جستجوی مقالات مرتبط با کلیدواژه « leaf length » در نشریات گروه « کشاورزی »

The importance of rapid, non-destructive, and accurate estimation of leaf area (LA) in agronomic and physiological studies is well known. The need for such estimates of leaf area in particular for leaves with unusual shapes has led to studies relating leaf dimensions and leaf area. However, a search of literature revealed that little information is available for short day onion (Allium cepa L.). The objective of this study was to develop a statistically validated regression model for leaf area prediction from simple non-destructive measurements for onion cultivated in the South of Iran.

In order to prepare the required plant samples to measure leaf area parameters, an experiment was conducted in the cropping year 2020-2021 in a field of 300 square meters located in Hormozgan province-Rahdad district. The short-day cultivar Takii was used because of its wide planting area in the province. 40 leaves were chosen at random from plants growing in the farm, half were left for validation of the model and the other 20 leaves were subjected to measurement and calibration. The standard method (LICOR LI-3000C) was used for measuring the actual areas of the leaves. Before measuring the leaf area, two main parameters related to leaf length and width were accurately determined for each leaf. To select the best variables and the regression model for estimating leaf area, the fitted simple and multiple linear regression were subjected to the stepwise elimination method. Finally, the accuracy of the selected models was validated using the root mean square error (RMSE) and coefficient of determination (R2).

All linear models for estimation of leaf area with width (W) and length (L) as well as models including both variables were subjected to regression analysis. The results indicated that leaf length (L) is more appropriate variable for estimating onion leaf area and leaf width (W) was not able to properly describe leaf area. Based on the findings of this research leaf area estimation model with both W and L had the best prediction, with RMSE% = 8.64, RMSE= 1.76 and R2= 0.91. (Area= 0.121 + 0.01537 L2 + 0.3225 L×W).

As the understanding of plant growth and development has been increasing, such mathematical models will be very useful tools for the prediction of leaf area for many plants without the use of expensive devices. Thus, the models from the present study will enable researchers of plant growth modeling to predict leaf area non-destructively with the equations developed.Keywords: Leaf Area, Leaf Length, Leaf Width, Regression, Coefficient of determination.

To study the effect of chemical and manure fertilizers on the yield of tobacco, cultivar K326, an experiment was conducted in Taqar Tappeh village (Golestan province) in 2016 in a randomized complete block design with four replications. Treatments including chemical fertilizer (100%), livestock manure (at two levels of 10 and 20 t/ha), the combination of chemical and manure fertilizers (10 t/ha of manure + 50% chemical fertilizer), and no fertilization (control) During the growing period and before harvest, necessary evaluations were performed on leaf length, leaf width, leaf chlorophyll index (spad), leaf fresh weight, leaf dry weight, leaf nicotine percentage, average price and gross income per hectare. The results showed that except for chlorophyll index, mean price and leaf nicotine percentage, other traits such as leaf length and width, fresh and dry leaf weight and gross yield per hectare were statistically significant. Comparison of means also showed that the highest leaf length (63.2 cm), leaf width (32.5 cm), leaf fresh weight (35851 kg/ha.), dry leaf yield (6343 kg/ha.) and gross income (508550072 Rials) was obtained from the combined treatment of 10 t/ha of manure + 50% chemical fertilizer. Therefore, the findings of this study showed that there is a possibility of combined application of chemical and livestock fertilizers without a significant reduction in tobacco leaf yield and no environmental degradation consequential in a sustainable agricultural system.

In order to investigate the effect of compensatory behavior of planting density, corm weight and planting depth on vegetative characteristics and yield of saffron stigma (Crocus. Sativus L.), a factorial split plot experiment with a randomized complete block design with three replications in the research center and Agricultural education and natural resources of Khorasan Razavi (Gonabad Research Station) was conducted in the cropping years 2018-2020. In this study, planting density treatment (in four levels of 60, 90, 120 and 150 corms per square meter) in the main plot and factorial planting depth (in two levels of 15±2 and 25±2 cm from the soil surface) and corm weight (in two Levels 4± 1 and 8 ± 1 gr) were located in the subplot. The results showed that increasing the density from 60 to 150 corms per square meter caused a significant increase in flower number, flower fresh weight and stigma dry weight, number of plants, number of leaves per plant, average length of a leaf and total leaf length per square meter. Accordingly, increasing the weight of coriander from 4 to 8 gr significantly increases flower number, flower fresh weight, stigma dry weight, number of plants, number of leaves per plant, average length of a leaf, total leaf length per square meter and total Leaf length per plant in the first and second years and reduced flower number, flower fresh weight and stigma dry weight in the third year. The results also showed that increasing the planting depth from 15 to 25 cm caused a significant decrease in all studied traits of saffron. The effect of dual and triple interactions on the studied traits was mainly significant. Overall, the results showed that the use of larger mother corms has a relative priority only in the early years and the importance of its effect decreases with increasing farm age. Based on this, it seems that it is possible to have a different strateg and with a combination of less depth and especially more density to compensate for the effect of corm weight and achieved more overall performance.

The aim of this study is to investigate the effect of foliar application of Acadian seaweed extract and Biomix liquid poultry manure on vegetative growth, corm, and yield of saffron. The experiment was conducted in a randomized complete block design with three replications in the city of Ferdows city during the 2017-2018 growing year. Experimental treatments included four levels of Acadian seaweed extract (0, 1, 1.5, and 2 kg. l000 L-1 water) and four levels of liquid Biomix liquid poultry manure (0, 4, 5, and 6 L. l000 L-1 water). The results showed a significant effect of treatments on the studied traits, such as maximum number of flowers (99.50 N. m-2), fresh yield of flowers (33.34 g.m-2), dry weight of saffron stigma (0.341 g. m-2), dry leaf weight (0.592 g plant-1), and leaf length (63.75 cm) obtained in 2 kg. l000 L-1 seaweed extract. Besides, the results showed a significant effect of liquid poultry manure on flower number and yield (94.250 N.m-2 and 32.285 g. m-2, respectively), leaf length (60.66 cm), fresh and dry leaf weight (0.74 and 0.46 g.m-2, respectively), and total weight of replacement corm (37.02 g.m-2). Also, the least amount of the mentioned traits were observed from the control treatment. The interaction between these two fertilizers was also significant in fresh and dry leaf weight and the total and average diameter of replacement corm. Thus, fresh and dry leaf weight (210% and 273%, respectively) were highest in the treatment of 2 kg. l000 L-1 of seaweed extract and 6 L. l000 L-1 of liquid poultry manure. Moreover, total and average diameter of replacement corm (33% and 50%, respectively) were highest in the treatment of 2 kg. l000 L-1 of seaweed extract and no liquid poultry manure. According to the results of this study, the use of Acadian seaweed extract (2 kg. l000L-1 water) alone or in combination with Biomix liquid poultry manure (6 L. l000 L-1 water) can play an important role in enhancing the vegetative growth, corm, and yield of saffron.

Information on nature and magnitude of present variability in a population is an important pre-requisite for starting any breeding program. Moreover, the knowledge about correlations among various characters and further partitioning them into direct and indirect effects is a rational approach to understanding such a relationship which is helpful for multiple trait selections. The present study was undertaken to determine the genetic variability and heritability of important economic characters, interrelationships among them and their direct and indirect effect on yield in Iranian onion landraces. Seeds of twenty landraces were planted using a randomized complete block design with three replications in East Azarbayjan Agricultural and Natural Resources Research and Education Center for two years. Thirty plants were selected at random in each plot to record the observations on yield/plant, leaf length, number of leaves/plant, bulb length, bulb diameter, number of centers, number of edible layers, bulb dry matter and shape index. Broad-sense heritability, expected genetic advance, genetic variability, correlation coefficient, and path coefficient analysis calculated. Analysis of variance showed significant effects for all studied traits. Therefore, sufficient genetic variability exists among the onion landraces.
The bulb yield per plant had the utmost phenotypic and genotypic coefficients of variation (PCV and GCV) (27.81% and 24.27%, respectively). This shows the prevalence of greater genetic variability among the genotypes which offers good opportunities for crop improvement through selection. Medium PCV and GCV were displayed in bulb diameter, number of leaves/plant, leaf length, number of center and shape index. But number of edible layers and bulb dry matter showed low GCV and PCV indicating less scope of selection as they are under the influence of environment.
The estimates of phenotypic coefficients of variation were higher than their corresponding genotypic coefficients of variation for all the traits. That might be due to interaction of genotype with environment to the same degree or other denoting environmental factors influencing the expression of these traits. A high degree of disparity between PCV and GCV for most of the traits showed their susceptibility to environmental fluctuations.
In present study, the estimates of broad-sense heritability ranged from 16% for number of edible layers to 88% for shape index. Heritability estimates were very high for bulb diameter, leaf length, and number of centers and shape index, indicating the possibility of success in selection. Heritability estimates were relatively high for yield/plant, bulb length and number of leaves/plant. In addition, moderate heritability estimate was observed for bulb dry matter. On the other hand, low heritability estimates was also observed for number of edible layers indicating the limited scope for improvement of this trait through selection.
The expected genetic advance expressed as a percentage of the mean by selecting the top 5% of the accessions, varied between 1.6% for number of edible layers to 43.55% for yield/plant. Genetic advance as percentage of mean was maximum for yield/plant followed by number of centers, shape index, leaf length, bulb diameter, number of leaves/plant and bulb length. Genetic coefficient of variation, heritability, and genetic advance were high in yield/plant. Therefore, yield/plant could be useful basis for selection.
In most traits, the genotypic correlation coefficients were higher than the phenotypic correlation coefficients which indicated the inherent association among various characters independent of environmental influence.
Bulb-yield/plant showed significant positive correlation with leaf length, leaf number, bulb diameter and bulb length at phenotypic and genotypic levels. So, improvement of leaf length, leaf number, and bulb diameter and bulb length traits could improve the capacity of the plants to synthesize and translocate photosynthates to the bulb.
The path analysis showed that bulb diameter has the largest positive direct effect on bulb-yield/plant. The indirect effect of length of leaves on onion yield through bulb diameter was considerable. Accordingly, selection of plants with larger leaf length and bulb diameter could be suitable for breeding onion for higher yield. The presence of negligible residual effect (0.06) indicated that most of the important traits contributing to yield were included in the path analysis. Results showed that potential of onion landraces with high genetic diversity in selection for development of cultivars with favorable agronomic and market traits is high. The high genetic coefficient of variation, heritability, and genetic advance were found in yield/plant. Therefore, yield/plant could be useful basis of selection. In addition, the path analysis showed that selection of plants with larger leaf length and bulb diameter could be suitable for breeding onion for higher yield.

Saffron is the main medicinal plant of Iran. In order to study the relations of sink and source between saffron leaves and corms, a split plot experiment was conducted on the basis of complete randomized block design with three replications in a field in the Ashkezar city of Yazd province during 2013-2014. The main plots and sub plots were irrigated with three levels (100%, 75% and 50% of ETc) and the fertilization management methods including control (without any fertilizer or manure), applying 10 t/ha cow manure, 10 t/ha vermicompost by spreading, 10 t/ha vermicompost buried under planting corm rows, 5 t/ha vermicompost buried under planting corm rows, or spraying 10 l/ha Humaster Saffron fertilizer for 1 or 2 times after flowering. The Pearson correlation coefficients were calculated between leaf length in every measuring stage and the weight of biggest corm at the end of the first year (as daughter corm). The results showed that correlation coefficients were decreased until 40 days after emergence and then increased. The highest correlation coefficient reached around 80 days after emergence and followed until the end of the growth period. The best corm yield was reached for 10 t/ha vermicompost buried under planting corm rows. Also under different irrigation regimes, the best results were obtained through full irrigation treatment.

Decrease in genome content may play a role in environmental adaptation. Many studies were reported significant correlation between genome size، weather condition and germination percentage. Relative genome content and its correlation with seedling establishment of 14 populations of tall fescue collected from various regions in Iran and two commercial tall fescue cultivars were studied under drought conditions. Results showed that except one entry diploid (Brojen = 2x)، all entries were hexaploid (6x). Cluster analysis revealed that the populations fell into four groups. Isfahan (Group II: average DNA content 17. 92 pg) and Ghochan (Group VІ: average DNA content 18. 56 pg) with 100% and 6. 7% final emergence and 8. 8، 2. 3 cm leaf length respectively in 40% FC soil water content wree the most tolerable and sensitive entries under drought stress. Relative genom content of the wild populations and two commercial cultivar were negatively correlated with emergence (r=-0. 56) and leaf length (r=-0. 61). The reduction in genome size may be a mechanism of adaptation to arid environments. The drought tolerance was observed among the entries that grouped in cluster I and II represent potentially useful germplasm for a breeding program.

CO2 enrichment in greenhouse is a suitable way which reduces production time، better growth vigor and also higher plant quality. The main aim of this study was to find out the effects of artificial CO2 enrichment under different light levels on rooting of the ornamental foliage Codiaeum variegatum. The experiment was planned as a split plot based on a completely randomized design. CO2 was considered as the main plots (380 as control، 750 and 1050 ppm) and these light intensities as the sub plots (10000 as control، 12000 and 14000 Lux) were used. Results showed a significant increase on measured traits with elevating levels of CO2 and light. Highest measured values of different traits were observed at 12000 Lux light intensity and 750 ppm CO2 enrichment. Light intensity × CO2 interaction had a significant effect on leaf length، leaf number، root quality، root volume، root length (P≤0. 01) and rooting percentage at (P≤0. 05). Spad chlorophyll unit was not noticeably significant. Rooting and plant growth generally raised along with both light intensity and CO2 elevation.

Spinach is an important leafy vegetable and consumed as fresh and processed. To study the effect of autumn sowing date and planting method on yield and yield components of spinach cv. Varamin 88, a field experiment was carried out in 2006-2007 and 2007-2008 growing seasons in agricultural research station of Varamin, Varamin, Iran. The experiment was conducted as split plot arrangement in randomized complete block design with four replocations. Three planting methods (flat, one row on the middle of 60 cm bed and two rows on 60 cm bed) were randomized in sub plots, and three autumn sowing dates (05 November, 21 November and 06 October) were assigned to main plots. Yield, length and width of leaf, duration from sowing to harvest, leaf number plant-1 and weight of ten plants were measured and recorded. Results showed that autumn sowing date of 05 November and planting of two rows on 60 cm bed was the best treatment for spinach cv. Varamin 88 in Varamin and similar regions.