Genetic mapping and legume synteny of aphid resistance in African cowpea (Vigna unguiculata L. Walp.) grown in California.

The cowpea aphid Aphis craccivora Koch (CPA) is a destructive insect pest of cowpea, a staple legume crop in Sub-Saharan Africa and other semiarid warm tropics and subtropics. In California, CPA causes damage on all local cultivars from early vegetative to pod development growth stages. Sources of CPA resistance are available in African cowpea germplasm. However, their utilization in breeding is limited by the lack of information on inheritance, genomic location and marker linkage associations of the resistance determinants. In the research reported here, a recombinant inbred line (RIL) population derived from a cross between a susceptible California blackeye cultivar (CB27) and a resistant African breeding line (IT97K-556-6) was genotyped with 1,536 SNP markers. The RILs and parents were phenotyped for CPA resistance using field-based screenings during two main crop seasons in a 'hotspot' location for this pest within the primary growing region of the Central Valley of California. One minor and one major quantitative trait locus (QTL) were consistently mapped on linkage groups 1 and 7, respectively, both with favorable alleles contributed from IT97K-556-6. The major QTL appeared dominant based on a validation test in a related F2 population. SNP markers flanking each QTL were positioned in physical contigs carrying genes involved in plant defense based on synteny with related legumes. These markers could be used to introgress resistance alleles from IT97K-556-6 into susceptible local blackeye varieties by backcrossing

A Novel Root-Knot Nematode Resistance QTL on Chromosome Vu01 in Cowpea.

The root-knot nematode (RKN) species Meloidogyne incognita and M. javanica cause substantial root system damage and suppress yield of susceptible cowpea cultivars. The narrow-based genetic resistance conferred by the Rk gene, present in some commercial cultivars, is not effective against Rk-virulent populations found in several cowpea production areas. The dynamics of virulence within RKN populations require a broadening of the genetic base of resistance in elite cowpea cultivars. As part of this goal, F1 and F2 populations from the cross CB46-Null (susceptible) x FN-2-9-04 (resistant) were phenotyped for M. javanica induced root-galling (RG) and egg-mass production (EM) in controlled growth chamber and greenhouse infection assays. In addition, F[Formula: see text] families of the same cross were phenotyped for RG on field sites infested with Rk-avirulent M. incognita and M. javanica The response of F1 to RG and EM indicated that resistance to RKN in FN-2-9-04 is partially dominant, as supported by the degree of dominance in the F2 and F[Formula: see text] populations. Two QTL associated with both RG and EM resistance were detected on chromosomes Vu01 and Vu04. The QTL on Vu01 was most effective against aggressive M. javanica, whereas both QTL were effective against avirulent M. incognita Allelism tests with CB46 x FN-2-9-04 progeny indicated that these parents share the same RKN resistance locus on Vu04, but the strong, broad-based resistance in FN-2-9-04 is conferred by the additive effect of the novel resistance QTL on Vu01. This novel resistance in FN-2-9-04 is an important resource for broadening RKN resistance in elite cowpea cultivars

A major QTL corresponding to the Rk locus for resistance to root-knot nematodes in cowpea (Vigna unguiculata L. Walp.).

Key messageGenome resolution of a major QTL associated with the Rk locus in cowpea for resistance to root-knot nematodes has significance for plant breeding programs and R gene characterization. Cowpea (Vigna unguiculata L. Walp.) is a susceptible host of root-knot nematodes (Meloidogyne spp.) (RKN), major plant-parasitic pests in global agriculture. To date, breeding for host resistance in cowpea has relied on phenotypic selection which requires time-consuming and expensive controlled infection assays. To facilitate marker-based selection, we aimed to identify and map quantitative trait loci (QTL) conferring the resistance trait. One recombinant inbred line (RIL) and two F2:3 populations, each derived from a cross between a susceptible and a resistant parent, were genotyped with genome-wide single nucleotide polymorphism (SNP) markers. The populations were screened in the field for root-galling symptoms and/or under growth-chamber conditions for nematode reproduction levels using M. incognita and M. javanica biotypes. One major QTL was mapped consistently on linkage group VuLG11 of each population. By genotyping additional cowpea lines and near-isogenic lines derived from conventional backcrossing, we confirmed that the detected QTL co-localized with the genome region associated with the Rk locus for RKN resistance that has been used in conventional breeding for many decades. This chromosomal location defined with flanking markers will be a valuable target in marker-assisted breeding and for positional cloning of genes controlling RKN resistance

Broad-based root-knot nematode resistance identified in cowpea gene-pool two

U suvremenom svijetu ekonomije i nepredvidivih promjena svaka organizacija primorana je proširivati svoje znanje i neprestano učiti. Sposobnost učenja je jedinstvena karakteristika svakog ljudskog bića, ali organizacije kao same, u kojima ljudi funkcioniraju tijekom svog života tu sposobnost nemaju. To može dovesti do nedostatka ideja vodilja koje ona treba pružiti dođu u situaciju da ne razumiju i ne mogu se suočiti s nastalom promjenom ili situacijom. Tu dolazi do povezanosti sa motivacijom, koja je jedna od temeljnih čimbenika uspješne i ugledne ogranizacije. Ona se može odrediti kao proces pokretanja aktivnosti radi ostvarenja određenih ciljeva te usmjeravanja aktivnosti na određene objekte i reguliranje načina na koji će se postupiti. Kako bi poduzeće učilo, mora napredovati, a kako bi napredovalo, mora postojati motivacija među zaposlenicima. Ovim se radom ističu upravljanje ljudskim potencijalima te naravno motivacija kao jedna od njih, a temeljni cilj istraživanja je spoznati nešto više o unaprjeđivanju i obrazovanju zaposlenika te analiziranje uloge motivacije u tvrtci Atlantic Grupa d.d.In the modern world of fast-paced economics and unpredictable changes, each organization has been forced to expand its knowledge and to continuously learn. Learning is a unique feature of every human being, but organizations like themselves, in which people work throughout their lives, do not have that ability. This can lead to a lack of idea of the guideline that needs to come into a situation that they do not understand and can not cope with the change or situation that is being created. Here comes to the connection with motivation, which is one of the fundamental factors of successful and reputable encounters. It can be defined as a process of initiating activities to achieve certain goals and directing activities to specific objects and regulating how to act. In order for an enterprise to learn, it must progress, and in order to progress, there must be motivation among employees. This paper emphasizes human resource management and of course motivation as one of them, and the main goal of the research is to know more about improving and educating employees and analyzing the role of motivation at Atlantic Grupa d.d

The genome of cowpea (Vigna unguiculata [L.] Walp.)

[EN] Cowpea (Vigna unguiculata [L.] Walp.) is a major crop for worldwide food and nutritional security, especially in sub-Saharan Africa, that is resilient to hot and drought-prone environments. An assembly of the single-haplotype inbred genome of cowpea IT97K-499-35 was developed by exploiting the synergies between single-molecule real-time sequencing, optical and genetic mapping, and an assembly reconciliation algorithm. A total of 519 Mb is included in the assembled sequences. Nearly half of the assembled sequence is composed of repetitive elements, which are enriched within recombination-poor pericentromeric regions. A comparative analysis of these elements suggests that genome size differences between Vigna species are mainly attributable to changes in the amount of Gypsy retrotransposons. Conversely, genes are more abundant in more distal, high-recombination regions of the chromosomes; there appears to be more duplication of genes within the NBS-LRR and the SAUR-like auxin superfamilies compared with other warm-season legumes that have been sequenced. A surprising outcome is the identification of an inversion of 4.2 Mb among landraces and cultivars, which includes a gene that has been associated in other plants with interactions with the parasitic weed Striga gesnerioides. The genome sequence facilitated the identification of a putative syntelog for multiple organ gigantism in legumes. A revised numbering system has been adopted for cowpea chromosomes based on synteny with common bean (Phaseolus vulgaris). An estimate of nuclear genome size of 640.6 Mbp based on cytometry is presentedS

Genetics of Resistance to Root-Knot Nematode and Fusarium Wilt in Cowpea Germplasm From Mozambique

Cowpea is a multi-purpose leguminous crop, and its importance as a resource to address food security issues plus production constraints imposed by biotic and abiotic stresses has attracted significant research. Aligned with these efforts, this dissertation describes the resistance found among 53 cowpea genotypes from Mozambique, to root-knot nematodes (RKN) (Meloidogyne incognita¬ and M. javanica) and Fusarium wilt (FW) [Fusarium oxysporum f. sp. tracheiphilum (Fot races 3 and 4)]. In the first chapter, an overview is provided about the significance of cowpea as a food security resource, constraints limiting production and research progress and status of cowpea production in Mozambique. Also, available genetic and genomic resources and their utility for cowpea breeding are described. In addition, the concept of plant resistance, types of resistance, mechanisms of plant resistance, disease quantification to RKN and FW, the genetic control of some cowpea diseases and practical example of successful cowpea breeding for diseases is discussed. The second chapter, describes a series of experiments that led to the discovery of seven cowpea genotypes with broad-based resistance to RKN using nematode reproduction and root-galling phenotypes. The effectiveness of resistance in FN-2-9-04 relative to virulence levels in RKN isolates and the relationship between resistances to different RKN isolates is described. In the third chapter, the genomic architecture of resistance to RKN in FN-2-9-04 is determined through a series of genetic analyses and quantitative trait locus (QTL) mapping. Two QTLs on chromosomes 1 and 4 were associated with the strong RKN resistance in FN-2-9-04. The fourth chapter describes the resistance found among the test cowpeas to Fot3 and Fot4 based on wilting and vascular discoloration phenotypes. The virulence profiles of Fot3 and Fot4 are compared, and the effectiveness of FW resistance in FN-2-9-04 and the relationship between wilting and vascular discoloration responses are discussed. In the fifth chapter, the genomic architecture of resistance to Fot4 in FN-2-9-04, determined through a series genetic analyses and QTL mapping, is described. Two QTL on chromosomes 3 and 8 were associated with Fot4 resistance in FN-2-9-04. These novel sources of nematode and Fusarium resistance are important for cowpea genetic improvement

Genetics of Resistance to Root-Knot Nematode and Fusarium Wilt in Cowpea Germplasm From Mozambique

Cowpea is a multi-purpose leguminous crop, and its importance as a resource to address food security issues plus production constraints imposed by biotic and abiotic stresses has attracted significant research. Aligned with these efforts, this dissertation describes the resistance found among 53 cowpea genotypes from Mozambique, to root-knot nematodes (RKN) (Meloidogyne incognita¬ and M. javanica) and Fusarium wilt (FW) [Fusarium oxysporum f. sp. tracheiphilum (Fot races 3 and 4)]. In the first chapter, an overview is provided about the significance of cowpea as a food security resource, constraints limiting production and research progress and status of cowpea production in Mozambique. Also, available genetic and genomic resources and their utility for cowpea breeding are described. In addition, the concept of plant resistance, types of resistance, mechanisms of plant resistance, disease quantification to RKN and FW, the genetic control of some cowpea diseases and practical example of successful cowpea breeding for diseases is discussed. The second chapter, describes a series of experiments that led to the discovery of seven cowpea genotypes with broad-based resistance to RKN using nematode reproduction and root-galling phenotypes. The effectiveness of resistance in FN-2-9-04 relative to virulence levels in RKN isolates and the relationship between resistances to different RKN isolates is described. In the third chapter, the genomic architecture of resistance to RKN in FN-2-9-04 is determined through a series of genetic analyses and quantitative trait locus (QTL) mapping. Two QTLs on chromosomes 1 and 4 were associated with the strong RKN resistance in FN-2-9-04. The fourth chapter describes the resistance found among the test cowpeas to Fot3 and Fot4 based on wilting and vascular discoloration phenotypes. The virulence profiles of Fot3 and Fot4 are compared, and the effectiveness of FW resistance in FN-2-9-04 and the relationship between wilting and vascular discoloration responses are discussed. In the fifth chapter, the genomic architecture of resistance to Fot4 in FN-2-9-04, determined through a series genetic analyses and QTL mapping, is described. Two QTL on chromosomes 3 and 8 were associated with Fot4 resistance in FN-2-9-04. These novel sources of nematode and Fusarium resistance are important for cowpea genetic improvement

Broad-based root-knot nematode resistance identified in cowpea gene-pool two

Cowpea (Vigna unguiculata L. Walp) is an affordable source of protein and strategic legume crop for food security in Africa and other developing regions; however, damage from infection by root-knot nematodes (RKN) suppresses cowpea yield. The deployment through breeding of resistance gene Rk in cowpea cultivars has provided protection to cowpea growers worldwide for many years. However, occurrence of more aggressive nematode isolates threatens the effectiveness of this monogenic resistance. A cowpea germplasm collection of 48 genotypes representing the cowpea gene-pool from Eastern and Southern Africa (cowpea has two major pools of genetic resources - Western Africa and Eastern/Southern Africa) was screened in replicated experiments under field, greenhouse and controlled-growth conditions to identify resistance to RKN, to determine the spectrum of resistance to RKN, the relative virulence (VI) among RKN species and isolates, and the relationship between root-galling (RG) and egg-mass production (EM). Analysis of variance of data for RG and EM per root system identified seven genotypes with broad-based resistance to Meloidogyne javanica (Mj), avirulent (Avr-Mi), and virulent (Mi) M. incognita isolates. Two of the 48 genotypes exhibited specific resistance to both Mi isolates. Most of the genotypes were resistant to Avr-Mi indicating predominance of Rk gene in the collection. Based on RG data, both Mj (VI = 50%) and Mi (VI = 42%) were fourfold more virulent than Avr-Mi (VI = 12%). Resistant genotypes had more effective resistance than the Rk-based resistance in cowpea genotype CB46 against Mj and Mi. Root-galling was correlated across isolates (Avr-Mi/Mj: r = 0.72; Mi/Mj: r = 0.98), and RG was correlated with EM (r = 0.60), indicating resistance to RG and EM is under control by the same genetic factors. These new sources of resistance identified in cowpea gene-pool two provide valuable target traits for breeders to improve cowpea production on RKN-infested fields.Cowpea (Vigna unguiculata L. Walp) is an affordable source of protein and strategic legume crop for food security in Africa and other developing regions; however, damage from infection by root-knot nematodes (RKN) suppresses cowpea yield. The deployment through breeding of resistance gene Rk in cowpea cultivars has provided protection to cowpea growers worldwide for many years. However, occurrence of more aggressive nematode isolates threatens the effectiveness of this monogenic resistance. A cowpea germplasm collection of 48 genotypes representing the cowpea gene-pool from Eastern and Southern Africa (cowpea has two major pools of genetic resources – Western Africa and Eastern/Southern Africa) was screened in replicated experiments under field, greenhouse and controlled-growth conditions to identify resistance to RKN, to determine the spectrum of resistance to RKN, the relative virulence (VI) among RKN species and isolates, and the relationship between root-galling (RG) and egg-mass production (EM). Analysis of variance of data for RG and EM per root system identified seven genotypes with broad-based resistance to Meloidogyne javanica (Mj), avirulent (Avr-Mi), and virulent (Mi) M. incognita isolates. Two of the 48 genotypes exhibited specific resistance to both Mi isolates. Most of the genotypes were resistant to Avr-Mi indicating predominance of Rk gene in the collection. Based on RG data, both Mj (VI = 50%) and Mi (VI = 42%) were fourfold more virulent than Avr-Mi (VI = 12%). Resistant genotypes had more effective resistance than the Rk-based resistance in cowpea genotype CB46 against Mj and Mi. Root-galling was correlated across isolates (Avr-Mi/Mj: r = 0.72; Mi/Mj: r = 0.98), and RG was correlated with EM (r = 0.60), indicating resistance to RG and EM is under control by the same genetic factors. These new sources of resistance identified in cowpea gene-pool two provide valuable target traits for breeders to improve cowpea production on RKN-infested fields