Characterizing offspring of Dutch elm disease-resistant trees (Ulmus minor Mill.)

Abstract Populations of Ulmus minor in Europe were severely damaged by Dutch elm disease (DED) pandemics. However, elm breeding programmes have permitted selection of resistant elm varieties currently used for reforestation. In restored elm forests, resistant (R) and susceptible (S) trees interbreed, but little is known about resistance in their offspring. In this work, growth, DED resistance and xylem anatomy in the offspring of two resistant U. minor trees (R1 and R2) were studied. To verify whether transmission of traits in offspring is determined by maternal or paternal trees, a complete randomized plot was established with clonal material from controlled crosses (R1 × S and R2 × S) and parent trees (R1, R2 and S). Trees were inoculated with O. novo-ulmi firstly at age 4 years and again at 5 years. Growth, susceptibility to DED and vessel size in offspring were closer to the traits of maternal than of paternal trees. This association disappeared after the second inoculation when symptoms increased. The more resistant trees in R1 × S and R2 × S had wide and narrow earlywood vessels, respectively, suggesting that water-conducting strategies and resistance mechanisms vary in offspring. Tylosis formation was related to resistance only in R2 × S offspring, possibly due to the narrow earlywood vessles of trees. Latewood vessels were normally narrower in the more resistant trees. This study sheds light on anatomical resistance mechanisms of elms against DED: (1) offspring exhibit high variability in responses among individuals, (2) narrow earlywood vessels are not a prerequisite for DED resistance and (3) barrier zones are not fully associated with tree resistance in offspring.

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Cellulose Nanofibers from a Dutch Elm Disease-Resistant Ulmus minor Clone

Polymers ◽

10.3390/polym12112450 ◽

2020 ◽

Vol 12 (11) ◽

pp. 2450 ◽

Cited By ~ 1

Author(s):

Laura Jiménez-López ◽

María E. Eugenio ◽

David Ibarra ◽

Margarita Darder ◽

Juan A. Martín ◽

...

Keyword(s):

Cellulose Nanofibers ◽

Barrier Properties ◽

Dutch Elm Disease ◽

Ulmus Minor ◽

Mechanical Pretreatment ◽

Pfi Refining ◽

First Time ◽

Mediated Oxidation ◽

Potential Use ◽

Selection Of

The potential use of elm wood in lignocellulosic industries has been hindered by the Dutch elm disease (DED) pandemics, which have ravaged European and North American elm groves in the last century. However, the selection of DED-resistant cultivars paves the way for their use as feedstock in lignocellulosic biorefineries. Here, the production of cellulose nanofibers from the resistant Ulmus minor clone Ademuz was evaluated for the first time. Both mechanical (PFI refining) and chemical (TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation) pretreatments were assessed prior to microfluidization, observing not only easier fibrillation but also better optical and barrier properties for elm nanopapers compared to eucalyptus ones (used as reference). Furthermore, mechanically pretreated samples showed higher strength for elm nanopapers. Although lower nanofibrillation yields were obtained by mechanical pretreatment, nanofibers showed higher thermal, mechanical and barrier properties, compared to TEMPO-oxidized nanofibers. Furthermore, lignin-containing elm nanofibers presented the most promising characteristics, with slightly lower transparencies.

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Selection of the optimal culture medium for cultivation Fusarium sporotrichioides Sherb

PROCEEDINGS OF V INTERNATIONAL SCIENTIFIC CONFERENCE “CURRENT STATE, PROBLEMS AND PROSPECTS OF THE DEVELOPMENT OF AGRARIAN SCIENCE” ◽

10.33952/2542-0720-2020--5-9-10-3 ◽

2020 ◽

Author(s):

I.L. Astapchuk ◽

◽

N.A. Marchenko ◽

G.V. Yakuba ◽

A.I. Nasonov ◽

...

Keyword(s):

Growth Rate ◽

Growth And Development ◽

Maximum Degree ◽

Culture Medium ◽

Culture Media ◽

High Variability ◽

Fusarium Sporotrichioides ◽

Cultural Characteristics ◽

Colony Diameter ◽

Selection Of

The influence of various culture media on the growth, morphological and cultural characteristics of the fungus F. sporotrichioides was studied. Ten culture media were used in our research. A comparative study of the growth rate of the F. sporotrichioides mycelium made it possible to identify two media that are the most suitable for the cultivation and identification of this species, namely carrot and tomato agar. We took into account such criteria as ensuring the maximum degree of sporulation, rapid growth and development of mycelium (the 7th day), colony diameter (71–78 mm), as well as the ease of preparation. Nirenberg culture medium can be used to obtain a large number of conidia of the fungus. Because of the high variability of cultural characteristics of F. sporotrichioides, we recommend using different composition of media.

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Alive and kicking, or, living on borrowed time? – Microsatellite diversity in natural populations of the endangered Ulmus minor Mill. sensu latissimo from Croatia

Acta Botanica Croatica ◽

10.1515/botcro-2016-0007 ◽

2016 ◽

Vol 75 (1) ◽

pp. 53-59 ◽

Cited By ~ 2

Author(s):

Marko Zebec ◽

Marilena Idžojtić ◽

Zlatko Šatović ◽

Igor Poljak ◽

Zlatko Liber

Keyword(s):

Genetic Diversity ◽

Natural Populations ◽

Genetic Bottleneck ◽

Dutch Elm Disease ◽

Significant Excess ◽

Mediterranean Populations ◽

Ulmus Minor ◽

Study Results ◽

The Impact ◽

Microsatellite Diversity

AbstractThe main objective of this research was to assess the genetic diversity of 5 natural field elm populations in Croatia. The study results suggest that the observed populations are characterized by a satisfactory amount of heterozygosity, and that the impact of the Dutch elm disease on the amount of genetic diversity in the sampled populations is currently negligible. However, one population displayed a significant excess of heterozygosity, implying a genetic bottleneck. The existence of a very clear genetic differentiation between the continental and the Mediterranean populations of Ulmus minor in Croatia was noticed.

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Target and Non–target site Mechanisms Confer Resistance to Glyphosate in Canadian Accessions ofConyza canadensis

Weed Science ◽

10.1017/wsc.2017.69 ◽

2017 ◽

Vol 66 (2) ◽

pp. 234-245 ◽

Cited By ~ 8

Author(s):

Eric R. Page ◽

Christopher M. Grainger ◽

Martin Laforest ◽

Robert E. Nurse ◽

Istvan Rajcan ◽

...

Keyword(s):

Ssr Markers ◽

Resistance Mechanisms ◽

Target Site ◽

Conyza Canadensis ◽

Weed Species ◽

Target Site Resistance ◽

Selection For ◽

Simple Sequence ◽

Growing Region ◽

Selection Of

Glyphosate-resistant populations ofConyza canadensishave been spreading at a rapid rate in Ontario, Canada, since first being documented in 2010. Determining the genetic relationship among existing Ontario populations is necessary to understand the spread and selection of the resistant biotypes. The objectives of this study were to: (1) characterize the genetic variation ofC. canadensisaccessions from the province of Ontario using simple sequence repeat (SSR) markers and (2) investigate the molecular mechanism (s) conferring resistance in these accessions. Ninety-eightC. canadensisaccessions were genotyped using 8 SSR markers. Germinable accessions were challenged with glyphosate to determine their dose response, and the sequences of 5-enolpyruvylshikimate-3-phosphate synthase genes 1 and 2 were obtained. Results indicate that a majority of glyphosate-resistant accessions from Ontario possessed a proline to serine substitution at position 106, which has previously been reported to confer glyphosate resistance in other crop and weed species. Accessions possessing this substitution demonstrated notably higher levels of resistance than non–target site resistant (NTSR) accessions from within or outside the growing region and were observed to form a subpopulation genetically distinct from geographically proximate glyphosate-susceptible and NTSR accessions. Although it is unclear whether other non–target site resistance mechanisms are contributing to the levels of resistance observed in target-site resistant accessions, these results indicate that, at a minimum, selection for Pro-106-Ser has occurred in addition to selection for non–target site resistance and has significantly enhanced the levels of resistance to glyphosate inC. canadensisaccessions from Ontario.

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Cultivars and plant improvement.

Guava: botany, production and uses ◽

10.1079/9781789247022.0006 ◽

2021 ◽

pp. 110-147

Author(s):

Sisir Mitra

Keyword(s):

South Africa ◽

Molecular Characterization ◽

Interspecific Hybridization ◽

Storage Life ◽

Inheritance Pattern ◽

Fruit Characteristics ◽

High Quality ◽

Breeding Programmes ◽

Selection Of ◽

Long Storage

Abstract The major objectives of guava breeding are aimed at improving both plant and fruit characteristics such as to develop high-yielding, high-quality dwarf cultivars with fruits of uniform shape, good size, attractive skin and pulp colour, fewer and/or soft seeds, resistant to wilt, nematodes and long storage life. Selection of superior seedlings has resulted in the development of a number of cultivars in different countries. This chapter describes the Psidium species used in breeding (Psidium cattleyanum, P. guineense, P. acutangulum, P. friedrichsthalianum, P. angulatum and P. littorale), objectives of breeding programmes, introduction and selection, inheritance pattern, interspecific hybridization, polyploidy, mutation and molecular characterization. Guava cultivars growing in different countries (Brazil, China, Egypt, India, Israel, Malaysia, Mexico, Pakistan, South Africa, Taiwan, Thailand, USA and vietnam) are also described.

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Sequence analysis of the mtDNA region correlated with Shaan 2A cytoplasmic male sterility in rapeseed (Brassica napus L.)

Czech Journal of Genetics and Plant Breeding ◽

10.17221/144/2012-cjgpb ◽

2012 ◽

Vol 48 (No. 3) ◽

pp. 139-142 ◽

Cited By ~ 1

Author(s):

L. Havlíčková ◽

V. Čurn ◽

E. Jozová ◽

V. Kučera ◽

M. Vyvadilová ◽

...

Keyword(s):

Cytoplasmic Male Sterility ◽

Male Sterility ◽

Molecular Level ◽

Brassica Napus L ◽

Cms Line ◽

Breeding Programmes ◽

Improved Cultivars ◽

Hybrid Cultivar ◽

Fertility Restorers ◽

Selection Of

Until now in Europe has not been cultivated any hybrid cultivar of oilseed rape based on the Shaan 2A cytoplasmic male sterility (CMS), a widely used CMS system in China. The aim of Czech breeders now is to produce new, improved cultivars of rapeseed based on this CMS system. Sterile Shaan 2A CMS line (S; rf/rf), its corresponding maintainers (N; rf/rf) and fertility restorers (S; Rf/Rf) were analyzed on molecular level for the presence of functional CMS cytoplasm. Two new primer pairs covering CMS-associated gene (so called orf224-1) present in Shaan 2A CMS line were developed and selection capability of the developed primers was successfully evaluated. These primers can be used for early selection of plants with functional Shaan 2A CMS system in breeding programmes.

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Genetic diversity in sorghum mini-core and elite rainy and post-rainy genotypes of India

Plant Genetic Resources ◽

10.1017/s1479262115000441 ◽

2016 ◽

Vol 15 (2) ◽

pp. 127-137

Author(s):

Kuyyamudi Nanaiah Ganapathy ◽

Sujay Rakshit ◽

Sunil Shriram Gomashe ◽

Suri Audilakshmi ◽

Krishna Hariprasanna ◽

...

Keyword(s):

Genetic Diversity ◽

Geographical Origin ◽

Crop Breeding ◽

Breeding Lines ◽

Breeding Programmes ◽

Working Groups ◽

Sorghum Genotypes ◽

Germplasm Accessions ◽

Selection Of ◽

Nei's Genetic Distance

Knowledge on genetic diversity is necessary to determine the relationships among the genotypes, which allow the selection of individual accessions for crop breeding programmes. The present study aimed at assessing the extent and pattern of genetic diversity within a set of 251 sorghum genotypes using SSR markers. A total of 393 alleles were detected from the 251 genotypes, with the number of alleles ranging from 2 (Xcup11) to 24 (Sb5-206) and an average of 10.07 alleles per primer pair. Pairwise Wright's FST statistic and Nei's genetic distance estimates revealed that the race and geographical origin were responsible for the pattern of diversity and structure in the genetic materials. In addition, the analysis also revealed high genetic differentiation between the rainy and post-rainy sorghum groups. Narrow diversity was observed among the different working groups in the rainy (restorers and varieties) and post-rainy (varieties and advanced breeding lines) sorghum groups. Neighbour-joining and STRUCTURE analysis also classified 44 elite lines broadly into two distinct groups (rainy and post-rainy). However, limited diversity within the rainy and post-rainy sorghum groups warranted an urgent need for the utilization of diverse germplasm accessions for broadening the genetic base of the Indian breeding programme. The diverse germplasm accessions identified from the mini-core accessions for utilization in breeding programmes are discussed.

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Policy of selecting bulls to breed bulls

Animal Science ◽

10.1017/s000335610002804x ◽

1987 ◽

Vol 44 (1) ◽

pp. 29-38 ◽

Cited By ~ 5

Author(s):

M. E. Goddard

Keyword(s):

Dairy Cattle ◽

Genetic Variance ◽

Selection Response ◽

Progeny Testing ◽

Cattle Breeding ◽

Sire Evaluation ◽

Dairy Cattle Breeding ◽

Breeding Programmes ◽

Computer Simulation Program ◽

Selection Of

ABSTRACTIn the breeding of dairy cattle the selection of bulls to breed young bulls for progeny testing is a crucial process. This paper compares several policies for making this selection based on the criteria-selection response, inbreeding depression, loss of genetic variance and variability of response. A number called the ‘effective number of new bulls to breed bulls selected each year’ (NBBe) is defined which is closely related to the last three of these criteria. Past studies of the design of dairy cattle breeding programmes have assumed that selection is within a group of bulls progeny tested in the same year (policy I). However, modern sire evaluation methods allow comparison of sires tested in different years. To evaluate the effect of selecting bulls to breed bulls from all available bulls (policy II) a computer simulation program was used. Policy II results in an increase in the response to selection but a substantial decrease in NBBe. When compared at the same NBBe, policy II results in a smaller selection response than policy I. A policy which allows the best bulls to be used for more than 1 year but which limits the maximum number of years for which they can be used, results in the best compromise. If bulls are to be used for several years there is little advantage to be gained from making more matings within each year to more high-rated bulls or to older, more reliably evaluated bulls.

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The effect of continued selection of phenotypic intermediates on gene frequency

Genetics Research ◽

10.1017/s0016672300034790 ◽

1964 ◽

Vol 5 (3) ◽

pp. 341-353 ◽

Cited By ~ 8

Author(s):

R. N. Curnow

Keyword(s):

Gene Frequency ◽

Selection Procedure ◽

High Variability ◽

Considerable Importance ◽

Selection Procedures ◽

Population Mean ◽

Section 8 ◽

Selection Of

The selection of animals or plants for high values of a certain character may favour not only genotypes associated with these high values but also genotypes associated with high variability. Any differences between genotypes in variability may therefore be of considerable importance in plant and livestock improvement programmes as well as in evolution. The effects of various selection procedures on variability have been studied in three recent experiments [Falconer & Robertson (1956) Falconer (1957) and Prout (1962)]. In these experiments one line was continued by selecting, in each generation, parents with values of a particular character near the population mean. Manning (1955, 1956) has described the effects of this kind of selection applied to cotton. Robertson (1956) derived and discussed the theory of such selection procedures when certain simplifying approximations can be made We shall obtain some more general results and show that Robertson was incorrect in saying that the selection procedure would lead to gene fixation even if the heterozygotes are less variable than the homozygotes. The importance of the results is discussed in section 8.

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Co-selection of antibiotic and heavy metal resistance in freshwater bacteria

Journal of Limnology ◽

10.4081/jlimnol.2016.1198 ◽

2016 ◽

Vol 75 (s2) ◽

Cited By ~ 34

Author(s):

Andrea Di Cesare ◽

Ester Eckert ◽

Gianluca Corno

Keyword(s):

Heavy Metal ◽

Resistance Genes ◽

Heavy Metal Resistance ◽

Resistance Mechanisms ◽

Metal Resistance ◽

Resistant Bacteria ◽

Human Pathogens ◽

Antibiotic Resistant Bacteria ◽

Antibiotic Resistant ◽

Selection Of

Antibiotic resistant bacteria are found in most environments, especially in highly anthropized waters. A direct correlation between human activities (e.g., pollution) and spread and persistence of antibiotic resistant bacteria (ARB) and resistance genes (ARGs) within the resident bacterial communities appears more and more obvious. Furthermore, the threat posed for human health by the presence of ARB and ARGs in these environments is enhanced by the risk of horizontal gene transfer of resistance genes to human pathogens. Although the knowledge on the spread of antibiotic resistances in waters is increasing, the understanding of the driving factors determining the selection for antibiotic resistance in the environment is still scarce. Antibiotic pollution is generally coupled with contamination by heavy metals (HMs) and other chemicals, which can also promote the development of resistance mechanisms, often through co-selecting for multiple resistances. The co-selection of heavy metal resistance genes and ARGs in waters, sediments, and soils, increases the complexity of the ecological role of ARGs, and reduces the effectiveness of control actions. In this mini-review we present the state-of-the-art of the research on antibiotic- and HM-resistance and their connection in the environment, with a focus on HM pollution and aquatic environments. We review the spread and the persistence of HMs and/or ARB, and how it influences their respective gene co-selection. In the last chapter, we propose Lake Orta, a system characterized by an intensive HM pollution followed by a successful restoration of the chemistry of the water column, as a study-site to evaluate the spread and selection of HMs and antibiotic resistances in heavily disturbed environments.

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