Frost-seeding of summer turnip rape in the subarctic

1992 ◽  
Vol 72 (3) ◽  
pp. 713-723
Author(s):  
Stephen D. Sparrow ◽  
Charles W. Knight

Previous research has indicated that spring-planted summer turnip rape (Brassica rapa L.) can produce good seed yields with high oil content in subarctic Alaska. However, short growing seasons often prevent seeds from reaching full maturity, resulting in high proportions of green seeds and lowered market quality. In an attempt to allow summer turnip rape seedlings to begin growth earlier in the growing season, we planted the seeds in frozen soil in late fall and early spring. Fall seeding of summer turnip rape always resulted in low plant populations, low seed yields, and high percentages of green seeds. Percentages of green seeds were highly variable and early spring seedings did not result in significantly lower percentages of green seeds than conventional (May) seedings. The effects of early spring frost-seeding on plant populations and seed yields were variable but only rarely did early spring seeding produce significantly higher seed yields than conventional seeding. Planting into barley (Hordeum vulgare L.) stubble resulted in poor stands which produced low seed yields. This study did not indicate any advantage from fall planting of summer turnip rape. Results from spring frost-seeding were not consistent; therefore, this practice cannot be recommended until these inconsistencies are better understood.Key words: Frost-seeding, summer turnip rape, subarctic, Alaska

2004 ◽  
Vol 84 (4) ◽  
pp. 1085-1091 ◽  
Author(s):  
Herb Cutforth ◽  
EG (Ted) O’Brien ◽  
Jason Tuchelt ◽  
Rick Rickwood

The climate of the prairies has warmed over the past century, especially during late winter and early spring. Some regions of the prairies have warmed faster than others. Climate change has been documented to affect living systems in North America, such as promoting earlier phenological development and longer growing seasons. We examined weather records gathered at several long-term weather-recording sites across the agricultural regions of the Canadian prairies for evidence of trends in last spring frosts, first fall frosts, and frost-free durations. During the latter half of the 20th century, the trends were towards earlier last spring frost dates and towards longer frost-free seasons in the agricultural regions of the Canadian prairies. Across most of the prairies the trends towards later first fall frost dates were smaller and generally not significant. The largest changes have occurred in the central and northern agricultural regions of Alberta, whereas the least change occurred over much of southern Alberta and in southern Manitoba. Key words: Last spring and first fall frost dates, frost-free season, agroclimatic indices, climate change, Canadian prairies


2000 ◽  
Vol 80 (2) ◽  
pp. 335-336 ◽  
Author(s):  
T. M. Choo ◽  
S. ter Beek ◽  
R. A. Martin ◽  
K. M. Ho ◽  
C. D. Caldwell ◽  
...  

AC Queens is a two-row, spring feed barley (Hordeum vulgare L.) cultivar developed by the Eastern Canada Barley Breeding Group, Agriculture and Agri-Food Canada. It has high yield, good test weight, good seed weight, and lodging resistance. AC Queens performs well in the Maritime Region of Canada. Key words: Barley, Hordeum vulgare L., cultivar description, high yield, high seed weight


2017 ◽  
Vol 39 (4) ◽  
Author(s):  
MATEUS DA SILVEIRA PASA ◽  
BRUNO CARRA ◽  
CARINA PEREIRA DA SILVA ◽  
MARLISE NARA CIOTTA ◽  
ALBERTO FONTANELLA BRIGHENTI ◽  
...  

ABSTRACT The low fruit set is one of the main factors leading to poor yield of pear orchards in Brazil. Ethylene is associated with abscission of flowers and fruitlets. Then, the application of ethylene synthesis inhibitors, such as AVG, is a potential tool to increase fruit set of pears. The objective of this study was to evaluate the effect of AVG, sprayed at different rates and timings, on fruit set, yield and fruit quality of ‘Rocha’ pear. The study was performed in a commercial orchard located in the municipality of São Joaquim, SC, during the growing seasons of 2014/2015 and 2015/2016. Plant material consisted of ‘Rocha’ pear trees grafted on quince rootstock ‘BA29’. AVG was tested at different rates (60 mg L-1 and 80 mg L-1) and timings [full bloom, one week after full bloom (WAFB), and two WAFB), either alone or in combination. The experiment was arranged in a randomized block design, with at least five single-tree replications. The fruit set, number of fruit per tree, yield, estimated yield, fruit weight, return bloom, and fruit quality attributes were assessed. Fruit set and yield were consistently increased by single applications of AVG at 60 and 80 mg L-1 at both one and two weeks after full bloom, without negatively affecting fruit quality attributes and return bloom.


2021 ◽  
Author(s):  
Farhan Hafeez ◽  
Lionel Bernard ◽  
Jean-Christophe Clement ◽  
Franck Poly ◽  
Thomas Pommier

Subalpine grassland ecosystems are important from biodiversity, agriculture, and touristic perspectives but their resilience to seasonally occurring climatic extremes is increasingly challenged with climate change, accelerating their vulnerability to tipping points. Microbial communities, which are central in ecosystem functioning, are usually considered as more resistant and highly resilient to such extreme events due to their functional redundancy and strong selection in residing habitats. To investigate this, we explored the soil microbial responses upon recurrent summer droughts associated with early snowmelt in grasslands mesocosms set-up at the Lautaret Pass (French Alps). Potential respiration, nitrification and denitrification were monitored over a period of two growing seasons along with quantification of community gene abundances of total bacteria as well as (de)nitrifiers. Results revealed that droughts had a low and short-term impact on bacterial total respiration supporting their hypothesized high resistance and ability to recover. Nitrification and abundances of the corresponding functional guilds showed relatively strong resistance to summer droughts but declined in response to early snowmelt. This triggered a cascading effect on denitrification but also on the abundances of denitrifying communities which could recover from all climatic extremes except from the summer droughts where nitrifiers were collapsed. Denitrification and the respective functional groups faced high impact of applied stresses with strong reduction in the abundance and activity of this specialized community. Although, the consequently lower microbial competition for nitrate may be positive for plant biomass production, warnings exist when considering the potential nitrogen leaching from these ecosystems as well as risks of greenhouses gases emission such as N2O


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3718 ◽  
Author(s):  
Ian S. Acuña-Rodríguez ◽  
Cristian Torres-Díaz ◽  
Rasme Hereme ◽  
Marco A. Molina-Montenegro

The increase in temperature as consequence of the recent global warming has been reported to generate new ice-free areas in the Antarctic continent, facilitating the colonization and spread of plant populations. Consequently, Antarctic vascular plants have been observed extending their southern distribution. But as the environmental conditions toward southern localities become progressively more departed from the species’ physiological optimum, the ecophysiological responses and survival to the expected global warming could be reduced. However, if processes of local adaptation are the main cause of the observed southern expansion, those populations could appear constrained to respond positively to the expected global warming. Using individuals from the southern tip of South America, the South Shetland Islands and the Antarctic Peninsula, we assess with a long term experiment (three years) under controlled conditions if the responsiveness of Colobanthus quitensis populations to the expected global warming, is related with their different foliar traits and photoprotective mechanisms along the latitudinal gradient. In addition, we tested if the release of the stress condition by the global warming in these cold environments increases the ecophysiological performance. For this, we describe the latitudinal pattern of net photosynthetic capacity, biomass accumulation, and number of flowers under current and future temperatures respective to each site of origin after three growing seasons. Overall, was found a clinal trend was found in the foliar traits and photoprotective mechanisms in the evaluated C. quitensis populations. On the other hand, an asymmetric response to warming was observed for southern populations in all ecophysiological traits evaluated, suggesting that low temperature is limiting the performance of C. quitensis populations. Our results suggest that under a global warming scenario, plant populations that inhabiting cold zones at high latitudes could increase in their ecophysiological performance, enhancing the size of populations or their spread.


2021 ◽  
Vol 31 (1) ◽  
pp. 45-50
Author(s):  
A. T. Omokanye ◽  
J. T. Amodu ◽  
S. O. Onifade

Forage, seed yields and herbage chemical composition of phasey bean Macroptilium lathyroides) were investigated at 3 intra-row plant spacings (15, 30 and 45cm between plants; 50 cm between roms), 4 phosphorus (P) fertilizer application rates (O), 50, 100 and 750 kg/ha P) and 5 harvest stages (uncut control, 6, 9, 12 and 15 weeks post sowing) in two growing seasons at Shika in northern Nigeria. The least intra-row plant spacing (15cm) produced higher (p<0.01) total DM vield (1.50 t/ha) than wider spacings. The proportion of leaf was least (40 %) in the widest spacing compared with other spacings (59-62 %). The P-fertilized plots produced 58-60% more total DM vields than the unfertilized plots and total DM yields increased with advanced plant growth. The highest percentage (61-63) of leaf was recorded from 6 to 12 weeks post sowing. Nitrogen level in herbage increased (p<0.05) with increased intra-row plant spacing and P application. Phosphorus and Calcium. Levels in herbage did not respond to intra-row plant spacing but increased with P application. The Ca:P ratios at the harvest stages were between 1:1 and 6:1. The highest seed yields (198 and 188 kg/ha) were recorded respectiely in the least intra-row plant spacing and the application of 100 kg Piha. Supplementation of calves on grasses/cereal stovers with phasey bean hay in a sustainable crop livestock production systems is suggested.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
R. Al-Sayaydeh ◽  
A. Al-Bawalize ◽  
Z. Al-Ajlouni ◽  
M. W. Akash ◽  
J. Abu-Elenein ◽  
...  

Barley (Hordeum vulgare L.) landraces collected previously from main production areas across Jordan are expected to perform well under stressful environments. In this study, the agronomic performance of 10 Jordanian barley landraces and three local cultivars was evaluated in two locations for two growing seasons. Clear significant variations for all studied traits were observed among the selected genotypes, environments, and their interactions. The local cultivar Rum and Baladi landrace showed the best yield performance, while Herawi and Nabawi landraces produced the lowest yield across all environments. Clustering analysis using genotypic data from the iSelect 9k SNP barley array showed a clear grouping based on row type with 100% similarity level between the Syfi and Arabi landraces. The characterized Jordanian landraces can be used to improve barley resilience against climate change and associated conditions and are recommended in breeding programs to improve productivity under dry conditions.


2020 ◽  
Vol 18 (3) ◽  
pp. 111-119
Author(s):  
Yinghu Zhang ◽  
Haiye Luan ◽  
Hui Zang ◽  
Hongyan Yang ◽  
Xiao Xu ◽  
...  

AbstractStarch content is an important trait in barley. To evaluate the genetic diversity and identify molecular markers of starch content in barley, 40 cultivated barley genotypes collected from different regions, including genotypes whose starch content is at either the high or low end of the spectrum (15), were used in this study. All the genotypes were re-sequenced by the double-digest-restriction associated DNA sequencing method, and a total of 299,103 single-nucleotide polymorphism (SNP) markers were obtained. The genotypes were divided into four sub-populations based on FASTSTRUCTURE, principal component analysis and neighbour-joining tree analysis. All four sub-populations had a high linkage disequilibrium, especially group 3, whose members were recently bred for malting in the Jiangsu coastal area. The starch content of the barley lines was evaluated during three growing seasons (2014–2017), and the average values of starch content across the three growing seasons at the low and high ends were 51.5 and 55.0%, respectively. The starch content was affected by population structure, the barley in group 2 had a low starch content, while the barley in group 4 had a high starch content. Twenty-six SNP markers were identified as being significantly associated with starch content (P ⩽ 0.001) based on the average values across the three growing seasons using the mixed linear model method. These SNP markers were located on chromosomes 1H and 4H, and were considered loci of qSC1-1 and qSC4-1, respectively. The major identified QTLs for starch content are helpful for further research on carbohydrates and for barley breeding.


1981 ◽  
Vol 32 (5) ◽  
pp. 783 ◽  
Author(s):  
WJ Collins

The effects of length of growing season and defoliation on seed yield and hard-seededness were examined in two strains of subterranean clover (Seaton Park, Midland B) grown in swards in the field. All plots were sown at the same time and the length of growing season was varied by altering the time of finish of the season (by withholding water). There were three length of growing season treatments: T1 (short), T2 (intermediate) and T3 (control). The defoliation treatments were D0, uncut (control), and D1, defoliated at weekly intervals until the commencement of flowering. Reducing the length of growing season drastically reduced seed yield. Thus when the growing season was only 3 weeks shorter than the control (i.e. T2 compared with T3), seed yields averaged over strains and defoliations were reduced by at least one half. With a further reduction of 2 weeks in the length of the season (T1) seed yields were only about one-third of those obtained in the control (T3). The reductions in seed yield were due to reductions in both the number of mature burrs produced and to a lesser extent in mean weight per seed. Although defoliation increased seed yield in all growing seasons, the effect when measured on a relative scale was greater in T2 than in either T1 or T3. But on an absolute scale the size of the response was greater in T2 and T3 than in T1. The rate of breakdown of hard-seededness was faster in Seaton Park than in Midland B, but it decreased in both strains with increasing length of growing season.


Author(s):  
Magdalena Daria Vaverková ◽  
Dana Adamcová ◽  
Jan Winkler ◽  
Eugeniusz Koda ◽  
Jana Červenková ◽  
...  

When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008–2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.


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