Elongation habit of mesocotyls and coleoptiles in weedy rice with high emergence ability in direct-seeding on dry paddy fields

2010 ◽  
Vol 61 (11) ◽  
pp. 911 ◽  
Author(s):  
Nam-Jin Chung
Keyword(s):  
Genetic Resources ◽  
Paddy Soil ◽  
Seedling Establishment ◽  
Large Scale ◽  
Soil Surface ◽  
Direct Seeding ◽  
Weedy Rice ◽  
Burial Depth ◽  
Sowing Depth ◽  
Rice Germplasm

Direct-seeding of rice on dry paddy soil could enable large-scale cultivation and cost-savings, but still has some problems including poor seedling establishment caused by low temperature and varied sowing depth. This research was performed to identify weedy rice genetic resources that may help to eliminate the problem of poor seedling establishment in direct-seeded rice on dry paddy soil in temperate regions. The genetic resources screened in this study were 128 genotypes consisting of 92 japonica weedy rices, 24 indica weedy rices, and 12 Korean bred cultivars. On average, weedy rice germplasm had superior abilities to emerge from greater depths than cultivated rices. Coleoptile and mesocotyl lengths were highly positively correlated with the emergence rate. Among the weedy rice germplasm, the japonica weedy rice WD-3 showed the highest level of emergence with the longest coleoptile and mesocotyl. The emergence ability of WD-3 was confirmed in both phytotron and field conditions. In the emerged plants in the field, the mesocotyl elongation increased with increasing burial depth in a logarithmic fashion, and coleoptile extension increased exponentially. The mesocotyl and coleoptile elongated to a length of seed burial depth, indicating that the mesocotyl and coleoptile of WD-3 could induce the safe development of the first leaf of the seedling at the soil surface. Therefore, the elongation habit of the mesocotyl and coleoptile of WD-3 could be one of the most important characteristics for the development of direct-seeding cultivars.

Direct seeding of black spruce in northwestern Ontario: Seedbed relationships

1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa
Keyword(s):  
Seedling Establishment ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil Surface ◽  
Direct Seeding ◽  
First Year ◽  
Strongly Correlated ◽  
Seedling Mortality ◽  
Northwestern Ontario ◽  
Seedbed Preparation

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination

Weedy rice (Oryza sativa) II. Response of Weedy Rice to Seed Burial and Flooding Depth

Weed Science ◽  
2012 ◽  
Vol 60 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Bhagirath Singh Chauhan
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
Production Costs ◽  
The Other ◽  
Weedy Rice ◽  
Burial Depth ◽  
Rice Accession ◽  
Seed Burial ◽  
Seedling Biomass ◽  
Flooding Depth

Weedy rice is a serious problem of cultivated rice in most of the rice-growing areas in Asia, causing increased production costs and yield losses in rice. A study was conducted to determine the response of weedy rice accessions from India (IWR), Malaysia (MWR), Thailand (TWR), and Vietnam (VWR) to seed burial and flooding depths. The greatest emergence for each weedy rice accession (97% for IWR, 82% for MWR, 97% for TWR, and 94% for VWR) was observed in seeds placed on the soil surface. Seedling emergence decreased with increase in burial depth. For the IWR accession, 0.5% of the seedlings emerged from 8-cm depth, whereas for the other three weedy rice accessions, no seedlings emerged from this depth. When seeds were sown on the soil surface, flooding depth ranging from 0 to 8 cm had no or very little effect on seedling emergence of different weedy rice accessions. On the other hand, flooding decreased seedling emergence in all weedy rice accessions when seeds were sown at 1 cm deep into the soil. Compared with seedling emergence, flooding had a more pronounced effect on seedling biomass for all weedy rice accessions. A flooding depth of 2 cm reduced seedling biomass by an amount greater than 85% of each weedy rice accession. The results of this study suggest that emergence and growth of weedy rice could be suppressed by deep tillage that buries seeds below their maximum depth of emergence (i.e., > 8 cm for the accessions studied) and by flooding fields as early as possible. The information gained from this study may help design cultural management strategies for weedy rice in Asia.

scholarly journals Effect of Digestate and Straw Combined Application on Maintaining Rice Production and Paddy Environment

2021 ◽  
Vol 18 (11) ◽  
pp. 5714
Author(s):  
Xue Hu ◽  
Hongyi Liu ◽  
Chengyu Xu ◽  
Xiaomin Huang ◽  
Min Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Surface Water ◽  
Soil Organic Matter ◽  
Paddy Soil ◽  
Rice Yield ◽  
Soil Surface ◽  
Rice Production ◽  
Straw Decomposition ◽  
Rice Grains ◽  
Combined Application

Few studies have focused on the combined application of digestate and straw and its feasibility in rice production. Therefore, we conducted a two-year field experiment, including six treatments: without nutrients and straw (Control), digestate (D), digestate + fertilizer (DF), digestate + straw (DS), digestate + fertilizer + straw (DFS) and conventional fertilizer + straw (CS), to clarify the responses of rice growth and paddy soil nutrients to different straw and fertilizer combinations. Our results showed that digestate and straw combined application (i.e., treatment DFS) increased rice yield by 2.71 t ha−1 compared with the Control, and digestate combined with straw addition could distribute more nitrogen (N) to rice grains. Our results also showed that the straw decomposition rate at 0 cm depth under DS was 5% to 102% higher than that under CS. Activities of catalase, urease, sucrase and phosphatase at maturity under DS were all higher than that under both Control and CS. In addition, soil organic matter (SOM) and total nitrogen (TN) under DS and DFS were 20~26% and 11~12% higher than that under B and DF respectively, suggesting straw addition could benefit paddy soil quality. Moreover, coupling straw and digestate would contribute to decrease the N content in soil surface water. Overall, our results demonstrated that digestate and straw combined application could maintain rice production and have potential positive paddy environmental effects.

Conservation of animal genetic resources: approaches and technologies for in situ and ex situ conservation

2008 ◽  
Vol 42 ◽  
pp. 71-85 ◽  
Author(s):  
J.A. Woolliams ◽  
O. Matika ◽  
J. Pattison
Keyword(s):  
Rural Communities ◽  
Genetic Resources ◽  
Large Scale ◽  
Production Systems ◽  
Regional Distribution ◽  
Livestock Production ◽  
Ex Situ ◽  
Animal Genetic Resources ◽  
The Face ◽  
Livestock Products

SummaryLivestock production faces major challenges through the coincidence of major drivers of change, some with conflicting directions. These are:1. An unprecedented global change in demands for traditional livestock products such as meat, milk and eggs.2. Large changes in the demographic and regional distribution of these demands.3. The need to reduce poverty in rural communities by providing sustainable livelihoods.4. The possible emergence of new agricultural outputs such as bio-fuels making a significant impact upon traditional production systems.5. A growing awareness of the need to reduce the environmental impact of livestock production.6. The uncertainty in the scale and impact of climate change. This paper explores these challenges from a scientific perspective in the face of the large-scale and selective erosion of our animal genetic resources, and concludes thai there is a stronger and more urgent need than ever before to secure the livestock genetic resources available to humankind through a comprehensive global conservation programme.

Seasonal cycles in germination and seedling emergence of summer and winter populations of catchweed bedstraw (Galium aparine) and wild mustard (Brassica kaber)

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Husrev Mennan ◽  
Mathieu Ngouajio
Keyword(s):  
Soil Depth ◽  
Cropping Systems ◽  
Seedling Emergence ◽  
Seed Mass ◽  
Soil Surface ◽  
Burial Depth ◽  
Galium Aparine ◽  
Wild Mustard ◽  
Seed Population ◽  
Brassica Kaber

Catchweed bedstraw and wild mustard each produce two populations per year: a winter population (WP) in June, and a summer population (SP) in September. Experiments were conducted to determine whether the WP and SP differ in seed mass and seasonal germination. Seeds of both weeds were buried at 0, 5, 10, and 20 cm in cultivated fields, and retrieved at monthly intervals for 24 mo for germination tests in the laboratory. Additionally, seedling emergence from seeds buried at 0, 5, and 10 cm in the field was evaluated for 1 yr. Seeds from the WP were heavier than those from the SP for both species. Germination of exhumed seeds was affected by burial depth and by seed population. It was highest for seeds that remained on the soil surface and declined with increasing depth of burial. The WP of catchweed bedstraw produced two germination peaks per year, whereas the SP and all populations of wild mustard had only one peak. The WP of both weeds germinated earlier than the SP. Seedling emergence for both species in the field was greater for the WP than for the SP. Increasing soil depth reduced seedling emergence of both the WP and SP of wild mustard and affected only the WP of catchweed bedstraw. We conclude that the WP and SP of catchweed bedstraw and wild mustard seeds used in this study differed in seed mass, seasonal germination, and seedling emergence. The ability of a WP to produce large seeds that germinate early and have two germination peaks per year could make these populations a serious problem in cropping systems.

scholarly journals Survival of Fusarium moniliforme, F. proliferatum, and F. subglutinans in Maize Stalk Residue

1998 ◽  
Vol 88 (6) ◽  
pp. 550-555 ◽  
Author(s):  
T. K. Cotten ◽  
G. P. Munkvold
Keyword(s):  
Fusarium Moniliforme ◽  
Fusarium Species ◽  
Soil Surface ◽  
Selective Medium ◽  
Burial Depth ◽  
Linear Pattern ◽  
Maize Field ◽  
Continuous Maize ◽  
Maize Plants

The roles of residue size and burial depth were assessed in the survival of Fusarium moniliforme, F. proliferatum, and F. subglutinans in maize stalk residue. Stalk pieces (small or large sizes) were soaked in a spore suspension of F. moniliforme, F. proliferatum, or F. subglutinans and placed in a field on the soil surface or buried at 15- or 30-cm depths. Residue pieces were recovered periodically, cultured on a selective medium, and microscopically examined for the presence of the inoculated Fusarium species. After 630 days, the inoculated Fusarium species were recovered from 0 to 50% of the inoculated stalk pieces in a long-term, continuous maize field, from 0 to 28% of the inoculated stalk pieces placed in a maize/soybean/oat rotation field, and from 0 to 25% of the noninoculated stalk pieces at both locations. Residue size and residue depth had significant effects on survival, but there were significant interactions among strain, depth, residue size, and time. Up to 343 days after placement in the field, survival of the three Fusarium species was not consistently different between buried residues and surface residues, but after 630 days, survival was greater from surface residues. Overall, fungus survival decreased more slowly in the surface residues than in the buried residues. Linear coefficients of determination ranged from 0.35 to 0.82 for the surface residues and from 0.81 to 0.98 for the buried residues. Decline in survival over time followed a more linear pattern in buried residues than in surface residues. Vegetative compatibility tests confirmed that F. moniliforme, F. proliferatum, and F. subglutinans strains can survive at least 630 days in surface or buried maize residue. These results demonstrate that maize residue can act as a long-term source of inoculum for infection of maize plants by these three Fusarium species.

Accumulation patterns of soil organic matter in forests as a legacy of historical charcoal burning

2021 ◽  
Author(s):  
Anna Schneider ◽  
Alexander Bonhage ◽  
Florian Hirsch ◽  
Alexandra Raab ◽  
Thomas Raab
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Large Scale ◽  
Soil Surface ◽  
Landscape Scale ◽  
Legacy Effects ◽  
Charcoal Production ◽  
Study Region ◽  
Land Use Legacies

&lt;p&gt;Human land use and occupation often lead to a high heterogeneity of soil stratigraphy and properties in landscapes within small, clearly delimited areas. Legacy effects of past land use also are also abundant in recent forest areas. Although such land use legacies can occur on considerable fractions of the soil surface, they are hardly considered in soil mapping and inventories. The heterogenous spatial distribution of land use legacy soils challenges the quantification of their impacts on the landscape scale. Relict charcoal hearths (RCH) are a widespread example for the long-lasting effect of historical land use on soil landscapes in forests of many European countries and also northeastern USA. Soils on RCH clearly differ from surrounding forest soils in their stratigraphy and properties, and are most prominently characterized by a technogenic substrate layer with high contents of charcoal. The properties of RCH soils have recently been studied for several regions, but their relevance on the landscape scale has hardly been quantified.&lt;/p&gt;&lt;p&gt;We analyse and discuss the distribution and ecological relevance of land use legacy soils across scales for RCH in the state of Brandenburg, Germany, with a focus on soil organic matter (SOM) stocks. Our analysis is based on a large-scale mapping of RCH from digital elevation models (DEM), combined with modelled SOM stocks in RCH soils.&amp;#160;The distribution of RCH soils in the study region shows heterogeneity at different scales. The large-scale variation is related to the concentration of charcoal production to specific forest areas and the small-scale accumulation pattern is related to the irregular distribution of single RCH within the charcoal production fields. Considerable fractions of the surface area are covered by RCH soils in the major charcoal production areas within the study region. The results also show that RCH can significantly contribute to the soil organic matter stocks of forests, even for areas where they cover only a small fraction of the soil surface. The study highlights that considering land use legacy effects can be relevant for the results of soil mapping and inventories; and that prospecting and mapping land use legacies from DEM can contribute to improving such approaches.&lt;/p&gt;

Effect of Environmental Factors on Germination and Emergence of Shortawn Foxtail (Alopecurus aequalis)

Weed Science ◽  
2017 ◽  
Vol 66 (1) ◽  
pp. 47-56 ◽  
Author(s):  
Ning Zhao ◽  
Qi Li ◽  
Wenlei Guo ◽  
Lele Zhang ◽  
Lu’an Ge ◽  
...  
Keyword(s):  
Seed Germination ◽  
Osmotic Potential ◽  
Control Strategies ◽  
Abiotic Factors ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Burial Depth ◽  
Effective Measure ◽  
Wide Range

Shortawn foxtail is an invasive grass weed infesting winter wheat and canola production in China. A better understanding of the germination ecology of shortawn foxtail would help to develop better control strategies for this weed. Experiments were conducted under laboratory conditions to evaluate the effects of various abiotic factors, including temperature, light, pH, osmotic stress, salt concentration, and planting depth, on seed germination and seedling emergence of shortawn foxtail. The results showed that the seed germination rate was greater than 90% over a wide range of constant (5 to 25C) and alternating (15/5 to 35/25C) temperatures. Maximum germination occurred at 20C or 25/15C, and no germination occurred at 35C. Light did not appear to have any effect on seed germination. Shortawn foxtail germination was 27% to 99% over a pH range of 4 to 10, and higher germination was obtained at alkaline pH values ranging from 7 to 10. Seed germination was sensitive to osmotic potential and completely inhibited at an osmotic potential of −0.6 MPa, but it was tolerant to salinity: germination even occurred at 200 mM NaCl (5%). Seedling emergence was highest (98%) when seeds were placed on the soil surface but declined with the increasing burial depth. No seedlings emerged when seeds were buried 6-cm deep. Deep tillage could be an effective measure to limit seed germination from increased burial depth. The results of this study will lead to a better understanding of the requirements for shortawn foxtail germination and emergence and will provide information that could contribute to its control.

Seed Germination Ecology of Itchgrass (Rottboellia cochinchinensis)

Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 182-187 ◽  
Author(s):  
Grace E-K. Bolfrey-Arku ◽  
Bhagirath S. Chauhan ◽  
David E. Johnson
Keyword(s):  
High Temperature ◽  
Seed Germination ◽  
Seedling Emergence ◽  
Soil Surface ◽  
The Philippines ◽  
Integrated Weed Management ◽  
Burial Depth ◽  
Soil Burial ◽  
Dark Regime ◽  
Temperature Pretreatment

Itchgrass is a weed of many crops throughout the tropics and one of the most important grass weeds of rainfed rice. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, high temperature pretreatment, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of itchgrass in the Philippines. Two populations were evaluated and the results were consistent for both populations. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C than at 35/25, 30/20, or 20/10 C. Light was not a requirement for germination, but a light/dark regime increased germination by 96%, across temperature and population. A 5-min high temperature pretreatment for 50% inhibition of maximum itchgrass germination ranged from 145 to 151 C with no germination when seeds were exposed to ≥ 180 C. The osmotic potential required for 50% inhibition of maximum germination was −0.6 MPa for itchgrass, although some seeds germinated at −0.8 MPa. Seedling emergence was greatest for seeds placed on the soil surface, and emergence declined with increasing soil burial depth; no seedlings emerged from seeds buried at 10 cm. The addition of rice residue to soil surface in pots at rates equivalent to 4 to 6 Mg ha−1reduced itchgrass seedling emergence. Since seedling emergence was greatest at shallow depths and germination was stimulated by light, itchgrass may become a problem in systems where soil is cultivated at shallow depths. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for itchgrass.

scholarly journals MOBILIZATION, CONSERVATION AND REPLENISHMENT OF GRAPEVINE GENETIC RESOURCES OF YA.I.POTAPENKO DON AMPELOGRAPHIC COLLECTION IN 2019

Russian vine ◽  
2020 ◽  
Vol 14 ◽  
pp. 30-36
Author(s):  
L.G. Naumova ◽  
◽  
V.A. Ganich ◽  
Keyword(s):  
Genetic Resources ◽  
Gene Pool ◽  
Large Scale ◽  
High Quality ◽  
Wine Making ◽  
Economically Valuable Traits ◽  
Grape Varieties

The article reflects the results of work on the mobilization, conservation, replenishment and study of genetic resources of grapevines of the Don ampelographic collection named after Ya.I. Potapenko (Novocherkassk, Ros-tov region) in 2019. Mobilization, conserva-tion, replenishment and study of plant bio-diversity, identification of new and assess-ment of stocks of used species, is gaining theoretical, scientific and practical signifi-cance, and is currently relevant. Most of the native and sparsely distributed grapevine varieties are now preserved only through col-lections. The process of grape selection is closely related to the need to preserve and replenish collections, since this is the main base for large-scale ampelographic and ge-netic selection works, which are currently effective and very effective in science and production and thus practically significant for the Russian grape-growing industry. Cur-rently, the preserved gene pool of grapevines in the collection includes 870 varieties, the collection is supplemented with 5 new grape varieties (Suholimanskij belyj, Traminer be-lyj, Granatovyj, Dostojnyj, Mriya). Two sources of economically valuable traits for high-quality wine – making were identified: Laсukere and Neizvestnyj donskoj varieties.

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