#x0D; &#x0D; Plant Tissue Cult. &amp; Biotech. 23(1): 59-66, 2013 (June)&#x0D; &#x0D; &#x0D; &#x0D; &#x0D; &#x0D;

Heritability of Boldness and Aggressiveness in the Zebrafish

Behavioural traits that are consistent over time and in different contexts are often referred to as personality traits. These traits influence fitness because they play a major role in foraging, reproduction and survival, and so it is assumed that they have little or no additive genetic variance and, consequently, low heritability because, theoretically, they are under strong selection. Boldness and aggressiveness are two personality traits that have been shown to affect fitness. By crossing single males to multiple females, we estimated the heritability of boldness and aggressiveness in the zebrafish, Danio rerio. The additive genetic variance was statistically significant for both traits and the heritability estimates (95 % confidence intervals) for boldness and aggressiveness were 0.76 (0.49, 0.90) and 0.36 (0.10, 0.72) respectively. Furthermore, there were significant maternal effects accounting for 18 and 9 % of the proportion of phenotypic variance in boldness and aggressiveness respectively. This study shows that there is a significant level of genetic variation in this population that would allow these traits to evolve in response to selection.

Root Phenomics-New Windows to Understand Plant Performance and Increase Crop Productivity

Roots with ideal characteristics are important for sustaining crop yields, particularly when plants are grown in soils with inadequate water and nutrients [1-4]. Understanding the development of roots and their interaction with the soil environment is vital to manipulate the root traits, and ultimately, the food security [5]. For instance, rice has a significant level of genetic variation in root traits [6-9], that can be harnessed for improving its adaptation to abiotic stresses. However, genetic improvement of root systems through phenotypic selection at the breeding level is impractical due to complexity in phenotyping root traits [3,10,11].