scholarly journals Optimizing Planting Density and Impact of Panicle Types on Grain Yield and Microclimatic Response Index of Hybrid Rice (Oryza sativa L.)

Author(s):  
Guotao Yang ◽  
Xuechun Wang ◽  
Farhan Nabi ◽  
Hongni Wang ◽  
Changkun Zhao ◽  
...  

AbstractThe architecture of rice plant represents important and complex agronomic traits, such as panicles morphology, which directly influence the microclimate of rice population and consequently grain yield. To enhance yield, modification of plant architecture to create new hybrid cultivars is considered a sustainable approach. The current study includes an investigation of yield and microclimate response index under low to high plant density of two indica hybrid rice R498 (curved panicles) and R499 (erect panicles), from 2017 to 2018. The split-plot design included planting densities of 11.9–36.2 plant/m2. The results showed that compared with R498, R499 produced a higher grain yield of 8.02–8.83 t/ha at a higher planting density of 26.5–36.2 plant/m2. The response index of light intensity and relative humidity to the planting density of R499 was higher than that of R498 at the lower position of the rice population. However, the response index of temperature to the planting density of R499 was higher at the upper position (0.2–1.4%) than at the lower position. Compared with R498, R499 at a high planting density developed lower relative humidity (78–88%) and higher light intensity (9900–15,916 lx) at the lower position of the rice population. Our finding suggests that erect panicles are highly related to grain yield microclimatic contributors under a highly dense rice population, such as light intensity utilization, humidity, and temperature. The application of erect panicle rice type provides a potential strategy for yield improvement by increasing microclimatic conditions in rice.

2021 ◽  
Vol 12 ◽  
Author(s):  
Adnan Noor Shah ◽  
Mohsin Tanveer ◽  
Asad Abbas ◽  
Mehmet Yildirim ◽  
Anis Ali Shah ◽  
...  

High plant density is considered a proficient approach to increase maize production in countries with limited agricultural land; however, this creates a high risk of stem lodging and kernel abortion by reducing the ratio of biomass to the development of the stem and ear. Stem lodging and kernel abortion are major constraints in maize yield production for high plant density cropping; therefore, it is very important to overcome stem lodging and kernel abortion in maize. In this review, we discuss various morphophysiological and genetic characteristics of maize that may reduce the risk of stem lodging and kernel abortion, with a focus on carbohydrate metabolism and partitioning in maize. These characteristics illustrate a strong relationship between stem lodging resistance and kernel abortion. Previous studies have focused on targeting lignin and cellulose accumulation to improve lodging resistance. Nonetheless, a critical analysis of the literature showed that considering sugar metabolism and examining its effects on lodging resistance and kernel abortion in maize may provide considerable results to improve maize productivity. A constructive summary of management approaches that could be used to efficiently control the effects of stem lodging and kernel abortion is also included. The preferred management choice is based on the genotype of maize; nevertheless, various genetic and physiological approaches can control stem lodging and kernel abortion. However, plant growth regulators and nutrient application can also help reduce the risk for stem lodging and kernel abortion in maize.


2020 ◽  
pp. 1662-1669
Author(s):  
Marcus Willame Lopes Carvalho ◽  
Edson Alves Bastos ◽  
Milton José Cardoso ◽  
Aderson Soares de Andrade Junior ◽  
Carlos Antônio Ferreira de Sousa

The objectives of this study were to: (i) evaluate the effect of different spatial arrangements on morpho-physiological characteristics and (ii) determine the optimal spatial arrangement to maximize grain yield of the maize hybrid BRS-3046 grown in the Mid-North region of Brazil. We tested two row spacings (0.5 and 1 m) and five plant densities (2, 4, 6, 8, 10 plants m-2), which corresponded to 10 different plant spatial arrangements. Different morphophysiological variables, gas exchange rates and grain yield were measured. The increased planting density led to a linear increase in LAI, regardless of row spacing, while the net CO2 assimilation rate increased until the density of 4 and 6 plants m-2, under a row spacing of 0.5 and 1.0 m, respectively. On the other hand, we found a linear reduction in the stomatal conductance with increasing planting density. The intercellular CO2 concentration and the transpiration rate were higher in the widest row spacing. The instantaneous efficiency of carboxylation, in turn, showed a slight increase up to the density of six plants m-2, then falling, regardless of row spacing. Increasing plant density resulted in a linear increase in plant height and ear insertion height, regardless of row spacing. However, it had an opposite effect on stem diameter. Grain yield, in turn, increased up to 7.3 plants m-2 at a row spacing of 0.5 m and 8 plants m-2 at a row spacing of 1.0 m. This spatial arrangement was considered as ideal for achieving maximum yield


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.


2021 ◽  
Author(s):  
Vince Ndou ◽  
Edmore Gasura ◽  
Pauline Chivenge ◽  
John Derera

Abstract Development of ideal breeding and crop management strategies that can improve maize grain yield under tropical environments is crucial. In the temperate regions, such yield improvements were achieved through use of genotypes that adapt high plant population density stress. However, tropical germplasm has poor tolerance to high plant population density stress, and thus it should be improved by temperate maize. The aim of this study was to estimate the genetic gains and identify traits associated with such gains in stable and high yielding temperate x tropical hybrids under low and high plant population densities. A total of 200 hybrids derived from a line x tester mating design of tropical x temperate germplasm were developed. These hybrids were evaluated for grain yield and allied traits under varied plant population densities. High yielding and stable hybrids, such as 15XH214, 15XH215 and 15XH121 were resistant to lodging and had higher number of leaves above the cob. The high genetic gains of 26% and desirable stress tolerance indices of these hybrids made them better performers over check hybrids under high plant population density. At high plant population density yield was correlated to stem lodging and number of leaves above the cob. Future gains in grain yield of these hybrids derived from temperate x tropical maize germplasm can be achieved by exploiting indirect selection for resistance to stem lodging and increased number of leaves above the cob under high plant density conditions.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Guangzhou Liu ◽  
Wanmao Liu ◽  
Yunshan Yang ◽  
Xiaoxia Guo ◽  
Guoqiang Zhang ◽  
...  

Abstract Marginal superiority is a common phenomenon in crops, and is caused by the competitiveness of individual plant for resources and crop adaptability to crowded growth conditions. In this study, in order to clarify the response of marginal superiority to maize morphology and plant-density tolerance, field experiments without water and nutrition stress were conducted at Qitai Farm in Xinjiang, China, in 2013–2014 and 2016–2019. The results showed that no more than three border rows of all the cultivars had marginal superiority under high density, about 90% of all the cultivars had no more than two border row that had marginal superiority and a significant negative correlation was observed between marginal superiority and population grain yield (first border row: y = − 2.193x + 213.9, p < 0.05; second border row: y = − 2.076x + 159.2, p < 0.01). Additionally, marginal superiority was found to have a significant positive relationship with plant density (first border row: y = 6.049x + 73.76, p < 0.01; second border row: y = 1.88x + 95.41, p < 0.05) and the average leaf angle above the ear (first border row: y = 2.306x + 103.1, p < 0.01). These results indicated that the smaller the leaf angle above the ear, the weaker the marginal superiority and the higher the grain yield. It suggests that the magnitude of marginal superiority in the border rows can be an indicator for plant-density tolerance under high density. What’s more, cultivars with small leaf angle above the ear can be selected to weaken the marginal superiority and improve grain yield under high plant density. Conversely, cultivars with a large leaf angle above the ear can be selected to achieve higher individual yield in intercropping systems with no more than four rows alternated with other crops.


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 232
Author(s):  
Nangial Khan ◽  
Fangfang Xing ◽  
Lu Feng ◽  
Zhanbiao Wang ◽  
Minghua Xin ◽  
...  

The number of cotton plants grown per unit area has recently gained attention due to technology expense, high input, and seed cost. Yield consistency across a series of plant populations is an attractive cost-saving option. Field experiments were conducted to compare biomass accumulation, fiber quality, leaf area index, yield and yield components of cotton planted at various densities (D1, 1.5; D2, 3.3; D3, 5.1; D4, 6.9; D5, 8.7; and D6, 10.5 plants m−2). High planting density (D5) produced 21% and 28% more lint yield as compared to low planting density (D1) during both years, respectively. The highest seed cotton yield (4662 kg/ha) and lint yield (1763 kg/ha) were produced by high plant density (D5) while the further increase in the plant population (D6) decreased the yield. The increase in yield of D5 was due to more biomass accumulation in reproductive organs as compared to other treatments. The highest average (19.2 VA gm m−2 d−1) and maximum (21.8 VM gm m−2 d−1) rates of biomass were accumulated in reproductive structures. High boll load per leaf area and leaf area index were observed in high planting density as compared to low, while high dry matter partitioning was recorded in the lowest planting density as compared to other treatments. Plants with low density had 5% greater fiber length as compared to the highest plant density, while the fiber strength and micronaire value were 10% and 15% greater than the lowest plant density. Conclusively, plant density of 8.7 plants m−2 is a promising option for enhanced yield, biomass, and uniform fiber quality of cotton.


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


2019 ◽  
Vol 50 (Special) ◽  
Author(s):  
Shenawa & Alfalahi

Methylation Sensitive Amplification Polymorphism (MSAP) was used to characterize the alterations in DNA methylation in maize (Zea mays L.) inbred lines and their half-daillels affected by plant densities (213333 plant h-1 and 13333 plant h-1). The two restriction was enzymes ( HpaII and MspI) succeeded in diagnosing a total of 23 specific loci, most of (22 loci) were Methylation Sensitive Loci (MSL), while the only one NML (No Methylated Loci) was monomorphic. Thirteen out of 22 MSL loci polymorphic, recording a were polymorphism percentage of 59%. Results of FeSOD gene expression cleared the different response of maize inbreds and hybrids to high plant density stress. Generally, the expression of  the targeted gene was increased in plants submitted to high plant density stress compared with low density. The inbred 3 and its single hybrid 1×3 achieved the highest level of gene expression under high planting density (5505.7 and 21098.6 copy, respectively), meanwhile, inbred 5 and it's single hybrid 4×5 gained the maximum level of FeSOD expression at the low plant density (8317.6 and 6862.1 copy, respectively). The response reached to its maximum limit in many of those genotypes, some other genotypes showed relatively steady performance along with higher stress, such as parent 1, that gave the lowest number of gene copies in both, high and low plant density (1375.8 and 1569.5 copy, respectively).


Author(s):  
Paramita Biswas ◽  
◽  
Ratikanta Ghosh ◽  

A field experiment was conducted during Summer and Kharif seasons of 2007-08 and 2008-09 at Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal, India to study the effect of hand weeding and Pretilachlor 50 EC @ 500 g a.i. ha-1 as pre-emergence on weed management of different varieties of hybrid and high yielding rice. The experiment was laid out in a split-plot design with three replications for both the years. It has been observed that Pretilachlor 50 EC @ 500 g a.i. ha-1 has a significant effect to control complex weed flora both in hybrid and high yielding varieties of rice but hand weeding twice gave the better result as expected. Among the varieties, the hybrid varieties recorded 36% and 32% more grain yield in Summer and Kharif seasons respectively than high yielding varieties (HYV). The high yielding variety 6444 (V2) showed more grain yield during Summer and Kharif seasons than that of the hybrid 6129 (V1), 97158 (V6), and 96110 (V3), respectively. Regarding weed management, hand weeding twice recorded (13% & 36%) higher grain yield during Summer than that of the chemical treatment and unweeded check, and (20% & 42%) during Kharif seasons respectively. Among the interaction, hand weeding combined with all varieties of hybrid rice recorded higher yield in comparison to other treatment combinations.


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