Susceptibility of subterranean clover varieties to rust under controlled environment and field conditions

1991 ◽  
Vol 31 (1) ◽  
pp. 77 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Rust Resistance ◽  
Subterranean Clover ◽  
Field Conditions ◽  
Controlled Environment ◽  
Good Resistance ◽  
Breeding Programs ◽  
Commercial Cultivars ◽  
Leaf Infection ◽  
High Degree ◽  
Field Plots

Thirty-two subterranean clover varieties, comprising 17 commercial cultivars, 1 named variety and 14 promising midseason breeding and introduced lines, were screened for resistance to rust (caused by Uromyces trifolii-repentis) under controlled environment conditions, and where possible, comparisons were made with their performance in field plots. There were large differences between varieties in the incidence and severity of rust on plants. Under controlled environment conditions, cvv. Gingin, Meteora and Enfield, and to a lesser extent Larisa and Trikkala, had the lowest levels of rust leaf infection, the lowest rust pustule densities and the smallest rust pustules. Seaton Park had a relatively low pustule density and CPI 89830F had relatively small pustules. Gingin and Enfield had the least leaf collapse. Green Range was the most susceptible under controlled environment conditions, followed by Bacchus Marsh, Karridale, CPI 47308C and CPI 89841E. Under field conditions, Enfield, Meteora, Trikkala and CPI 89822H were rust free, while Larisa, CPI 47308C, CPI 65328F, 75S13-12, 76841-1, CPI 89830F and CPI 89880J had good resistance. Green Range was clearly the most susceptible under field conditions, followed by Seaton Park, Karridale, Bacchus Marsh, CPI 89774F and CPI 89841E. While there was often good correlation between the field and controlled environment data for the different parameters, the resistance rankings of some varieties varied widely, depending upon whether screened under controlled environment or field conditions. Green Range, Karridale, Seaton Park and CPI 89841E were highly susceptible to rust under both controlled and field conditions, indicating that either environment could be successfully used to identify highly susceptible varieties. The high degree of resistance observed in Enfield, Gingin and Meteora, and to a lesser extent in Larisa and Trikkala, suggests their value as parents in breeding programs for rust resistance.

Susceptibility of subterranean clover varieties to powdery mildew under controlled environment and field conditions

1991 ◽  
Vol 31 (1) ◽  
pp. 81 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Powdery Mildew ◽  
Subterranean Clover ◽  
Field Conditions ◽  
Controlled Environment ◽  
Excellent Correlation ◽  
Good Resistance ◽  
Breeding Programs ◽  
Leaf Infection ◽  
High Degree ◽  
Field Plots

Thirty-three subterranean clover varieties, comprising 16 commercial cultivars and 17 promising midseason breeding and introduced lines, were screened for resistance to powdery mildew (caused by Erysiphe polygonii) under controlled environment conditions, and where possible, comparisons were made with their performance in field plots. There were large differences between varieties in the incidence and severity of powdery mildew on plants. Under controlled environment conditions, Tallarook, CPI 47308C, CPI 89860D, 75S13-12, CPI 6.53284 CPI 89820D and Clare had the lowest levels of leaf infection, the lowest mildew sporulation scores and the least amount of leaf scorching from mildew infection. Karridale had the highest level of leaf infection, followed by 69837-1, 76841-1, Junee, Bacchus Marsh and 69S37-3. Under field conditions, Tallarook, CPI 47308C, CPI 65328A and CPI 65328F were mildew-free, while CPI 89777C, CPI 89860D, CPI 89830F, CPI 89841E, Clare and Rosedale had good resistance. Junee was clearly the most susceptible under field conditions, followed by 76S41-1, 69837-3, Karridale, Bacchus Marsh and 69S37-1. There was generally excellent correlation between the different powdery mildew disease parameters, namely leaf infection, mildew sporulation and leaf scorch, measured under controlled environment conditions, and there was also good overall correlation between controlled environment and field data. Bacchus Marsh, Junee, 69337-1, 69837-3 and 76341-1 were highly susceptible under both controlled environment and field conditions, indicating that either environment could be used to identify highly susceptible varieties. Under controlled environment conditions, a high degree of resistance was observed in Clare, CPI 47308C, CPI 65328A, CPI 89820D, CPI 89860D and 75S13-12, while field plots of the varieties Tallarook, CPI 47308C and CPI 65328A showed a complete absence of powdery mildew. These varieties may have value as parents in breeding programs for powdery mildew resistance.

Response of subterranean clover varieties to Cercospora disease under a controlled environment and in the field

1991 ◽  
Vol 31 (3) ◽  
pp. 333 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Subterranean Clover ◽  
Field Conditions ◽  
Controlled Environment ◽  
Individual Resistance ◽  
Controlled Conditions ◽  
Resistant Lines ◽  
Commercial Cultivars ◽  
High Degree

Seventeen commercial cultivars of subterranean clover and 10 introduced lines were screened for resistance to cercospora disease (caused by Cercospora zebrina) under a controlled environment, and responses were compared with their performance in the field. There were large differences between varieties in the severity of cercospora disease under both conditions. There was, overall, good correlation between data from the field and those from the controlled environment for the different parameters. Daliak, Dalkeith, Esperance, Mt Barker, Nungarin and Rosedale were highly susceptible to cercospora disease under both controlled environment and field conditions, while Clare, Larisa, Meteora and Yarloop were assessed as having a high degree of resistance under both conditions. A few individual resistance rankings varied widely between the 2 conditions. The results indicate that controlled conditions can be used to identify resistant lines.

scholarly journals Identification of leaf rust resistance genes Lr34 and Lr46 in common wheat (Triticum aestivum L. ssp. aestivum) lines of different origin using multiplex PCR

2021 ◽  
Vol 16 (1) ◽  
pp. 172-183
Author(s):  
Agnieszka Tomkowiak ◽  
Roksana Skowrońska ◽  
Michał Kwiatek ◽  
Julia Spychała ◽  
Dorota Weigt ◽  
...  
Keyword(s):  
Multiplex Pcr ◽  
Leaf Rust ◽  
Common Wheat ◽  
Fungal Pathogens ◽  
Rust Resistance ◽  
Leaf Rust Resistance ◽  
Field Conditions ◽  
Pcr Marker ◽  
Specific Sequence ◽  
Cereal Species

Abstract Leaf rust caused by the fungus Puccinia recondita f. sp. tritici is one of the most dangerous diseases of common wheat. Infections caused by fungal pathogens reduce the quantity and quality of yields of many cereal species. The most effective method to limit plant infection is to use cultivars that show rust resistance. Genetically conditioned horizontal-type resistance (racial-nonspecific) is a desirable trait because it is characterized by more stable expression compared to major (R) genes that induce racially specific resistance, often overcome by pathogens. Horizontal resistance is conditioned by the presence of slow rust genes, which include genes Lr34 and Lr46. This study aimed to identify markers linked to both genes in 64 common wheat lines and to develop multiplex PCR reaction conditions that were applied to identify both genes simultaneously. The degree of infestation of the analyzed lines was also assessed in field conditions during the growing season of 2017 and 2018. Simple sequence repeat anchored-polymerase chain reaction (SSR-PCR) marker csLV was identified during analysis in line PHR 4947. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. In addition to gene Lr34, gene Lr46 was identified in this genotype. Lines PHR 4947 and PHR 4819 were characterized by the highest leaf rust resistance in field conditions. During STS-PCR analyses, the marker wmc44 of gene Lr46 was identified in most of the analyzed lines. This marker was not present in the following genotypes: PHR 4670, PHR 4800, PHR 4859, PHR 4907, PHR 4922, PHR 4949, PHR 4957, PHR 4995, and PHR 4997. The presence of a specific sequence has also been confirmed in multiplex PCR analyses. Genotypes carrying the markers of the analyzed gene showed good resistance to leaf rust in field conditions in both 2017 and 2018. Research has demonstrated that marker assisted selection (MAS) and multiplex PCR techniques are excellent tools for selecting genotypes resistant to leaf rust.

scholarly journals Influence of Flower Thrips on Fusarium Hardlock Severity

Plant Disease ◽  
2007 ◽  
Vol 91 (11) ◽  
pp. 1423-1429 ◽  
Author(s):  
D. J. Mailhot ◽  
J. J. Marois ◽  
D. L. Wright
Keyword(s):  
Gossypium Hirsutum ◽  
Untreated Control ◽  
Yield Loss ◽  
Fusarium Verticillioides ◽  
Field Conditions ◽  
Control Group ◽  
Flower Thrips ◽  
The Impact ◽  
Field Plots

Cotton (Gossypium hirsutum) fiber is sometimes affected by hardlock, which is characterized by a failure of the fiber to expand outward from the boll at maturity. Because affected fiber is inaccessible to mechanical harvesters, yield loss can be considerable. Hardlock has been linked to infection by Fusarium verticillioides. The involvement of flower thrips (Frankliniella spp.), which are commonly found in cotton flowers, was explored. At 1100 h, approximately 10% of cotton flowers contained thrips that were carrying F. verticillioides. The effect of thrips and/or Fusarium in flowers and bolls was explored under greenhouse conditions. Exposing flowers to Fusarium and thrips resulted in bolls with the most severe symptoms. Exposure to either Fusarium or thrips alone resulted in more hardlock than was noted in the control group. The impact of thrips was also evaluated under field conditions. Field plots were treated with insecticides, a fungicide, both, or left untreated. Insecticides reduced thrips numbers and reduced hardlock severity. The fungicide had no impact on thrips numbers and was less effective at reducing hardlock. Combining insecticide and fungicide applications was no more effective than using insecticides alone, although it more frequently increased yield. The untreated control plots generally had the most severe hardlock and lowest yields. Reducing hardlock severity resulted in higher yields, although not consistently. These studies suggest that thrips increase the severity of hardlock, and reducing their numbers may diminish hardlock severity.

Response of Early, Medium, and Late Maturing Peanut Breeding Lines to Field Epidemics of Tomato Spotted Wilt

1999 ◽  
Vol 26 (2) ◽  
pp. 100-106 ◽  
Author(s):  
A. K. Culbreath ◽  
J. W. Todd ◽  
D. W. Gorbet ◽  
S. L. Brown ◽  
J. A. Baldwin ◽  
...  
Keyword(s):  
High Oleic Acid ◽  
Breeding Programs ◽  
Breeding Lines ◽  
High Oleic ◽  
Tomato Spotted Wilt ◽  
Arachis Hypogaea L ◽  
Early Maturing ◽  
Late Maturity ◽  
Field Plots ◽  
Maturity Groups

Abstract Epidemics of tomato spotted wilt, caused by tomato spotted wilt Tospovirus (TSWV), were monitored in field plots of runner-type peanut (Arachis hypogaea L.) cultivars Georgia Green and Georgia Runner and numerous breeding lines from four different breeding programs as part of efforts toward characterizing breeding lines with potential for release as cultivars. Breeding lines were divided into early, medium and late maturity groups. The tests were conducted near Attapulgus, GA and Marianna, FL in 1997 and in Tifton, GA and Marianna, FL in 1998. Epidemics in some early and medium maturing breeding lines, including some genotypes with high oleic acid oil chemistry, were comparable to those in Georgia Green, the cultivar most frequently used in the southeastern U.S. for suppression of spotted wilt epidemics. No early maturing breeding lines had lower spotted wilt final intensity ratings or higher yields than Georgia Green. However, spotted wilt intensity ratings in some late maturing lines and a smaller number of medium maturing lines were significantly lower than those of Georgia Green. Several of those lines also produced greater pod yields than Georgia Green. Results from these experiments indicated that there is potential for improving management of spotted wilt though development of cultivars that suppress spotted wilt epidemics more than currently available cultivars. There was no indication that differences in spotted wilt ratings corresponded to differences in numbers of thrips adults or larvae.

Distribution and variability in development of the genus Trigonella in Asia Minor and its possible use in Australian environments

1981 ◽  
Vol 32 (5) ◽  
pp. 793 ◽  
Author(s):  
GM Halloran ◽  
AL Pennell
Keyword(s):  
Flowering Time ◽  
Subterranean Clover ◽  
Asia Minor ◽  
Vernalization Response ◽  
Developmental Patterns ◽  
Late Flowering ◽  
Commercial Cultivars ◽  
Wide Variability ◽  
Upper Level ◽  
Autumn Sowing

A number of Trigonella species were examined for their possible use in Australian environments. There was a wide variability in flowering time in Trigonella. Under an outdoor autumn sowing the range in flowering time was comparable with that found within early- to late-flowering Australian commercial cultivars of subterranean clover. The upper level of vernalization response was much lower in Trigonella than in subterranean clover. Good prospects exist within Trigonella for selecting genotypes with close adaptation (in terms of appropriate developmental patterns) to a range of Australian environments, a range at least as wide as that now occupied by subterranean clover and annual medic.

scholarly journals Polymorphisms and gene expression in the almond IGT family are not correlated to variability in growth habit in major commercial almond cultivars

2021 ◽  
Author(s):  
Álvaro Montesinos ◽  
Chris Dardick ◽  
María José Rubio-Cabetas ◽  
Jérôme Grimplet
Keyword(s):  
Gene Expression ◽  
Critical Role ◽  
Gene Families ◽  
Fruit Trees ◽  
Hormonal Responses ◽  
Breeding Programs ◽  
Branch Angle ◽  
Conserved Domain ◽  
Family Gene ◽  
High Degree

Almond breeding programs aimed at selecting cultivars adapted to intensive orchards have recently focused on the optimization of tree architecture. This multifactorial trait is defined by numerous components controlled by processes such as hormonal responses, gravitropism and light perception. Gravitropism sensing is crucial to control the branch angle and therefore, the tree habit. A gene family, denominated IGT family after a share conserved domain, has been described as involved in the regulation of branch angle in several species, including rice and Arabidopsis, and even in fruit trees like peach. Here we identified six members of this family in almond: LAZY1 , LAZY2 , TAC1 , DRO1 , DRO2 , IGT-like . After analyzing their protein sequences in forty-one almond cultivars and wild species, little variability was found, pointing a high degree of conservation in this family. Gene expression was analyzed in fourteen cultivars of agronomical interest comprising diverse tree habit phenotypes. Only LAZY1 , LAZY2 and TAC1 were expressed in almond shoot tips during the growing season. No relation was established between the expression profile of these genes and the tree habit. However, some insight has been gained in how LAZY1 and LAZY2 are regulated, identifying the IPA1 almond homologues and other transcription factors involved in hormonal responses as regulators of their expression. Besides, we have found various polymorphisms that could not be discarded as involved in a potential polygenic origin of regulation of architectural phenotypes. Therefore, we have established that unlike many species, IGT family genes do not play a critical role in the control of tree habit in currently commercialized almond cultivars, with other gene families contributing to the variability of these traits.

scholarly journals From ‘ontological metaphor’ to semiotic make-believe: giving shape and substance to fictive objects of conception with the ‘globe gesture’

Signo ◽  
2016 ◽  
Vol 41 (70) ◽  
pp. 29 ◽  
Author(s):  
Jean-Remi Lapaire
Keyword(s):  
Mental Representations ◽  
Controlled Environment ◽  
Cognitive Artifact ◽  
Emotional Appeal ◽  
Physical Presence ◽  
Sense Of Reality ◽  
Suspension Of Disbelief ◽  
Set Up ◽  
High Degree

Speakers are moving cognizers who engage in bodily acts of conceptualization. The “globe gesture” is among the most spectacular forms of “manual thinking” (Streeck 2009) used in formal talk. A characterization of the kinesic action typical of the “globe gesture” is first provided that shows how “the image of a bounded, supportable object” is created (McNeill 1992) and set up in gesture space. As conceptual objects are created and masses of semantic substance fashioned, visible shape is given to shapeless mental representations. A powerful semiotic trick is performed with a simple cognitive artifact. Interestingly, a willing suspension of disbelief is required of speakers and listeners who must temporarily give up their rational conceptions of visibility, materiality and palpability to watch the symbolic manipulation of invisible objects. The basic expressive properties of the “globe gesture” are next characterized: outlining and isolating objects of conception; neutralizing semantic specification; establishing a joint focus of attention and imagination; shaping, displaying and unifying content; creating a sense of reality and existence through physical presence. Iconic modifications of the standard metaphoric hand configuration, virtuosic elaborations and creative blends are finally examined before reporting the results of an experimental study of the globe gesture’s heuristic properties in a controlled environment. 14 students attending a multimodal “kineflective” seminar used the hand configuration to engage in “choreographic thinking” (Forsythe 2009) and develop a haptic understanding of derivation, nominalization, substantivation, conceptual reification. The globe gesture acted as a facilitator so long as a high degree of generality was maintained but was promptly discarded when words with a strong emotional appeal were introduced (e.g. sadness, madness). Emblems and iconic gestures were spontaneously performed instead.

Leggett Oat

2007 ◽  
Vol 87 (3) ◽  
pp. 509-512 ◽  
Author(s):  
J. W. Mitchell Fetch ◽  
S. D. Duguid ◽  
P. D. Brown ◽  
J. Chong ◽  
T. G. Fetch ◽  
...  
Keyword(s):  
Avena Sativa ◽  
Rust Resistance ◽  
Barley Yellow Dwarf Virus ◽  
Kernel Weight ◽  
Crown Rust ◽  
Good Resistance ◽  
Beta Glucan ◽  
Milling Quality ◽  
Crown Rust Resistance ◽  
Yellow Dwarf Virus

Leggett is the first oat (Avena sativa L.) cultivar released in western Canada carrying the crown rust resistance gene Pc94. Leggett carries the crown rust resistance combination Pc68 and Pc94, which provides good resistance to the crown rust populations currently present on the eastern Canadian Prairies. As a result of the presence of Pc94 providing resistance to oat crown rust, this line should exhibit excellent yield stability in the rust-prone regions of the prairies. Leggett has very good resistance to loose and covered smut, resistance to the prevalent races of oat stem rust other than NA67, but poor tolerance to barley yellow dwarf virus (BYDV). Leggett has kernel characteristics suited to milling end uses, with high test weight and 1000-kernel weight and high percent plump kernels. The beta-glucan content of Leggett is equal to or higher than that of the checks, making it a desirable milling quality cultivar. Key words: Oat, Avena sativa L., cultivar description, crown rust resistance, milling oat, Pc94

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