Seedling survival, yield and seed production of three species of annual medics exposed to lucerne aphids

1980 ◽  
Vol 20 (105) ◽  
pp. 457 ◽  
Author(s):  
GM Lodge ◽  
LR Greenup
Keyword(s):  
Seed Production ◽  
Seedling Survival ◽  
Germination Percentage ◽  
Aphid Species ◽  
The Other ◽  
Survival Yield ◽  
Matter Production ◽  
Annual Medics ◽  
Seed Yields ◽  
Field Plots

The effects of spotted alfalfa aphids and blue-green aphids on the seedling survival, yield and seed production of Medicago truncatula var. truncatula cultivars Cyprus and Jemalong, M. polymorpha var. vulgaris and M. minima var. minima were investigated in field plots to which three insecticide treatments were applied: sprayed continuously to the post-flowering and haying-off stage; sprayed only until flowering ; and unsprayed. In the unsprayed plots all four medics were suitable hosts for both aphid species. The highest number of blue-green aphids developed on M. truncatula cv. Cyprus and the highest number of spotted alfalfa aphids on M. polymorpha var. vulgaris. Aphid numbers were relatively low from emergence to establishment and had no effect on the seedling mortalities of the medics in the unsprayed plots. The relatively low aphid numbers through winter also had no effect on dry matter production, but as numbers of both species increased in the spring the mean yields from all the unsprayed plots at successive harvests in September, October and November were reduced by 50, 54 and 55%, respectively. Flowering commenced in M. truncatula cv. Cyprus, M, polymorpha and M. minima before aphid numbers were high enough to reduce herbage yields in the unsprayed plots. However, M. truncatula cv. Jemalong flowered 10-1 4 days after the other medics, and its seed yields from the unsprayed plots were significantly lower than those of M. truncatula cv. Cyprus. The germination percentage of seed produced in the unsprayed plots of M, polymorpha was significantly lower than that of the other unsprayed medics.

Evaluation of pasture legumes sown into a prepared seedbed at Tamworth, New South Wales. 2. Seed production and seed reserves

1993 ◽  
Vol 33 (3) ◽  
pp. 299 ◽  
Author(s):  
GM Lodge
Keyword(s):  
Seed Production ◽  
New South ◽  
New South Wales ◽  
Pasture Legumes ◽  
South Wales ◽  
Medicago Scutellata ◽  
Seed Reserves ◽  
Annual Medics ◽  
Perennial Legumes ◽  
Seed Yields

Plots sown in 1983 were used to examine the seed production and reserves (residual hardseeds) of 15 annual legumes over 5 years at Tamworth in northern New South Wales. Seed production characteristics were measured in 1983 for these annuals, and for 6 perennial legumes. After the annuals had set seed in 1983, an area of the plots was sprayed to prevent flowering in subsequent years, and the rates of decline in seed reserves were compared with those from areas that seeded annually. Seed yields of the perennials were often significantly lower than those of the annuals except Trifolium glomeratum. Seed yields of T. subterraneum var. subterraneum cvv. Seaton Park and Woogenellup were significantly higher than those of cv. Nungarin and T. subterrarzeum var. brachycalycinum cv. Clare. Seed numbers were lowest for Medicago scutellata cv. Sava among the annual medics, and for Nungarin among subterranean clovers. There was little relationship between the mean number of seeds produced from 1983-86 and maturity grading, and between seed numbers and relative dry matter yield. Seed reserves decreased over 5 years by more than 90% in the sprayed treatments of all species. This decrease was not continuous, with the largest declines occurring from December 1983 to August 1984. In the sprayed treatments of Seaton Park, Woogenellup, and Clare, and in both treatments of Astragalus hamosus cv. Ioman, Vicia dasycarpa var. villosa cv. Namoi, and T. hirtum cv. Hykon, none of the original 1983 seed was recovered in 1987. For the annual medics and Nungarin, the number of residual hardseeds in the sprayed treatments in 1987 was about 3-5% of the seed produced in 1983. From 1983 to 1987, seed numbers in the unsprayed treatments declined by 7040% for the annual medics and by 85-95% for Seaton Park, Woogenellup, and Clare. Long-term persistence of annual medics and Nungarin depended on seed production in most years and the maintenance of a high number of residual hardseeds in the soil. In contrast, the mid- and late-maturing subterranean clovers Woogenellup and Clare had low seed reserves and were dependent on seed production in most years for their continued regeneration.

Seed production and persistence of Carnamah and other early strains of Trifolium subterraneum in the wheatbelt of Western Australia

1967 ◽  
Vol 7 (24) ◽  
pp. 25 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Western Australia ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Growing Season ◽  
Early Flowering ◽  
The Other ◽  
Factors Affecting ◽  
Seed Yields

Seed production and persistence of the Carnamah, Northam A, Dwalganup, and Geraldton strains of subterranean clover (Trifolium subterraneum L.) were examined in undefoliated swards in the wheatbelt of Western Australia. The early flowering characteristic of Carnamah was not always associated with higher seed yields. Only when there was a well-defined, early finish to the growing season, or when flowering was very much earlier in Carnamah (viz., following an early 'break' to the season), did this strain clearly outyield both Northam A and Geraldton. The seed yield of Dwalganup was generally inferior to that of the other strains. Factors affecting regeneration are discussed. Under low rainfall conditions, poorer germination-regulation of Carnamah, compared with Geraldton and Northam A, would be expected to result in poorer persistence unless offset by higher seed yields in the Carnamah strain.

Seed production and seed survival under grazing of annual medics (Medicago spp.) in north Syria

1988 ◽  
Vol 110 (3) ◽  
pp. 455-463 ◽  
Author(s):  
P. S. Cocks
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Native Species ◽  
Seasonal Pattern ◽  
Seed Survival ◽  
Medicago Rigidula ◽  
Good Guide ◽  
Annual Medics ◽  
Seed Yields ◽  
Striking Contrast

SummaryThree experiments which measured seed production and seed survival of annual medics (Medicago spp.) were conducted at Tel Hadya in north Syria. In Expts 1 and 2, conducted in consecutive years, the effects of rate and date of sowing on seed yield and its components were measured, while in Expt 3, the residual seed under summer grazing was monitored. In all three experiments seed permeability was observed at frequent intervals in summer and autumn. Selected ecotypes of three native medics (Medicago rigidula (L.) All., M. rotata Boiss. and M. noeana Boiss.) were compared with cultivars of M. truncatula Gaertn. and M. polymorpha (L.).Seed production was greatest at sowing rates of 20–40 kg/ha. The native species produced more seed (up to 1000 kg/ha) than the cultivars (less than 500 kg/ha), although not significantly so in the case of the late-flowering ecotype of M. noeana. Seed yields of 500–1000 kg/ha were considered to be sufficient to perpetuate the pastures, but even higher seed yields are desirable.Seed yield was closely related to number of pods in all ecotypes and, in Expt 2, up to 95% of flowers failed to produce mature pods. Flowers were more likely to mature at high sowing rate (256 kg/ha), in striking contrast to flower production itself which was greatest at sowing rates of less than 30 kg/ha. Flowers produced early in the season (before mid-April) were far more likely to give mature pods than late-produced flowers.In late October, seeds of the native species were less permeable (10%) than those of the cultivars (30%), although their permeability was similar to that of the cultivars in Australia. In the three experiments the seasonal pattern of permeability varied, although there was a tendency for seeds to gain permeability in autumn. In Expt 1 there was a strong suggestion that the change from impermeability to permeability was reversible.Ewes grazing mature pods gained weight, apparently as long as pod availability exceeded 10 kg/ha. It was clear that the condition of ewes was not a good guide to appropriate stocking rate for persistence of pastures, and that farmers will have to use other methods to assist them in grazing management.

Seed production and its components in bred populations and cultivars of winter-green Setaria sphacelata at two levels of applied nitrogen fertiliser

1994 ◽  
Vol 34 (2) ◽  
pp. 153 ◽  
Author(s):  
JB Hacker
Keyword(s):  
Seed Production ◽  
Germination Percentage ◽  
Nitrogen Fertiliser ◽  
Setaria Sphacelata ◽  
Low Levels ◽  
Tiller Density ◽  
Seed Yields ◽  
Positive Effect ◽  
Inflorescence Length ◽  
Applied Nitrogen

Seed production of 2 experimental winter- green varieties of Setaria sphacelata, EHB (released as cv. Solander) and EHC, was compared with the winter-green cv. Narok in a split-plot experiment with 2 levels of applied nitrogen (N) fertiliser. The experiment continued for 3 years (6 harvests), and 3 subharvests at 1-2-week intervals were taken at each major harvest to allow for possible phenological differences between varieties. Total numbers of basal tillers, and of basal and aerial tillers with inflorescences, were counted at each harvest. Ripe and shedding inflorescences were counted, dried, and threshed by hand, and the seed was sieved and aspirated. The aspirated seed was stored for 6 months, the percentage of spikelets containing caryopses was evaluated, and samples were germinated in petri dishes. Aspirated seed yields of Solander were mostly 50-100% higher than those of Narok, except where yields were generally low, associated with low levels of applied N, and in later harvests of the experiment. All 3 entries showed a progressive decrease in seed production over time, and no consistent phenological difference was apparent. The improved seed production of Solander was associated with a markedly higher tiller fertility, lower basal tiller density, and slightly longer inflorescences. Germination percentage of Solander was consistently lower than that of Narok, and it was postulated that this was due to a higher level of seed dormancy. Nitrogen fertiliser had a marked positive effect on seed production, inflorescence numbers, tiller fertility, basal tiller density, and inflorescence length in all populations.

Germination, Growth, and Seed Production ofIpomoea hederaceawhen Planted at Monthly Intervals

Weed Science ◽  
1983 ◽  
Vol 31 (6) ◽  
pp. 837-840 ◽  
Author(s):  
Robert J. Thullen ◽  
Paul E. Keeley
Keyword(s):  
Seed Production ◽  
Air Temperature ◽  
Temperature Regime ◽  
Vegetative Growth ◽  
The Other ◽  
Ipomoea Hederacea ◽  
Field Plots

In 1979 and 1980, ivyleaf morningglory [Ipomoea hederacea(L.) Jacq. # IPOHE] seed were planted in field plots at monthly intervals beginning with March and continuing through October. During the first 9 weeks, seedlings from the July plantings grew more rapidly than those from the other monthly plantings and produced the heaviest fresh weights. Vegetative growth slowed after the 9-week harvest and seedlings from June plantings had heavier fresh weights at the 12-week harvest. Plants from the July planting produced the greatest number of seed at both the 9- and 12-week harvests. After scarifying, seed produced by plants from April through August (12-week harvest) germinated best with the 27/32 C night/day air temperature regime, but also germinated at 15/21, 21/27, and 27/32 C regimes. Ivyleaf morningglory seed did not germinate at an air temperature regime of 10/15 C. With an air temperature regime of 32/38 C the germination of some lots began to decrease.

The effects of frosts on seed production in subterranean clover (Trifolium subterraneum)

1971 ◽  
Vol 11 (49) ◽  
pp. 202 ◽  
Author(s):  
WR Scott
Keyword(s):  
New Zealand ◽  
Seed Production ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
The Other ◽  
The Past ◽  
Seed Yields

Six cultivars of subterranean clover, Geraldton, Yarloop, Woogenellup, Clare, Mount Barker, and Tallarook, were grown as ungrazed swards at 1,700 feet a.s.1. in the Mackenzie Country of South Canterbury, New Zealand. In this very frosty environment seed yields tended to increase with increasing lateness of flowering although Clare and perhaps Tallarook appeared to be more frost susceptible than the other cultivars. It is suggested that the deleterious effects of frosts in reducing the seed yields of subterranean clover may have been overemphasized in the past and that the trend for seed yields to increase with increasing lateness of flowering can be partially explained by differences in runner production.

A comparison of the persistence of Medicago truncatula cv. Paraggio with other annual medics in the Victorian Mallee

1993 ◽  
Vol 33 (4) ◽  
pp. 443 ◽  
Author(s):  
RA Latta ◽  
PE Quigley
Keyword(s):  
Plant Regeneration ◽  
Seed Production ◽  
Medicago Truncatula ◽  
Seed Set ◽  
Agricultural Productivity ◽  
The Other ◽  
Plant Densities ◽  
Seed Reserves ◽  
Annual Medics ◽  
Better Than

The annual medic Medicago truncatula cv. Paraggio has been widely sown in pastures throughout the Victorian Mallee region; however, its ability to persist in cereal pasture rotations is not known. Seed permeability and production, and plant regeneration of Paraggio, were studied in the field over 4 years, and the changes in its seed reserve were examined under 3 different cereal-pasture rotations. When compared with medic cvv. Parabinga, Harbinger, and Jemalong, Paraggio had up to twice the level of permeable seed over the summer-autumn period in 2 years (7-36% v. 2.5-19%). Paraggio produced 336-928 kg/ha of seed over 3 years, and after seed production was halted, it regenerated at densities of 150-1438 plants/m2 over the next 4 years. These results were generally the same as, or better than, the other cultivars. When seed set occurred in 1 and 2 years in the pasture phase of a 2- and 3-year rotation, respectively, Paraggio seed reserves were maintained at >4000 seeds/m2. This study demonstrated that Paraggio resulted in superior plant densities when grown in a number of typical rotations. It persisted satisfactorily and is expected to improve agricultural productivity in shor-tterm cereal-pasture rotations.

Nodulation and growth of pasture legumes with naturalised soil rhizobia. 1. Annual Medicago spp.

2000 ◽  
Vol 40 (7) ◽  
pp. 939 ◽  
Author(s):  
R. A. Ballard ◽  
N. Charman
Keyword(s):  
Dry Matter ◽  
Early Growth ◽  
The Other ◽  
Dry Matter Production ◽  
Soil Suspension ◽  
Pasture Legumes ◽  
Matter Production ◽  
Annual Medics ◽  
Annual Medicago ◽  
Inoculation Treatment

The ability of 11 species of annual medics (Medicago doliata, M. laciniata, M. littoralis, M. minima, M. orbicularis, M. polymorpha, M. praecox, M. rigidula, M. rigiduloides, M. tornata and M. truncatula) to nodulate and fix nitrogen with naturalised rhizobia from 28 South Australian soils was assessed. The number of rhizobia in the soils was estimated. Medic shoot dry matter production and nodulation were measured, after inoculation of medic seedlings with a soil suspension, in 2 glasshouse experiments. The number of medic rhizobia ranged from 0.4 10 2 to 1.5 10 6 per gram soil. Medicago laciniata was the only medic species tested which was not consistently nodulated by the soil rhizobia. While all the other species formed nodules, they varied widely in their ability to form an effective symbiosis. Symbiotic performance (which indicates how much growth the medic line achieved, when compared to an effective inoculation treatment) of the medic species ranged from 3% (M. rigiduloides) to 67% (M. praecox). Herald (M. littoralis) achieved a symbiotic performance of 49% and it was estimated that this would be insufficient to meet the nitrogen requirements of a Herald-based pasture during early growth. The symbiotic performance of Santiago (M. polymorpha) was low (17%) and erratic (from –6 to 72%). The ability of the rhizobia to form an effective symbiosis varied widely also between soil regions. For example, the rhizobia in Riverland soils resulted in only 31% of the shoot dry matter of those in Eyre Peninsula soils, in association with M. polymorpha. There are significant opportunities to improve the symbiotic performance of a number of the species of annual medics examined in this study. Options to improve the effectiveness of the symbiosis of medics with naturalised soil rhizobia are discussed.

The domestication of the native grasses Danthonia richardsonii Cashmore and Danthonia linkii Kunth for agricultural use. II. Agronomic and morphologic variation

1993 ◽  
Vol 44 (1) ◽  
pp. 79 ◽  
Author(s):  
GM Lodge ◽  
AJ Schipp
Keyword(s):  
Seed Production ◽  
Dry Matter ◽  
Basal Area ◽  
Morphological Characters ◽  
Dry Matter Production ◽  
Plant Variety ◽  
Matter Production ◽  
Morphologic Variation ◽  
Agricultural Use ◽  
Seed Yields

Seven accessions of Danthonia richardsonii Cashmore and three plants of Danthonia linkii Kunth, selected for high inflorescence seed yield were further assessed in a comparative field experiment at Tamworth, N.S.W. The agronomic and morphological variation of these lines, three unselected native ecotypes and D. richardsonii cv. Hume also were examined as part of the process of identifying lines that met the criteria for registration in the schemes operated by the Registrar of Plant Variety Rights and the Registrar of Australian Herbage Plant Cultivars. Thirty plants of each line were planted in spaced nursery rows (1x1 m) on a black earth soil in July 1990 and agronomic and morphological characters were assessed in 1990-92. From these data the D. richardsonii accession T487 and D. linkii T28 were chosen to be registered as D. richardsonii cv. Taranna and D. linkii cv. Bunderra. cv. Taranna had higher (P < 0.05) seed production than all other D. richardsonii accessions, except T489. It was distinguishable from the latter accession by its significantly wider inflorescence. Compared with cv. Hume, the only other known cultivar of D. richardsonii, cv. Taranna had higher dry matter production in spring (P < 0.05), higher seed production, flowered earlier and had a shorter and wider inflorescence (P < 0.05) with a wider glume. It also differed from cv. Hume in having longer and wider (P < 0.05) flag and third tiller-leaves. There are no known cultivars of D. linkii. Compared with the accessions it was tested against, cv. Bunderra had significantly higher seed yields and dry matter production. It was also distinct from those accessions in having a higher number of reproductive tillers, a larger basal area and longer and wider flag and third tiller-leaves (P < 0.05).

An agronomic evaluation of Medicago tornata cv. Tornafield, a new medic cultivar

1970 ◽  
Vol 10 (45) ◽  
pp. 405
Author(s):  
ML Poole
Keyword(s):  
Seed Production ◽  
Western Australia ◽  
Seed Coat ◽  
Acid Soil ◽  
The Other ◽  
Burr Formation ◽  
Winter Rainfall ◽  
Agronomic Evaluation ◽  
Annual Medics ◽  
Better Than

An experiment was carried out to compare Tornafield, the first commercial cultivar of M. tornata, with other annual medics in terms of top growth, burr and seed production, times of flowering and burr formation, and seed coat impermeability. Medicago tornata CV. Tornafield, M. littoralis CV. Harbinger, and M. truncatula CV. Jemalong were sown at two seeding rates, 6 and 60 lb per acre, and three times of planting, May, June, and July, into a sandy surfaced slightly acid soil in a winter rainfall environment of Western Australia. There were no significant differences in total top growth. In several other characteristics Torafield appeared to be superior. It set more seed than the other medics although it flowered a week late than Harbinger medic, and its seed coat impermeability declined more rapidly in the following summer. This suggests that it may regenerate better than medics available at present. It is concluded that M. tornata is a promising pasture species worthy of further testing.

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