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.

Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides. 2. Seed yield and quality

1995 ◽  
Vol 35 (4) ◽  
pp. 475 ◽  
Author(s):  
GA Sandral ◽  
BS Dear ◽  
NE Coombes
Keyword(s):  
Seed Yield ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Germination Percentage ◽  
Yield Response ◽  
Wagga Wagga ◽  
Herbicide Treatment ◽  
Herbicide Treatments ◽  
Saving Effect ◽  
Seed Yields

The effect of broadleaf herbicides on seed set by Trifolium subterraneum (subterranean clover) cultivars was examined at 2 sites (Wagga Wagga and Canowindra) over 2 years. Five commonly used herbicide treatments (bromoxynil, MCPA, 2,4-DB, MCPA + terbutryn, MCPA + diuron) were applied at 2 rates to 7 cultivars of subterranean clover. Significant site x cultivar x herbicide interactions were observed. Seed yields were either unaffected or depressed by up to 66% at the higher rainfall site (Canowindra), whereas at the lower rainfall site (Wagga Wagga) some herbicide x cultivar combinations showed increases in seed yield up to 115%. The increase in seed yield was greater at the lower herbicide rate. The variation in seed yield with herbicide treatment was largely a result of a change (P<0.001) in the number of seeds set (R = 0.94 at Wagga Wagga; R = 0.85 at Canowindra). Seed size was also correlated (P<0.001) with seed yield at both sites but explained less of the variation (R = 0.23 at Wagga Wagga; R = 0.47 at Canowindra). The reduction in herbage yield as a result of herbicide application was a poor indicator of the subsequent seed yield response at both sites. Cultivar Trikkala was consistently most tolerant to the herbicide treatments, showing either no change in seed yield at the wetter site or large increases in seed yield at the lower rainfall site. In contrast, the seed yield of Dalkeith was depressed by 2,4-DB at both sites in both years by 39-66%. Increases in seed yield, which were most pronounced in cultivars of midseason maturity (Trikkala, Junee, Seaton Park) and least in later maturing cultivars (Karridale, Clare) and in the very early flowering Dalkeith, were attributed in part to a water-saving effect of the herbicide treatments. Cultivar maturity ranking was negatively correlated (P<0.001) with seed yield (R=-0.73 at Wagga Wagga; R=-0.45 at Canowindra). The germination percentage of seed produced by the cultivars was unaffected by herbicide treatment, although the number of abnormal radicles formed by germinating seed was higher in the 2,4-DB and MCPA treatments.

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.

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.

Adaptation of lentil (Lens culinaris Medik) to short season Mediterranean-type environments: response to sowing rates

1998 ◽  
Vol 49 (7) ◽  
pp. 1057 ◽  
Author(s):  
K. H. M. Siddique ◽  
S. P. Loss ◽  
K. L. Regan ◽  
D. L. Pritchard
Keyword(s):  
Seed Yield ◽  
Seed Weight ◽  
Plant Density ◽  
Germination Percentage ◽  
Yield Response ◽  
Individual Plant ◽  
Asymptotic Model ◽  
Growing Conditions ◽  
The Cost ◽  
Seed Yields

The growth and seed yield response of lentil (cv. Digger) to sowing rate (20-120 kg/ha) was studied at 13 sites over 3 seasons in the cropping regions of south-western Australia. The economic optimum plant density was estimated by fitting an asymptotic model to the data and calculating the sowing rate above which the cost for additional seed was equivalent to the revenue that could be achieved from the extra seed yield produced, assuming a 10% opportunity cost. On average across all sites and seasons, only 51% of sown seeds emerged. Increasing sowing rate resulted in greater dry matter production at ˚owering and maturity, and fewer pods per plant. Harvest index (0·31-0·36), number of seeds per pod (1·13-1·84), and mean seed weight (2·9-3·6 g/100 seeds) remained relatively stable with changes in sowing rate. The asymptotic models fitted to seed yields accounted for 1-73% of the total variance in the data, except at one site where a model could not be found to provide an adequate fit to the data. In addition to this site, another 5 sites were excluded from further consideration where the percentage of variance accounted for was <25% or the predicted optimum densities and seed yield potentials were well beyond the range of the data. The economic optimum of the remaining 7 sites ranged from 96 to 228 plants/m2, with a mean of 146 plants/m2. These results suggest that lentil yields may be improved by increasing sowing rates beyond those currently targeted in southern Australia (100-125 plants/m2). On the basis of these results, targeting a density of about 150 plants/m2 by using a sowing rate of approximately 90-110 kg/ha is recommended, depending on mean seed weight and germination percentage of the seed. Even higher sowing rates may be optimum where the growing conditions are unfavourable and individual plant growth is limited.

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.

The effect of copper supply on vegetative and seed yield of pasture legumes and the field calibration of a tissue test for detecting copper deficiency. I. Subterranean clover (Trifolium subterraneum and Trifolium yanninicum)

1989 ◽  
Vol 40 (4) ◽  
pp. 817 ◽  
Author(s):  
JD McFarlane
Keyword(s):  
Seed Yield ◽  
Dry Matter ◽  
Copper Deficiency ◽  
Critical Concentration ◽  
Leaf Tissue ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Soil Types ◽  
Yield Response ◽  
Pasture Legumes

Three cultivars of subterranean clover (Trifolium subterraneum L. cvv. Woogenellup, Nungarin; Trifolium yanninicum cv. Trikkala) were grown on three copper-deficient soil types at seven rates of copper, applied at sowing, to determine their vegetative and seed yield response to copper fertilizer.On two soil types, symptoms of copper deficiency were apparent where no copper was supplied. On the third, symptoms appeared only in one season, after the site was waterlogged. On the three soil types, the symptoms disappeared when 0.125 kg Cu/ha was applied at sowing. although at this rate vegetative and seed yields were reduced by as much as 44% and 59% respectively.The proposed critical concentration range in youngest open leaf tissue for both diagnosing maximum vegetative dry matter and predicting maximum seed yield is 3.0-4.5 mg Cu/kg for Woogenellup and Nungarin subterranean clover. Trikkala subterranean clover had higher critical concentration ranges for diagnosing maximum vegetative dry matter (4.0-6.0 mg Culkg) and predicting maximum seed yield (4.5-7.0 mg Cu/kg). It was not clear whether this difference was due to a higher internal requirement for copper of Trikkala or overlying environmental conditions affecting the external copper supply at the time of sampling.For whole top tissue (WT), there was no difference in the critical concentration range between the three cultivars for diagnosing maximum vegetative yield (3.0-4.0 mg Cu/kg). However, the critical concentration in WT for predicting maximum seed yield was higher for Trikkala (5.0-6.0 mg Cu/kg) than Woogenellup and Nungarin (3.5-4.5 mg Cu/kg). In the pasture situation, a critical concentration of 5.0-6.0 mg Cu/kg in the WT should be adopted when animal requirement is considered.Seed copper concentration for predicting maximum seed or vegetative yield was not a reliable indicator of copper status of subterranean clover.

Differential tolerance of Trifolium subterraneum L. (subterranean clover) cultivars to broadleaf herbicides 1. Herbage yield

1995 ◽  
Vol 35 (4) ◽  
pp. 467 ◽  
Author(s):  
BS Dear ◽  
GA Sandral ◽  
NE Coombes
Keyword(s):  
Seedling Survival ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Yield Reduction ◽  
Herbicide Application ◽  
Herbicide Treatments ◽  
Herbage Yield ◽  
Relative Tolerance ◽  
Differential Cultivar ◽  
Rate Of Recovery

The differential tolerance of 7 Trifolium subterraneum (subterranean clover) cultivars to 5 broadleaf herbicide treatments applied at 2 rates was examined at 2 sites over 2 years. The herbicide treatments and the rate of active ingredient applied (kg a.i./ha) were 2,4-DB (0.8, 1.6), MCPA (0.5, 1.0), bromoxynil (0.28, 0.56), MCPA (0.15, 0.3) + terbutryn (0.275, 0.4125), and MCPA (0.25, 0.375) + diuron (0.25, 0.375). The herbage yield of all cultivars at 30 and 60 days after herbicide application (DAA) was suppressed by all herbicides except 2,4-DB at 60 DAA. There was marked variation in cultivar tolerance, with Trikkala being the most tolerant to all herbicides. Seaton Park was the most sensitive to MCPA + terbutryn, MCPA + diuron, and bromoxynil, while Karridale was the most sensitive to MCPA. Log10(sprayed yield) log10(unsprayed yield) was an appropriate measure of relative tolerance of cultivars to herbicide. While herbage yields and yield reduction due to the herbicides varied between sites and years, the effect of the herbicides and the relative responses of the cultivars were similar across years and sites. Herbage yield meaned over the 2 herbicide rates was reduced by 16-71% at 30 DAA depending on herbicide and cultivar, and by 445% at 60 DAA. A mixture of MCPA + terbutryn or MCPA + diuron caused the largest reduction in herbage (47-71%) at 30 DAA, while MCPA and 2,4-DB caused the smallest (16-56%) reduction. Neither the maturity ranking of the cultivar nor the cultivar vigour measured at 30 DAA influenced sensitivity to the herbicides. The rate of recovery (kg DM/ha.day) by the cultivars at 30-60 DAA was greatest in the MCPA, 2,4-DB, and bromoxynil treatments (80-120 kg DM/ha.day) and least in the MCPA + diuron treatment (71-84 kg DM/ha.day) and was not related to maturity ranking. Doubling the rate of herbicide increased herbage yield suppression and resulted in slower growth rates but did not affect seedling survival. The magnitude of the reduction in herbage yield has important implications for choice of herbicide and needs to be balanced against the likely loss due to weed competition. The identification of significant differential cultivar tolerance suggests that worthwhile improvements in tolerance can be achieved through plant breeding or selection.

scholarly journals Yield of subterranean clover after post-emergence herbicide application for broadleaf weed control

2020 ◽  
Vol 82 ◽  
pp. 121-128
Author(s):  
Breanna J. O. Taylor ◽  
Rainer W. Hofmann ◽  
Derrick J. Moot
Keyword(s):  
Field Experiment ◽  
Weed Control ◽  
Seed Set ◽  
Subterranean Clover ◽  
Acetolactate Synthase ◽  
Herbicide Application ◽  
Trifoliate Leaf ◽  
Leaf Stage ◽  
Rumex Obtusifolius ◽  
Herbage Yield

A field experiment was established in Lincoln, Canterbury in autumn 2018 to evaluate the effect of acetolactate synthase (ALS) inhibiting herbicides on subterraneun (sub) clover. Two herbicides, imazethapyr and flumetsulam, were applied to seven sub clover cultivars at the 4-5 trifoliate leaf stage during July 2018. By December 2018, both herbicides had reduced the broadleaf weed yield by 1000 kg DM/ha. Sub clover herbage yield in spring (3 Oct 2018) increased only for ‘Antas’ and ‘Napier’ cultivars but all cultivars had an increase in total annual herbage yield when herbicides were applied. Plots were managed for seed set so re-establishment was examined. Imazethapyr had a longer residual than flumetsulam with greater control of broad-leaved dock (Rumex obtusifolius) eight months after application. Herbicide application had no effect on subsequent sub clover emergence the following year. This experiment demonstrated the potential to establish a pure sward of sub clover with the use of ALS inhibiting herbicides, which could be used to create a high legume base in pasture before overdrilling grass the following year.

Responses of soybean genotypes to intercropping with maize in the Southern Guinea Savanna, Nigeria

2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa
Keyword(s):  
Seed Yield ◽  
Block Design ◽  
Field Trials ◽  
Yield Response ◽  
Ecological Zone ◽  
Land Equivalent Ratio ◽  
Guinea Savanna ◽  
Days To Maturity ◽  
Soybean Genotypes ◽  
Location Interaction

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.

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