Hazelnut floral phenology in southern Ontario

2021 ◽  
Author(s):  
Toktam Taghavi ◽  
Alireza Rahemi ◽  
Adam Dale ◽  
Dragan Galic ◽  
John M. Kelly
Keyword(s):  
Early Spring ◽  
Growing Degree Days ◽  
Degree Days ◽  
Southern Ontario ◽  
Floral Phenology ◽  
Male Flowers ◽  
Compatible Pollen ◽  
Pollen Shed ◽  
Continental Climate ◽  
Female Flowers

Hazelnut (Corylus avellana) is a monoecious, dichogamous plant species that flowers in winter and early spring. In traditional hazelnut growing regions, hazelnut cultivars generally express protandry where the male flowers bloom before the female flowers. Nut set requires that compatible pollen be shed when the stigmas of the main cultivar are receptive. In this study, the floral phenology and date of leaf budbreak of five selections and 19 hazelnut cultivars from Europe and North America were observed over four years in southern Ontario, and results were compared with cumulative growing degree days. In the continental climate of southern Ontario, most cultivars showed protogyny. Flowering dates varied over the years with pollination occurring in a period of 2 - 3 weeks in early spring. These cultivars were classified into early, mid, and late blooming types. A growing degree day model was a better tool than average daily temperatures to predict the flowering dates of catkins and female flowers. Averaged over years, most of the cultivars in this study have a female bloom that is likely too early for the pollen shed by most of the other cultivars. This would likely impact yields in a commercial orchard. However, ‘Jefferson’, ‘Gene’, and ‘Epsilon’ have late females that are receptive when other cultivars are shedding pollen.

scholarly journals Management of Primocane-fruiting Blackberry: Impacts on Yield, Fruiting Season, and Cane Architecture

HortScience ◽  
2012 ◽  
Vol 47 (5) ◽  
pp. 593-598 ◽  
Author(s):  
Bernadine C. Strik ◽  
John R. Clark ◽  
Chad E. Finn ◽  
Gil Buller
Keyword(s):  
Early Spring ◽  
Management Systems ◽  
High Yield ◽  
Late Winter ◽  
Growing Degree Days ◽  
Degree Days ◽  
Branch Number ◽  
Node Number ◽  
Berry Weight

Primocane management systems were compared for ‘Prime-Jan’® and ‘Prime-Jim’®, primocane-fruiting blackberry (Rubus L. subgenus Rubus, Watson), grown in a field planting in Aurora, OR. Treatments studied were: 1) no manipulation of primocanes (untipped; no floricanes); 2) untipped primocanes growing in the presence of floricanes; 3) untipped primocanes grown with rowcover in late winter to early spring; and 4) primocanes “soft-tipped” at 1 m to encourage branching. Date of primocane first bloom and cane height at bloom were unaffected by cultivar and were only affected by primocane management in 2005. The number of growing degree-days to first bloom ranged from 1272 to 1390 depending on year. Primocane management did not affect ovule or drupelet number per berry or percent drupelet set. ‘Prime-Jim’ had more drupelets and greater weight per berry in 2005 than ‘Prime-Jan’. Fruit harvested earlier in the season had more ovules and drupelets than later harvested fruit in 2004. Primocanes that grew in the presence of floricanes were longer and bloomed later but did not differ in yield from untipped canes grown only for a primocane crop. Use of rowcover in 2005 advanced bloom and harvest, improving yield 73% compared with untipped control canes. Soft-tipping primocanes increased yield 114% to 150% compared with untipped canes (5.6 vs. 2.4 t·ha−1) through increasing branch and node number per cane and percentage of fruiting nodes; soft-tipping did not delay harvest. Yield/cane was negatively correlated with the number of fruiting canes/plot but positively correlated with branches/cane, total branch and cane length, number of nodes and percent fruiting nodes, fruit/cane, and berry weight. The proportion of fruiting nodes was greater on branches than on the main cane illustrating the importance of managing this type of blackberry to increase branch number for high yield.

In situ emergence timing of large and small crabgrass in residential turfgrass of southern Ontario

2013 ◽  
Vol 93 (3) ◽  
pp. 503-509 ◽  
Author(s):  
Fawn A. Turner ◽  
Rene C. Van Acker
Keyword(s):  
Growing Season ◽  
Growing Degree Days ◽  
Degree Days ◽  
Cool Season ◽  
Digitaria Sanguinalis ◽  
Reliable Measure ◽  
Southern Ontario ◽  
Management Approaches ◽  
Large Crabgrass

Turner, F. A. and Van Acker, R. C. 2013. In situ emergence timing of large and small crabgrass in residential turfgrass of southern Ontario. Can. J. Plant Sci. 93: 503–509. Large, Digitaria sanguinalis (L.) Scop., and small, Digitaria ischaemum (Schreb.) ex Muhl., crabgrass are problem weeds in turfgrass. Due to an increasing number of cosmetic pesticide bans in Canada there is a need to better understand the biology and ecology of crabgrass in order to develop and hone management approaches. The assessment of crabgrass recruitment timing is particularly relevant to its management, including the timing of alternative herbicide applications. This study focused on determining the emergence timing of established populations of large and small crabgrass in typical residential turfgrass stands in southern Ontario. Small crabgrass emerged earlier than large crabgrass at 346 and 515 growing degree days (GDD), respectively. In typical southern Ontario lawns both small and large crabgrass emerge after cool-season turfgrass has established and emergence continues late into the summer. For example, even within the last 2 wk of July we observed over 700 seedlings m–2 of large crabgrass emerging in some observation plots. This study also confirmed that small crabgrass emerges earlier than large crabgrass. There was a greater difference in emergence timing between species rather than among sites, suggesting that it is important to differentiate between species when timing management approaches. The late and prolonged emergence of crabgrass makes residential lawns that are not well maintained susceptible to infestation for a long portion of the growing season. This study also demonstrated that cumulative GDD may be a reliable measure for tracking crabgrass emergence suggesting, that it could be used as a tool for management, including the application of alternative herbicides. This study reinforces the importance of maintaining healthy and dense turf stands throughout the season as a deterrent to crabgrass infestations.

Evaluation of Finger Millet Varieties under Rainfed Condition of Eastern India

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
M. K. Singh ◽  
VINOD KUMAR ◽  
SHAMBHU PRASAD
Keyword(s):  
Field Experiment ◽  
Finger Millet ◽  
Yield Potential ◽  
Growing Degree Days ◽  
Eastern India ◽  
Degree Days ◽  
Rainfed Condition ◽  
Net Returns ◽  
Humid Environment ◽  
Use Efficiency

A field experiment was carried out during the kharif of 2014 and 2015 to evaluate the yield potential, economics and thermal utilization in eleven finger millet varieties under the rainfed condition of the sub-humid environment of South Bihar of Eastern India. Results revealed that the significantly higher grain yield (20.41 q ha-1), net returns (Rs 25301) and B: C ratio (1.51) was with the finger millet variety ‘GPU 67’ but was being at par to ‘GPU28’and ‘RAU-8’, and significantly superior over remaining varieties. The highest heat units (1535.1oC day), helio-thermal units (7519.7oC day hours), phenothermal index (19.4 oC days day-1) were recorded with variety ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ and lowest in ‘VL 149’ at 50 % anthesis stage. Similarly, the highest growing degree days (2100 oC day), helio-thermal units (11035.8 oC day hours) were noted with ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ at maturity. The highest heat use efficiency (0.97 kg ha-1 oC day) and helio-thermal use efficiency (0.19 kg ha-1 oC day hour) were in ‘GPU 67’ followed by ‘VL 315’.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

Studies in the Alismataceae. XI. Development of the inflorescence and flowers of Wiesneria triandra (Dalzell) Micheli

2000 ◽  
Vol 77 (11) ◽  
pp. 1569-1579
Author(s):  
W A Charlton
Keyword(s):  
Shoot Development ◽  
Annual Plant ◽  
Foliage Leaf ◽  
The Family ◽  
Unisexual Flowers ◽  
Male Flowers ◽  
Female Flowers

Wiesneria triandra (Dalzell) Micheli is an unusual annual plant of the Alismataceae with spike-like inflorescences bearing unisexual flowers. Shoot development follows the sympodial pattern of other Alismataceae, but the cycle is so condensed that initiation of each foliage leaf is followed by inflorescence formation. The plant develops a tufted habit by the formation of an unusual accesory bud adjacent to each inflorescence. Male flowers have three sepals, three petals, three stamens, and usually three carpellodes; female flowers have a similar perianth, three staminodes, and three or more carpels. Up to the first three carpels, floral parts are arranged in alternating trimerous whorls. Additional carpels may occur above and between those of the first whorl. The androecium is particularly unusual for the Alismataceae since it has conventional alternation of stamens with petals rather than the antipetalous pairs of stamens commonly perceived in the family, but the phylogenetic postion of Wiesneria within the family (as revealed by other studies) indicates that the apparently conventional androecium of Wiesneria represents a derived state rather than a primitive one. The unisexual flowers also represent a derived state.

Pollination ecology of Monstera obliqua (Araceae) in French Guiana

2007 ◽  
Vol 23 (5) ◽  
pp. 607-610 ◽  
Author(s):  
Mathieu Chouteau ◽  
Melanie McClure ◽  
Marc Gibernau
Keyword(s):  
French Guiana ◽  
Pollination Ecology ◽  
Lower Portion ◽  
Floral Rewards ◽  
Pollination Mechanisms ◽  
Unisexual Flowers ◽  
Male Flowers ◽  
Female Flowers

Data on pollination ecology of Araceae are still scarce and most concern species belonging to the subfamily Aroideae (García-Robledo et al. 2004, Gibernau 2003, Ivancic et al. 2004, 2005; Maia & Schlindwein 2006). In this subfamily, inflorescences consist of unisexual flowers: female flowers are located in the lower portion and the male flowers are in the upper portion of the inflorescence (Mayo et al. 1997). In the documented neotropical Aroideae, pollinators are nocturnal beetles and pollination mechanisms take place within a floral chamber during a short flowering cycle (generally 24–48 h) with floral rewards (sterile flowers rich in proteins and/or lipids) for the beetle pollinators, the secretion of resin to secure pollen on the pollinator, and the production of heat and odours (Chouteau et al. 2007, García-Robledo et al. 2004, Gibernau & Barabé 2002, Gibernau et al. 1999, 2000, 2003; Maia & Schlindwein 2006, Young 1986).

Differential nectar production between male and female flowers in a wild cucurbit: Cucurbita maxima ssp. andreana (Cucurbitaceae)

2002 ◽  
Vol 80 (11) ◽  
pp. 1203-1208 ◽  
Author(s):  
Lorena Ashworth ◽  
Leonardo Galetto
Keyword(s):  
Reproductive Output ◽  
Male Flower ◽  
Female Flower ◽  
Cucurbita Maxima ◽  
Nectar Production ◽  
Male And Female ◽  
Nectar Sugar Composition ◽  
Nectar Sugar ◽  
Male Flowers ◽  
Female Flowers

In dioecious and monoecious plants that depend on animal vectors for reproduction, pollinators have to be attracted to male and female flowers for pollination to be effective. In the monoecious Cucurbita maxima ssp. andreana, male flowers are produced in greater quantity, are spatially more exposed to pollinators and offer pollen in addition to nectar as floral rewards. Nectar traits were compared between male and female flowers to determine any differences in the characteristics of the main reward offered to pollinators. Nectar chemical composition and sugar proportions were similar between flower types. Total nectar sugar production per female flower was threefold higher than per male flower, and nectar removal did not have any effect on total nectar production in both flower morphs. Pollinators reduced nectar standing crops to similar and very scarce amounts in both flower types. Results indicate indirectly that pollinators are consuming more nectar from female flowers, suggesting that the higher nectar production in female flowers may be a reward-based strategy to achieve the high female reproductive output observed in this species.Key words: Cucurbitaceae, Cucurbita maxima ssp. andreana, nectar production, nectar sugar composition, removal effects, standing crop.

scholarly journals Growth and Development of Purple Nutsedge Based on Days or Thermal Units

2015 ◽  
Vol 33 (2) ◽  
pp. 165-173 ◽  
Author(s):  
R.S.O. Lima ◽  
E.C.R. Machado ◽  
A.P.P. Silva ◽  
B.S. Marques ◽  
M.F. Gonçalves ◽  
...  
Keyword(s):  
Plant Growth ◽  
Mathematical Models ◽  
Growth And Development ◽  
Dry Matter ◽  
Cyperus Rotundus ◽  
Growing Degree Days ◽  
Plant Growth And Development ◽  
Degree Days ◽  
Purple Nutsedge ◽  
Independent Trials

This work was carried out with the objective of elaborating mathematical models to predict growth and development of purple nutsedge (Cyperus rotundus) based on days or accumulated thermal units (growing degree days). Thus, two independent trials were developed, the first with a decreasing photoperiod (March to July) and the second with an increasing photoperiod (August to November). In each trial, ten assessments of plant growth and development were performed, quantifying total dry matter and the species phenology. After that, phenology was fit to first degree equations, considering individual trials or their grouping. In the same way, the total dry matter was fit to logistic-type models. In all regressions four temporal scales possibilities were assessed for the x axis: accumulated days or growing degree days (GDD) with base temperatures (Tb) of 10, 12 and 15 oC. For both photoperiod conditions, growth and development of purple nutsedge were adequately fit to prediction mathematical models based on accumulated thermal units, highlighting Tb = 12 oC. Considering GDD calculated with Tb = 12 oC, purple nutsedge phenology may be predicted by y = 0.113x, while species growth may be predicted by y = 37.678/(1+(x/509.353)-7.047).

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