scholarly journals Effect of plant density and seed position on mother plant on physiological characteristic of cocklebur (Xanthium strumarium) seeds

2014 ◽  
Vol 32 (1) ◽  
pp. 61-68
Author(s):  
A. Foroughi ◽  
J. Gherekhloo ◽  
F. Ghaderi-Far

Experiments were conducted in 2010 to determine the influence of plant density and seed position on the mother plant on seed physiological characteristics of cocklebur (Xanthium strumarium). Cocklebur burs were collected in fall of 2010 from Research Farm of University of Agricultural Sciences and Natural Resources of Gorgan, Iran. The experiment was established as factorial arrangement using a completely randomized design with three replications. The factors included different densities of cocklebur (0, 2, 4, 6 and 8 plant m-2) and the top and bottom parts of the canopy. Non dormant seeds were used for determining cardinal temperatures and tolerance to salinity and drought stresses. Base, optimum and ceiling germination temperatures were estimated between 7.09 to 12.33, 32 to 35 and 44 to 45 respectively in different treatments. Salinity stress up to 300 Mm and osmotic potential 8 bar inhibited the germination completely. Comparison of base temperatures and sigmoid equation coefficients showed that seeds produced in the top had higher germination than those that produced at the bottom of the mother plant. It seems plant densities through seed position on the mother plant affect seed quality. Likewise changes of light quality and quantity in shade environment increased seed dormancy in matured seeds. Shade environment affect seed germination on mother plant that increased dormancy of seeds maturing under shade be an adaptive response that reduces the probability of germination of offspring under unfavorable (shade, competitive) conditions.

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)


HortScience ◽  
1993 ◽  
Vol 28 (8) ◽  
pp. 809-811 ◽  
Author(s):  
Victor M. Sanchez ◽  
F.J. Sundstrom ◽  
N. Suzanne Lang

This study investigated the influence of plant size, as determined by plant density, and fruit load variation on the production and quality of bell pepper (Capsicum annuum L.) seeds. Six-week-old `Resistant Giant no. 4' bell pepper seedlings were transplanted 15, 30, 45, and 60 cm apart. Plants spaced 45 cm apart were not thinned or were thinned to one or three fruit per plant. Pepper plants grown at low plant densities produced larger fruit and seeds that germinated faster and at higher percentages than plants grown at higher densities. Assimilate export rate (AER) increased linearly with plant spacing. At harvest, C exchange rate (CER) and AER of plants with nonthinned fruit loads were ≈ 300% and 500% higher, respectively, than those of plants with one or three fruit. Fruit thinning decreased CER and AER; however, seeds produced by plants with one or three fruit had significantly higher germination percentages than plants with full fruit loads. These observations suggest that the high CERS of smaller plants with nonthinned fruit loads may have been insufficient to compensate completely for the higher sink demands. Therefore, crop cultural practices that increase the ratio of pepper plant size to total fruit count may increase the quality of seeds produced by those plants.


2013 ◽  
Vol 33 (4) ◽  
pp. 718-729 ◽  
Author(s):  
José Amilton Santos Júnior ◽  
Hans R. Gheyi ◽  
Doroteu H. G. Filho ◽  
Frederico A. L. Soares ◽  
Nildo da S. Dias

In order to identify alternatives for the use of saline water in agricultural production, the effects of the use of brackish water in the preparation of the nutrient solution for the cultivation of sunflower (cv. EMBRAPA 122-V2000) were studied in hydroponic system on consumption and efficiency of water use for the production of achenes and biomass. A completely randomized design was used, analyzed in a 5x2 factorial scheme with three replications. The factors studied were five levels of salinity of nutrient solution (1.7 - control; 4.3; 6.0; 9.0; and 11.5dS m-1) and two plant densities - one or two plants per vessel. It was concluded that the water consumption of sunflower is a variable sensitive to the salinity of the nutrient solution, especially after the fourth week of crop, and that the efficiency of water use in the production of achenes and biomass of sunflower is greater when the plant density increases from one to two plants per vessel, even under saline stress.


2010 ◽  
Vol 14 ◽  
pp. 75-83
Author(s):  
C.N. Merfield ◽  
J.G. Hampton ◽  
S.D. Wratten ◽  
P. Prapanoppasin ◽  
P. Yeeransiri

The hypothesis that by increasing carrot (Daucus carota) plant density the contribution to seed yield by the primary umbels would increase, and that therefore both seed yield and seed quality would increase, was examined in two experiments in different years in Canterbury. A radial trial design provided plant densities from 2 to 84 plants/m2 and from 4 to 100 plants/m2 in experiments one and two respectively. Seed yield increased with increasing plant density in both experiments, and at the highest density the primary umbels contributed 90% (experiment one) and 60% (experiment two) of the seed yield. In both experiments seeds from the primary umbels had a greater thousand seed weight and higher germination than those from the other order umbels, and for the second experiment they also had higher seed vigour. The quality of seeds from the primary umbels was consistently higher than that of seeds from the secondary umbels across all plant densities, and for the latter, both germination and seed vigour declined as plant density increased. These results therefore support the hypothesis, and densities higher than the 20 plants/m2 currently used commercially have the potential to increase both seed yield and quality. Keywords: seed production, primary umbels, germination, vigour, plants/m2


Italus Hortus ◽  
2021 ◽  
Vol 28 (3) ◽  
pp. 25
Author(s):  
Alessio Tallarita

With the perspective of reintroducing peanut cultivation in southern Italy about six decades after its dismissal, research was carried out with the aim to identify the best performing farming management in terms of yield and quality. In this respect, the effect of the factorial combination between four plant densities (6.1, 7.8, 10.3, and 12.1 plants m-2) and two harvest times (100 and 110 days after planting) was assessed on pod and seed yield, as well as on seed quality, antioxidant activity, and elemental composition. The later harvest time determined a 26.9% dry weight increase, but a 14.3% decrease in the number of seeds per pod. Plant density significantly influenced all the yield and growth indices except for mean seed weight. Yield and growth of each plant were best affected by the lowest plant density, whereas the opposite trend was recorded for the same parameters referred to the surface area unit. The density of 12.1 plants m-2 resulted in a 32% reduction in pods per plant compared to 6.1 plants m-2, but had the greatest effect on seed production per m-2. The leaf area index was the highest with the density of 12.1 plants m-2. The total dry weight increased by 1.7-fold from 6.1 to 12.1 plants m-2. Compared to the first harvest time, in the second one the protein content decreased by 6.8%, and total polyphenols and antioxidant activity decreased by 11.2% and 7.6%, respectively. The second harvest time led to a depletion of N, P, and Mg, by 6.8%, 6.2%, and 6.8%, respectively, and a 7.1% Ca increase. The reintroduction of peanut cultivation in southern Italy is a realistic goal, though further studies regarding the crop system management are needed.


2020 ◽  
pp. 1977-1982
Author(s):  
Nguyen Van Minh ◽  
Dinh Thai Hoang ◽  
Nguyen Van Loc ◽  
Nguyen Viet Long

Because of rainfall shortage, quinoa has the potential to supersede traditional crops that contribute to agricultural production less effectively. The current study determined the quinoa genotypes and plant density suitable for production under rain-fed conditions in red basalt soil regions. The experiments were conducted in the rainy and dry seasons of 2018/2019 using split-plot designs with three replications. In these, the main factor consisted of four quinoa genotypes and the subfactor four plant densities (13.3, 10.0, 8.0 and 6.6 plants m-2) with a row interval of 50cm and a plant interval of 15, 20, 25 and 30cm, respectively. The current study’s results showed that plant density significantly affected polynomial trends on panicle length, panicle number/plant, seed number/panicle, 1000-seed weight, seed yield, protein content, and ash content. The plant density of 8.0 plants m-2 seems to be the optimal density for quinoa under the studied conditions. Results here also indicate significant differences among quinoa genotypes for agronomical and seed quality performance. Better performances of quinoa occurred in the dry season compared to the rainy season. Atlas and Cahuil were the best adaptive quinoa genotypes in the red basalt soil regions


2002 ◽  
Vol 127 (5) ◽  
pp. 855-859 ◽  
Author(s):  
Haim Nerson

Field experiments were conducted in 1996 and 1997 to examine the effects of plant density on yield and quality of fruit and seeds of muskmelons (Cucumis melo L.). Two open-pollinated cultivars, Noy Yizre'el (Ha'Ogen type) and TopMark (western U.S. shipper type), were grown at plant densities ranging from 0.5 to 16.0 plants/m2 under commercial conditions. The highest marketable fruit yields were achieved with plant densities of 2 to 4 plants/m2. In contrast, the highest seed yields were obtained at 8 to 12 plants/m2. Seed yield index [seed yield (g)/fruit yield (kg)] was used as a parameter to define seed production efficiency. High seed yield was closely related to high value of the seed yield index. High seed yield indexes resulted from high plant densities (up to 12 plants/m2), at which the crops produced many, but relatively small fruit. In all cases, the seed yield per fruit (seed number and seed size) increased with increasing fruit weight. However, the sum of the seed yield of two small fruit was always greater than the seed yield of one, double-sized fruit. There was a clear exception with extremely small fruit (<500 g), which produced both low seed yields and poor seed quality. A positive relationship was found between fruit size and seed size in both cultivars. Nevertheless, relatively small seeds (25 to 30 mg) extracted from relatively small fruit (500 to 1000 g) showed the best performance in terms of germination and emergence percentages and rates, and in the vegetative development vigor of the seedlings.


2017 ◽  
Vol 38 (2) ◽  
pp. 595 ◽  
Author(s):  
André Sampaio Ferreira ◽  
Claudemir Zucareli ◽  
Alvadi Antonio Balbinot Junior ◽  
Flavia Werner ◽  
Antonio Eduardo Coelho

The seeding rate influences the intraspecific competition, which might affect the development and quality of seeds in soybean. However, the impact of seeding rate on the physical and physiological qualities of soybean seeds needs to be better elucidated. This study aimed to evaluate the effects of soybean plant density on the seed size as well as the effects of the interaction between the plant density and seed size on the seed mass, green seed occurence, and physiological seed quality. The experiments were carried out in the growing seasons of the years 2013/14 and 2014/15 in a Latossolo Vermelho distroférrico, under a randomized complete block design, using the NK 7059 RR cultivar with six replications. Four plant densities (150, 300, 440, and 560 thousand viable seeds ha–1) were evaluated. After the classification of seeds into four sizes, using a set of sieves, a 4 ×4 factorial scheme was used for the statistical analysis of the four plant densities and four seed sizes. The seed samples were evaluated for the seed mass, green seed percentage, germination, and vigor. Under thermal and water stress during seed development, an increase in the seeding rate led to a reduction in the green seed occurrence and an increase in the seed size and mass. However, in the absence of thermal and water stress, the seed size and mass were not altered by the seeding rate and, there was no occurrence of green seeds.


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