Genotypic variation in resistance to Kabatiella caulivora in Trifolium subterraneum subspecies yanninicum

1979 ◽  
Vol 30 (4) ◽  
pp. 651 ◽  
Author(s):  
PE Beale ◽  
N Thurling
Keyword(s):  
Genotypic Variation ◽  
Principal Component ◽  
Trifolium Subterraneum ◽  
Intrinsic Rate ◽  
Early Growth ◽  
Development Rate ◽  
Disease Development ◽  
Accurate Approximation ◽  
Development Delay ◽  
Kabatiella Caulivora

The development of a clover scorch epidemic was studied at Denmark, W.A., by using 62 lines of Trifolium subterraneum including 29 subspecies yanninicum genotypes. Total disease development (TDD), the intrinsic rate of disease development (Rate) and time to 50% disease development (Delay) were calculated from fortnightly observations from August to December. Principal component analyses of the data lent support to the view that TDD is a good measure of disease expression. TDD ranged from 16 to 139 disease days (maximum possible 140). Nine yanninicum genotypes that had TDD values of less than 28 disease days are considered to have potential in breeding for resistance. Within these nine genotypes there was, however, considerable variation in Rate and Delay. A positive correlation between early growth and TDD, and a negative correlation between flowering date and TDD, are seen as possible problems in breeding resistant cultivars. Scoring plants once in the middle of the period of maximum disease development and also at the end of the season should provide a reasonably accurate approximation of TDD and delay.

Humidity, free water and light in relation to development of Kabatiella caulivora (Kirchn.) Karak in Trifolium subterraneum L. cv.Yarloo

1975 ◽  
Vol 26 (3) ◽  
pp. 511
Author(s):  
K Helms
Keyword(s):  
Light Intensity ◽  
Plant Growth ◽  
Free Water ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Disease Development ◽  
Kabatiella Caulivora ◽  
Spread Of Infection ◽  
Moisture Conditions ◽  
And Control

The effects of moisture conditions on disease development and plant growth were examined in subterranean clover plants which were inoculated with K. caulivora 4 weeks after sowing and were maintained after inoculation at 20°C and with a light intensity of 2000 f.c. In plants which received 100% relative humidity (RH) with free water on leaves, for at least 4 days after inoculation, 15–20% of leaves developed lesions within 11 days. In plants which received continuously 90% RH with free water on leaves, or 100% RH without free water on leaves, less than 1.5% of leaves developed lesions within 11 days. There was no evidence of spread of infection in plants maintained for 11 or 25 days after inoculation. The effects of light intensities of 2000, 500 and 125 f.c. on disease development and plant growth were examined in plants which received 100% RH with free water on leaves and were grown for 25 days after inoculation, either in simulated swards or in standard pots. In most treatments a reduction in light intensity from 2000 to 500 f.c. reduced the growth of plants but had no effect on the percentage of diseased leaves, whereas a reduction in light intensity from 500 to 125 f.c. reduced growth and increased the percentage of diseased leaves of plants grown in swards from 30 to 70% and in standard pots from 10 to 35%. There were mortalities among both inoculated and control plants grown under 125 f.c. : in swards, 80–90% of inoculated plants and 30–40% of control plants died, whereas in standard pots 20–30% of inoculated plants and only occasional control plants died. The data show that environmental conditions favourable for the development of the disease were unfavourable for growth of control plants.

Corrigendum - Humidity, free water and light in relation to development of Kabatiella caulivora (Kirchn.) Karak in Trifolium subterraneum L. cv.Yarloo

1975 ◽  
Vol 26 (3) ◽  
pp. 511
Author(s):  
K Helms
Keyword(s):  
Light Intensity ◽  
Plant Growth ◽  
Free Water ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Disease Development ◽  
Kabatiella Caulivora ◽  
Spread Of Infection ◽  
Moisture Conditions ◽  
And Control

The effects of moisture conditions on disease development and plant growth were examined in subterranean clover plants which were inoculated with K. caulivora 4 weeks after sowing and were maintained after inoculation at 20°C and with a light intensity of 2000 f.c. In plants which received 100% relative humidity (RH) with free water on leaves, for at least 4 days after inoculation, 15–20% of leaves developed lesions within 11 days. In plants which received continuously 90% RH with free water on leaves, or 100% RH without free water on leaves, less than 1.5% of leaves developed lesions within 11 days. There was no evidence of spread of infection in plants maintained for 11 or 25 days after inoculation. The effects of light intensities of 2000, 500 and 125 f.c. on disease development and plant growth were examined in plants which received 100% RH with free water on leaves and were grown for 25 days after inoculation, either in simulated swards or in standard pots. In most treatments a reduction in light intensity from 2000 to 500 f.c. reduced the growth of plants but had no effect on the percentage of diseased leaves, whereas a reduction in light intensity from 500 to 125 f.c. reduced growth and increased the percentage of diseased leaves of plants grown in swards from 30 to 70% and in standard pots from 10 to 35%. There were mortalities among both inoculated and control plants grown under 125 f.c. : in swards, 80–90% of inoculated plants and 30–40% of control plants died, whereas in standard pots 20–30% of inoculated plants and only occasional control plants died. The data show that environmental conditions favourable for the development of the disease were unfavourable for growth of control plants.

Genotype × environment interactions for resistance to Kabatiella caulivora in Trifolium subterraneum subspecies yanninicum

1980 ◽  
Vol 31 (6) ◽  
pp. 1111 ◽  
Author(s):  
PE Beale ◽  
NA Goodchild
Keyword(s):  
Plant Breeding ◽  
Rank Order ◽  
South Australia ◽  
Trifolium Subterraneum ◽  
Disease Development ◽  
Similar Data ◽  
Breeding Strategies ◽  
Genotype X Environment ◽  
Kabatiella Caulivora ◽  
Clover Scorch

Genotype x environment interactions of resistance to clover scorch in Trifoliurn subterraneurn subspecies yanninicum were studied by growing 11 subterraneum clover genotypes at three sites in Western Australia and one site in South Australia. Similar data from the previous year at one site were utilized to study genotype x season interactions. Clover scorch damage was assessed by scoring at fortnightly intervals from which total disease development was calculated. A combination of established methods called by us significant rank order, in which analysis of variance is followed by a ranking process, is developed and discussed. Interactions based on significant rank order are demonstrated, and the implications of these interactions for plant breeding strategies are discussed.

scholarly journals Genotypic variation in tolerance to salinity of common beans cultivated in Western Cameroon as assessed at germination and during early seedling growth

2017 ◽  
Vol 2 (1) ◽  
Author(s):  
Eric B. Kouam ◽  
Simon M. Ndo ◽  
Marie S. Mandou ◽  
Asafor H. Chotangui ◽  
Christopher M. Tankou
Keyword(s):  
Common Bean ◽  
Seedling Growth ◽  
Growth Parameters ◽  
Block Design ◽  
Genotypic Variation ◽  
Substantial Reduction ◽  
Germination Percentage ◽  
Early Growth ◽  
Coefficient Of Velocity ◽  
Germination Experiments

AbstractThis study was carried out to determine effects of salinity on germination and seedling development of commercially important common bean genotypes in Cameroon. The seeds of eight genotypes were used for both trials. The germination experiments were carried out on petri dishes in the laboratory while early growth trials continued in plastic pots in the screenhouse. Both stages were setup using a randomized complete block design with three replications. Germination and early growth trials of the different genotypes were studied using distilled water as control or osmotic potentials of 50, 100, 150 and 200mM NaCl to study the effects of salinity on germination and seedling growth characteristics. Leaf concentrations of Na+ and K+ were determined. At the germination level, germination percentage, germination index and the coefficient of velocity of germination decreased with increasing salinity while the mean germination time and time to 50% germination increased with increasing level of salt. All the growth variables decreased with increasing salinity with the exception of the root length which was not affected by salinity. It was observed that increasing salinity induced a significant increase in leaf Na+ and substantial reduction in the accumulation of K+ in the leaves. For ions accumulation, germination variables and growth parameters, significant differences at 0.001 probability levels were found among salinity treatments, common bean genotypes and most of their interactions. Significant correlations were found between all germination variables and between most growth parameters. From the effect of salt application, the common bean genotypes namely KEBCB049, KEB-CB053 and Mac-33 were the most tolerant while KEB-CB055 and KEB-CB050 were the most sensitive. The results confirm that there is genotypic variation in salinity tolerance and that the most tolerant genotypes should be further explored in selection programs, with the aim that they should be promoted for cultivation in tropical zones affected by salinity.

Resistance to race 1 of Kabatiella caulivora in subterranean clover (Trifolium subterraneum L.) cultivars and breeding lines

2008 ◽  
Vol 59 (6) ◽  
pp. 561 ◽  
Author(s):  
P. G. H. Nichols ◽  
M. P. You ◽  
M. J. Barbetti
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Breeding Lines ◽  
Race 1 ◽  
Kabatiella Caulivora ◽  
Selection For ◽  
Race 2 ◽  
Resistant Progeny ◽  
Clover Scorch

Twenty-eight cultivars and 106 F6-derived breeding lines of subterranean clover (Trifolium subterraneum) were screened in the field for their response to clover scorch disease caused by race 1 of Kabatiella caulivora. Eleven of the cultivars, including Denmark and Goulburn, were classified as resistant. Breeding lines with Denmark parentage had 55% of progeny with resistance, while those of Goulburn had only 19% of resistant progeny, suggesting different modes of inheritance. Selection for resistance to race 2 of K. caulivora in the F4 generation markedly increased the probability of selecting F6-derived lines with resistance to race 1, suggesting linkage between genes for resistance to both races.

Variation in susceptibility of cultivars of Trifolium subterraneum to Kabatiella caulivora and in pathogenicity of isolates of the fungus as shown in germination-inoculation tests

1975 ◽  
Vol 26 (4) ◽  
pp. 647 ◽  
Author(s):  
K Helms
Keyword(s):  
Western Australia ◽  
New South ◽  
South Australia ◽  
Trifolium Subterraneum ◽  
Leaf Production ◽  
South Wales ◽  
Kabatiella Caulivora ◽  
Susceptible Group ◽  
Time Of Harvest ◽  
Different Parts

Seedlings of six cultivars of Trifolium subterraneum were tested during germination for resistance to Kabatiella caulivora, and gave results comparable with those obtained with seedlings inoculated by spraying at 1–4 weeks after sowing. Advantages of the method were that a large number of seedlings could be screened under uniform conditions with the minimum of time and space. Within the more susceptible group of cultivars, Woogenellup and Bacchus Marsh were usually more susceptible than Yarloop and Mt. Barker; these in turn were more susceptible than Clare, and Clare more susceptible than Daliak. For all cultivars except the highly resistant cultivar, Daliak, there was a correlation between the rate of trifoliolate leaf production and susceptibility to the disease, the most susceptible being those with most leaves expanded at the time of inoculation and with most leaves present at the time of harvest. Physiologic specialization in isolates of the pathogen from different parts of Australia was demonstrated. In general, one isolate from South Australia was more pathogenic than a group of isolates from South Australia, Victoria and Western Australia; these in turn were more pathogenic than one isolate from New South Wales, which was somewhat atypical in culture, and one from Victoria which was markedly atypical in culture.

scholarly journals Genotypic Variation in Nitrogen Uptake during Early Growth among Rice Cultivars under Different Soil Moisture Regimes

2013 ◽  
Vol 16 (3) ◽  
pp. 238-246 ◽  
Author(s):  
Maya Matsunami ◽  
Toshinori Matsunami ◽  
Kazuhiro Kon ◽  
Atsushi Ogawa ◽  
Ikuko Kodama ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Nitrogen Uptake ◽  
Genotypic Variation ◽  
Early Growth ◽  
Rice Cultivars ◽  
Moisture Regimes

Embryonic Development, Early Growth, and Meristic Variation in Rainbow Trout (Salmo gairdneri) Exposed to Combinations of Light Intensity and Temperature

1975 ◽  
Vol 32 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Wen-hwa Kwain
Keyword(s):  
Rainbow Trout ◽  
Embryonic Development ◽  
Mortality Rates ◽  
Early Growth ◽  
Development Rate ◽  
Salmo Gairdneri ◽  
Initial Weight ◽  
Light Intensities ◽  
Incubation Periods ◽  
Meristic Variation

Lowest mortality rates of rainbow trout (Salmo gairdneri) embryos were obtained at temperatures of 7 and 10 C and light intensities of 0.2 and 20 lx. Temperatures of 3 and 15 C and an intensity of 400 lx were near the thresholds for development. Eggs exposed to 0.2 lx required 111 days to reach 50% hatch at 3 C, but 26 days at 15 C; those exposed to 20 lx, 97 days at 3 C and 25 days at 15 C.Growth rates of rainbow trout 145 days after hatch were significantly different (P < 0.05) at 10 and 3 C, and 20, 2, and 0.2 lx. The fastest growth occurred at 10 C and 2 lx, and the lowest growth at 3 C and 0.2 lx. For increment of body weight it was about 23.8%/day of initial weight and 6.6% at 3 C. At light intensities of 20, 2, and 0.2 lx, the rate per day was 24.7, 17.2, and 11.2%, respectively. However, increases in length occurred at a much reduced rate.Variations in numbers of vertebrae, gill rakers, and fin rays were positively correlated with the embryonic development rate. Longer incubation periods were usually associated with more meristic elements, regardless of the environmental factors involved.

Genotypic variation for seed yield components in white clover (Trifolium repens L.)

2000 ◽  
Vol 51 (6) ◽  
pp. 657 ◽  
Author(s):  
M. Z. Z. Jahufer ◽  
F. I. Gawler
Keyword(s):  
Seed Yield ◽  
White Clover ◽  
Yield Components ◽  
Early Stage ◽  
Genotypic Variation ◽  
Principal Component ◽  
Positive Association ◽  
Genotypic Correlation ◽  
Yield Attributes ◽  
Seed Yield Components

Seed yield is an important criterion that determines the commercial acceptability of new cultivars. Often, the seed yielding capacity of a forage cultivar is tested only in the final stages of its development. A more efficient strategy would be to screen and select plants for seed yield at an early stage of breeding. An important objective of the National White Clover Breeding Program based at the Agriculture Victoria Pastoral and Veterinary Institute, Hamilton, is to assess the genetic diversity for important morphological attributes among germplasm accessions. A set of 53 accessions, which included germplasm collected from Morocco and Tunisia and a range of commercial cultivars, was characterised for seed yield components. The seed yield components were number of ripe inflorescences, number of florets per ripe inflorescence, number of seeds per pod, floret size, and inflorescence height. Potential seed yield was estimated. The magnitude of genotypic variation, together with the accession mean repeatability estimates, indicated the presence of genetic variation among the 53 accessions for all attributes. Both phenotypic and genotypic correlation coefficients indicated a strong positive association between total number of ripe inflorescences and seed yield. There was also a positive phenotypic and genotypic correlation between seed yield and number of florets per inflorescence. Cluster analysis of the 53 accessions based on seed yield components resulted in the generation of 6 groups. Principal component analysis helped to identify 5 accessions that could be potentially useful in improving the seed yield of white clover germplasm selected for superior agronomic and herbage yield attributes.

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