Herbage and seed yield losses in six varieties of subterranean clover from rust (Uromyces trifolii-repentis)

1991 ◽  
Vol 31 (2) ◽  
pp. 225 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Late Spring ◽  
Yield Losses ◽  
Herbage Yield ◽  
Field Plots

Studies were conducted to determine the herbage and seed yield losses caused by rust (Uromyces trifolii-repentis Liro) in field plots of 6 subterranean clover varieties. By early October (mid spring), rust caused large reductions in herbage production in varieties Green Range (25.9%), Mount Barker (24.8%), Woogenellup (20.3%), Mulwala (18.7%) and Karridale (15.2%). By the beginning of November (late spring), herbage yield losses were greater in Mulwala (50.5%), Green Range (49.4%), Woogenellup (36.9%) and Mount Barker (34.1%). Rust also caused large reductions in seed yield in Green Range (89.4%), Mulwala (84.8%), Karridale (70.2%), Woogenellup (67.2%) and Mount Barker (39.5%). The variety Larisa was highly resistant to rust, with no significant (P>0.05) reduction in herbage or seed yield.

Lucerne, phalaris, and wallaby grass in short-term pasture phases in two eastern Australian wheatbelt environments. 2. Effect of perennial density and species on subterranean clover populations and the relative success of 3 clover cultivars of different maturity

2007 ◽  
Vol 58 (2) ◽  
pp. 123 ◽  
Author(s):  
B. S. Dear ◽  
G. A. Sandral ◽  
J. M. Virgona ◽  
A. D. Swan ◽  
B. A. Orchard ◽  
...  
Keyword(s):  
Seed Yield ◽  
Seed Bank ◽  
Seedling Survival ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Climatic Conditions ◽  
Perennial Species ◽  
Growing Season Length ◽  
Herbage Yield ◽  
Clover Seed

The effect of the density of 3 perennial species, phalaris (Phalaris aquatica L.), wallaby grass (Austrodanthonia richardsonii Kunth), and lucerne (Medicago sativa L.), on seed set, regeneration, and the relative competitiveness of 3 cultivars of subterranean clover (Trifolium subterraneum L.) was examined in 2 environments in the south-eastern Australian wheatbelt. Seed yields of subterranean clover were inversely related to perennial density at both sites over the first 2 years, the relationship varying with perennial species. Phalaris depressed the seed yield of clover more than lucerne and wallaby grass in the second and third year at equivalent densities. Clover seed yield was positively related to clover herbage yield in late spring at both sites, and inversely related to perennial herbage yield. Clover seed yield displayed an increasing linear relationship with the proportion of light reaching the clover understorey in spring, which in turn was inversely related to perennial density and perennial herbage yield. Clover seedling regeneration in mixed swards in autumn was positively related to the size of the summer seed bank, but negatively related to perennial density. Clover seedling survival following a premature germination at Kamarah was inversely correlated to the density of phalaris and lucerne in the sward. The relative competitiveness of the 3 subterranean clover cultivars varied between sites, with climatic conditions (rainfall and growing-season length) having a greater effect on the relative cultivar performance than companion perennial species or density. The later maturing subterranean clover cv. Goulburn became the dominant cultivar at the wetter site, constituting 72% of the seed bank, but declined to only 3–8% of the seed bank at the drier site. The proportion of the early flowering cultivar Dalkeith in the seed bank increased over time at the drier site and was highest (53%) in plots with the highest perennial density. We concluded that although perennial pasture species will depress clover seed yield and subsequent regeneration, these effects could be minimised by reducing perennial densities and exploiting variations in competitiveness between perennial species as identified in this study. Sowing earlier maturing subterranean clover cultivars would only be an advantage in increasing clover content in low-rainfall environments. The findings suggest that clover seed reserves and regeneration could also be increased by using grazing management to reduce the level of shading of clover by perennials, a factor associated with reduced clover seed yield.

Effect of time of application of MCPA and bromoxynil in relation to flowering on subterranean clover seed yield and quality

1996 ◽  
Vol 36 (2) ◽  
pp. 177 ◽  
Author(s):  
BS Dear ◽  
GA Sandral ◽  
JE Pratley ◽  
NE Coombes
Keyword(s):  
Seed Yield ◽  
Recovery Period ◽  
Subterranean Clover ◽  
Germination Percentage ◽  
Yield Component ◽  
Yield Response ◽  
Herbicide Application ◽  
Early Application ◽  
Primary Yield ◽  
Herbage Yield

The importance of stage of phenological development and cultivar maturity ranking in influencing the seed yield response of subterranean clover (Trifolium subterraneum L.) to broadleaf herbicides was examined in a field study in southern New South Wales. The herbicides, bromoxynil (200 g a.i./L) at 1.4 L/ha and MCPA (500 g a.i./L) at 1.0 Wha, were applied 6 (TI) and 3 weeks (T2) before flowering, and at 5% flowering (T3) to 7 cultivars ranging from early to late flowering. The stage of phenological development at herbicide application, the maturity ranking of the cultivar and the herbicide applied, all influenced seed set. Application of bromoxynil at T1 did not reduce seed yield of any cultivar but increased seed yield of 4 cultivars by up to 30%. MCPA applied at the same time reduced seed yield in 1 cultivar by 26% and increased yields in 4 others by up to 57%. Application of bromoxynil at T3 caused reductions in seed yield in 3 of the 7 cultivars. MCPA applied at this time was more damaging than bromoxynil with all cultivars showing large seed yield reductions ranging from 22 to 64%. Despite large reductions in herbage yield as a result of some herbicide treatments, there was only a low correlation (r = 0.3, P<0.01) between herbage yield at full flower and seed yield. Our findings suggest that the reduction in herbage yield and change in canopy structure as a result of the early application of herbicides stimulated seed production. Seed number was the primary yield component responsible for the change in seed yield with a high correlation (r = 0.86, P<0.01) between these 2 parameters. Seed size was relatively insensitive to herbicide treatment but varied markedly with cultivar. Germination percentage of seed produced by swards treated with bromoxynil was unaffected, even when applied at T3, whereas MCPA lowered germination percentage of almost all cultivars if applied within 3 weeks of the commencement of flowering. The maturity ranking of the cultivars was highly negatively correlated with percentage seed yield loss (r = -0.80, P<0.01) when either herbicide was applied at T3, the seed yield of the early flowering cultivars being most depressed by the herbicides. Length of recovery period between herbicide application and flowering was shown to be very important in influencing seed yield, the effect being modified by both herbicide and cultivar maturity.

Infection of subterranean clover swards with bean yellow mosaic potyvirus: losses in herbage and seed yields and patterns of virus spread

1994 ◽  
Vol 45 (7) ◽  
pp. 1427 ◽  
Author(s):  
RAC Jones
Keyword(s):  
Field Experiments ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Losses ◽  
Grazing Experiment ◽  
Growing Seasons ◽  
Heavy Grazing ◽  
Herbage Yield ◽  
Seed Yields ◽  
Grazed Swards

During 1989-92, subterranean clover ( Trifolium subterraneum L.) was grown in field experiments in which swards of six cultivars were infected with bean yellow mosaic potyvirus (BYMV) by transplanting small BYMV-infected subterranean clover plants into them. The swards were then grazed by sheep or mown to simulate grazing. The infected transplants were the primary virus source for subsequent spread by aphids. Spread initially centred on infected transplants resulting in circular expanding infected patches. Later, secondary patches, isolated affected plants and more generalized infection sometimes developed. The extent of spread within swards from the transplants varied with cultivar, BYMV isolate, site and year. Final BYMV incidence ranged from 12% of plants symptom-affected by isolate MI in cv. Junee in 1991 to 100% by isolate SMB in cv. Leura in 1992. BYMV spread mostly occurred in spring and was increased around the edges of areas of bare ground in swards. In two experiments at one site in which 'mini swards' of cvv. Green Range, Karridale and Leura were mown repeatedly, BYMV-infection decreased herbage yields (dry weights) by 12-16% while seed yields were decreased significantly (by 37-40010) in one experiment. In a grazing experiment at a second site with swards of cvv. Esperance and Karridale, BYMV-infection decreased overall yields of herbage by 18-39% and seed by 11-12%; herbage yield losses within symptom-affected patches were 28-49%. In a further grazing experiment at this site with swards of cvv. Junee and Karridale, BYMV-induced losses determined from symptom-affected patches were 21-29% for herbage and 15-25% for seed. In a grazing experiment with swards of cvv. Denmark and ~ e u r a ' at a third site, BYMV-induced overall herbage yield decreases of 8-12% were still recorded despite extensive BYMV spread to control swards; yield losses within symptom-affected patches were 18-25% for herbage and 35-47% for seed. Seed yield losses were due to decreased seed size (mean seed weight), fewer seeds being produced, or both. Estimates of the effects of different levels of BYMV infection on herbage yields in partially infected grazed swards were obtained for cvv. Denmark, Karridale and Leura by plotting individual quadrat data for herbage dry weights against % symptom-affected plants. Losses increased in proportion to the level of infection, but their magnitude also varied with cultivar and experiment. It is concluded that BYMV infection of subterranean clover pastures is cause for concern, not only as regards herbage yield losses but also as regards depletion of the seed bank, which, when compounded year by year, results in pasture deterioration. Early and prolonged aphid activity, reseeding the pasture with susceptible cultivars, heavy grazing and extended growing seasons are all likely to magnify BYMV-induced losses.

Influence of cultivar and season on the response of Trifolium subterraneum to simazine

1992 ◽  
Vol 32 (8) ◽  
pp. 1095 ◽  
Author(s):  
BS Dear ◽  
DJ Conlan ◽  
MF Richards ◽  
NE Coombes
Keyword(s):  
Seed Set ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Response ◽  
Yield Losses ◽  
Lolium Rigidum ◽  
Herbage Yield ◽  
Annual Grasses ◽  
Clover Seed ◽  
Seed Yields

The tolerance of 6 cultivars of Trifolium subterraneum (subterranean clover) to simazine applied at 0.63 and 1.25 kg a.i./ha was determined under weedfree conditions in the field by measuring herbage and seed yields. Large herbage yield losses occurred as a result of the simazine in spring in the 2 years of the experiments. In 1989, spring herbage yield losses of the cultivars at the 0.63 and 1.25 kg/ha simazine rates averaged 56 and 82%, respectively. In 1990 the spring herbage yield losses were 27 and 51%. Significant variation in tolerance was observed between cultivars in both years, with Trikkala being the most tolerant and Karridale the most susceptible cultivar. Rate of herbicide had the greatest effect on herbage yield, with cultivar having a smaller effect. In 1989, with relatively favourable spring conditions, clover seed yields were depressed by simazine, but in 1990 when drier conditions prevailed during flowering and seed set, seed yields were unaffected or slightly increased by simazine in all cultivars except the early-flowering cultivar Dalkeith. Seed yields of simazine-treated swards were 196-1480 kg/ha in 1989 and 359-686 kg/ha in 1990. The seed yield response in 1990 suggests that herbicides which retard growth in winter help to conserve soil water and, therefore, may benefit seed filling later in the season. The presence of Lolium rigidum at spraying did not reduce the effect of the herbicide on clover herbage yield and had no effect on seed set. Although simazine may reduce herbage yields and, in some cases, seed yields, its use may be justified for the control of annual grasses when other factors such as disease control, pasture quality, and level of weed competition are considered.

The tolerance of three transgenic subterranean clover (Trifolium subterraneum L.) lines with the bxn gene to herbicides containing bromoxynil

2003 ◽  
Vol 54 (2) ◽  
pp. 203 ◽  
Author(s):  
B. S. Dear ◽  
G. A. Sandral ◽  
D. Spencer ◽  
M. R. I. Khan ◽  
T. J. V. Higgins
Keyword(s):  
Leaf Area ◽  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Biochanin A ◽  
Leaf Stage ◽  
Agronomic Characteristics ◽  
Herbage Yield ◽  
Transgenic Lines

A bxn gene, coding for the nitilase enzyme that catalyses the detoxification of the herbicide bromoxynil, was inserted into subterranean clover (Trifolium subterraneum L. subsp. yanninicum). The agronomic characteristics of 3 transgenic lines (BXN 5, 7, 10) and their response to herbicides containing bromoxynil, were compared with that of the non-transgenic parent, cv. Gosse, in 1 glasshouse and 2 field experiments.The application of bromoxynil at 1.5 L/ha resulted in a 50% reduction in the spring herbage yield of the non-transgenic control but no reduction in BXN 5 and 7. The level of the phyto-oestrogens, genistein and biochanin A, in the leaf tissue were low in Gosse and the 2 transgenic lines, BXN 7 and 10, but the level of genistein increased significantly (P < 0.05) from 0.85% in Gosse to 1.43% dry weight in BXN 5, and biochanin A increased from 0.35% in Gosse to 0.73% in BXN 5. The application of the herbicides bromoxynil, bromoxynil+MCPA, and Jaguar (bromoxynil+diflufenican) at the cotyledon stage in a glasshouse study significantly reduced the leaf area of the non-transgenic Gosse, but did not reduce the leaf area of the 3 transgenic lines. When applied at the 4–5 leaf stage, the leaf area of Gosse was again reduced by all the herbicides, but only the bromoxynil+MCPA treatment reduced the leaf area of the transgenic lines relative to the control. The application of bromoxynil or Jaguar at the 4–5 leaf stage depressed the herbage yield of Gosse by about 62% compared with 0–24% in the 3 transgenic lines. In the field studies, BXN 5 and 10 had similar seed yields to Gosse in the absence of herbicide application, but the seed yield of BXN 7 was significantly less than the other 2 transgenic lines. The level of hard-seed in BXN 7 was also lower at 25% compared with 55–57% in the other transgenic lines and Gosse.These findings stress the need to carefully assess the agronomic qualities of transgenic lines prior to release as although tolerance to bromoxynil may be greatly increased by the bxn gene, other important agronomic characteristics, such as seed yield, hardseededness, and isoflavone content, may change as result of the gene or transformation process.

Resistance and associated yield losses from rust (Uromyces trifolii-repentis Liro) in midseason cultivars of Trifolium subterraneum L. var. subterraneum L. and var. yanninicum Katzn. et Morley

1995 ◽  
Vol 35 (1) ◽  
pp. 73 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Field Study ◽  
Seed Yield ◽  
Trifolium Subterraneum ◽  
Yield Losses ◽  
Commercial Cultivars ◽  
Herbage Yield ◽  
Seed Yields

A field study was conducted to quantify the effect of rust on the herbage production and seed yield of 4 new midseason cultivars of Trifolium subterraneum (Denmark, Gosse, Goulburn, Leura) and to compare their performance with 8 current commercial cultivars. Leura, Gosse, and Goulburn were all resistant to rust, with Leura most resistant. Denmark was not resistant to rust, but was much less susceptible than Green Range and marginally less susceptible than Mt Barker. By the end of the season, rust had reduced herbage yield in Green Range, Junee, Karridale, and Seaton Park (32, 23, 22, 18%, respectively) but did not affect any new cultivar. Rust reduced the seed yields of all cultivars except Goulburn, Larisa, and Leura. Seed yields of Green Range, Woogenellup, Mt Barker, Seaton Park, Denmark, Esperance, Karridale, Gosse, and Junee were reduced by 75, 70, 58, 55, 49, 47, 40, 40, and 38%, respectively. Rust also reduced the size of seed in all cultivars except Goulburn.

Studies on the fungicidal control of bulb rot caused by Botrytis allii in onions for the production of seeds

1983 ◽  
Vol 100 (3) ◽  
pp. 519-525 ◽  
Author(s):  
G. Kritzman
Keyword(s):  
Seed Yield ◽  
Secondary Infection ◽  
Primary Source ◽  
Grey Mould ◽  
Yield Losses ◽  
Onion Bulbs ◽  
Onion Seed ◽  
Botrytis Allii ◽  
Bulb Rot ◽  
Field Plots

SUMMARYBotrytis allii, grey mould, is the major cause of bulb and seed yield losses of growing onion seeds in Israel. Nursery treatments with iprodione or vinclozolin significantly decreased the number of diseased onion bulbs which were supplied to the farmers from 24% in the control to 8% in the treated plots and resulted in higher yield of seed with increases of 45% in seed weight per plant. Onion bulbs under non-irrigated conditions in the mountains were found to be more susceptible to the disease, as well as to secondary infection, than irrigated onions that were grown in the plains. Chemical treatment of the bulbs before planting significantly reduced the rate of secondary infection in the field and decreased seed losses. The survival of B. allii propagules and their importance as a primary source of inoculum in growing onions for seed were studied in the central mountainous region of Israel. From 197 to 1532 B. allii propagules per g soil were found in the field plots, this as the result of only one season growing onion seed. Ninety-one per cent of the total planted healthy bulbs were infected in the highly contaminated plots after 150 growing days. The surviving B. allii propagules reduced the seed yield, from 14·4 in the less contaminated plots to 10·4 g/plant in the highly contaminated.

Relative resistance, associated yield losses and phyto-oestrogen production from fungal foliar diseases in new and old annual Medicago cultivars

1995 ◽  
Vol 46 (2) ◽  
pp. 441 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Seed Yield ◽  
Seed Weight ◽  
Susceptible Cultivar ◽  
Yield Losses ◽  
Relative Resistance ◽  
Foliar Disease ◽  
Foliar Diseases ◽  
Herbage Yield ◽  
Stems And Leaves ◽  
Annual Medicago

The relative resistance, associated herbage and seed yield losses and phyto-oestrogen production from fungal foliar diseases in two new annual Medicago cultivars, viz. M. sphaerocarpos cv. Orion and M. truncatula cv. Caliph, were compared with those of four old cultivars, viz. M. murex cv. Zodiac, M. polymorpha var. brevispina cw. Santiago and Circle Valley, and M. truncatula cv. Cyprus. Orion was much more resistant to Phoma stem disease than Circle Valley and Santiago, but was more susceptible than Zodiac. However, Orion was the most susceptible cultivar to Phoma leaf disease. Orion and Caliph were susceptible to Leptosphaerulina stem disease, resembling Santiago, but much more susceptible than Circle Valley and Zodiac. Caliph was comparable with Cyprus with moderate susceptibility to both Phoma and Leptosphaerulina on stems. Both Caliph and Cyprus were resistant to Pseudopeziza. In mid-October and early November, foliar diseases reduced overall herbage yield of the six varieties by 16.2 and 20.3% respectively, compared with the fungicide-treated plots of the same cultivars. Foliar diseases reduced seed yield by 37.3%, and mean seed weight by 13- 7% compared with fungicide treated plots. Foliar disease in the disease block increased the content of the phyto-oestrogen coumestrol in stems from 230 to 500 ppm and in pods from 30 to 130 ppm, compared with the fungicide block. There was a positive correlation between the severity of Phoma on stems and leaves and the level of coumestrol in stems and pods. Orion produced large amounts of coumestrol in stems and pods in response to foliar diseases (e.g. 470 ppm in stems) but less than Zodiac. Caliph also produced large amounts of coumestrol in stems and pods in response to foliar diseases (e.g. 230 ppm in stems), and was similar to Cyprus but had less coumestrol than all other cultivars tested (stems) or Zodiac, Circle Valley and Santiago (pods). Orion carried the highest level of P. medicaginis seed contamination (28%), followed by Santiago (15%), Cyprus (11%), Circle Valley (l0%), Zodiac (10%) and Caliph (6%).

scholarly journals Quantification of Avoidable Yield Losses in Oilseed Brassica Caused by Insect Pests

2011 ◽  
Vol 51 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Jagdev Kular ◽  
Sarwan Kumar
Keyword(s):  
Seed Yield ◽  
Yield Loss ◽  
Insect Pests ◽  
Block Design ◽  
Maximum Yield ◽  
The Other ◽  
Yield Losses ◽  
Eruca Sativa ◽  
Mustard Aphid ◽  
Randomized Block Design

Quantification of Avoidable Yield Losses in OilseedBrassicaCaused by Insect PestsA six year field study was conducted from 2001-2002 to 2006-2007 at Punjab Agricultural University, Ludhiana, India to study the losses in seed yield of differentBrassicaspecies (B. juncea, B. napus, B. carinata, B. rapaandEruca sativa) by the infestation of insect pests. The experiment was conducted in two different sets viz. protected/sprayed and unprotected, in a randomized block design, with three replications. Data on the infestation of insect pests, and seed yield were recorded at weekly intervals and at harvest, respectively. The loss in seed yield, due to mustard aphid and cabbage caterpillar, varied from 6.5 to 26.4 per cent.E. sativasuffered the least loss in seed yield and harboured the minimum population of mustard aphid (2.1 aphids/plant) and cabbage caterpillar (2.4 larvae/plant). On the other hand,B. carinatawas highly susceptible to the cabbage caterpillar (26.2 larvae/plant) and suffered the maximum yield loss (26.4%).

EFFECT OF PASMO DISEASE ON SEED YIELD AND THOUSAND KERNEL WEIGHT OF FLAX

1950 ◽  
Vol 28c (5) ◽  
pp. 493-512 ◽  
Author(s):  
W. E. Sackston
Keyword(s):  
Seed Yield ◽  
Yeast Extract ◽  
Kernel Weight ◽  
Potato Dextrose Agar ◽  
Seedling Stage ◽  
Flowering Stage ◽  
Thousand Kernel Weight ◽  
Stages Of Growth ◽  
Positive Correlations ◽  
Field Plots

The pasmo pathogen sporulated freely on potato dextrose agar containing yeast extract. Spores suspended in water with gelatin as a spreader–sticker were sprayed onto flax plants at different stages of growth in field plots. Heaviest infections of pasmo resulted from inoculations at the flowering stage, lighter infections from inoculations on seedlings, and lightest infections from inoculations on ripening plants. Diluting the concentration of spores in the inoculum reduced disease intensity. The four flax varieties in the tests differed in reaction to pasmo. In decreasing order of susceptibility they were: Viking, Redwing, Royal, and Crystal. Heavy infections of pasmo caused premature ripening and reduced the seed yield and weight per thousand kernels of all four varieties. The effects of pasmo infection on seed yield and kernel weight were similar to those caused by a hot, dry climate, and by flax rust. Seed yield and kernel weight were reduced most markedly by inoculation at the flowering stage, less severely by inoculation at the seedling stage, and least of all by inoculation at the time of ripening. Seed yield and kernel weight from plots inoculated when the plants were ripening did not differ significantly from the uninoculated checks. Highly significant positive correlations between the data for seed yield and kernel weight indicated that much of the loss in yield resulted from a reduction in the size of individual seeds.

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