EFFECT OF ALTERING PLANT DENSITY ON GROWTH CHARACTERISTICS OF SUMMER RAPE

1990 ◽  
Vol 70 (1) ◽  
pp. 139-149 ◽  
Author(s):  
M. J. MORRISON ◽  
P. B. E. McVETTY ◽  
R. SCARTH

The effect of 15- and 30-cm row spacings and 1.5, 3.0, 6.0 and 12.0 kg ha−1 seeding rates on growth characteristics, as measured by growth analysis, of summer rape (Brassica napus L.) was studied under southern Manitoba growing conditions. Growing degree days (GDD) was used in the growth analysis formulae as a measurement of time. Over all seeding rates, summer rape grown in rows spaced 15 cm apart produced more dry weight (W), a greater leaf area index (LAI) and a greater leaf area duration (LAD) than when grown in rows spaced 30 cm apart. The 15-cm row spacing treatments had a higher crop growth rate (CGR) and a greater net assimilation rate (NAR) than the 30-cm row spacing treatments. Summer rape grown at seeding rates of 6.0 and 12.0 kg ha−1 had a greater W, LAI and LAD during vegetative development than summer rape grown at seeding rates of 1.5 and 3.0 kg ha−1. This was primarily due to increased plant density. After flowering there were no differences for W, LAI and LAD attributable to differences in seeding rates. Summer rape grown at seeding rates of 6.0 and 12.0 kg ha−1 had a lower CGR and NAR during flowering than that grown at 1.5 and 3.0 kg ha−1 seeding rates indicating that plants produced from lower seeding rates were more photosynthetically efficient than plants produced from higher seeding rates.Key words: Brassica napus, growth analysis, row spacing, seeding rates, rape (summer)

1978 ◽  
Vol 58 (3) ◽  
pp. 587-595 ◽  
Author(s):  
J. M. CLARKE ◽  
G. M. SIMPSON

Growth analysis of field-grown rape (Brassica napus L.) was carried out during 1975 and 1976 at Saskatoon. Plant morphology was altered by the use of four planting densities under three water regimes. High seeding rates and non-irrigated conditions caused a greater proportion of dry matter production to occur before flowering than after flowering, while the reverse occurred at low seeding rates and under irrigated conditions. Leaf area index reached a maximum near the start of flowering, and then declined rapidly. Pod surface area was increased by irrigation and was higher at the high seeding rates than at the low seeding rates. Maximum leaf area index was correlated with seed yield. Correlations between pod area and seed yield were poor, particularly in 1976. The growth functions mean net assimilation rate [Formula: see text] and mean crop growth rate [Formula: see text] were influenced by both seeding rates and irrigation. There was an increase in [Formula: see text] during the ripening phase, suggesting increased photosynthetic efficiency. No evidence of a distinct optimum leaf area index was found.


1990 ◽  
Vol 70 (1) ◽  
pp. 127-137 ◽  
Author(s):  
M. J. MORRISON ◽  
P. B. E. McVETTY ◽  
R. SCARTH

To determine the effects of varying plant densities on summer rape (Brassica napus L.), the cultivar Westar was seeded in 15- and 30-cm row spacings at seeding rates of 1.5, 3.0, 6.0, and 12.0 kg ha−1. Plants seeded in 15-cm rows yielded more per area, produced more pods per plant and lodged less than those in 30-cm rows. Higher yields were associated with a more even plant distribution and a lower degree of intra-row competition. There were no significant protein, oil and chlorophyll concentration differences between the row spacing treatments. The highest yields (kg ha−1) were achieved with the 1.5 and 3.0 kg ha−1 seeding rates. Summer rape compensated for lower plant densities with the production of more branch racemes. As seeding rate increased, competitive mortality increased, resulting in greater etiolation at bolting, and greater lodging at harvest. Seed oil and protein concentrations were not affected by seeding rate. However, seed chlorophyll concentration decreased with increased seeding rate.Key words: Brassica napus, plant density, seed quality, rape (summer)


2020 ◽  
Vol 38 (1) ◽  
pp. 69
Author(s):  
Fernando Abasolo Pacheco ◽  
Carlos Michel Ojeda Silvera ◽  
Jonathan Enrique Cervantes Molina ◽  
Enma Moran Villacreses ◽  
Daniel Vera Aviles ◽  
...  

The production of the turnip (Brassica napus L.) in Ecuador, depends largely on the use of agrochemicals, whose indiscriminate use causes negative effects on the environment. Agricultural homeopathy has emerged as an ecological alternative to improve the health status of plants. In order to help improve the sustainable production of vegetables, the effect of two centesimal dynamics (7CH and 31CH) of three homeopathic medicines for human use was evaluated: Silicea terra (SiT), Natrum muriaticum (NaM) and Phosphoricum acidum (PhA ), on the germination, emergence and vegetative development of B. napus plants, applying a completely randomized 2×3+1 block design with three repetitions for the three stages of the crop. The variables evaluated during germination and emergence were: percentage of germination and emergence, length of stem and radicle, fresh weight of the aerial part and radicle, dry weight of the aerial part and radicle. The variables evaluated during vegetative development were: plant height, stem diameter, number of leaves, weight, leaf area and productive yield. Signif icant differences were recorded in all the variables and stages of development studied. The highest germination values corresponded to SiT-7CH and PhA-7CH (100%), surpassing the control group (83.5%). The PhA-7CH and NaM-31CH treatments stimulated stem growth in the germination stage (3.40 cm) and NaM-7CH root growth (4.07 cm) in the emergence stage. During the vegetative development, the plants with the highest production were those treated with NaM-7CH. The highest prof itability of the crop (71.33%), with a benef it / cost ratio of 1.7% was obtained with SiT-7CH. The results obtained suggest that agricultural homeopathy has potential in horticulture, since all treatments favorably influenced the response variables during germination, emergence and vegetative development of (Brassica napus L.).


Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 609-615 ◽  
Author(s):  
Michael S. Defelice ◽  
William W. Witt ◽  
Michael Barrett

Monoculture velvetleaf had greater dry weight, growth rate, leaf area index, and height than velvetleaf grown in association with conventional or no-tillage corn. Velvetleaf planted 5 weeks after corn had significantly lower dry weight, leaf area index, and height compared to velvedeaf planted at the same time as corn. The combination of interference from corn and delayed planting caused a significant reduction in velvetleaf population at the end of the season, delayed the date of 50% velvetleaf flowering, increased the number of days required for 50% flowering, and reduced the number of capsules per plant. Velvetleaf dry weight/hectare and leaf area index increased as plant population increased. Velvetleaf dry weight, leaf area, capsules, and seed/plant decreased as plant density increased. There were no differences in vegetative or reproductive growth between velvetleaf grown in conventional or no-tillage areas.


1991 ◽  
Vol 18 (1) ◽  
pp. 30-37 ◽  
Author(s):  
David P. Davis ◽  
Timothy P. Mack

Abstract Growth characteristics of three commonly planted peanut cultivars were measured during the 1988 and 1989 growing seasons at the Wiregrass Substation in Headland, Ala., to develop equations for predicting leaf area index (LAI) from other growth varibales. These equations were needed to allow rapid estimation of leaf area loss from foliar-feeding insects or foliar-fungal pathogens. Conventionally planted and tilled fields of Florunner, Sunrunner and Southern Runner peanut (Arachis hypogaea L.) were sampled for plant vegetative stage, reproductive stage, height, number of leaves, leaf area, leaf dry weight, number of pods, pod dry weight, stem dry weight, and stand density. Most growth characteristics increased linearly (p<0.05) with time in both years. LAI was significantly correlated (P<0.05) with most growth variables for each cultivar. Linear regression was used to create equations for prediction of LAI from leaf dry weight (range of R2 = 0.93 to 0.97) and number of leaves (range of R2 = 0.74 to 0.95) for each cultivar, and all cultivars combined. Equations were also developed to predict LAI from plant height (range of R2 = 0.85 to 0.96) and plant vegetative stage (range of R2 = 0.81 to 0.83). These equations should be useful to those who wish to estimate LAI from other growth variables.


2011 ◽  
Vol 49 (No. 9) ◽  
pp. 422-426 ◽  
Author(s):  
H. Ozer

Rapeseed (Brassica napus L.) is an important alternate oilseed crop in eastern Anatolia, Turkey. No information on plant density for rapeseed is available in this region. Therefore a study was initiated to investigate the effects of spacings between rows and spacings within rows on the yield and agronomic characteristics of two genotypes of spring rapeseed (Tower and Lirawell) in Erzurum, eastern Anatolia, during 1994 and 1995. The effects of spacings between or within rows on the yield and yield components of Tower and Lirawell, two cultivars of Brassica napus L., were studied for 2 years inErzurum,Turkey. Rows were spaced at 15, 30 and45 cm. Spacings within rows were 5, 10 and15 cm. The results of this study suggested that seed yield was significantly affected by spacings between rows but not by spacings within rows, and that rape yields were higher at the narrow (15 cm) row spacing compared to the middle (30 cm) and wider (45 cm) spacings.


2000 ◽  
Vol 5 (2) ◽  
pp. 69
Author(s):  
M.A. Cheema ◽  
M.A. Malik ◽  
A. Hussain ◽  
S.H. Shah ◽  
S.M.A. Basra

A field study was carried out to determine growth and yield of canola (Brassica napus L.) at different inter row (30, 45, and 60 cm) and intra row (10, 15, and 20 cm) spacing between 1995-97. The closer row Spacing of 30 cm significantly increased leaf area index (LAD, total dry matter (TDM) in both the seasons over wider spacing of 45 and 60 cm. Similarly closer plant spacing of 10 cm also enhanced LA! and TDM over 15 or 20 cm plant spacing. Seed and oil yield was significantly increased in first row spacing compared with 45 or 60 cm row spacing in both seasons. Swd yield was linearly related to TDM yield, harvest index was not changed. The results suggest that closer spacing of 30 cm is optimum for maximizing seed and oil yield for canola under the agro-ecological conditions of Faisalabad.  


Biologija ◽  
2016 ◽  
Vol 62 (1) ◽  
Author(s):  
Raouf Seyed Sharifi ◽  
Ali Namvar

Crop phenology is one of the most important aspects of crop yield determination and it is essential to predicting physiological responses under varying field conditions. In order to evaluate plant density and intra-row spacing effects on phenology, dry matter accumulation, and leaf area index of maize in second cropping, a factorial experiment based on randomized complete block design was conducted at the research farm of the University of Mohaghegh Ardabili. Experimental factors were: plant population at three levels (7, 9, and 11 plants m–2) with three levels of intra-row spacing (45, 60, and 75 cm). The results showed that the maximum plant height (179.07  cm), total dry matter (592  g  m–2) in 83–91 days after sowing, days to 50% anthesis (45 days), days to 50% silking (50 days), LAI (4.07) in 63–70 days after sowing were observed in the plots with 11 plants m–2 and intra-row spacing of 45 cm. Based on the results, it was concluded that application of 11 plants m–2 with row spacing of 45 cm can be recommended for profitable maize production.


2013 ◽  
Vol 93 (6) ◽  
pp. 1229-1236 ◽  
Author(s):  
H. R. Kutcher ◽  
T. K. Turkington ◽  
G. W. Clayton ◽  
K. N. Harker

Kutcher, H. R., Turkington, T. K., Clayton, G. W. and Harker, K. N. 2013. Response of herbicide-tolerant canola ( Brassica napus L.) cultivars to four row spacings and three seeding rates in a no-till production system. Can. J. Plant Sci. 93: 1229–1236. Appropriate management practices are important to reduce input costs and to optimize yield and crop quality. The objective of this study was to determine the optimum row spacing (23, 31, 46 and 61 cm) and seeding rate (3.2, 6.4 and 9.6 kg ha−1, or 87, 173 and 260 seeds planted m−2) for two herbicide-tolerant canola (Brassica napus L.) cultivars (an open-pollinated and a hybrid) under a no-till production system. Plant density and yield varied with row spacing, with the effect being linear in both cases. Plant density decreased with wider row spacing, from 112 plants m−2 at the 23-cm row spacing to 83 plants m−2 at the 61-cm row spacing. Yield decreased with wider row spacing, from 2397 kg ha−1 at the 23-cm row spacing to 2138 kg ha−1 at the 61-cm row spacing. Results from this study indicate that herbicide-tolerant cultivars of canola grown in no-till production systems under conditions of adequate soil fertility, effective weed management, minimal disease pressure, and good flea beetle control, produced the highest plant densities and yields at row spacing of 24–31 cm, that seeding rates in the range of 3.2–9.6 kg ha−1 had no effects on yield, and that a hybrid cultivar performed better than open-pollinated cultivars in terms of plant density, earliness and duration of flowering, and seed size. The study helps to better define the response of plant density and seed yield in herbicide-tolerant canola cultivars to changes in row spacing and seeding rate. In particular, the results of this study suggest that plant density may not be a reliable predictor of canola yield, although row spacing is an important consideration.


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