scholarly journals Leaf Senescence, Root Morphology, and Seed Yield of Winter Oilseed Rape (Brassica napus L.) at Varying Plant Densities

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Ming Li ◽  
Muhammad Shahbaz Naeem ◽  
Shafaqat Ali ◽  
Liyan Zhang ◽  
Lixin Liu ◽  
...  

In this study, the yield and yield components were studied using a conventional variety Zhongshuang 11 (ZS 11) and a hybrid variety Zhongyouza 12 (ZYZ 12) at varying plant densities. The increase in plant density led to an initial increase in seed yield and pod numbers per unit area, followed by a decrease. The optimal plant density was 58.5 × 104 plants ha−1 in both ZS 11 and ZYZ 12. The further researches on physiological traits showed a rapid decrease in the green leaf area index (GLAI) and chlorophyll content and a remarkable increase in malondialdehyde content in high plant density (HPD) population than did the low plant density (LPD) population, which indicated the rapid leaf senescence. However, HPD had higher values in terms of pod area index (PAI), pod photosynthesis, and radiation use efficiency (RUE) after peak anthesis. A significantly higher level of dry matter accumulation and nitrogen utilization efficiency were observed, which resulted in higher yield. HPD resulted in a rapid decrease in root morphological parameters (root length, root tips, root surface area, and root volume). These results suggested that increasing the plant density within a certain range was a promising option for high seed yield in winter rapeseed in China.

2020 ◽  
Vol 28 (s1) ◽  
pp. 145-163
Author(s):  
O.G. Moatshe ◽  
V.E. Emongor ◽  
T.V. Balole ◽  
S.O. Tshwenyane

Safflower (Carthamus tinctorius L.) is a temperate plant grown in arid and semi-arid regions of the world, and is the most drought tolerant oilseed crop. The objective of this study was to evaluate the effect of genotype and plant density on growth, phenology and yield of safflower. Treatments included five safflower genotypes and six plant densities laid out in a randomised block design. Increasing plant density from 62,500 to 100,000 plants ha-1 significantly (P < 0.05) increased leaf area index (LAI), leaf area duration (LAD), total leaf chlorophyll content (Tchl) and net assimilation rate (NAR) at all phenological stages in both winter and summer. For all genotypes, the highest LAI, LAD, Tchl, NAR, total dry matter accumulation (TDM) and seed yield resulted at a plant density of 100,000 plants ha-1. Maximum LAI, LAD, NAR and Tchl were observed at 50% flowering, compared to other phenological stages in all genotypes and plant densities. In general, genotype ‘Sina’ at 100,000 plants ha-1 significantly (P < 0.05) had the highest LAI, LAD, Tchl, TDM and seed yield compared to other genotypes and plant densities in both summer and winter.


2019 ◽  
Vol 50 (6) ◽  
Author(s):  
Al-Mohmadi & Al-Ani

A field experiment was condueted at the experimental Farm, College of Agriculture University of AL-Anbar in replace location (Abu-Gheaib) in spring season of 2017. While in Fall season it was applied at AL-saqluwiya-Anbar Province 10 km west north of Falluga city to study the effect of four levels of licorice extractor (Glycyrrhiza glabra L.) (0,2,4 and 6) g.L-1 water and three (53,333, 66,666 and 88,888 plant) plant.ha-1. On growth and grain yield of Sorghum cv. Rabih. The experiment was applied using R.C.B.D. arranged in split plots with three replications. levels of plant densities were used as main-plot, while licorice extractor were used as sub-plot. Foliar application of licorice extractor was applied during vegetative growth. The results showed that, high plant density (88888) plant.h-1 significantly increase plant height and leaf area index, while most of traits were not significantly influenced by plant density including grain yield. Results revealed that foliar application of licorice extractor with 2,4,6 g.L-1 of water significantly influenced grain yield in spring season compane with control treatment and it is amounted to (9.62, 9.55 and 9.78) t.h-1 respectively. There were significant interaction between Licorice extractor and plant density in spring and fall season in grain yield. The higher grain yield of 10.31 and 10.33 t.h-1 were obtained when sorghum plants were sowing at hight density and sprayed with Licorice extractor at level          4 g.L-1 respectively


Author(s):  
Ioannis Roussis, Ioanna Kakabouki, Dimitrios Bilalis

Agronomic practices such as plant density and fertilizer management are referred to comprise crop environment, which influences plant growth, productivity, and ultimately the yield. The objective of the current study was to evaluate the influence of plant density and fertilization on the growth and growth indices of Nigella sativa crop and to determine the association between yield and growth characteristics at both the single plant and crop stand level. The 2-year experiment was laid out in a split-plot design, with three replications, two main plots (200 and 300 plants m-2) and four sub-plots (fertilization treatments: control, compost, farmyard manure and inorganic fertilizer). The highest absolute growth rate (AGR) (0.0321 g day-1) and relative growth rate (RGR) (0.0714 g g-1 day-1) values were recorded when plants subjected to low-density and inorganic fertilization, while the highest crop growth rate (CGR) (8.0342 g m-2 day-1) was obtained under high-plant density and inorganic fertilization. Concerning specific leaf area (SLA), the highest value (196.28 cm2 g-1) was found in inorganic fertilized treatment. Leaf area index (LAI), Leaf area duration (LAD) and Biomass duration (BMD) were positively affected by both plant density and fertilization with the greatest values observed under high-density and fertilization. In conclusion, plant densities higher than 200 plants m-2 lead to higher crop growth, but lower growth of individual plants and decreased seed yield, while the application of inorganic fertilizers increases crop growth and yield as these fertilizers contain higher levels of nitrogen with high solubility and therefore quick availability for the crop than the organic fertilizers.


2016 ◽  
Vol 8 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Catherine Waithira Njuguna ◽  
Hellen Wangechi Kamiri ◽  
John Robert Okalebo ◽  
Wilson Ngetich ◽  
Syphilline Kebeney

Abstract Maize is the main staple food in Kenya with over 90% of Kenyans relying on it. While the annual national consumption is increasing, the production of this crop has been on the decline in the last two decades. Maize production in Kenya fell by 33.4% in 2013 with Nyeri among the counties said to be grappling with the production of this crop. Land pressure is one of the major causes of decreased availability of food as well as soil depletion and encroachment upon fragile ecosystems such as wetlands. Nitrogen is a key nutrient in the production of maize, and its deficiency is a major factor limiting its production. This study investigated the effect of N application at 120 kg N/ha and maize density on the Leaf Area Index in reclaimed wetland soils in an experimental set-up comprising a randomized complete block design with three replications. The research was carried out in Nyeri County, Kenya. Leaf Area Index (LAI) was determined using the given SunScan formula. Measurements were done continuously until crop physiological maturity. Results indicated that the leaf area index increased with nitrogen application and reduced with spacing for most treatments. There were no significant differences between the two methods (Copy Method and SunScan). Leaf Area Index (LAI) was high in treatments containing nitrogen and high plant density. It was concluded that high plant density gives high LAI. 50 cm * 12.5 cm (-N) and 50 cm * 12.5 cm (+N) are the recommended plant densities for the site.


1975 ◽  
Vol 85 (2) ◽  
pp. 247-254 ◽  
Author(s):  
R. P. Singh ◽  
K. P. P. Nair

SUMMARYData are presented from an experiment made in two crop seasons, to examine the effects of plant density and degree of defoliation at different stages of growth in maize at Pantnagar, India, on the dry-matter accumulation in different plant parts, leaf area index (LAI), time of silking and grain yield components.Different patterns of dry-matter accumulation in various plant parts was observed. Silking was delayed by increasing plant density. Defoliation (even partial) at the 16th fully expanded leaf stage resulted in substantial reduction in LAI and such yield components as number of ears, ear length, ear diameter and 1000-grain weight. On the other hand, partial defoliation done at the 10th fully expanded leaf stage to simulate an ‘erectophile canopy’ led to yield increases even under high plant density (90000 plants/ha) in the Kharif (rainy season), mainly through an increase in number of ears, 1000-grain weight and grain to stover ratio coupled with a reduction in barrenness and percentage of lodging. It is suggested that an increase in the photosynthetic efficiency per unit area of leaf resulting from the ‘erectophile canopy’ is the reason for these effects.


1995 ◽  
Vol 125 (1) ◽  
pp. 87-93 ◽  
Author(s):  
C. Aguilera-Diaz ◽  
L. Recalde-Manrique

SUMMARYA factorial experiment on Vicia faba L. cv. Alameda with three plant densities at three levels of nitrogen fertilization was done for three years (1984–87) at Granada. Yield varied markedly from 403 to 579 g/m2 between seasons. The mean increase in plant population density from 10 to 16 plants/m2 raised seed yield, but a further increase to 21 plants/m2 did not increase yield significantly. There was, however, considerable variation in the response to increasing density (Dl to D3) within each N level (N0, N1 and N2). Application of 30 kg N/ha at the start of flowering increased mean seed yield only at the lowest plant density and in 1986, but 60 kg N/ha increased yield by 135% on average over the 3 years. The highest N application rate resulted in consistently higher overall yields at each plant density. Leaf area index (LAI) showed a significant increase at 20 seeds/m2 compared with that at 10 seeds/m2 but there was no further increase at 30 seeds/m2. Harvest index (HI) was mainly affected by the annual weather conditions, and ranged from 47–4 in 1986 to 62–6 in 1987. HI was related to the mean temperature at flowering (April).


Author(s):  
L. S. Sampaio ◽  
R. Battisti ◽  
M. A. Lana ◽  
K. J. Boote

Abstract Crop models can be used to explain yield variations associated with management practices, environment and genotype. This study aimed to assess the effect of plant densities using CSM-CROPGRO-Soybean for low latitudes. The crop model was calibrated and evaluated using data from field experiments, including plant densities (10, 20, 30 and 40 plants per m2), maturity groups (MG 7.7 and 8.8) and sowing dates (calibration: 06 Jan., 19 Jan., 16 Feb. 2018; and evaluation: 19 Jan. 2019). The model simulated phenology with a bias lower than 2 days for calibration and 7 days for evaluation. Relative root mean square error for the maximum leaf area index varied from 12.2 to 31.3%; while that for grain yield varied between 3 and 32%. The calibrated model was used to simulate different management scenarios across six sites located in the low latitude, considering 33 growing seasons. Simulations showed a higher yield for 40 pl per m2, as expected, but with greater yield gain increments occurring at low plant density going from 10 to 20 pl per m2. In Santarém, Brazil, MG 8.8 sown on 21 Feb. had a median yield of 2658, 3197, 3442 and 3583 kg/ha, respectively, for 10, 20, 30 and 40 pl per m2, resulting in a relative increase of 20, 8 and 4% for each additional 10 pl per m2. Overall, the crop model had adequate performance, indicating a minimum recommended plant density of 20 pl per m2, while sowing dates and maturity groups showed different yield level and pattern across sites in function of the local climate.


2016 ◽  
Vol 96 (1) ◽  
pp. 151-159 ◽  
Author(s):  
Gan Yantai ◽  
K. Neil Harker ◽  
H. Randy Kutcher ◽  
Robert H. Gulden ◽  
Byron Irvine ◽  
...  

Optimal plant density is required to improve plant phenological traits and maximize seed yield in field crops. In this study, we determined the effect of plant density on duration of flowering, post-flowering phase, and seed yield of canola in diverse environments. The field study was conducted at 16 site-years across the major canola growing area of western Canada from 2010 to 2012. The cultivar InVigor® 5440, a glufosinate-resistant hybrid, was grown at five plant densities (20, 40, 60, 80, and 100 plants m−2) in a randomized complete block design with four replicates. Canola seed yield had a linear relationship with plant density at 8 of the 16 site-years, a quadratic relationship at 4 site-years, and there was no correlation between the two variables in the remaining 4 site-years. At site-years with low to medium productivity, canola seed yield increased by 10.2 to 14.7 kg ha−1 for every additional plant per square metre. Averaged across the 16 diverse environments, canola plants spent an average of 22% of their life cycle flowering and another 27% of the time filling seed post-flowering. Canola seed yield had a negative association with duration of flowering and a positive association with the days post-flowering but was not associated with number of days to maturity. The post-flowering period was 12.7, 14.7, and 12.6 d (or 55, 68, and 58%) longer in high-yield experiments than in low-yield experiments in 2010, 2011, and 2012, respectively. We conclude that optimization of plant density for canola seed yield varies with environment and that a longer post-flowering period is critical for increasing canola yield in western Canada.


2022 ◽  
Vol 12 ◽  
Author(s):  
Yushi Zhang ◽  
Yubin Wang ◽  
Churong Liu ◽  
Delian Ye ◽  
Danyang Ren ◽  
...  

Increasing use of plant density or/and nitrogen (N) application has been introduced to maize production in the past few decades. However, excessive planting density or/and use of fertilizer may cause reduced N use efficiency (NUE) and increased lodging risks. Ethephon application improves maize lodging resistance and has been an essential measure in maize intensive production systems associated with high plant density and N input in China. Limited information is available about the effect of ethephon on maize N use and the response to plant density under different N rates in the field. A three-year field study was conducted with two ethephon applications (0 and 90 g ha−1), four N application rates (0, 75, 150, and 225 kg N ha−1), and two plant densities (6.75 plants m−2 and 7.5 plants m−2) to evaluate the effects of ethephon on maize NUE indices (N agronomic efficiency, NAE; N recovery efficiency, NRE; N uptake efficiency, NUpE; N utilization efficiency, NUtE; partial factor productivity of N, PFPN), biomass, N concentration, grain yield and N uptake, and translocation properties. The results suggest that the application of ethephon decreased the grain yield by 1.83–5.74% due to the decrease of grain numbers and grain weight during the three experimental seasons. Meanwhile, lower biomass, NO3- and NH4+ fluxes in xylem bleeding sap, and total N uptake were observed under ethephon treatments. These resulted in lower NAE and NUpE under the ethephon treatment at a corresponding N application rate and plant density. The ethephon treatment had no significant effects on the N concentration in grains, and it decreased the N concentration in stover at the harvesting stage, while increasing the plant N concentration at the silking stage. Consequently, post-silking N remobilization was significantly increased by 14.10–32.64% under the ethephon treatment during the experimental periods. Meanwhile, NUtE significantly increased by ethephon.


Author(s):  
Manpreet Jaidka ◽  
J.S. Deol ◽  
Ramanjit Kaur ◽  
R. Sikka

Effect of detopping and mepiquat chloride on morphological, physiological and yield attributes of soybean cultivar ‘SL 544’ was studied. A two year investigation was conducted at Punjab Agricultural University, Ludhiana, during kharif seasons of 2014 and 2015. The experiment was laid-out in randomized complete block design (RCBD) with eight treatments viz. control, detopping (removal of 4-5 cm apical portion of main stem) at 50-55 days after sowing (DAS), mepiquat chloride @ 200 ppm (50-55 DAS), mepiquat chloride @ 200 ppm (50-55 + 65-70 DAS), mepiquat chloride 250 ppm (50-55 DAS), mepiquat chloride @ 250 ppm (50-55 + 65-70 DAS), mepiquat chloride @ 300 ppm (50-55 DAS) and mepiquat chloride @ 300 ppm (50-55 + 65-70 DAS) with four replications. Detopping had a non-significant effect on leaf area index, SPAD value, PAR interception, abscission of reproductive parts, seeds per pod, 100-seed weight, pod length and stover yield of soybean. It significantly decreased plant height, increased total dry matter accumulation/plant, number of flowers and pods/plant, pod setting percentage and seed yield over control during 2014 and 2015. At crop harvest, detopping developed optimized source-sink relationship by means of distribution of total dry matter between stem, foliage and pods by 20.4, 14.9 and 64.6 % during 2014 while 22.6, 20.1 and 57.4 % during 2015, respectively. Mepiquat chloride posed a non-significant effect on plant height, PAR interception, number of flowers/plant, number of seeds/pod, pod length and stover yield of soybean but it significantly decreased leaf area index, abscission of reproductive parts while increased the dry matter accumulation/plant, number of pods/plant, 100-seed weight and seed yield relative to control. At harvest, two foliar applications of mepiquat chloride @ 250 ppm resulted in optimized source-sink relationship by the distribution of total dry matter among stem, foliage and pods by 20.6, 10.9 and 68.5 % during 2014 while 19.5, 7.6 and 72.9 % during 2015, respectively. Occurrence of more rainfall during 2015 as compared to 2014 caused mepiquat chloride to hike seed yield as compared to detopping which is clearly witnessed by increase in pod dry weight per plant during 2015 than 2014. Conclusively, both detopping and mepiquat chloride resulted in enhancement in source-sink relationship and seed yield of soybean.


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