scholarly journals Evidence of apple blotch resistance in wild apple germplasm (Malus spp.) accessions

2020 ◽  
Author(s):  
Thomas Wöhner ◽  
Ofere Francis Emeriewen ◽  
Monika Höfer
Keyword(s):  
Gene Pool ◽  
Field Survey ◽  
Recent Literature ◽  
Germplasm Collection ◽  
Economic Losses ◽  
Apple Breeding ◽  
High Interest ◽  
Breeding Programmes ◽  
Apple Cultivars ◽  
Inoculation Assay

AbstractDiplocarpon coronariae causes apple blotch, which results in significant economic losses. Resistance to apple blotch in commercial apple cultivars has not been reported in recent literature. The Malus germplasm collection from the Fruit Genebank of the Julius Kühn-Institut that is maintained in Dresden, Germany consists of 516 accessions of about 49 Malus species. This apple gene pool was evaluated for resistance to Diplocarpon coronariae. A four-year field survey was subsequently followed by artificial inoculation of field-selected accessions. Fifteen accessions that represent nine different species and hybrids were confirmed to be highly resistant following a repeated inoculation assay in the laboratory. The results from this investigation is of high interest to breeders for future apple breeding programmes and investigations of resistance to Diplocarpon coronariae.

scholarly journals Evaluation of a Cider Apple Germplasm Collection of Local Cultivars from Spain for Resistance to Fire Blight (Erwinia amylovora) Using a Combination of Inoculation Assays on Leaves and Shoots

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1223-1227 ◽  
Author(s):  
Alejandro Martínez-Bilbao ◽  
Amaya Ortiz-Barredo ◽  
Emilio Montesinos ◽  
Jesús Murillo
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Integrated Management ◽  
Germplasm Collection ◽  
Direct Selection ◽  
Breeding Programs ◽  
Detached Leaf ◽  
Apple Cultivars ◽  
Apple Production ◽  
Inoculation Assay

Fire blight, caused by the bacterium Erwinia amylovora, is among the three most important diseases of apple. A major effective method for its integrated management is the reduction of the susceptibility of the host. Cider apple production in Spain is based on local apple cultivars with minimum crop management and phytosanitary control. After the entry of fire blight in Spain, the selection and planting of cultivars with low susceptibility to this disease has thus become of paramount importance. In consequence, and as part of a wider characterization effort, we undertook the evaluation of an apple germplasm collection of local apple cultivars from Spain for susceptibility to fire blight. Because of the quarantine status of E. amylovora in Europe, we evaluated the use of a detached leaf inoculation assay in combination with a traditional shoot inoculation assay to reduce the amount of plant material to evaluate and to minimize pathogen manipulation. Comparison of the susceptibility values for 78 apple cultivars indicated a low but significant correlation (r = 0.56; α = 0.01) between the leaf and shoot inoculation methods. Although the detached leaf assay was not reliable for the direct selection of cultivars with low susceptibility, it was useful to optimize resources and limit the potential dispersal of the pathogen by allowing the exclusion of medium and highly susceptible cultivars from further evaluation. Shoot inoculation of 103 apple cultivars allowed the identification of 48 cultivars with high levels of resistance to fire blight, which could serve as starting material both for apple production and for breeding programs.

scholarly journals Current trends in apple tree breeding (Malus Mill.)

2020 ◽  
pp. 5-11
Author(s):  
O. V. Kalinina ◽  
Yu. V. Burmenko ◽  
N. Yu. Svistunova
Keyword(s):  
Cost Effective ◽  
Tree Breeding ◽  
Industrial Sector ◽  
Crop Breeding ◽  
Relevant Today ◽  
Planting Material ◽  
Current Trends ◽  
Breeding Programmes ◽  
Apple Cultivars ◽  
Modern Breeding

Apples are among the most significant fruit crops in Russian horticulture. The wide variety, as well as the prominent economic potential of the crop, both enable its cultivation across many climate zones and bring orchard farming in general to the attention of investors in the agro-industrial sector. Breeders have met the rising challenges inherent in creating varieties that are superior in terms of productivity, abiotic- and biotic stress resistance, fruit quality and competitive fast-return capacity. In the present article, current research in apple breeding including methods for intensive selection is reviewed with a focus on breeding programmes for creating adaptive varieties having a high commercial and consumer value. Classical breeding can be complemented with modern techniques for an earlier selection of commercially valuable genotypes, identification of primary genotypes, as well as the creation of new donors and cultivars. The research achievements of leading national institutions in the development of apple varieties reflect additions to the Catalog of State-Permitted Cultivars of Agricultural Crops over the last decade. Most of the 422 permitted adapted apple cultivars are highly marketable due to having best-before-consumption dates in the winter. Despite current success in national orchard farming, further endeavours in crop breeding remain relevant today. Comprehensive research engaging genetics, physiology, phytopathology, virology, agrochemistry and nursery is essential for improving modern breeding programmes with the aim of supplying producers with high-quality planting material for a cost-effective, low pesticide, environmentallystable product.

scholarly journals Molecular characterization and genetic diversity studies of Indian soybean (Glycine max (L.) Merr.) cultivars using SSR markers

2021 ◽  
Author(s):  
S. P. Jeevan Kumar ◽  
C. Susmita ◽  
K. V. Sripathy ◽  
Dinesh K. Agarwal ◽  
Govind Pal ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Molecular Characterization ◽  
Ssr Markers ◽  
Crop Yield ◽  
Gene Pool ◽  
Stress Factors ◽  
Soybean Cultivars ◽  
Genetic Base ◽  
Purity Analysis ◽  
Breeding Programmes

Abstract Background The genetic base of soybean cultivars in India has been reported to be extremely narrow, due to repeated use of few selected and elite genotypes as parents in the breeding programmes. This ultimately led to the reduction of genetic variability among existing soybean cultivars and stagnation in crop yield. Thus in order to enhance production and productivity of soybean, broadening of genetic base and exploring untapped valuable genetic diversity has become quite indispensable. This could be successfully accomplished through molecular characterization of soybean genotypes using various DNA based markers. Hence, an attempt was made to study the molecular divergence and relatedness among 29 genotypes of soybean using SSR markers. Methods and results A total of 35 SSR primers were deployed to study the genetic divergence among 29 genotypes of soybean. Among them, 14 primer pairs were found to be polymorphic producing a total of 34 polymorphic alleles; and the allele number for each locus ranged from two to four with an average of 2.43 alleles per primer pair. Polymorphic information content (PIC) values of SSRs ranged from 0.064 to 0.689 with an average of 0.331. The dendrogram constructed based on dissimilarity indices clustered the 29 genotypes into two major groups and four sub-groups. Similarly, principal coordinate analysis grouped the genotypes into four major groups that exactly corresponded to the clustering of genotypes among four sub-groups of dendrogram. Besides, the study has reported eight unique and two rare alleles that could be potentially utilized for genetic purity analysis and cultivar identification in soybean. Conclusion In the present investigation, two major clusters were reported and grouping of large number of genotypes in each cluster indicated high degree of genetic resemblance and narrow genetic base among the genotypes used in the study. With respect to the primers used in the study, the values of PIC and other related parameters revealed that the selected SSR markers are moderately informative and could be potentially utilized for diversity analysis of soybean. The clustering pattern of dendrogram constructed based on SSR loci profile displayed good agreement with the cultivar’s pedigree information. High level of genetic similarity observed among the genotypes from the present study necessitates the inclusion of wild relatives, land races and traditional cultivars in future soybean breeding programmes to widen the crop gene pool. Thus, hybridization among diverse gene pool could result in more heterotic combinations ultimately enhancing genetic gain, crop yield and resistance to various stress factors.

scholarly journals Pigeonpea composite collection and identification of germplasm for use in crop improvement programmes

2011 ◽  
Vol 9 (01) ◽  
pp. 97-108 ◽  
Author(s):  
H. D. Upadhyaya ◽  
K. N. Reddy ◽  
Shivali Sharma ◽  
R. K. Varshney ◽  
R. Bhattacharjee ◽  
...  
Keyword(s):  
Agronomic Traits ◽  
Crop Improvement ◽  
Germplasm Collection ◽  
Sources Of Resistance ◽  
Abiotic And Biotic Stresses ◽  
Biotic Stresses ◽  
Mini Core Collection ◽  
Breeding Programmes ◽  
Simple Sequence ◽  
High Seed Yield

Pigeonpea (Cajanus cajan(L.) Millsp. is one of the most important legume crops as major source for proteins, minerals and vitamins, in addition to its multiple uses as food, feed, fuel, soil enricher, or soil binder, and in fencing, roofing and basket making. ICRISAT's genebank conserves 13,632 accessions of pigeonpea. The extensive use of few parents in crop improvement is contrary to the purpose of collecting a large number of germplasm accessions and has resulted in a narrow base of cultivars. ICRISAT, in collaboration with the Generation Challenge Program, has developed a composite collection of pigeonpea consisting of 1000 accessions representing the diversity of the entire germplasm collection. This included 146 accessions of mini core collection and other materials. Genotyping of the composite collection using 20 microsatellite or simple sequence repeat (SSR) markers separated wild and cultivated types in two broad groups. A reference set comprising 300 most diverse accessions has been selected based on SSR genotyping data. Phenotyping of the composite collection for 16 quantitative and 16 qualitative traits resulted in the identification of promising diverse accessions for the four important agronomic traits: early flowering (96 accessions), high number of pods (28), high 100-seed weight (88) and high seed yield/plant (49). These accessions hold potential for their utilization in pigeonpea breeding programmes to develop improved cultivars with a broad genetic base. Pigeonpea germplasm has provided sources of resistance to abiotic and biotic stresses and cytoplasmic-male sterility for utilization in breeding programmes.

scholarly journals Identification and multi-environment validation of resistance to rust (Uromyces viciae-fabae) in Vicia faba

2017 ◽  
Vol 68 (11) ◽  
pp. 1013 ◽  
Author(s):  
Josefina C. Sillero ◽  
María M. Rojas-Molina ◽  
Amero A. Emeran ◽  
Mohamed Kharrat ◽  
Johanna Winkler ◽  
...  
Keyword(s):  
Vicia Faba ◽  
Phenotypic Expression ◽  
Germplasm Collection ◽  
Environment Interaction ◽  
Genotype Environment Interaction ◽  
Complete Resistance ◽  
Stability Of Resistance ◽  
Breeding Programmes ◽  
The Mediterranean ◽  
Efficiency Of Selection

A germplasm collection of 484 accessions of Vicia faba was screened for resistance to rust (Uromyces viciae-fabae) under field conditions. Accessions varied in the levels of rust infection, although no complete resistance was identified. Stability of resistance of the 39 most-resistant accessions was tested in a multi-location experiment in Austria, Egypt, Tunisia, United Kingdom and Spain over three additional field seasons. Genotype × environment interaction accounted for 43% of the sum of squares of the multi-environment evaluation, revealing instability of the phenotypic expression across environments. This might hamper the efficiency of selection suggesting the need for selection in different environments. Three possible mega-environments were discerned in the studied area, Mediterranean (Spain, Tunisia and Egypt), Oceanic (UK) and Continental (Austria). Córdoba (Spain) and Kafr El-Sheik (Egypt) showed as ideal environments for rust resistance screenings within Mediterranean environment. Several accessions (300, 303, 311, 313, 720, 1196 and 1271) were grouped as moderately to highly resistant in the three defined mega-environments. These accessions showed clear differences both in terms of reduced disease severity and high stability, which make them good candidates for international faba bean breeding programmes. Concerning each mega-environment, accessions 300 and 311 were the most resistant and stable ones across the Mediterranean one, followed by accessions 720, 1022, 1272, 1320 and BPL261. On the contrary other accessions (313, 452, 481 and 1196) were the most resistant in Oceanic and Continental environments. However, 452 and 481 were susceptible in the Mediterranean mega-environment. This contrasting performance across the environments was also supported by contradictory performance of the checks BPL261 and Baraca in Oceanic and Continental environments, suggesting differential virulence in rust populations, which deserves further attention.

Risk of Cold-Hardy Apple Cultivars for Injury From the Brown Marmorated Stink Bug (Hemiptera: Pentatomidae)

2019 ◽  
Author(s):  
Hailey N Shanovich ◽  
Eric C Burkness ◽  
Robert L Koch
Keyword(s):  
United States ◽  
The United States ◽  
Economic Losses ◽  
Brown Marmorated Stink Bug ◽  
Stink Bug ◽  
Cultivar Selection ◽  
Choice Tests ◽  
Apple Cultivars ◽  
Potential Impact ◽  
Cold Hardy

Abstract An invasive species, the brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), has emerged as a serious pest of orchard crops in the United States with the highest economic losses to date in Mid-Atlantic apple, Malus domestica Borkh. (Rosales: Rosaceae). If populations continue to grow and spread in the Midwest, H. halys has the potential to become a significant apple pest in the region. The purpose of this study was to assess the risk for injury from H. halys to several popular cold-hardy apple cultivars (Haralson, Honeycrisp, and Zestar!) grown in the Midwestern United States utilizing both field no-choice tests and laboratory choice tests at multiple timings. Results from the field no-choice tests revealed a greater risk for Honeycrisp from H. halys injury compared with Zestar! in mid-August. Results from the laboratory choice tests revealed a greater risk for injury by H. halys for Honeycrisp compared with Zestar! at all timings tested and a greater risk for Haralson compared with Honeycrisp at a later timing. These results echo previous findings in that relative maturity of the fruit seems to play a role in determining the risk of an apple cultivar to H. halys injury. These results also serve as the first assessment of the potential impact of H. halys on different cold-hardy apple cultivars, which will help guide growers in cultivar selection and identifying which apple cultivars should be prioritized for scouting and management efforts.

scholarly journals Diversity Assessment of the Montenegrin Maize Landrace Gene Pool Maintained in Two Gene Banks

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1503
Author(s):  
Vojka Babić ◽  
Violeta Andjelkovic ◽  
Zoran Jovovic ◽  
Milosav Babic ◽  
Vladimir Vasic ◽  
...  
Keyword(s):  
Gene Pool ◽  
Sustainable Use ◽  
Separate Analysis ◽  
Maize Breeding ◽  
Gene Banks ◽  
Diversity Assessment ◽  
Yellow Orange ◽  
Breeding Programmes ◽  
Maize Landraces ◽  
Joint Monitoring

Due to the loss of agro-biodiversity, there is a strong effort to find apparent and efficient mechanisms for the conservation and sustainable use of genetic diversity. A joint monitoring of the diversity and collections structure of the Montenegrin maize landraces conserved in the Serbian (MRIZPGB) and Montenegrin (MGB) gene banks has been conducted in order to improve the composition of the collections and to identify and eliminate possible redundancy. Based on a separate analysis of white- and yellow-orange maize landraces, it can be concluded that the diversity and evolution of distinct maize landraces grown and collected in Montenegro have been simultaneously shaped by both environmental (i.e., natural selection) and socially driven factors (farmers’ selection, migration and colonization processes of the human population). Although it has been determined that the authenticity and variability of the Montenegrin maize landraces gene pool have largely been preserved in the MRIZPGB collection, a significant amount of redundancy was observed. The obtained results will contribute to the cost-efficient conservation of the maize gene pool in the Montenegrin and Serbian gene banks. The recognized and well-preserved original variability of the MRIZPGB and MGB Montenegrin gene pool represents a valuable source for pre-breeding activities on broadening the white and flint maize breeding programmes under temperate conditions.

Genetic diversity of bean (Phaseolus) landraces and wild relatives from the primary centre of origin of the Southern Andes

2012 ◽  
Vol 10 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Teresa Avila ◽  
Matthew W. Blair ◽  
Ximena Reyes ◽  
Pierre Bertin
Keyword(s):  
Genetic Diversity ◽  
Common Bean ◽  
Gene Pool ◽  
Morphological Characteristics ◽  
Germplasm Collection ◽  
Genetic Distances ◽  
Phaseolus Lunatus ◽  
Group Method ◽  
Common Beans ◽  
Southern Andes

The Southern Andes, especially the inter-Andean valleys of south Bolivia, is thought to be a probable point of domestication within the primary centre of diversity for Andean common beans (Phaseolus vulgaris L.). The national Phaseolus germplasm collection of Bolivia is maintained by the Pairumani Foundation and consists of 449 accessions where most of the accessions are of common bean but some are of related cultivated and wild species. The goal of this study was to determine the genetic diversity of this collection by sampling 174 accessions of P. vulgaris and an outgroup of eight Phaseolus augusti, two Phaseolus lunatus and one Phaseolus coccineus genotype. The genetic diversity and population structure were estimated using 29 microsatellite markers. High levels of polymorphism were found, with a total of 311 alleles identified and an average of 10.7 alleles per marker. Correspondence analysis and an unweighted pair group method with arithmetic mean-based dendrogram distinguished P. vulgaris from the other species of Phaseolus. Common bean accessions were separated into two groups: the first one including Andean controls and most accessions from high altitudes with morphological characteristics and growth habits typical of this gene pool; the second one including Mesoamerican controls and accessions from low altitudes. Inside the Andean gene pool, the wild accessions were diverse and separated from the weedy and cultivated accessions. Low geographical distances between collection sites (up to 100 km) were shown to be related to low genetic distances. These results are important for the conservation of common beans in the Southern Andes.

scholarly journals Analysis of the Variability of Floral and Pollen Traits in Apple Cultivars—Selecting Suitable Pollen Donors for Cider Apple Orchards

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1717
Author(s):  
Alvaro Delgado ◽  
Muriel Quinet ◽  
Enrique Dapena
Keyword(s):  
Phenotypic Diversity ◽  
Phenotypic Variability ◽  
Germplasm Collection ◽  
Flowering Phenology ◽  
Floral Biology ◽  
Biennial Bearing ◽  
Oceanic Climate ◽  
Apple Cultivars ◽  
Local Germplasm ◽  
Flowering Intensity

Most apple trees (Malus domestica Borkh.) are self-incompatible and fruit yield depends on cross-pollination between genetically compatible cultivars with synchronous flowering. Flowering intensity can vary strongly among years due to the biennial bearing habit of the cultivars. The knowledge of the phenological stages and floral and pollen characteristics is essential to select suitable pollen donors. We evaluated the phenotypic variability of flowering-related traits (i.e., flowering phenology, flowering intensity, pollen production and pollen quality) in 45 apple cultivars over two successive flowering seasons. Large phenotypic variability was found among the studied cultivars indicating that the local germplasm collection provides a good source of genetic and phenotypic diversity. However, low correlations were observed between floral biology traits and, consequently, the improvement in one trait seems not to affect other traits. Some of the cultivars such as ‘Perurico’ and ‘Raxila Dulce’ regularly produced copious amounts of high-quality pollen which can improve the pollen load dispersion leading to a most effective pollination process. We did not identify statistically significant correlations between pollen attributes and the biennial bearing phenomenon. The large variation in bloom dates from year-to-year observed under a typical Oceanic climate makes it advisable to combine cultivars in new plantings.

scholarly journals Something old, something borrowed: Admixture and adaptation in human evolution

2018 ◽  
Author(s):  
Michael Dannemann ◽  
Fernando Racimo
Keyword(s):  
Human Evolution ◽  
Ancient Dna ◽  
Gene Pool ◽  
Recent Literature ◽  
Genetic Material ◽  
Modern Human ◽  
Human Populations ◽  
Modern Humans ◽  
Functional Assays ◽  
Over Time

Almost a decade ago, the sequencing of ancient DNA from archaic humans - Neanderthals and Denisovans - revealed that modern and archaic humans interbred at least twice during the Pleistocene. The field of human paleogenomics has now turned its attention towards understanding the nature of this genetic legacy in the gene pool of present-day humans. What exactly did modern humans obtain from interbreeding with Neanderthals and Denisovans? Were introgressed genetic material beneficial, neutral or maladaptive? Can differences in phenotypes among present-day human populations be explained by archaic human introgression? These questions are of prime importance for our understanding of recent human evolution, but will require careful computational modeling and extensive functional assays before they can be answered in full. Here, we review the recent literature characterizing introgressed DNA and the likely biological consequences for their modern human carriers. We focus particularly on archaic human haplotypes that were beneficial to modern humans as they expanded across the globe, and on ways to understand how populations harboring these haplotypes evolved over time.

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