Selection for root hair length in white clover (Trifolium repens L.)

Euphytica ◽  
1979 ◽  
Vol 28 (2) ◽  
pp. 489-494 ◽  
Author(s):  
J. R. Caradus
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Root Hair ◽  
Hair Length ◽  
Root Hair Length ◽  
Trifolium Repens L ◽  
Selection For

Observations on resistance in white clover (Trifolium repens L.) to the stem nematode (Ditylenchus dipsaci (Kühn) Filipjev)

1988 ◽  
Vol 110 (1) ◽  
pp. 145-154 ◽  
Author(s):  
R. Cook ◽  
D. R. Evans
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Significant Positive Correlation ◽  
Leaf Size ◽  
Nematode Reproduction ◽  
Long Period ◽  
Plant Collections ◽  
Ditylenchus Dipsaci ◽  
Trifolium Repens L ◽  
Selection For

SummaryThe expression of symptoms of stem nematode reproduction on a total of 53 white clovers (26 cultivars, 14 genepools and 13 introductions from plant collections) was studied in a series of field and glasshouse experiments. Seedlings or stolon-tip cuttings were inoculated with nematodes and the clovers classified by the proportion of plants which developed symptoms. Significant differences were found between varieties although in each test the majority was intermediate between more resistant and susceptible extremes. There was significant positive correlation between tests, in spite of different inoculation methods and different average levels of susceptibility. Very large-leaved cv. Aran was more resistant than most other clovers tested, and small-leaved cv. S. 184 was more susceptible. There was no general correlation of leaf size with reaction to stemnematode. Small-leaved cv. Pronitro was also resistant while several large-leaved cultivars were susceptible. In observations of plants exposed to nematodes over a long period, either by sequential inoculations or through perpetuating latent infections, apparently resistant plants eventually succumbed and supported nematode reproduction. It has not been determined whether this was because selection for virulence in the nematodes had occurred.

scholarly journals The sensitivity of white clover root hairs to aluminium

1996 ◽  
Vol 6 ◽  
pp. 137-140
Author(s):  
D.A. Care
Keyword(s):  
White Clover ◽  
Root Hair ◽  
Root Hairs ◽  
Aluminium Tolerance ◽  
Hair Length ◽  
Pastoral Systems ◽  
Root Hair Length ◽  
Clover Root ◽  
Low Ionic Strength ◽  
Two Populations

Two populations of white clover, selected for long (L) and short (S) root hairs from the cultivar Tamar, were used to determine the root hair response curve to a range of aluminium (Al) concentrations similar to those found under field conditions. Seeds from the L and S populations were germinated and grown in low ionic strength hydroponic culture. Al was added to give final concentrations of 0, 2.5, 5, 7.5 and 10 ìM Al in solution. After 4 weeks plants were harvested and subsampled for root hair analysis. Mean root hair length, root hair number and total root hair length were recorded. Mean root hair length decreased by about 30% at 2.5 ìM Al, and by 70% at 10 ìM Al, but the most Al sensitive parameter was root hair number. Root hair numbers decreased by 70% at only 2.5 ìM Al, and at 10 ìM Al, had decreased by 99%. This pruning effect on total root hair length and number has major implications for the root hair functions of nutrient acquisition, preserving the moisture film, anchorage and nodulation. These are discussed in relation to New Zealand pastoral systems. Keywords: aluminium tolerance, nodulation, root hairs, root pulling, Trifolium repens L., white clover

scholarly journals ADAPTATION OF WHITE CLOVER TO MOISTURE STRESS

1987 ◽  
pp. 143-149 ◽  
Author(s):  
D.R. Woodfield ◽  
J.R. Caradus
Keyword(s):  
Plant Breeding ◽  
White Clover ◽  
Trifolium Repens ◽  
Moisture Stress ◽  
Root Characteristics ◽  
Trifolium Repens L ◽  
Selection For

In a series of four experiments, the w-seeding ability and shoot and root characteristics of dryland white clover populations (Trifolium repens L.), and the effect of selection for root characteristics within white clover were examined. There was little evidence that dryland populations were better at re-seeding than Huia, but dryland populations were more taprooted than populations collected from moister environments. Root morphologies of dryland populations were similar to that of Huia but were smaller leaved, although not as small leaved as Tahora. Evidence that selection for more taprooted, smaller-leaved types of white clover would be successful is also presented. Keywords: root type, drought, re-seeding, plant breeding, survival

scholarly journals Response to selection for increased taproot diameter

1996 ◽  
Vol 6 ◽  
pp. 141-143
Author(s):  
D.R. Woodfield ◽  
J.R. Caradus ◽  
G.R. Cousins ◽  
T. Dunn
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Growth Habit ◽  
Leaf Size ◽  
Moisture Stress ◽  
Response To Selection ◽  
Short Term ◽  
Grazing Systems ◽  
Trifolium Repens L ◽  
Selection For

Increased taproot diameter is an important component in maintaining white clover (Trifolium repens L.) growth, nitrogen fixation and persistence during short-term moisture stress. Previous reports indicated selection for large taproot diameter would result in commensurate increases in leaf size and poorer growth habit. The current research investigates the response to selection for taproot diameter and the association between taproot diameter and leaf size in large-leaved clovers suited to dairy grazing systems. Taproot diameter increased by 2.4% per cycle while leaf size and growth habit were not significantly altered. Furthermore, while taproot diameter did not increase between cycle 2 and 3, the root index which measures the ratio of taproot diameter to leaf size increased linearly across all three cycles. These results suggest it is possible to select white clovers for dairying which have larger taproot diameter while maintaining a suitable growth habit. Keywords: dairying, drought, genetic improvement, root morphology, Trifolium repens L., white clover,

scholarly journals Genetic control of white clover seed yield potential

2004 ◽  
pp. 111-117 ◽  
Author(s):  
D.R. Woodfield ◽  
I.J. Baird ◽  
P.T.P. Clifford
Keyword(s):  
Genetic Control ◽  
Seed Yield ◽  
White Clover ◽  
Trifolium Repens ◽  
Yield Potential ◽  
Commercial Viability ◽  
Keywords Genetics ◽  
Trifolium Repens L ◽  
Selection For ◽  
Clover Seed

Improving the seed yield potential of new white clover (Trifolium repens L.) cultivars is critical to their commercial viability and to overcoming the increasing pressures from land use change in Canterbury. The genetic control and response to selection was investigated for two seed yield characteristics, inflorescence density (no./m2) and seed yield per inflorescence (g/ inflorescence). Inflorescence density and seed yield per inflorescence were both responsive to selection and acted independent of one another to increase seed yield. Selection for high inflorescence density resulted in 34% higher seed yield than the low inflorescence density selection. This change in seed yield was associated with a 33% higher inflorescence density, while seed yield per inflorescence was unchanged. Similarly, selection for seed yield per inflorescence resulted in a 17% difference in seed yield between the high (HYI) and low (LYI) seed yield per inflorescence selections. This change in seed yield was associated with a 24% higher yield per inflorescence for the HYI selection, while inflorescence density remained unchanged. These results confirm that both mechanisms are under independent genetic control and can be utilized to increase seed yield of new white clover cultivars. Keywords: genetics, inflorescence density, seed production, Trifolium repens, white clover

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