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.

Nutrient problems in sown pasture on an acid soil. 2. Role of lime and superphosphate

1980 ◽  
Vol 20 (106) ◽  
pp. 568 ◽  
Author(s):  
KD McLachlan
Keyword(s):  
Plant Growth ◽  
Acid Soil ◽  
Phosphorus Uptake ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Titratable Acidity ◽  
Yield Response ◽  
P 16 ◽  
Exchangeable Magnesium

A study was made of the role of superphosphate and lime on subterranean clover (Trifolium subterraneum) production on an infertile acid soil in pot culture. Both fertilizers increased the exchangeable calcium in this deficient soil. Lime and superphosphate were involved in nodulation of the clover plants. There was no evidence of the direct involvement of either of them in the nitrogen fixation process, but they did increase nitrogen uptake by the plants. Once the legume functioned adequately, full expression of the yield response to phosphorus on this deficient soil followed. Most efficient phosphorus use occurred at the lime 1255, superphosphate 2000 kg ha-1 level (lime 1/2, P 16). Heavy lime dressing reduced exchangeable magnesium and the phosphorus available to the plant. Aluminium and pH were involved in the effects observed. Lime reduced CaCl2-extractable aluminium and the titratable acidity in the soil. Phosphate increased the CaCl2-extractable aluminium and apparently reduced the titratable aluminium. The combined treatments reduced these three attributes and promoted increased plant growth. Increased plant growth was associated with increased aluminium uptake by the plants, which suggests that the real effect of aluminium may have been on the calcium and phosphorus uptake by the plants, rather than on the toxic nature of the element itself.

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.

Distribution of magnesium in subterranean clover (Trifolium subterraneum L.) in relation to supply

1990 ◽  
Vol 41 (3) ◽  
pp. 499 ◽  
Author(s):  
BJ Scott ◽  
AD Robson
Keyword(s):  
Plant Growth ◽  
Shoot Growth ◽  
Leaf Tissue ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Solution Culture ◽  
Tissue Concentrations ◽  
Deficiency Symptoms ◽  
Young Leaves ◽  
Supply Current

The objectives of this study were to examine Mg distribution in subterranean clover (Trifolium subterraneum L.), to identify an appropriate tissue for diagnosis of deficiency and to establish minimum tissue concentrations associated with maximum plant growth. Plants were grown in solution culture with both discontinued (40 8M and 160 8M reduced to nil) and constant supply (0, 5, 10, 20, 40, 80, 160 8M Mg). Magnesium was depleted from old leaves when Mg supply to the roots was interrupted. However, deficiency symptoms occurred first on the young tissue under these conditions. Under constant but inadequate supply, initial deficiency symptoms occurred in old tissue. Symptoms in leaves were associated with Mg concentrations in the leaf of < 1046 8g g-1 with constant root supply and 586 8g g-1 when supply was interrupted. At luxury constant supply, concentrations of Mg tended to be higher in the older leaves than in the young leaves; the reverse occurred with inadequate supply. Tissue choice for diagnosis was not critical, but the minimum Mg concentration in tissue commensurate with maximum shoot growth varied from 740 8g g-1 for the unifoliate leaf to 1310 8g g-1 in the youngest open leaf (YOL), when plants were grown under constant Mg supply. Current supply of Mg to roots was reflected more rapidly in the concentrations in young leaf than in old leaf tissue.

Effects of environmental factors on the growth of two varieties of subterranean clover (Trifolium subterraneum L.)

1957 ◽  
Vol 8 (3) ◽  
pp. 226 ◽  
Author(s):  
CR Millikan
Keyword(s):  
Light Intensity ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
High Light Intensity ◽  
Relative Increase ◽  
Phosphate Level ◽  
Night Temperature ◽  
Varietal Differences ◽  
Total Growth ◽  
The Individual

A water culture experiment is described in which the effects of day and night temperature, photoperiod, light intensity, and phosphate level on the total growth (T + R) and top/root ratio (T / R) of the Dwalganup and Mt. Barker varieties of subterranean clover were studied. The individual or combined effect of increases in photoperiod and in light intensity was to increase (T + R) in both varieties. With Dwalganup the relative increase in top growth was greater than that in root growth, whereas with Mt. Barker the reverse occurred. With a 16-hr photoperiod varietal differences in the response of (T + R) to day temperature occurred depending on the level of phosphate in the solution. In general, T / R increased with day temperature, although the magnitude of the increase was affected by photoperiod, phosphate level, and variety. The response of total growth (T + R) in each variety to phosphate was independent of day temperature at an 8-hr photoperiod, but at 16 hr it was greatest at 17°C for both varieties. The growth (T + R) response to phosphate was greater for Dwalganup than Mt. Barker, the condition favouring the greatest difference being high light intensity, or a 20°C day temperature combined with long photoperiod. These varietal differences in total growth due to different level of phosphate in the presence of other variables were associated with differential effects on the relative top/root ( T / R ) growth within and between the varieties. Different night temperatures had no differential effect on total growth of plants at an 8-hr photoperiod, but at 16 hr there were highly significant interactions between day and night temperature in both varieties. The sense of the interaction was reversed by an increase in phosphate level in the substrate. Runner stem development was a more sensitive indicator of the interaction than total growth (T + R).

Variation in, and inheritance of seedling and adult-plant resistance in subterranean clover (Trifolium subterraneum L.) to leaf scorch (Kabatiella caulivora) (Kirch.) Karak

1990 ◽  
Vol 41 (1) ◽  
pp. 115 ◽  
Author(s):  
M Chandrashekar ◽  
GM Halloran
Keyword(s):  
Dominant Gene ◽  
Recessive Gene ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Single Recessive Gene ◽  
Seedling Resistance ◽  
Kabatiella Caulivora ◽  
The Cross ◽  
Clover Scorch ◽  
Adult Plants

The disease reaction of seedlings (2 weeks old) from a field collection of subterranean clover (Trifolium subterraneum) to clover scorch (Kabatiella caulivora (Kirch.) Karak), revealed 89 immune plants out of a total of 1530. However, with adult plants (15-16 weeks old) only one plant remained immune. In the F2 population of the cross of the cultivars (Daliak X Woogenellup (D X W), seedling resistance was conditioned by a single dominant gene and in the cross (Enfield X Woogenellup) (EX W) by a single recessive gene. However, with adult plants, resistance in the (D X W) F2 was conditioned by a single recessive gene and that in the (EX W) F2 by two recessive genes. The effect of increasing age in reducing the proportion of plants resistant to clover scorch in both studies indicates that caution is needed in evaluating resistance to clover scorch in epidemiological, breeding and genetic studies.

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.

Sources of variation in the resistance of subterranean clover to clover scorch (Kabatiella caulivora) in the field

1975 ◽  
Vol 15 (75) ◽  
pp. 541 ◽  
Author(s):  
DL Chatel ◽  
CM Francis
Keyword(s):  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
North African ◽  
Test Conditions ◽  
South West ◽  
Sources Of Variation ◽  
Kabatiella Caulivora ◽  
Clover Scorch

The resistance of 307 varieties of subterranean clover (Trifolium subterraneum) to the clover scorch disease pathogen was assessed in three locations in south west Australia. Disease intensity as measured by visual ratings of sward damage was found to vary with variety and location. Resistance was independent of subspecies groupings but dependent on country of origin. Spanish and Portugese varieties were generally less susceptible than North African selections. Disease severity was also related to plant characters by correlation and multiple regression analysis. Late maturing varieties were most resistant under the test conditions and rapidly growing earlier varieties, with large pale leaves and thick petioles, were least resistant.

Infection of Subterranean Clover (Trifolium subterraneum) by Kabatiella caulivora

2001 ◽  
Vol 149 (11-12) ◽  
pp. 699-705 ◽  
Author(s):  
K. L. Bayliss ◽  
J. Kuo ◽  
K. Sivasithamparam ◽  
M. J. Barbetti ◽  
E. S. Lagudah
Keyword(s):  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Kabatiella Caulivora

Studies on seed pelleting as an aid to legume seed inoculation. I. Coating materials, adhesives, and methods of inoculation

1962 ◽  
Vol 13 (4) ◽  
pp. 638 ◽  
Author(s):  
J Brockwell
Keyword(s):  
Plant Growth ◽  
Podzolic Soil ◽  
Gum Arabic ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Legume Seed ◽  
Coating Materials ◽  
Seed Inoculation ◽  
Clover Seed

The influence of seed-pelleting techniques on the inoculation and nodulation of subterranean clover (Trifolium subterraneum L.) was studied in the laboratory and in the field on podzolic soil where clover nodulation following conventional seed inoculation practices was often unsatisfactory. Seed pellets were prepared with the use of 10 different coating materials, three adhesives, and two methods of inoculation. These were sown immediately after preparation or stored for short periods before sowing, and were examined in terms of inoculant survival, nodulation, and plant growth. It was shown that subterranean clover seed pelleted with a lime, blood plus dolomite, or lime plus blood plus dolomite coating attached to the seed with a 45% solution of gum arabic and inoculated by incorporating a commercial peat inoculant within the pellet can be stored for up to 4 weeks before sowing and the viability of the inoculant retained. This is reflected in improved nodulation and in growth of the seedling subsequently produced. Ecological considerations in respect of the establishment of the inoculum in the soil are discussed.

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