The effects of tungstate and nitrogen source on the dry weight and nitrogen yields, and molybdenum and tungsten content, of white clover (Trifolium repens)

1976 ◽  
Vol 45 (1) ◽  
pp. 201-212 ◽  
Author(s):  
B. F. Quin ◽  
J. H. Hoglund
Keyword(s):  
Nitrogen Source ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Weight ◽  
Tungsten Content ◽  
Nitrogen Yields ◽  
And Tungsten

Third generation progress in breeding white clover for resistance to root-knot nematode

1996 ◽  
Vol 6 ◽  
pp. 163-166
Author(s):  
J. Van den Bosch ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
Control Method ◽  
Dry Weight ◽  
Third Generation ◽  
Root Knot Nematode ◽  
Root Dry Weight ◽  
Wide Range ◽  
Meloidogyne Sp

Root-knot nematode (Meloidogyne sp.) reduces growth and nutrition of white clover (Trifolium repens L.) in New Zealand, and breeding resistant cultivars (with low galls per gram of root) is the preferred control method. Resistant and susceptible selections were bred from a wide range of white clover lines for three generations. In the third generation there were significant differences between seed lines from the selections for number of galls, root dry weight, visual growth score and galls/gram of root dry weight. Resistant selections had 43% of the susceptible selections' galls per gram, and 50% of the number of galls. Germplasm showing resistance to Meloidogyne spp. in the USA showed partial resistance to the local Meloidogyne sp. Two resistant and two susceptible genotypes were also compared for nematode egg production; resistant genotypes had a mean of 3,460 eggs/plant, compared to 25,030 for susceptible genotypes. Keywords: breeding, Meloidogyne sp., resistance, rootknot nematode, screening, selection, Trifolium repens, white clover

Density of Trifolium repens plants in mixed swards under intensive grazing by sheep

1989 ◽  
Vol 113 (1) ◽  
pp. 81-86 ◽  
Author(s):  
M. J. M. Hay ◽  
J. L. Brock ◽  
V. J. Thomas
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Weight ◽  
Rotational Grazing ◽  
Grazed Pastures ◽  
Point Density

SUMMARYDensities of physiologically independent plants of white clover were studied in New Zealand in pastures stocked at 22·5 ewes plus lambs/ha by set stocking, rotational grazing or a combination of both systems. Plants were sampled once a month for 1 year (1984/85) by taking turves and washing out the plants. Numbers of growing points and stolon dry weight per plant were obtained. At each sampling fifty, 50 mm diameter pasture plugs were taken from each sward and growing point density and stolon mass/m2 of white clover were measured. The density of white clover plants in the swards was estimated on the basis of both stolon dry weight and number of growing points.The two estimates gave similar results. There was a trend of lowest densities in set-stocked pastures (334/m2), intermediate densities in combination management pastures (431/m2) and highest densities in the rotationally grazed pastures (553/m2). The overall mean density of white clover plants was 439/m2 and the range was 193–811/m2.The structure of swards under the three systems of grazing differed and this was considered to contribute towards the variation in density of white clover plants in the various swards.

Effectiveness of recurrent selection of white clover (Trifolium repens) for resistance to New Zealand populations of clover cyst nematode (Heterodera trifolii)

Nematology ◽  
1999 ◽  
Vol 1 (5) ◽  
pp. 449-455 ◽  
Author(s):  
Chris F. Mercer ◽  
John Van Den Bosch ◽  
Kylie J. Miller
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Trifolium Repens ◽  
Recurrent Selection ◽  
Dry Weight ◽  
The Third ◽  
Resistant Lines ◽  
Shoot Weight ◽  
Nematode Development ◽  
Selection Of

Abstract Selections of white clover resistant or susceptible to Heterodera trifolii in earlier rounds of a recurrent selection programme were intercrossed and selected in three further rounds of selection. Resistance and susceptibility were measured by comparisons of cysts per gram of root dry weight (cpg). In the third, fourth, and fifth rounds of recurrent selection, the mean cpg of progenies from resistant parents was 23% (n = 974), 6% (n = 870) and 11% (n = 98) of that of progenies from susceptible parents. In each selection round, the resistant selections had 31, 4 and 7% of the number of cysts on susceptible selections. The percentages of immune plants (i.e. with 0 cysts) in the resistant groups were 1, 39, and 50% after the third, fourth, and fifth rounds of recurrent selection, respectively. Inoculum from 16 populations of H. trifolii from around New Zealand was added to two resistant and two susceptible white clover lines. After one generation of nematode development there were fewer cysts on the resistant lines for each population tested. Two resistant and two susceptible lines were compared in a glasshouse trial for their reaction to parasitism by H. trifolii . Infection reduced the shoot weight of all four lines but resistant lines grew better than either one or both susceptible lines at 109, 126, and 160 days after inoculation. In contrast, the uninfected lines did not differ in shoot weight over five samplings. More cysts were recovered from susceptible lines (means of 370 and 430 cysts per plant) than from resistant lines (means of 41 and 56 cysts per plant). Results indicate that development of a white clover cultivar resistant to H. trifolii is achievable and that the resistance will be effective against the nematode in most of New Zealand. The growth study indicated that advantages will be conferred in pastures where the presence of H. trifolii causes major limitations to white clover growth and persistence. Zusammenfassung- Die Wirksamkeit einer mehrfach wiederholten Selektion von Weissklee (Trifolium repens) auf Resistenz gegen das Kleezystenalchen (Heterodera trifolii)- In einem fruheren Selektionsprogramm gegen Heterodera trifolii resistente oder anfallige Weisskleeselektionen wurden gekreuzt und in weiteren Selektionsrunden selektiert. Resistenz und Anfalligkeit wurden durch Vergleich der Anzahl der Zysten je Gramm Wurzeltrockengewicht (cpg) bestimmt. In der dritten, vierten und funften Runde der Wiederholungsselektion betrugen die cpg-Werte bei Nachkommen von resistenten Eltern 23% (n = 974), 6% (n = 870) und 11% (n = 98) der Werte bei Nachkommen anfalliger Eltern. In jeder der Selektionsrunden hatten die resistenten Selektionen nur 31, 4 und 7% der Zystenzahlen an den anfalligen Selektionen. Nach der dritten, vierten bzw. funften Selektionsrunde betrugen die Anteile immuner Pflanzen (d.h. mit 0 Zysten) 1, 39 bzw. 50%. Das Inoculum von 16 Populationen aus ganz Neuseeland wurde an zwei resistente und zwei anfallige Weisskleelinien gegeben. Nach einer Generation der Nematodenentwicklung waren an den resistenten Linien bei jeder der untersuchten Populationen weniger Zysten. Die Reaktion von zwei resistenten und zwei anfalligen Linien auf einen Befall mit H. trifolii wurde in einem Gewachshausversuch gepruft. Der Befall verringerte das Sprossgewicht aller vier Linien, doch wuchsen die resistenten Linien nach 109, 126 und 160 Tagen besser als die beiden anfalligen Linien. Im Gegensatz dazu unterschieden sich die Linien bei Nichtbefall bei funf Probenahmen im Sprossgewicht nicht voneinander. An den anfalligen Pflanzen wurden mehr Zysten gefunden (im Mittel 370 und 430 je Pflanze) als an den resistenten Pflanzen (im Mittel 41 und 56 je Pflanze). Die Ergebnisse zeigen, dass die Entwicklung einer gegen H. trifolii resistenten Weisskleesorte erreichbar ist, und dass diese Resistenz gegen die Nematoden im grossten Teil Neuseelands wirksam sein wird. Die Wachstumsuntersuchungen haben gezeigt, dass die Vorteile besonders auf solchen Weideflachen deutlich werden, wo die Anwesenheit von H. trifolii erhebliche Einschrankungen des Wachstums und des Uberdauerns von Weissklee verursacht.

scholarly journals Adaptation of Trifolium repens × T. uniflorum hybrid clovers to drought stress

2014 ◽  
Vol 76 ◽  
pp. 183-188
Author(s):  
Keith Widdup ◽  
Shirley Nichols ◽  
Warren Williams ◽  
Isabelle Verry ◽  
Ben Harvey
Keyword(s):  
Water Stress ◽  
Drought Resistance ◽  
White Clover ◽  
Trifolium Repens ◽  
Performance Indicator ◽  
Field Evaluation ◽  
Dry Weight ◽  
Moisture Stress ◽  
Backcross Generation ◽  
Shoot Dry Weight

Abstract White clover (Trifolium repens L.) is valued for its contribution to pasture quality and utilisation by animals, compatibility with grass, and fixation of nitrogen. However, it is limited by poor adaptation to drought. Hybridisation with Trifolium uniflorum L. may have potential to improve the drought resistance of white clover. An experiment in a rain shelter facility with contrasting moisture treatments, and a field evaluation under dryland conditions, were used to compare the agronomic potential of these interspecific hybrids (ISH) with white clover in moisture limited conditions. In the rain shelter experiment, there were smaller effects of water stress on shoot dry weight (DW), leaf area, internode length and senescence of first backcross generation hybrids compared with white clover and second backcross generation hybrids. Differences in photosynthetic responses were possibly influenced by the effect of root DW allocation on water uptake. In the field evaluation, growth scores of a wider range of hybrid families during summer moisture stress concurred with the results under water stress in the rain shelter. Growth of some ISH families outperformed the best white clover cultivars, particularly in the third and most stressful summer and this result was a key performance indicator of the value of the hybrids for drought prone areas. These findings using early, unselected, hybrid populations indicate the potential for further selection of elite, adapted cultivars from ISH breeding strategies. Keywords: Interspecific clover hybrid, drought resistance, rain shelter, field evaluation

scholarly journals Progress towards clover cyst nematode resistant white clover

1996 ◽  
pp. 237-241
Author(s):  
J. Van den Bosch ◽  
C.F. Mercer
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Egg Production ◽  
First Generation ◽  
Control Method ◽  
Dry Weight ◽  
Mean Value ◽  
Cyst Nematode ◽  
Wide Range ◽  
The Mean

Clover cyst nematode (Heterodera trifolii) reduces growth and nutrient uptake of white clover (Trifolium repens) in New Zealand, and breeding resistant cultivars is the preferred control method for ecological and economic reasons. Resistant and susceptible selections were taken from a wide range of white clover seedlines. Selected plants were intercrossed and reselected over two cycles of selection. Cysts per gram of root dry weight (cysts/ g) was the measure of resistance used, with low cysts/g plants being more resistant. The mean cysts/ g value of the progenies from resistant parents was 69% of the mean value of the progenies from susceptible parents in the first generation, and 38% in the second generation. Root weights were similar, while the resistant selections had 58% and 34% (first and second generations respectively) of the number of cysts in the susceptible selections. There were no immune plants (0 cysts) in the first generation and only two in the second. Counts were made of cysts, eggs per cyst and eggs per plant on clones of two resistant and two susceptible genotypes. The resistant genotypes had lower counts than the susceptible genotypes in terms of cysts per plant (means of 6 cf. 108), eggs per cyst (11 cf. 21) and eggs per plant (35 cf. 1650). The differences in numbers of cysts between resistant and susceptible lines increased during two generations of selection, supporting earlier results that indicated that progress in breeding for resistance was possible. Furthermore, the resistance is also acting on clover cyst nematode egg production which would further reduce recruitment to later generations of clover cyst nematode. Keywords: breeding, Heterodera trifolii, resistance, screening, selection, Trifolium repens

Drought resistance of Trifolium repens×Trifolium uniflorum interspecific hybrids

2014 ◽  
Vol 65 (9) ◽  
pp. 911 ◽  
Author(s):  
S. N. Nichols ◽  
R. W. Hofmann ◽  
W. M. Williams
Keyword(s):  
Water Stress ◽  
Drought Resistance ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Weight ◽  
Root Diameter ◽  
Internode Length ◽  
Lateral Spread ◽  
Interspecific Hybridisation ◽  
Leaf Lamina

White clover (Trifolium repens L.) is a widely used and highly valued temperate legume; however, its productivity and survival are restricted under dryland and drought conditions. This study investigated whether drought resistance of white clover could be improved by interspecific hybridisation with Trifolium uniflorum L. After almost 4 months without irrigation in a rain-shelter facility, shoot dry weight (DW) decreased significantly less in first-generation backcross (BC1) hybrids (–47%) than second-generation backcross (BC2) hybrids (–68%) and white clover (–69%). Stolon morphological parameters such as internode length and leaf lamina area also decreased less under water stress in the BC1 hybrids than in BC2 and white clover. There was also lower senescence in BC1 under water stress than in the other clover types. Genotypes with smaller changes in leaf lamina area, internode length, senescence and lateral spread had smaller changes in shoot DW, and there were significant correlations between constitutive levels of some characteristics and the effect of water stress on shoot DW. Under water stress, the growth form of the BC1 hybrids was compact, dense and prostrate, whereas white clover was more spreading and open. Increased allocation of dry matter to roots under drought, and greater root diameter, may also have influenced the ability of BC1 hybrids to maintain water uptake and key physiological processes. Overall, the data confirm that the drought resistance of white clover can be improved through hybridisation with T. uniflorum.

scholarly journals Differences in resource allocation to stolon branches of Kopu white clover genotypes induced by manipulation of rooting

1996 ◽  
Vol 6 ◽  
pp. 145-148
Author(s):  
M. Lã-Tscher ◽  
M.J.M. Hay
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Resource Sharing ◽  
Dry Weight ◽  
Experimental Period ◽  
Vascular Bundles ◽  
Nutrient Distribution ◽  
Radioactive Phosphorus ◽  
32P Uptake ◽  
Trifolium Repens L

White clover (Trifolium repens L.) genotypes of the cv. Grasslands Kopu which had differing numbers of vascular bundles within their stolons were tested for potential for resource sharing between shoot branches on either side of parent axis. Genotypes with a high (10-13) number of vascular bundles (H-genotypes) had larger leaves, thicker stolons but lower node appearance rates than genotypes with a low (8-9) number of vascular bundles (L-genotypes). In the first experiment all roots on one side of the parent axis were severed two days before plants were labelled with 32P (uptake period 24 h). In H-genotypes, distribution of radioactive phosphorus (32P) exported from a nodal root was restricted largely to near-side branches, i.e. branches which were on the same side of the parent axis as the source root, with only 4% allocated to far-side branches. In contrast about 20% of 32P exported from the source root was transported to far-side branches in L-genotypes. In the second experiment, where all far-side roots were severed three weeks before harvest, growth of far-side branches was similarly reduced in L-genotypes and Hgenotypes. When root formation along one side of the parent axis was prevented during the entire experimental period the mean ratio of total dry weight between nearand far-side branches was higher in H-genotypes compared to L-genotypes. Keywords: branch development, nutrient distribution, phosphorus, vascular bundle, white clover, Trifolium repens L.

scholarly journals Frequent grazing by sheep reduced caucasian clover cover and rhizome mass in ryegrass pasture

1998 ◽  
pp. 203-206
Author(s):  
R.J. Lucas ◽  
A.J.E. Moorhead ◽  
W.W. Nichol ◽  
J.R. Sedcole ◽  
P. Jarvis
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Growth Form ◽  
Grazing Intensity ◽  
Dry Weight ◽  
High Fertility ◽  
Rotational Grazing ◽  
Trifolium Ambiguum ◽  
Kura Clover ◽  
Neotyphodium Lolii

The responses of hexaploid caucasian clover (Trifolium ambiguum) to four contrasting grazing regimes were compared with those of white clover (T. repens) in an endophytic (Neotyphodium lolii) hybrid ryegrass pasture on a fertile lowland site. After 2 years, frequent grazing (set stocking) by sheep reduced caucasian clover cover to 10% compared with 25.5% in infrequent grazing (rotational grazing) treatments (mean spelling time 25 days). Similarly, frequent grazing reduced caucasian clover rhizome plus root dry weight (780 kg DM/ha when sampled to 100 mm depth in frequently grazed plots, compared with 3220 kg DM/ha for infrequent). Under frequent grazing treatments, mean white clover cover was 21%, under infrequent hard grazing it was 26% and under lax infrequent grazing it was 14%. The reduction in ryegrass tiller population from 5720/m2 in the infrequently and laxly grazed treatments to 4150/ m2 in the frequently hard grazed pastures indicated the severity of that hard grazed treatment. These results show that in lowland ryegrass pastures on high fertility sites, the stoloniferous growth form of white clover may be superior to the rhizomatous strategy of caucasian clover when grazing by sheep is frequent throughout spring, summer and autumn. Keywords: caucasian clover, cover, grazing frequency, grazing intensity, kura clover, rhizomes, ryegrass, Trifolium ambiguum, Trifolium repens, white clover

scholarly journals Heritable differences in white clover for response to phosphorus: new prospects for low input pastoral systems

1991 ◽  
pp. 59-66
Author(s):  
J.R. Caradus' ◽  
A.D. Mackay' ◽  
S. Wewala ◽  
J.Dunlop' A.L. Hart' ◽  
M.G. Lambert' ◽  
...  
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Dry Weight ◽  
Pastoral Systems ◽  
The Third ◽  
Shoot Dry Weight ◽  
Low Phosphorus ◽  
Low Phosphorus Tolerance ◽  
Trifolium Repens L ◽  
Breeding Application

Three large glasshouse experiments were conducted to identify white clover (Trifolium repens L.) genotypes, and develop experimental seed lines, with increased tolerance of low-phosphorus (P) soils. The first compared the P response of 119 white clovercultivars; the second, the P response of 110 white clover genotypes from 11 selected cultivars; and the third the P response of progeny from crosses between genotypes selected for differences in response to added P. There were significant differences among cultivars and genotypes for shoot dry weight response to added P. Evaluation of progeny showed that high P response was dominant over low P response, the general combining abilities of all high P response genotypes were greater than that of the low P response genotypes, and that narrow sense heritabilities for P response were moderate (~0.4). The chances of manipulating differences in P response by breeding, application of the results to dateandfuturedirectionsofthisworkarediscussed. Keywords white clover, Trifolium repens, phosphorus response, low-phosphorus tolerance, heritability, breeding, combining ability

Nutrient responses and macronutrient composition of some Trifolium repens×Trifolium uniflorum interspecific hybrids

2014 ◽  
Vol 65 (4) ◽  
pp. 370 ◽  
Author(s):  
S. N. Nichols ◽  
R. W. Hofmann ◽  
W. M. Williams ◽  
J. R. Crush
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Dry Weight ◽  
Transgressive Segregation ◽  
Sand Culture ◽  
Interspecific Hybridisation ◽  
Root Characteristics ◽  
Macronutrient Composition ◽  
Soil P ◽  
Matter Production

Interspecific hybridisation is being utilised in white clover (Trifolium repens L.) breeding programs to overcome factors currently restricting productivity and persistence. Valuable new traits that may be introduced from the wild relative T. uniflorum include root characteristics and other adaptations to its natural, Mediterranean habitat. This study examined the effect of hybridisation on growth and macronutrient composition of white clover compared with T. uniflorum and T. repens × T. uniflorum backcross 1 (BC1) hybrids in two glasshouse sand culture experiments. Shoot and root dry weights of BC1 hybrids were greater than of white clover in low-concentration nutrient treatments but not in a more concentrated treatment. Decreases in dry weight with decreasing nutrient treatment strength were also smaller for some BC1 hybrids compared with white clover and other hybrid families. Most foliar macronutrient levels were adequate for white clover growth, but mean shoot or leaf phosphorus (P) concentrations were below published critical levels. Higher dry matter production under these low internal P concentrations suggests that some T. repens × T. uniflorum BC1 hybrids may be more tolerant of lower soil P levels than white clover. Such adaptations are likely to have been inherited from T. uniflorum. However, transgressive segregation may also be occurring, as T. uniflorum was larger than white clover in some, but not all, cases of low nutrient supply.

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