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.

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.

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 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.

An inexpensive portable freezer for in situ freezing in the field

2002 ◽  
Vol 32 (12) ◽  
pp. 2160-2168 ◽  
Author(s):  
Yves Dubuc ◽  
Jean Dubuc ◽  
Francine J Bigras
Keyword(s):  
Picea Glauca ◽  
White Spruce ◽  
Field Conditions ◽  
Natural Conditions ◽  
Dry Ice ◽  
Ambient Temperatures ◽  
Programmable Controller ◽  
Controlled Conditions ◽  
Large Trees

A portable freezer was developed to apply frost to branches of large trees to study their growth and recuperation after frost application under natural conditions. The freezer measures 37.5 × 63.5 × 31.5 cm and weighs approximately 3 kg. It consists of two compartments, a freezing compartment and a dry ice compartment. The portable freezer provides a ramp-and-soak freezing pattern using a programmable controller. The nonfreezing temperature plateaus can be set from 1 to 6°C and maintained for 0 to 12 h. The cooling and warming rates can be programmed from 1 to 12°C·h–1. Test temperatures can be maintained for a period of time ranging from 0 to 12 h at set temperatures. Freezers were tested without samples under controlled conditions at ambient temperatures of 0, –5, –10, 5, 15, 20, and 25°C. Under these conditions, the cooling and warming rates showed a deviation of less than ±1°C·h–1 at a set rate of 2°C·h–1. The freezer provides test temperatures as low as –38°C and –47°C at ambient temperatures of 20 and –10°C, respectively. Freezers were also tested under field conditions on attached branches in mature white spruce (Picea glauca (Moench) Voss) trees under hardening conditions.

Design and testing of twig chambers for ozone fumigation and gas exchange measurements in mature trees

1994 ◽  
Vol 102 ◽  
pp. 541-546 ◽  
Author(s):  
Wilhelm M. Havranek ◽  
Gerhard Wieser
Keyword(s):  
Gas Exchange ◽  
Net Photosynthesis ◽  
Ambient Air ◽  
Field Conditions ◽  
Chamber System ◽  
Mature Trees ◽  
Diurnal Courses ◽  
Controlled Conditions ◽  
Design And Testing

SynopsisA twig chamber system was developed for the exposure of mature trees to ozone (O3) under field conditions. The fumigation system allowed the exact control of O3 concentrations in the chambers, the measurement of O3 uptake as well as gas exchange measurements under ambient and controlled conditions during and after O3 fumigation. Because of differences in individual twigs the system should provide the exposure of replicates to different O3 treatments. Tests showed that temperature, humidity and O3 concentrations inside the chambers were comparable with diurnal courses observed in the field. Comparative gas exchange measurements indicated that there were no differences in net photosynthesis and conductance of twigs outside the chambers and twigs which remained within the chambers for 23 weeks receiving ambient air.

scholarly journals Characterization of Fusarium Yellows Resistance in Collard

Plant Disease ◽  
2001 ◽  
Vol 85 (8) ◽  
pp. 890-894 ◽  
Author(s):  
Mark W. Farnham ◽  
Anthony P. Keinath ◽  
J. Powell Smith
Keyword(s):  
United States ◽  
Disease Incidence ◽  
Southeastern United States ◽  
Critical Factor ◽  
Controlled Environment ◽  
Infested Soil ◽  
Cole Crops ◽  
Commercial Cultivars ◽  
Significant Temperature

The yellows disease of cole crops, caused by Fusarium oxysporum f. sp. conglutinans, can be very damaging to collard. Growers in the southeastern United States frequently produce collard in hot, summer months when conditions for yellows development are favorable, and thus, incidence of this disease is increasing. A collection of essentially all U.S. commercial cultivars of collard, various landraces of collard, and other representative cole crops was evaluated for response to artificial inoculation with F. oxysporum f. sp. conglutinans under controlled-temperature conditions. In addition, the same collection was evaluated following transplanting for response to naturally infested soil in the field during summer 1997 and 1998. In all trials, genotype had the most significant effect on percentage of diseased plants, and genotype responses ranged from resistant (0 to 20% diseased) to susceptible (61 to 100% diseased). There was a significant temperature effect on percentage of diseased plants in one growth chamber experiment with five genotypes that resulted primarily from an increase in disease incidence for the cultivar Blue Max at 30°C compared with 25°C. Temperature was not significant in a second experiment with 20 genotypes. In the field, although significant differences were observed among genotypes and between years, a significant genotype × year interaction was not detected for percentage of diseased plants, indicating a similar ranking of genotypes for resistance between years. There was a significant correlation between results from controlled-environment studies and the field. A resistant response to F. oxysporum f. sp. conglutinans was expressed in certain cultivars of collard, including Flash, Heavicrop, and Morris Heading, and also in specific landraces. This resistance was stable in relatively high temperature environments used in evaluations. Results of this research indicate that choice of cultivar is a critical factor in producing collard where conditions favor infection by F. oxysporum f. sp. conglutinans. This information will aid in development of new yellows-resistant cultivars.

GROWTH OF BEAN ACCESSIONS AT VARIOUS TEMPERATURES

1979 ◽  
Vol 59 (1) ◽  
pp. 81-85 ◽  
Author(s):  
S. FREYMAN ◽  
G. A. KEMP ◽  
D. B. WILSON
Keyword(s):  
Growth Rate ◽  
Phaseolus Vulgaris ◽  
Leaf Area ◽  
Dry Matter ◽  
Early Growth ◽  
Controlled Environment ◽  
Phaseolus Vulgaris L ◽  
Canadian Prairie ◽  
Bean Cultivar ◽  
Commercial Cultivars

Growth and rates of photosynthesis of two accessions and two cultivars (Great Northern 1140 and Sutter Pink) of bean (Phaseolus vulgaris L.) were compared at 10, 15, and 23 °C in a controlled environment cabinet. The leaf area, dry matter, and rate of total apparent photosynthesis of one of the accessions was significantly higher after growth for 13 days at 10 °C than that of the commercial cultivars. This advantage was not maintained at 23 °C. In another experiment, growth of the same four cultivars was compared at light/dark temperatures of 10/10, 15/12, and 23/18 °C. The two accessions established a higher leaf area and accumulated more dry matter at the cooler temperatures than the commercial cultivars, but lost this advantage at the highest temperatures. In a field trial, the accessions had a similar rapid early growth but fell behind later in the season. Ideally, a bean cultivar for the Canadian prairie should incorporate the accession’s ability for rapid growth and leaf expansion at cool temperatures with a growth rate during mid-summer comparable to that of Great Northern 1140.

scholarly journals Investigations on the Genetics of Resistance to Root-knot Nematodes (Meloidogyne incognita) in Tobacco (Nicotianatabacum)

2000 ◽  
Vol 19 (1) ◽  
pp. 17-23
Author(s):  
R Honarnejad ◽  
M ShoaiDeylami
Keyword(s):  
Meloidogyne Incognita ◽  
Diallel Cross ◽  
Additive Variance ◽  
Root Knot Nematodes ◽  
Partial Dominance ◽  
Resistant Lines ◽  
Reciprocal Differences ◽  
Additive Gene ◽  
High Degree ◽  
Selection Of

AbstractThe analysis of a full diallel cross of ten tobacco varieties showed that genetic control of resistance to root-knot nematodes (Meloidogyne incognita) in tobacco was governed by partial dominance. When measuring the overall genetic variance, the portion of additive variance was found to be very substantial. This property may well be inherited by progenies and with a high degree of heritability (0.60-0.63). Partitioning the total sums of squares of the genotypes into the sum of squares for general (GCA) and specific combining ability (SCA) of parents and hybrids points to additive and non-additive gene activities in generating resistance to root-knot nematodes in tobacco. Because of significant reciprocal differences, the maternal cytoplasm plays an important role in the inheritance of resistance to root-knot nematodes. The proportion of additive and heritable variance was significant and to such an extent (60 %) that a selection for resistant lines might be a promising project. Since some varieties show a high GCA for resistance, they could be regarded as donors for resistance for progenies. In addition, the significantly high SCA and resistance of several hybrids would suggest successful selection of lines with resistance to root-knot nematodes in tobacco.

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