Sowing

About: Sowing is a research topic. Over the lifetime, 33888 publications have been published within this topic receiving 273438 citations. The topic is also known as: seeding.

Biocontrol of Fusarium and Verticillium Wilt of Tomato by Penicillium oxalicum under Greenhouse and Field Conditions

Abstract: Treatments with conidia of Penicillium oxalicum produced in a solid-state fermentation system were applied at similar densities (6 x 10 6 spores/g seedbed substrate) to tomato seedbeds in water suspensions (Tl: 5 days before sowing, or T2: 7 days before transplanting; 15 days after sowing), or in mixture with the production substrate (T3: 7 days before transplanting; 15 days after sowing). Treatments T2 and T3 significantly (P = 0.05) reduced fusarium wilt of tomato in both greenhouse (artificial inoculation) (33 and 28%, respectively) and field conditions (naturally infested soils) (51 and 72%, respectively), while treatment Tl was efficient only in greenhouse (52%). Verticillium wilt disease reduction was obtained with T3 in two field experiments (56 and 46%, respectively), while Tl and T2 reduced disease only in one field experiment (52% for both T1 and T2). Treatment with conidia of P. oxalicum plus fermentation substrate (T3) resulted in better establishment of a stable and effective population of P. oxalicum in seedbed soil and rhizosphere providing populations of approx. 10 7 CFU/g soil before transplanting. Results indicate that it will be necessary to apply P. oxalicum at a rate of approx. 10 6 -10 7 CFU/g in seedbed substrate and rhizosphere before transplanting for effective control of fusarium and verticillium wilt of tomato, and that formulation of P. oxalicum has a substantial influence on its efficacy.

Interactions between seed priming treatments and nine seed lots of carrot, celery and onion. II. Seedling emergence and plant growth

Abstract: SUMMARY Samples of three seed lots of each of three cultivars of carrot, celery and onion were primed in polyethylene glycol solution for two weeks at 15 °C. Seedling emergence was recorded in the field for carrot and onion and in the glasshouse for celery. Compared to the untreated control, priming increased the percentage seedling emergence in certain poorly-emerging seed lots of carrot and celery, but had no effect on onion. Mean emergence times were reduced by priming in all seed lots, by 3–5, 5–8 and 3–9 days in carrot, celery and onion respectively. The largest effects occurred in the slowest-emerging seed lots. There were significant interactions between priming and seed lots within cultivars in carrot and celery and between priming and cultivars in celery and onion. Priming generally reduced the spread of emergence times, but the effects were not statistically significant in carrot. Drying back the primed seeds had no effect on percentage emergence in onion, but reduced it (compared to primed seed which had not been dried-back) in certain carrot and celery seed lots. Primed and dried-back seeds emerged later than primed seeds, by up to 1·5, 2·6 and 2·6 days in carrot, celery and onion respectively. The spread of emergence times was generally larger for primed and dried-back seeds than for primed seeds, but the differences were not always statistically significant. Plant fresh weights were recorded 9, 7 and 12 wk after sowing for carrot, celery and onion, respectively. In each species, mean plant weight was inversely related to seedling emergence time; thus plants grown from primed seed were always heavier than the controls, by up to 33%, 182% and 47% in carrot, celery and onion respectively.

Re‐creating Semi‐natural Communities: Effect of Sowing Rate on Establishment of Calcareous Grassland

Abstract: Restoration ecologists are increasingly aware of the potential to re-create chalk grassland on abandoned farmland. Success is often hampered by lack of desirable species in the seed bank and by poor dispersal from nearby sites. In certain schemes, the input of seed may be essential. Locally collected seed is desirable but availability is limited. We examined whether lower sowing rates than currently recommended may be successfully utilized, facilitating more-efficient use of available seed. Experimental plots on former agricultural land were sown at different rates in a randomized complete block, and the vegetation was surveyed for two years. We compared species richness and cover for chalk grassland plants and weeds - species not associated with chalk grassland communities. Values for cover and abundance were matched with data for communities of the British National Vegetation Classification (NVC). Species richness for chalk grassland plants increased with sowing rate and with time, although after two years there was no significant difference between the treatments sown at 0.4, 1.0, and 4.0 grams of seed per square meter. Weed species decreased with increasing rate and time. After two seasons, the vegetation on all treatment plots was similar to that of recognized NVC chalk grassland communities, while the controls were dominated by weeds and showed signs of developing into species-poor grassland. Higher rates rapidly eliminated weeds, but even a small inoculum of seed seemed to significantly enhance establishment of desirable plants and to reduce weed cover. We conclude that lower sowing rates would enable the desired vegetation to become established successfully, under appropriate conditions and management regimes. Lower rates allow for the re-creation of sizable areas using local seed, and they minimize damage to donor sites.

Accumulation of Seed Vigour During Development and Maturation

Abstract: Physiological maturity (PM, maximum accumulation of dry seed weight) represents maximum yield in grain crops and is proposed to represent maximum seed quality (germination and vigour) for planting purposes of all crops We investigated the relationship of seed maturation to seed quality for five agronomic and four horticultural crops in several field environments Annual evaluations of several soyabean (Glycine max (L) Merr) cultivars were made from 1982 to 1992, while one single cross hybrid of maize (Zea mays L) was tested from 1985 to 1994 All other crops were evaluated for two production years, except wheat (Triticum aestivum L em Thell) with one year High seed viability occurred first (early in development) for all crops and was followed by maximum standard germination at or before PM in all crops except tomato (Lycopersicon esculentum Mill) and pepper (Capsicum spp) Maximum seed vigour occurred at or slightly before PM in crops harvested as dry seed, but after PM for crops with seed harvested from fleshy fruits (tomato, pepper) When soyabean and maize plants were stressed by defoliation, drought or high temperatures during seed development, seed maturation was accelerated, but maximum seed vigour occurred at or before PM Thus, the maximum expression of seed vigour was closely related to the occurrence of PM in all crops harvested as dry seed