Seed production in cluster clover (Trifolium glomeratum L.). 2 Effect of sowing time and sowing rate on flowering time, abortion, seed size, and hardseededness

1998 ◽  
Vol 49 (6) ◽  
pp. 965 ◽  
Author(s):  
F. P. Smith ◽  
P. S. Cocks ◽  
M. A. Ewing
Keyword(s):  
Flowering Time ◽  
Seed Production ◽  
Seed Size ◽  
Western Australia ◽  
Seed Quality ◽  
Seed Mass ◽  
Above Ground Biomass ◽  
Sowing Time ◽  
Growing Seasons ◽  
Small Seed

An ecotype of cluster clover (Trifolium glomeratum L.) common to the wheatbelt of Western Australia was sown in pure undefoliated swards at rates in the range 2-256 kg/ha, on 2 dates to give growing seasons 13 and 18 weeks in length. Irrigation was phased out at the time of flowering of late-sown plots. The treatments generated a scale of seed production in cluster clover from 148 kg/ha (43 000 seeds/m2) to 1640 kg/ha (389 000 seeds/m2). Delayed sowing was more important in reducing seed production than was increasing sowing rate. By comparison with the early-sown plots, the late-sown plots had less above-ground biomass at flowering (2053 v. 2728 kg/ha); 48-66% fewer inflorescences per m2; a shorter vegetative phase (9 days); fewer seeds per inflorescence (26 v. 31); and lesser seed mass (337 µg v. 436 µg). There was little effect of the treatments on hardseededness except that hardseededness after 1 season in the field was higher in seeds from late-sown swards at high sowing rate (58%) than from late-sown swards at low sowing rate or early-sown swards (40%). Neither sowing rate nor sowing time influenced the within season pattern of hardseed breakdown. The results indicate that cluster clover is capable of massive seed production, and that even under highly stressed conditions seed production is maximised by a high reproductive allocation and small seed size. Despite conditions which reduced seed production by up to 90%, cluster clover is able to maintain its seed quality. Relatively few inviable seeds are produced and hardseededness is either unaffected or enhanced.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

The seed ecology of Aegilops triuncialis: linking trait variation to growing conditions

2017 ◽  
Vol 27 (3) ◽  
pp. 183-198 ◽  
Author(s):  
Andrew R. Dyer
Keyword(s):  
Seed Mass ◽  
Seed Viability ◽  
Seed Type ◽  
Aegilops Triuncialis ◽  
Trait Variation ◽  
Growing Seasons ◽  
Small Seed ◽  
Annual Grasses ◽  
Growing Conditions ◽  
Plastic Responses

AbstractAdaptive plastic responses in invasive species allow for establishment and persistence despite the lack of genetic matching to new environments. The capacity of annual species to invade habitats to which they are not adapted is likely to be predicated on post-invasion seed trait variation correlated with conditions in the new habitat. To test this, I compared variation in seed traits and germination patterns of Aegilops triuncialis, an invasive annual grass, from 69 sample populations from 24 sites in California (USA) across 13 years. Seed mass, germination fractions, seed viability, and strength of induced dormancy between dimorphic seed pairs were used to investigate plastic variation within and among populations, across two general soil types, and among two widespread maternal genotypes. I found that seed mass variation was constrained although both seed types showed a 3-fold range among populations, 20–25% variation within populations between years, and was positively correlated with longer growing seasons. However, induced seed dormancy in the small seed type was correlated with large seed mass and to late-season precipitation, suggesting that longer growing seasons influence the strength of maternal and sibling chemical signals that induce dormancy in the small seeds. Thus variation in small seed germination fractions varies with the growing conditions experienced by the maternal plant. The greater longevity of the small seed type suggests that plasticity in germination in this species may contribute to seed bank formation, which is atypical of invasive annual grasses in California, and this may contribute to the persistence and spread of A. triuncialis in invaded ranges.

DISEASES AND PESTS OF GRASS SEED CROPS

1990 ◽  
Vol 5 ◽  
pp. 25-27
Author(s):  
R.E. Falloon
Keyword(s):  
Soil Moisture ◽  
Seed Production ◽  
Seed Quality ◽  
Unit Area ◽  
Crop Growth ◽  
Seeding Rate ◽  
Sowing Time ◽  
Grass Seed ◽  
Crop Establishment ◽  
Seed Crops

This paper will discuss the diseases and pests that affect grass seed production. In order to put the diseases and pests into perspective, the principlesof grass seed production will be considered. The components of yield of any crop for which seed is the product are: number of plants per unit area; number of inflorescences per plant; number of seeds per inflorescence; seed weight, Many factors can influence these components, for example: (1) crop establishment (cultivation, seed quality, seeding rate, sowing time, soil moisture and fertility can all affect numbers of plants) (2) crop growth (soil moisture, fertility, grazing and weeds can affect crop growth and influence numbers of inflorescences and numbers and weight of seeds).

scholarly journals Seed production and seed quality of the dune building grass Panicum racemosum Spreng

1994 ◽  
Vol 8 (2) ◽  
pp. 193-203 ◽  
Author(s):  
Cesar Vieira Cordazzo ◽  
Anthony John Davy
Keyword(s):  
Seed Production ◽  
Clonal Growth ◽  
Seed Quality ◽  
Seed Mass ◽  
Coastal Dunes ◽  
Cultivated Plants ◽  
Strong Negative Correlation ◽  
Seed Characteristics ◽  
The Relationship

Seed production, pollination requirement, seed characteristics related to quality and the relationship between number and mass of seeds were examined for Panicum racemosum in three successional populations in southern Brazilian coastal dunes. The seed production was generally low and declined further between the frontal dunes and the backdunes, dropping from 4.05 seeds per panicle in the former to 1.8 seeds in the latter. However fertility (% fertile florets) did not differ among the three habitats. Plants cross-pollinated in a glasshouse showed an increase in seed production to 41.4 seeds compared to no seed production in self-pollinated plants. Caryopses varied in mass from 3.2 to 12.2 mg with a mean of 7.98 mg. A strong negative correlation was found between mean individual seed mass and the total number of seeds per panicle in a natural population. However, this relationship did not persist in seeds produced by cultivated plants in the glasshouse. The causes of low seed production appear to be mainly pollen self-incompatibility and additionally competition for nutrients between sexual reproduction and allocation to clonal growth. Under conditions of nutrient shortage, Panicum racemosum probably allocates resources more to clonal growth and to fewer, but well-endowed seeds. This would permit emergence from deeper burial sand, faster growth and greater survival of seedlings.

Impact of insects and fungi on doublegee (Emex australis) in the Western Australian wheatbelt

1998 ◽  
Vol 49 (5) ◽  
pp. 767 ◽  
Author(s):  
John K. Scott ◽  
Roger G. Shivas
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Western Australia ◽  
Seed Quality ◽  
Dry Weight ◽  
High Density ◽  
Exclusion Experiment ◽  
Emex Australis ◽  
Study Sites ◽  
Western Australian

Biotic influences on doublegee(Emex australis Steinheil) seed production wereinvestigated as a precursor to the introduction of new insect biologicalcontrol agents for this weed, and to investigate the cause of doublegeedecline in the northern and central wheatbelt of Western Australia since 1990.The symptoms of the decline are doublegee plants of reduced size withdistorted leaves, collapsed stems, and smaller achenes(the spiny seed-bearing fruit) that crumble when mature.Three sites were investigated in 1992 by surveys for insects and fungi, andinsect and fungus exclusion experiments.Emex stem blight (Phomopsis emicis R. G. Shivas) waspresent at the 3 study sites. The Watheroo site had comparatively high levelsof dock aphids (Brachycaudus rumexicolens Patch) ondoublegee plants, the Badgingarra site had a comparatively high density ofdock sawfly (Lophyrotoma analis Costa) on doublegee, andvery few insects were present on doublegee at the Wongan Hills site. Viruseswere not detected in samples of plants showing the effects of decline.The exclusion experiment showed a significant effect of removing insects andfungi on achene dry weight at the Watheroo site. There was no treatment effectat the Badgingarra and Wongan Hills sites. The biology of the fungus and theaphid lead to the conclusion that the primary cause of doublegee decline isthe dock aphid. This indicates that biological control againstE. australis might be achieved by using insects thatindirectly affect seed quality.

scholarly journals Effect of sowing date on quality seed production of sweet pepper in Bangladesh

2017 ◽  
Vol 28 (3) ◽  
pp. 216-221
Author(s):  
NU Mahmud ◽  
R Chakma ◽  
NU Ahmed ◽  
MAU Zaman ◽  
A Hossain
Keyword(s):  
Seed Production ◽  
Seed Weight ◽  
Seed Quality ◽  
Agricultural Research ◽  
Block Design ◽  
Sowing Date ◽  
Sweet Pepper ◽  
Fruit Weight ◽  
Sowing Time ◽  
Seed Technology

A field experiment was conducted to study the effect of sowing date on quality seed production of sweet pepper at the research farm of Seed Technology Division, Bangladesh Agricultural Research Institute, Gazipur, during 2011-2012. The aim of this study was to find out the optimum sowing date for quality seed production of sweet pepper. The treatments were 4 four sowing dates viz. 15 October, 30 October, 15 November and 30 November. Seeds were sown in seed bed for 1st sowing on 30 September, for 2nd sowing on 15 October, for 3rd sowing on 30 October and for 4th sowing on 15 November. The experiment was laid out in randomized complete block design (RCB) with three replications. The highest individual fruit weight, 1000 seed weight was obtained from the October 15 sowing date in the year of 2011-2012 and it was significantly different from all other dates of sowing. Maximum seed yield (86.2 kg ha-1) was recorded in 2nd sowing date (15 October) followed by 3rd sowing date (30 October) treatment while the lowest was found from 4th sowing date (15 November) (30.72, kg ha-1). Maximum seed quality as measured by moisture content, dry weight, vigour index and germination percentage were obtained at different sowing date. Maximum seed weight (mass maturity) was achieved at 1st sowing when average seed moisture contents were 5% and 4%, respectively. For high seed quality, sweet pepper is better sowing time at 2nd sowing time (15 October) which could be regarded as the point of physiological maturity.Progressive Agriculture 28 (3): 216-221, 2017

Response of chickpea (Cicer arietinum L.) varieties to time of sowing in Mediterranean-type environments of south-western Australia

2006 ◽  
Vol 46 (3) ◽  
pp. 395 ◽  
Author(s):  
K. L. Regan ◽  
K. H. M. Siddique ◽  
N. J. Brandon ◽  
M. Seymour ◽  
S. P. Loss
Keyword(s):  
Seed Yield ◽  
Western Australia ◽  
Agronomic Traits ◽  
Growing Season ◽  
Northern Region ◽  
Grain Legume ◽  
Sowing Time ◽  
Growing Seasons ◽  
Legume Crop ◽  
Seed Yields

Chickpea has become an important grain legume crop in Australia over the last decade. New varieties with improved seed yield and quality are being developed in Australia with varied phenological and agronomic traits. This study examined the optimum time of sowing of several desi chickpea varieties (Dooen, T1587, Sona and Tyson) varying in phenology over a range of dryland Mediterranean-type environments in south-western Australia. Chickpea showed good adaptation, particularly in the northern grain belt of Western Australia where growing conditions are warmer than southern areas. Seed yields varied widely depending on the time of sowing, location and seasonal conditions. Mean seed yields greater than 1000 kg/ha and up to 2000 kg/ha were achieved, but in some cases seed yields were less than 800 kg/ha. In the northern region, seed yield was almost doubled by sowing in early-May (1625 kg/ha) compared with late-June (754 kg/ha). In contrast to this, seed yields were generally lower in the southern regions and greater from late-June sowings (865 kg/ha) compared to earlier mid-May sowings (610 kg/ha). Seed yields were not clearly increased by altering sowing time to match the phenology of the variety to the growing season rainfall and temperatures, except at the early sowing times (April and early-May) where Tyson out-yielded all other varieties. This is most likely due to the lack of photoperiod-responsive, long-duration varieties to match early sowing and low temperatures limiting vegetative and reproductive growth in all varieties, especially in southern areas. However, it is likely that early flowering varieties will show greater adaptation and yield performance in short growing seasons, while later flowering varieties will be better suited to longer growing seasons. The study found that there were significant differences in the optimum sowing time between northern, central and southern sites, based on differences in mean daily temperatures and length of the growing season. Generally, the greatest seed yields were produced by sowing between mid to late June at southern sites, and early May at central and northern sites.

scholarly journals Relationship Between Plant Density and Fruit and Seed Production in Muskmelon

2002 ◽  
Vol 127 (5) ◽  
pp. 855-859 ◽  
Author(s):  
Haim Nerson
Keyword(s):  
Seed Production ◽  
Seed Size ◽  
Seed Yield ◽  
Field Experiments ◽  
Seed Quality ◽  
Plant Density ◽  
Small Fruit ◽  
Plant Densities ◽  
Seed Yields ◽  
High Seed Yield

Field experiments were conducted in 1996 and 1997 to examine the effects of plant density on yield and quality of fruit and seeds of muskmelons (Cucumis melo L.). Two open-pollinated cultivars, Noy Yizre'el (Ha'Ogen type) and TopMark (western U.S. shipper type), were grown at plant densities ranging from 0.5 to 16.0 plants/m2 under commercial conditions. The highest marketable fruit yields were achieved with plant densities of 2 to 4 plants/m2. In contrast, the highest seed yields were obtained at 8 to 12 plants/m2. Seed yield index [seed yield (g)/fruit yield (kg)] was used as a parameter to define seed production efficiency. High seed yield was closely related to high value of the seed yield index. High seed yield indexes resulted from high plant densities (up to 12 plants/m2), at which the crops produced many, but relatively small fruit. In all cases, the seed yield per fruit (seed number and seed size) increased with increasing fruit weight. However, the sum of the seed yield of two small fruit was always greater than the seed yield of one, double-sized fruit. There was a clear exception with extremely small fruit (<500 g), which produced both low seed yields and poor seed quality. A positive relationship was found between fruit size and seed size in both cultivars. Nevertheless, relatively small seeds (25 to 30 mg) extracted from relatively small fruit (500 to 1000 g) showed the best performance in terms of germination and emergence percentages and rates, and in the vegetative development vigor of the seedlings.

scholarly journals Size, physiological quality, and green seed occurrence influenced by seeding rate in soybeans

2017 ◽  
Vol 38 (2) ◽  
pp. 595 ◽  
Author(s):  
André Sampaio Ferreira ◽  
Claudemir Zucareli ◽  
Alvadi Antonio Balbinot Junior ◽  
Flavia Werner ◽  
Antonio Eduardo Coelho
Keyword(s):  
Water Stress ◽  
Seed Size ◽  
Seed Quality ◽  
Plant Density ◽  
Seed Mass ◽  
Soybean Plant ◽  
Seeding Rate ◽  
Green Seed ◽  
Plant Densities ◽  
The Impact

The seeding rate influences the intraspecific competition, which might affect the development and quality of seeds in soybean. However, the impact of seeding rate on the physical and physiological qualities of soybean seeds needs to be better elucidated. This study aimed to evaluate the effects of soybean plant density on the seed size as well as the effects of the interaction between the plant density and seed size on the seed mass, green seed occurence, and physiological seed quality. The experiments were carried out in the growing seasons of the years 2013/14 and 2014/15 in a Latossolo Vermelho distroférrico, under a randomized complete block design, using the NK 7059 RR cultivar with six replications. Four plant densities (150, 300, 440, and 560 thousand viable seeds ha–1) were evaluated. After the classification of seeds into four sizes, using a set of sieves, a 4 ×4 factorial scheme was used for the statistical analysis of the four plant densities and four seed sizes. The seed samples were evaluated for the seed mass, green seed percentage, germination, and vigor. Under thermal and water stress during seed development, an increase in the seeding rate led to a reduction in the green seed occurrence and an increase in the seed size and mass. However, in the absence of thermal and water stress, the seed size and mass were not altered by the seeding rate and, there was no occurrence of green seeds.

Introgression of genes for small seed size from Glycine soja into Glycine max

1990 ◽  
Author(s):  
Allen Rubin LeRoy
Keyword(s):  
Glycine Max ◽  
Seed Size ◽  
Glycine Soja ◽  
Small Seed
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