Response to selection for grazing tolerance in winter-active populations of phalaris (Phalaris aquatica L.). 1. Persistence under grazing in three environments

2009 ◽  
Vol 60 (11) ◽  
pp. 1097 ◽  
Author(s):  
R. A. Culvenor ◽  
S. P. Boschma ◽  
K. F. M. Reed
Keyword(s):  
Linear Response ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Response To Selection ◽  
North West ◽  
Phalaris Aquatica ◽  
Grazing Tolerance ◽  
The North ◽  
Breeding Populations ◽  
Selection For

Forage grass cultivars must have adequate grazing tolerance for use in the grazing systems for which they are intended. Response to 2 cycles of selection for persistence under heavy grazing pressure was examined in 3 winter-active breeding populations of the productive perennial grass, phalaris (Phalaris aquatica L.), from 2000 to 2003, at Bulart in western Victoria and Rye Park on the Southern Tablelands and Tamworth on the North-West Slopes of New South Wales. There was one continuously grazed and one rotationally grazed set of plots at Bulart to examine the effect of grazing management. All sites were affected by drought in later years but drought stress was most severe at Tamworth. A strongly positive linear response to selection was observed in an analysis of persistence measured as frequency of phalaris plant base across the 3 sites (excluding the rotational treatment at Bulart), but response interacted with site. By 2003, linear response averaged 14% frequency units or 34–40% proportional response per cycle at Rye Park and the continuously grazed plots at Bulart, sites that were environmentally suited to survival of phalaris. In contrast, response to selection was absent or slightly negative at Tamworth where conditions were drier and hotter. Populations responded similarly in analyses across all 3 sites but 1 population was less responsive when analyses were restricted to Bulart and Rye Park. Herbage mass measurements in 2001 at Bulart and 2002 at Rye Park indicated positive responses to selection, which were increasingly linked to frequency over time. Rotationally grazed plots at Bulart displayed higher frequency than continuously grazed plots after 3 years of grazing. The experiment showed that grazing tolerance was a heritable trait in the populations tested when environmental constraints were not limiting and that useful improvements in persistence had been obtained compared with existing cultivars.

Comparative levels of dimethyltryptamine- and tyramine-related alkaloid toxins in Australian cultivars and some wild populations of Phalaris aquatica

2005 ◽  
Vol 56 (12) ◽  
pp. 1395 ◽  
Author(s):  
R. A. Culvenor ◽  
K. F. M. Reed ◽  
S. E. McDonald
Keyword(s):  
Perennial Grass ◽  
Acid Soils ◽  
Fresh Weight ◽  
North West ◽  
Phalaris Aquatica ◽  
Grazing Tolerance ◽  
The North ◽  
Breeding Populations ◽  
Related Alkaloid ◽  
Wild Accessions

Phalaris (Phalaris aquatica L.) is a temperate perennial grass which occasionally causes toxicity in livestock. Immunoassays (ELISAs) were used to measure the level of the dimethyltryptamine and related alkaloid group (TRYP) and the tyramine-related group of alkaloids (TYR) in cultivars, breeding populations and wild accessions of phalaris. Herbage was sampled from grazed swards or spaced plants at several sites and times. Component alkaloids in 4 cultivars were also determined by thin-layer chromatography (TLC). Levels of TYR were higher than TRYP at all times of sampling. Alkaloid levels varied widely with site and sampling time, green herbage sampled in autumn being much higher than herbage sampled from July onwards. Plants sampled in autumn usually appeared moisture stressed and this may have been 1 factor causing high alkaloid levels in autumn. Comparative levels of TRYP in older cultivars agreed with published information. Two semi-winter dormant cultivars, Australian and the new and closely-related Australian II, were both higher than other cultivars in TRYP (maximum levels 18–20 mg/100 g fresh weight) but similar to most in TYR. Among winter-active cultivars, Holdfast and Sirolan were very low in TRYP (maximum levels <0.5 mg/100 g fresh weight) but Holdfast was the highest of all cultivars in TYR. While we argue on the basis of the TLC analyses and from previous work that the bulk of TYR in phalaris cultivars is N-methyltyramine, Holdfast was an exception in having one-third of its TYR as the less toxic hordenine in TLC analyses. Other new cultivars, Landmaster and Atlas PG, and breeding populations being developed as potential cultivars for acid soils or with improved grazing tolerance were generally higher than Holdfast and Sirolan, and similar to Sirosa, in TRYP (maximum levels 1–5 mg/100 g fresh weight). All were less than Holdfast in TYR. Two sets of wild accessions, 1 of which is being used in the development of a cultivar for the North-West Slopes of NSW, were relatively high in TYR alkaloids.

Recurrent selection for grazing tolerance in winter-active populations of the perennial grass, Phalaris aquatica L.

2006 ◽  
Vol 12 ◽  
pp. 89-92
Author(s):  
Richard Culvenor ◽  
Suzanne Boschma ◽  
Kevin Reed
Keyword(s):  
Recurrent Selection ◽  
Perennial Grass ◽  
Grazing Pressure ◽  
Soil Conditions ◽  
Environment Interaction ◽  
Response To Selection ◽  
North West ◽  
Phalaris Aquatica ◽  
Eastern Australia ◽  
Selection For

Phalaris (Phalaris aquatica L.) is a perennial grass of Mediterranean origin used widely by the sheep and cattle industries of south-eastern Australia. Winter-active cultivars released since the 1970's have the potential for higher herbage productivity than the earlier, semi-winter dormant cultivars but have been reported to be less persistent under sub-optimal grazing management and soil conditions. To improve genetic potential for persistence in winter-active phalaris, a program of recurrent selection was conducted by subjecting three populations of half-sib families to two cycles of selection for persistence under heavy, largely continuous grazing pressure. Cycle 2 progeny families and bulked seedlots of each generation were grown in separate grazed plot trials in Western Victoria and the Southern Tablelands and North-West Slopes of New South Wales from 1999-2003 to assess response to selection. Positive linear response to selection was observed in all populations at the Western Victorian and Southern Tablelands sites. Response to selection was absent and persistence was very low under higher temperature and drought stress on the North-West Slopes. This high level of genotype × environment interaction for persistence was also observed among final generation families. Families with better persistence than current winteractive cultivars at the two southern sites were identified in each population and a new cultivar is being formed from the parents.

Response to selection for grazing tolerance in winter-active populations of phalaris (Phalaris aquatica L.). 2. Correlated response in yield potential, plant characteristics, and alkaloid levels

2009 ◽  
Vol 60 (11) ◽  
pp. 1107 ◽  
Author(s):  
R. A. Culvenor ◽  
S. P. Boschma ◽  
K. F. M. Reed
Keyword(s):  
Seedling Growth ◽  
Growth Habit ◽  
Perennial Grasses ◽  
Yield Potential ◽  
Correlated Response ◽  
Individual Plant ◽  
Response To Selection ◽  
Phalaris Aquatica ◽  
Grazing Tolerance ◽  
Selection For

Phenotypic changes in populations of perennial grasses are known to occur in response to natural or deliberate selection under grazing. These changes may have agronomic significance. Associated changes in morphology and yield potential of young stands in response to 2 cycles of selection for grazing tolerance were examined in 3 winter-active breeding populations of the perennial grass, phalaris (Phalaris aquatica L.). Levels of alkaloids which potentially could affect palatability were also examined. There was a decline in seedling growth and autumn and winter yield in spaced plants of 6.3–7.5% per cycle pooled across populations. Seedling growth measured in sown swards at 2 sites was not affected by selection. Visually estimated sward yield in the second year, ignoring large gaps, agreed with the spaced plant results but the decline was not significant at P ≤ 0.05 when herbage yield was measured by mowing, probably due to effects of plant density. On balance, it was concluded that a decline in individual plant yield of 6–7% per cycle had occurred but this could be compensated by higher density, particularly over time as differences in persistence under grazing developed. The most pronounced morphological response to selection under grazing was towards a more densely tillered growth habit, although one exception occurred. There was also a tendency towards a more prostrate growth habit and later heading, but this was significant only for the most erect and earliest maturing population. Two cycles of selection did not significantly affect summer activity or area of plant base in any population. Tryptamine alkaloids were below the level likely to affect palatability but tended to increase with selection, particularly in a very low tryptamine base population, which suggested that they may play a role in persistence. Because of potentially deleterious effects on yield, care is required in using this selection method. A balance of yield potential and grazing tolerance appropriate to the management system is needed.

SUCCESSIONAL TRANSFORMATION OF FALLOW RECLAIMED LANDS AGROPHYTOCENOSIS IN THE NORTH-WEST OF RUSSIA UNDER AGROTECHNOGENIC IMPACT CONDITIONS

1970 ◽  
pp. 54-59
Author(s):  
Е. V. Dubina-Chekhovich ◽  
L. P. Evstratova ◽  
O. N. Bakhmet
Keyword(s):  
Perennial Grass ◽  
Total Yield ◽  
Phleum Pratense ◽  
Mining Company ◽  
North West ◽  
The North ◽  
Anthriscus Sylvestris ◽  
Motley Grass ◽  
Substantial Decline ◽  
Chamaenerion Angustifolium

It was determined during the study that a technogenic succession of perennial gramineous motley grass phytocenosis took place on reclaimed agricultural lands near mining company. The goal of a study was to estimate the shift in botanical composition and productivity of perennial agrophytocenosis on reclaimed fallow soils under aerial technogenic influence in Karelia. Over the last three years perennial gramineous herbs (Bromopsis inermis L., Phleum pratense L.) and motley grass (Urtica dioica L., Anthriscus sylvestris L., Chamaenerion angustifolium L.) are dominant in phyto-association. As we move away from mining location (100, 200, 300 meters) a gradual natural shift in vegetation takes place. The quantity of gramineous herbs decreases (from 77,8 to 42,9%) and the quantity of motley grass increases (from 21,2 to 56,8%) as compared to a control plot (16,5 and 82,9% accordingly). Low level of rainfall at the first half of summer, which is normal for Karelian climate, presence of polluting substances in soil and on surface caused substantial decline in growth of valuable fodder such as Bromopsis inermis (linear indicator 20,7 – 31,8 centimeters) as compared to background conditions (40,2 centimeters). Also, the mentioned above circumstances caused increase of total yield of perennial grass (13,2 – 16,4 – 22,0 tons per hectare; background – 28,0 tons per hectare) as we move away from mining location.

scholarly journals Trophodynamics of nekton communities in the epipelagic layer of the North-West Pacific in summer and winter seasons

2017 ◽  
Vol 188 (1) ◽  
pp. 181-203
Author(s):  
Svetlana V. Naydenko ◽  
Alexey A. Khoruzhiy
Keyword(s):  
Grazing Pressure ◽  
Trophic Levels ◽  
North West ◽  
The North ◽  
Energy Flows ◽  
Pacific Waters ◽  
Seasonal And Interannual Dynamics ◽  
The Pacific ◽  
Nekton Communities ◽  
June July

Trophic links between nekton and plankton are analyzed using the data collected in trawl surveys conducted by Pacific Fish. Res. Center (TINRO) in the Pacific waters at Kuril Islands and East Kamchatka in June-July of 2004-2016 and in the central and western parts of the Subarctic Front zone and adjacent subarctic waters in February-April of 2009-2011. Spatial, seasonal and interannual dynamics of nekton communities are detected, as well as changes in their composition and abundance. The most significant changes were caused by mass migrations of subtropical species, as in summer of 2014-2016. In these cases, new components were involved in the food web and energy flows between the low and upper trophic levels were changed, in the first place concerning to copepods, then to euphausiids, amphipods, and small-sized nekton prey. There were no such significant interannual changes in the energy flows in winter. The estimates of daily and seasonal energy flows between low and upper trophic levels, as well as the consumption rate of forage resources indicate no excess of allowable grazing pressure upon forage resources in the upper pelagic layer of the surveyed areas.

scholarly journals New Data on Distribution and Population Number of Large Raptors in Northern Usturt Within Atyrau Province, Kazakhstan

2020 ◽  
pp. 82-102
Author(s):  
Ilya E. Smelansky ◽  
◽  
Andrey A. Tomilenko ◽  
Anna N. Barashkova ◽  
Alexander A. Yakovlev ◽  
...  
Keyword(s):  
Average Distance ◽  
Golden Eagle ◽  
Population Number ◽  
North West ◽  
The North ◽  
Breeding Populations ◽  
Nesting Density ◽  
Eagle Owl ◽  
Saker Falcon ◽  
Imperial Eagle

In May and June 2018 and June 2019 we surveyed breeding populations of large raptors (principally Golden Eagle Aquila chrysaetos, Eastern Imperial Eagle Aquila heliaca, Steppe Eagle Aquila nipalensis, Long-Legged Buzzard Buteo rufinus, Saker Falcon Falco cherrug and Eagle Owl Bubo bubo) in the north-west of the Ustyurt Plateau within the boundaries of the Atyrau Province, Kazakhstan. The area surveyed was ca. 1000 km2 represented the wider area of 3400 km2. Total 12 species of birds of prey were recorded and 8 of them considered as large raptors. Golden Eagle was found nesting on the Donyztau escarpment, 4 breeding territories were recorded and 3 of them successful; nesting density is estimated at about 5.0–6.7 pairs per 100 km of cliffs, the distance between neighboring pairs was ca. 6 km. Imperial Eagle: 5 breeding territories found on the Donyztau and Zheltau escarpments, 4 of them successful; average nesting density is 3.8 pairs per 100 km of cliffs. Steppe Eagle: 14 breeding territories (25 nests) revealed, among them 6 are successful (1–2 nestlings) and on other 3 breeding was failed; average nesting density is estimated at 1.3 pairs per 100 km2. Average distance between neighboring active nests is 2.5 km in Sholkara hill ridge but the distance between successful nests here is much bigger and makes about 13 km. Long-Legged Buzzard: 13 breeding territories (30 nests) found, of which 11 territories were actually occupied and 8 of them had successful breeding. Saker Falcon is found nesting on Donyztau escarpment: 4 breeding territories, including 3 successful; the average nesting density is 6.7 pairs per 100 km of cliffs. Eagle Owl recorded throughout the surveyed area; 11 breeding territories revealed, the average nesting density is 7 breeding territories per 100 km of cliffs and steep slopes. Two other species, Short-toad Eagle and Cinereous Vulture, recorded only occasionally, nesting in the area is not found. In general, our findings demonstrate the area is important for conserving several species of large raptors in the Atyrau Province.

Evaluation of phalaris (Phalaris aquatica L.) germplasm for persistence under grazing on the North-West Slopes, New South Wales

2005 ◽  
Vol 56 (7) ◽  
pp. 731 ◽  
Author(s):  
R. A. Culvenor ◽  
S. P. Boschma
Keyword(s):  
North Africa ◽  
New South ◽  
Reproductive Development ◽  
Wild Populations ◽  
North West ◽  
Phalaris Aquatica ◽  
The North ◽  
South Wales ◽  
Wide Range ◽  
Summer Dormancy

The survival of available cultivars of introduced temperate perennial grasses has been less than adequate under grazing on the North-West Slopes of New South Wales. A wide range of germplasm of the Mediterranean perennial grass, phalaris (Phalaris aquatica L.), was assessed for persistence, seedling vigour, winter yield potential, time of reproductive development, and summer dormancy in grazed swards at 3 sites (Manilla, Tamworth, Purlewaugh) from 1998 to 2001. The aim was to understand population characteristics that influence persistence in this environment and to identify persistent populations. Good establishment was achieved after above-average winter–spring rainfall in 1998. Persistence was high during the first year of grazing (1999) but declined under lower rainfall during 2000 at the Manilla and Tamworth sites. By 2001, a wide range in persistence had developed at these 2 sites. A group of wild populations, mainly from North Africa, was identified as being more persistent at both sites than any available cultivar. Two early cultivars, Sirocco and CPI 19305, were also relatively persistent. None of the germplasm survived a subsequent severe drought in 2002 at Manilla and Tamworth. Persistence remained high despite higher grazing pressure at the Purlewaugh site until the 2002 drought year, when changes in survival correlated with those at the other sites occurred. Biplot analysis indicated that early reproductive development and high summer dormancy were associated with persistence in both wild and bred populations. High seedling and winter growth potential was less strongly associated with persistence. Wild and bred germplasm from North Africa displayed these characteristics to a marked extent, whereas germplasm from southern Europe and Sardinia did not and was less persistent. A group of wild populations mainly from Morocco was identified as the basis for cultivar development.

scholarly journals Lessons from a GWAS study of a wheat pre-breeding program: pyramiding resistance alleles to Fusarium crown rot

2020 ◽  
Author(s):  
Marcos Malosetti ◽  
Laura B. Zwep ◽  
Kerrie Forrest ◽  
Fred A. van Eeuwijk ◽  
Mark Dieters
Keyword(s):  
Complex Traits ◽  
Selection Process ◽  
Breeding Program ◽  
Crown Rot ◽  
Response To Selection ◽  
Qtl Detection ◽  
Gwas Study ◽  
Fusarium Crown Rot ◽  
Breeding Populations ◽  
Selection For

AbstractMuch has been published on QTL detection for complex traits using bi-parental and multi-parental crosses (linkage analysis) or diversity panels (GWAS studies). While successful for detection, transferability of results to real applications has proven more difficult. Here, we combined a QTL detection approach using a pre-breeding populations which utilized intensive phenotypic selection for the target trait across multiple plant generations, combined with rapid generation turnover (i.e. “speed breeding”) to allow cycling of multiple plant generations each year. The reasoning is that QTL mapping information would complement the selection process by identifying the genome regions under selection within the relevant germplasm. Questions to answer were the location of the genomic regions determining response to selection and the origin of the favourable alleles within the pedigree. We used data from a pre-breeding program that aimed at pyramiding different resistance sources to Fusarium crown rot into elite (but susceptible) wheat backgrounds. The population resulted from a complex backcrossing scheme involving multiple resistance donors and multiple elite backgrounds, akin to a MAGIC population (985 genotypes in total, with founders, and two major offspring layers within the pedigree). A significant increase in the resistance level was observed (i.e. a positive response to selection) after the selection process, and 17 regions significantly associated with that response were identified using a GWAS approach. Those regions included known QTL as well as potentially novel regions contributing resistance to Fusarium crown rot. In addition, we were able to trace back the sources of the favourable alleles for each QTL. We demonstrate that QTL detection using breeding populations under selection for the target trait can identify QTL controlling the target trait and that the frequency of the favourable alleles was increased as a response to selection, thereby validating the QTL detected. This is a valuable opportunistic approach that can provide QTL information that is more easily transferred to breeding applications.

The effects of phosphorus, sulphur and stocking rate on the yield, chemical and botanical composition of natural pastures, North-West Slopes, New South Wales

1979 ◽  
Vol 19 (101) ◽  
pp. 698 ◽  
Author(s):  
GM Lodge ◽  
EA Roberts
Keyword(s):  
Dry Matter ◽  
Perennial Grass ◽  
Botanical Composition ◽  
Stocking Rate ◽  
North West ◽  
The North ◽  
South Wales ◽  
Natural Pasture ◽  
Stocking Rates ◽  
Pasture Yield

The effects of phosphorus (P), sulphur (S) and stocking rate on the dry matter yield, and chemical and botanical composition of natural pasture were examined from November, 1971 to May, 1976 in a 20 point central composite design. P and S were applied annually at five levels (0, 6, 15, 23, 29 kg P ha-1; 0, 14, 34, 54, 67 kg S ha-1) and the plots were grazed continuously at five stocking rates (2.2, 3.2, 4.8, 6.3, 7.3 dry ewes ha-1). Each of the factors, P, S, and stocking rate affected total dry matter. At 4.8 and 6.3 sheep ha-1 the optimum rate of P was 15 kg ha-1, but at 3.2 sheep ha-1 it increased from 15 kg ha-1 to 23 kg ha-1 over the period. S had little effect on yield at the start and end of the experiment, but in between its effect depending on stocking rate; at 3.2 sheep ha-1 low levels (<I4 kg ha-1) were optimal, but at 4.8 and 6.3 sheep ha-1 very high levels (>54 kg ha-1) were needed. The quantity of green grass and legume was low in winter and was not consistently affected by any of the factors. The level of N in the green grass remained at less than 2%. Over the period of the experiment the basal cover of perennial grass and the frequency of annual legume declined, while the percentage of bare ground and annual grass increased. These changes over time could not be related to any of the factors, except that the percentage of A. ramosa declined at the higher stocking rates. In some years high stocking rate decreased the percentage of A. ramosa and S. variabilis, and increased that of C. truncata, D. linkii, K. phleoides and T. glomeratum. In terms of pasture yield, fertilized perennial grass pastures on the North-West Slopes have potential carrying capacities of at least 4.8 dry sheep ha-1. However, to support this high stocking rate without significantly affecting pasture yield high levels of S, around 54 kg ha-1, and moderate levels of P, around 15 kg ha-1, are required. At this higher stocking rate no major changes in botanical composition occurred.

Selection for seed retention in Phalaris tuberosa L.

1963 ◽  
Vol 14 (6) ◽  
pp. 755 ◽  
Author(s):  
JR McWilliam
Keyword(s):  
Genetic Variation ◽  
Perennial Grass ◽  
Economic Problem ◽  
Base Population ◽  
Response To Selection ◽  
Seed Shattering ◽  
Commercial Strain ◽  
Seed Retention ◽  
Eastern Australia ◽  
Selection For

Loss of seed from the maturing inflorescence (seed shattering) is common in grasses and constitutes a serious economic problem in many species. This paper reports the results of artificial selection to improve seed retention in Phalaris tuberosa, an important perennial grass in south-eastern Australia. A study of the factors controlling the loss of seed in this species has revealed that the seed lies free within the inflorescence at maturity, and its loss is promoted by the opening of the glumes. This in turn is influenced by the structure of the inflorescence. The highest seed retention has been found in plants with a short rigid inflorescence containing a large number of densely packed spikelets. Wide variation for seed retention exists between strains of P. tuberosa. The lowest value (25%) was found for natural ecotypes from Algeria and Morocco, and the highest for a selection from a strain of the Australian commercial type obtained from Argentina (81%). An estimate of the heritability for seed retention was high (0.92 ± 0.11), and most of the genetic variation appeared to be additive. There was a marked response to selection for high seed retention. With the Argentine variety as the base population, an increase of 29% in the average level of seed retention was achieved from the first cycle of selection. This level represents an increase of 60% by comparison with the widely grown commercial strain. The importance of high seed retention in relation to the economics of Phalaris seed production is briefly discussed.

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