Combination Of Plant Density Research Articles

Managing White Mold on Common Bean with Type III Growth Habit by Integrating Partial Resistance, Plant Density, and Fungicide.

The combination of plant density, fungicide, and levels of genotype resistance to white mold (WM) has not been studied for its effect on performance of common bean with type III growth habit under WM pressure. We established four sprinkler-irrigated trials in the fall to winter season in Brazil, combining density (8, 14, 20, or 26 plants/m2), genotype (susceptible or partially resistant to WM), and fungicide to manage WM (two fluazinam applications or without fluazinam) at 0.5 m row spacing in fields infested with sclerotia. One trial was established in a warm region, aiming to obtain low WM pressure. For three trials, the linear mixed model was used. WM pressure in the trials ranged from low to high. Genotype × density × fungicide and genotype × density interactions were not significant for incidence, severity, and yield for all trials. In the three trials, severity was 29% lower at eight than at 26 plants/m2, and yield at 14 plants/m2 (3,294 kg/ha) was 14% higher than yield at eight plants/m2 (P = 0.035) where fluazinam was applied. However, without fluazinam, density did not affect yield. In conclusion, choices of plant density for type III bean cultivars do not need to take into account their resistance levels to WM in the fall to winter season. However, fungicide treatment to manage WM affects the choice of density, with 8 to 12 plants/m2 recommended if fungicide is not an option to manage WM (as in organic systems), and 10 to 14 plants/m2 recommended if fungicide applications are likely.

Effects of plant density and mepiquat chloride application on cotton boll setting in wheat–cotton double cropping system

Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction. Boll-setting period synchronisation and more yield bolls distributed at the upper and middle canopy layers are also required for harvesting. The objective of this study is to quantify the individual and interaction effects of plant density and plant growth regulator mepiquat chloride (MC) on temporal and spatial distributions of yield bolls, as well as yield and yield components. During the 2013–2016 cotton growing seasons, the experiments were conducted on a short-season cotton cultivar CRRI50 at Yangzhou University, China. Various combinations of plant density (12.0, 13.5 and 15.0 plants m−2) and MC dose (180, 270 and 360 g ha−1) were applied on cotton plants. The combination of 13.5 plants m−2 and 270 g ha−1 MC resulted in the greatest boll number per unit area, the highest daily boll setting number and more than 90% of bolls positioned within 45–80 cm above the ground. In conclusion, appropriate MC dose in combination of high plant density could synchronize boll-setting period and retain more bolls at the upper and middle canopy layers without yield reduction in the system of direct-seeded cotton after wheat harvest, and thus overcome the labor-intensive problem in current transplanting cropping system.

Plant density and nitrogen topdressing of high-altitude main-season corn

An appropriate combination of plant density with nitrogen (N) fertilization can optimize corn growth and increase grain yields. This study evaluated the effects of nitrogen topdressing rates and plant density levels on the agronomic performance of corn. The early hybrid DKB 240 YG, with high yield potential and stability, was evaluated in two summer crops in Mauá da Serra, Paraná (950 m asl), in a Cfb climate, on a Rhodic Eutrudox. The experiment was arranged in randomized complete blocks and subdivided plots with four replications. The plant densities (60,000; 75,000; 90,000 and 105,000 plants ha-1) were assessed in the plots and the nitrogen (ammonium nitrate 32% N) topdressing rates (0, 60, 120, 180 and 240 kg ha-1) in the subplots. The stem diameter, plant height, ear insertion height and grain yield were evaluated. The stem diameter, plant height, ear insertion height and grain yield were influenced by the interaction between plant density and nitrogen topdressing under the tested high-altitude edaphoclimatic conditions. The stem diameter of corn plants decreased due to the increase in plant density whereas nitrogen topdressing attenuated this reduction. Maximum plant height was observed at a density of 75,000 plants ha-1 associated with a topdressing of 169 kg ha-1 of N, and highest ear insertion at 60,000 plants ha-1 and 168 kg ha-1 of N. Corn yield was highest at a density of 105,000 plants ha-1 associated with a topdressing of 185 kg N ha-1 of N.

The influence of seed sowing norms rate and row spacing on the yield of sorghum grain grown at eastern forest-steppe of Ukraine

In fact, there are no data on the effect of different combinations of plant density and the shape of their nutrition zone on the level of grain productivity of various stem systems (main and lateral rods of different orders) and their contribution to the total production of the plant yield capacity. This is precisely why our research was aimed to identifying the optimal combinations of sowing rates with sowing practices, which would allow for the development of the largest sorghum hybrid grain production capacity and determine the effect of different systems of stems on the formation of the highest cereal productivity of grain sorghum hybrids. The aim of research was to determine the connection between the components of growing technology (seeding rates and ways of sowing) that reflect the level of coenotic stress in plant crops.

Field Population Density Effects on Field Yield and Morphological Characteristics of Maize

The objective of this study was to evaluate the effect of population density and row spacing on field yield and other morphological characteristics of two commercial F1 maize hybrids of different biological cycle (Costanza and LG3535) in a four-year period. Field experiments were conducted in a split-split plot design, in two population densities and three types of row spacing, involving single or twin rows. Ten plants from each plot were selected randomly and plant height, ear emergence height, ear length, ear diameter, number of grain rows per ear, grains number per ear, grain weight per ear, spindle weight per ear, and spindle diameter were measured. Grain yield of each plot was measured and field yield, thousand kernel weight and bulk density were calculated. Four years of experimentation clarified that environmental conditions may distort all other effects of the factors studied. This study points out the best combination of plant density and row configuration. High populations and twin or narrow rows (50 cm) were found to be important for maximizing yield of modern maize hybrids. Differences between hybrids were not significant, although Costanza exhibited greater mean field yield performance (14,364 kg/ha). Plant density was a significant factor and yield was increasing from low to high plant population (from 13,900 to 14,527 kg/ha). Plant density and genetic materials affected thousand kernel weights that showed the highest value at low plant density (364 g). Row spacing showed a significant interaction with year. Generally, twin or narrow rows favored many characteristics, especially height characteristics. Plant height reached 320 cm and ear height reached 149 cm. Ear diameter was favored by low plant density. Some ear characteristics were found to be depended on the genotype behavior in the certain environmental conditions. For spindle weight per ear, a total interaction between years, row spacing, hybrids, and plant density was found. For spindle diameter, various significant interactions were found, including years (maximum also in 2009), row spacing, and plant density and also row spacing, hybrids, and plant density. Many correlations were found significant especially between yield and thousand kernel weight, spindle weight per ear, and ear diameter that may prove to be useful for plant breeders.

Correlation and Regression Studies of Rice Varieties Influenced by Combination of Plant Density and Fertilizer Levels

Correlation and Regression Studies of Rice Varieties Influenced by Combination of Plant Density and Fertilizer Levels

Respuesta de fertilización y densidad de siembra en líneas de maíz.

An experiment was carried out in the Cotaxtla Experimental Field during the 1995 spring-summer cycle to study effects of soil mineral fertilization and population density in six parentallines of the best hybrids from tropical Mexico. The experimental desigp. used was the randomized block s in divided plots with two repetitions, and a complete factorial treatment design 24. Large plots consisted of lines LE-36, LE-37, LRB-14, D-539, POB 21 and POB 43. Small plots were formed by the treatments resulting from the combination of plant density (PD) at 50, and 62.5 thousand pl/ha, nitrogen (N), phosphorus (P) and potassium (K) at 161-184,46-69 and 0-60 kilograms per hectare, respectively. Out of the 18 variables studied, only 4 were not significant for the lines. The density of 62,500 pVha showed the highest grain yield. However, the same trait did not respond to a more intense fertilization with N-P-K, but the combination of each major primary element at its highest level helped to stop the negative effect of high density in grain traits. There was an additive effect in the interaction lines x density for grain yieId. This variable increased in all lines when there was a greater number of pIants per area unit.

Comprehensive Evaluation Method for Effects of Nitrogen on Summer Maize Varieties at Different Stages

Understanding nitrogen effects at various maize growing stages will benefit to fertilization regime recommendation and thus improve grain yield. Three maize varieties, Xundan 20, Nonghua 101, and Zhongnongda 4, were cultivated with different combinations of plant density and fertilizer levels in the experiment. During the growth period, daily temperature was recorded and leaf, stem, bract, spike-stalk and grain were sampled for the analysis of nitrogen concentration. Considering the three main factors which are genetic characteristics, environment impacts(light and temperature) and population differences affecting nitrogen effect comprehensively, the modified BLUP(Best Linear Unbiased Prediction) method was used to evaluate and analyse the nitrogen effect on different maize varieties and different organs at various growing stages. The results showed that correlation coefficients(r) between simulated daily dry matter accumulation and observed data were ranged from 0.88 to 0.99. Comparing independent sample to test evaluation model, paired t-test analysis showed no significant difference at P 0.05. The fitting effect was good in this model. For different growth stages and different maize varieties, there were significant differences for the parameters of nitrogen effect. The fixed effect of nitrogen showed significant difference at various growth stages and in different nitrogen constituents at the same stage. In conclusion, modified BLUP method can be well used to evaluate and analyse characteristics of the nitrogen effect, which can explain the function and influence of nitrogen accumulation on dry matter production at each growth stage of different maize varieties. It can further illustrate the biological law in maize, such as the common characteristics of nitrogen effect, the genetic differences between the varieties and the influence mechanism of sunlight, temperature and population.

Tillering responses of rice to plant density and nitrogen rate in a subtropical environment of southern China

Plant density and nitrogen (N) input are two important factors influencing the tiller production in rice. However, it is not clear whether the negative effect of reducing planting density on tiller number per unit land area and consequently on grain yield can be offset by applying more N fertilizer. To address this question, field experiments were conducted at the Experimental Farm of Guangxi University, Guangxi Province, China in early and late rice-growing seasons in 2012. Two hybrid rice cultivars, Shenyou 9516 and Y-liangyou 087, were grown under two combinations of plant density and N rate: a locally recommended combination (C1); a combination of a reduced plant density and an increased N rate (C2). Y-liangyou 087 had higher tillering capacity than Shenyou 9516. Tiller number was largely lower in late season than in early season. High leaf area index and low N concentration in shoot were responsible for the low tiller number in late season. Number of maximum tillers and panicles per m2 and grain yield were lower in early season but higher or equal in late season under C2 compared to those under C1. The higher maximum tillers per m2 under C2 in late season was attributed to large increase in maximum tillers per hill. Although maximum tillers per hill under C2 in early season were also increased, this increase was not sufficient to compensate for the reduced plant density. Similar to maximum tillers per hill, N uptake per hill was largely higher under C2 than under C1 in late season, while in early season the difference was relatively small. Daily temperature during the initial 20 days after transplanting was approximately 5°C higher in late season than in early season, which was partly responsible for the larger difference in N uptake per hill between C1 and C2 in late season than in early season. Our results suggest that the decreased tiller number per unit land area and grain yield caused by reducing plant density cannot necessarily be compensated for by applying more N fertilizer.

The interaction of stem strength with plant density and nitrogen application in wheat progeny from parents with varying stem strength

Lodging is largely influenced by the strength of the stem, which is determined by the length of the internodes, the thickness of the stem and stem cortex and the solidity of the stem. The aim of this study was to study the effect of different N treatments and plant densities on stem strength of selected cultivars and their hybrids. Four combinations of plant density and N fertilizer were evaluated. Plant height, length and diameter of each internode, stem cortex and pith thickness, breaking weight and stem strength were measured. When plant density and N fertilizer increased, stem strength decreased, but the combined effect of these two factors was higher than when applied separately. The cultivar which performed the best in all treatments was a double haploid which expressed the solid stem trait for all internodes. Cultivars and hybrids with normal stems performed the poorest. Breaking weight was positively correlated with stem strength for all four treatments. Shorter internodes caused stronger stems. Stem cortex thickness was also positively correlated with stem strength for all the treatments. This shows that the thicker the stem cortex and the thicker the pith, the stronger the stem of the plant.

Application of the CSM-CERES-Rice model for evaluation of plant density and nitrogen management of fine transplanted rice for an irrigated semiarid environment

The objectives of this study were to evaluate the performance of the cropping system model (CSM)-CERES-Rice to simulate growth and development of an aromatic rice variety under irrigated conditions in a semiarid environment of Pakistan and to determine the impact of various plant densities and nitrogen (N) application rates on grain yield and economic return. The crop simulation model was evaluated with experimental data collected in experiments that were conducted in 2000 and 2001 in Faisalabad, Punjab, Pakistan. The experimental design was a randomized complete block design with three replications and included three plant densities (one seedling hill−1, PD1; two seedlings hill−1, PD2; and three seedlings hill−1, PD3) and five N fertilizer regimes (control, N0; 50 kg ha−1, N50; 100 kg ha−1, N100; 150 kg ha−1, N150; and 200 kg ha−1, N200). To determine the most appropriate combination of plant density and N levels, four plant densities from one seedling hill−1 to four seedlings hill−1 and 13 N levels ranging from 0 to 300 kg N ha−1 (52 scenarios) were simulated for 35 years of historical daily weather data under irrigated conditions. The evaluation of CSM-CERES-Rice showed that the model was able to simulate growth and yield of irrigated rice in the semiarid conditions, with an average error of 11% between simulated and observed grain yield. The results of the stimulation analysis result showed that two seedlings hill−1 along with 200 kg N ha−1 (PD2N200) produced the highest yield as compared to all other scenarios. Furthermore, the economic analysis through the mean gini dominance also showed the dominance of this treatment (PD2N200) compared to the other treatment combinations. Thus, the management scenario that consisted of two seedlings hill−1 and 200 kg N ha−1 was the best for high yield and monitory return of irrigated rice in the semiarid environment. The mean monetary returns ranged from 291 US $ ha−1 to 1 460 US $ ha−1 among the 52 production options that were simulated. This approaching was demonstrated as effective way to optimize the density and N management for high yield and monetary return. It will help the rice production.

INTERACTIVE EFFECTS OF DURATION OF LONG-DAY PERIOD AND PLANT DENSITY ON EXTERNAL QUALITY OF CUT CHRYSANTHEMUM

To quantify the effect of duration of long-day (LD) period and plant density on several chrysanthemum external quality aspects, a greenhouse experiment was conducted under summer conditions. Chrysanthemum ‘Reagan Improved’ was planted in May and grown under three durations (2, 9 and 16 days) of LD period combined with three plant densities (48, 64 and 80 plants m-2). Plant height linearly increased with duration of LD period. Decreasing LD period from 16 to 2 days resulted in 25% shorter plants, but a marketable height was always reached (> 65 cm). Plant height showed an optimum response to plant density, however this effect was rather small (= 7%). Total number of flowers and flower buds per plant (NoF) increased with increased assimilate supply, measured as total plant fresh mass (TFM), whereas individual flower size (area and dry mass) was not affected. For example, plants that received 16 days of LD period and grown at 48 plants m-2 were the heaviest (91.5 g plant-1) and obtained the highest NoF (28 flowers plant-1). In contrast, 2 days of LD period and 80 plants m-2, resulted in 57% lighter plants with 67% less flowers. A model to predict NoF was developed based on TFM (NoF= 0.353 TFM – 5.66; R2= 0.93). It was concluded that a similar TFM could be obtained using several combinations of plant density and duration of LD, without affecting either NoF or individual flower size. A photosynthesis-driven crop growth model was validated and used to quantify this trade-off, when aiming at a certain TFM. It was shown that such trade-off is dependent on the planting date throughout the year

A simple model to interpret the effects of sunflower crop management on the occurrence and severity of a major fungal disease: Phomopsis stem canker

Phomopsis stem canker ( Diaporthe helianthi Munt.-Cvet. et al.) causes drastic reductions in yield and oil content in the sunflower ( Helianthus annuus L.) crop. The use of disease-tolerant genotypes and fungicides is the basis of current disease control. Both for economic and environmental reasons, control by means of cultural practices should be promoted more. From 1992 to 2002, INRA and Cetiom collaborated to study the effects of sunflower crop management on the frequency and severity of Phomopsis attacks. As plant density and nitrogen rate significantly affect the development of sunflower leaf area, use of the fraction of photosynthetically active radiation intercepted by the canopy (fPARi) was suggested as a synthetic indicator of canopy management. In 1994, an exponential relation was observed between the proportion of sunflower stems bearing a Phomopsis lesion in mid-August and the fPARi by the canopy at anthesis in early July. This relation was successfully tested for a range of unprotected situations (1994–2000) corresponding to moderate infection pressure and various combinations of plant density and N fertilization. Such a reference curve was used to analyse the response of sunflower to stem canker infection in a range of cultural conditions: (1) high inoculum; (2) drought during head development or soon after leaf infection; (3) application of a fungicide at the early stages of flower bud development; (4) late sowing (May); (5) use of very susceptible or resistant genotypes. This simple model could help to interpret the origin of genotypic susceptibility to stem canker (crop architecture and/or physiology) and also to predict the potential risk of disease development for a given management scenario.

Estimating loss in grain yield due to suboptimal plant density and non-uniformity in plant spacing

The percentage loss in grain yield for a crop of raingrown sunflower was quantified, using a multiple regression technique, for 9 combinations of plant density and uniformity in plant spacing. For each combination, partitioning loss in grain yield involved the reduction in grain yield (g/m2), the number of plants involved and the effective area of crop which those plants represented (m2). Relative to an achievable yield potential of 692 kg/ha, any reduction in grain yield was mainly due to the lack of plants at a density less than 5.00/m2 (7.4% yield reduction) and to non-uniformity in plant spacing at a density greater than 5.001m2 (5.6% yield reduction). The multiple regression technique is considered more valuable than other methods because it provides quantitative estimates of per cent loss in grain yield attributable to suboptimal plant density and non-uniformity in plant spacing. The technique should be of value in assessing the effect of poor crop establishment at a site or in evaluating improved crop establishment. A more general relationship capable of predicting per cent loss in grain yield based on data taken at the time of establishment is still required.

Alternative production strategies for greenhouse tomatoes using supplemental lighting

The yield response of greenhouse tomatoes ( Lycopersicon esculentum Mill. ‘Vendor’) was examined under both natural light conditions (light available from the sun) and with the addition of 6.48 moles m −2 day −1 supplemental light from a high-pressure sodium (HPS) source. Tomato crop yield significantly increased as plant population density increased when HPS lighting was employed. No significant yield increase was obtained with increased plant density under natural light conditions. Four production strategies (representing four combinations of plant density and the number of trusses produced per plant) were tested. A significant yield increase was obtained with HPS lighting relative to the unlit control for all of the production strategies used. Similar total yields were obtained regardless of the production strategy when HPS lighting was used.

Competition between two annual herbs, Atriplex gmelini C.A. Mey and Chenopodium album L., in mixed cultures irrigated with seawater of various concentrations.

Atriplex gmelini and Chenopodium album were grown in mixed stands with various combinations of plant density and mixing ratio, and irrigated with seawater of different concentrations (f) to formulate the effect of changing concentration on the competitive relationship between the species.In single-species stands, the mean plant weight (w)∼plant density (ρ) relation for each level of seawater concentration could well be described by Shinozaki-Kira's reciprocal equation of crowding effect. On the other hand, the response of w to f followed Hozumi-Shinozaki's formulation for an optimum growth factor at respective levels of ρ.By introducing the density conversion factor (q) that enabled the conversion of the density of one species to that of the other species on the basis of their effects on growth of respective species, the results of mixed culture experiments could be successfully formulated by similar reciprocal equations. The dependence of q and coefficient values of the equations on seawater concentration was also formulated in a way similar to the case of pure stands.Based on all these quantitative relations, a comprehensive formulation was developed to describe the effects of plant density and seawater concentration on the growth of two species in mixed stands. The behavior of species biomass in mixed stands was then examined by means of the formulation.It was thereby demonstrated that the relative dominance of two species in a mixed stand was strongly affected not only by total plant density and density ratio between the two species but also by concentration of irrigated seawater. Even the optimum seawater concentration that resulted in the maximum species biomass differed between pure and mixed cultures.