scholarly journals Leaf Removal Affects Maize Morphology and Grain Yield

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 269 ◽  
Author(s):  
Guangzhou Liu ◽  
Yunshan Yang ◽  
Wanmao Liu ◽  
Xiaoxia Guo ◽  
Jun Xue ◽  
...  

Increasing planting density is an important practice associated with increases in maize yield, but densely planted maize can suffer from poor light conditions. In our two-year field experiments, two morphologically different cultivars, ZD958 (less compact) and DH618 (more compact), were planted at 120,000 plants ha−1 and 135,000 plants ha−1, respectively. We established different leaf area index (LAI) treatments by removing leaves three days after silking: (1) control, no leaves removed (D0); (2) the two uppermost leaves removed (D1); (3) the four uppermost leaves removed (D2); (4) the leaves below the third leaf below the ear removed (D3); (5) the leaves of D1 and D3 removed (D4); (6) the leaves of D2 and D3 removed (D5). Optimal leaf removal improved light distribution, increased photosynthetic capacity and the post-silking source-sink ratio, and thus the grain yield, with an average LAI of 5.9 (5.6 and 6.2 for ZD958 and DH618, respectively) for the highest yields in each year. Therefore, less-compact cultivars should have smaller or fewer topmost leaves or leaves below the ear that quickly senesce post-silking, so as to decrease leaf area and thus improve light distribution and photosynthetic capacity in the canopy under dense planting conditions. However, for more compact cultivars, leaves below the ear should senesce quickly after silking to reduce leaf respiration and improve the photosynthetic capacity of the remaining top residual leaves. In future maize cultivation, compact cultivars with optimal post-silking LAI should be adopted when planting densely.

2005 ◽  
Vol 41 (3) ◽  
pp. 365-382 ◽  
Author(s):  
R. B. PRASAD ◽  
R. M. BROOK

Maize and soybean are commonly intercropped in the drier zones of the western mid-hills in Nepal, but farmers report that productivity of soybean has been declining in recent years. Two researcher managed on-farm field experiments were conducted in the mid-hills environment of Nepal during 2001 and 2002, and one glasshouse experiment at the University of Wales, Bangor during 2003, to determine whether varying densities of maize and soybean influenced productivity of the system and to what extent soybean exhibited adaptation to shade. In neither season was maize yield affected by the presence of soybean, but grain yield of soybean was reduced in mixture by means of 59 and 53% during 2001 and 2002 respectively. Biomass and grain yield of maize were greatest at 53×103 plants ha−1 and least at the lowest density, whilst conversely biomass and grain yield of soybean increased. With increasing maize density, rates of accumulation of dry matter and leaf area index also increased, the latter resulting in decreasing transmission of light to the intercropped soybean. Soybean exhibited no photosynthetic adaptation to shade, but the specific leaf area was greater in artificially shaded and intercropped plants. Land equivalent ratios of all intercrops were greater than unity (1.30 to 1.45), indicating higher efficiency of intercropping compared to sole crops. Given the low plasticity in response of the maize canopy to variations in density, it is suggested that soybean could be better grown under maize by increasing between-row spacing of maize from 0.75 to 1.0 m to improve light transmission to the understorey, resulting in higher overall productivity of the intercropping system, and also that soybean germplasm be screened for adaptation to shade.


2021 ◽  
Vol 12 (5) ◽  
pp. 594-602
Author(s):  
L. Rana ◽  
◽  
H. Banerjee ◽  
D. Mazumdar ◽  
S. Sarkar ◽  
...  

The field experiments were conducted at farmer’s field, Madandanga village under Chakdaha Block of Nadia district in West Bengal during rabi season 2014-15 and 2015-16. Treatments were distributed in split-factorial design, with three varieties (P ‘3533’, P ‘3396’, P ‘30V92’) in the main plot and three planting density (55,555, 66,666, 83,333 plants ha-1) × three sowing dates (November 20, November 30, December 10) combinations in the sub-plots, replicated thrice. Irrespective of planting density and sowing date, the variety ‘P30V92’ produced the highest yield, followed by ‘P3396’ and ‘P3533’. The significantly highest grain and stover yield was obtained in high density planting (83,333 plants ha-1), accounting 44.2 and 39.6% more than low planting density (55,555 plants ha-1), respectively. The maximum grain and stover yields were obtained from Nov. 20 sown plants; being 7.71 and 11.95% more than the grain yield derived from late sown (Dec. 10) plants. A correlation study showed that among the growth and yield components, leaf area index (0.96) and shelling percentage (0.91) exhibited highly positive direct effects on the grain yield of hybrid maize. However, other growth attributes, namely P uptake (0.88), K uptake (0.86) and plant height (0.81) exerted comparatively low positive direct effects on the grain yield of hybrid maize. Further, the standard regression equation revealed a significant relationship of shelling percentage (p≤0.01), leaf area index (p≤0.01) and uptake of P (p≤0.05) with grain yield.


Author(s):  
Yanyan Yan ◽  
Peng Hou ◽  
Fengying Duan ◽  
Li Niu ◽  
Tingbo Dai ◽  
...  

AbstractIn this work, we sought to understand how breeding has affected photosynthesis and to identify key photosynthetic indices that are important for increasing maize yield in the field. Our 2-year (2017–2018) field experiment used five high-yielding hybrid maize cultivars (generated in the 1970s, 2000s, and 2010s) and was conducted in the Xinjiang Autonomous Region of China. We investigated the effects of planting density on maize grain yield, photosynthetic parameters, respiration, and chlorophyll content, under three planting density regimens: 75,000, 105,000, and 135,000 plants ha−1. Our results showed that increasing planting density to the medium level (105,000 plants ha−1) significantly increased grain yield (Y) up to 20.32% compared to the low level (75,000 plants ha−1). However, further increasing planting density to 135,000 plants ha−1 did not lead to an additional increase in yield, with some cultivars actually exhibiting an opposite trend. Interestingly, no significant changes in photosynthetic rate, dark respiration, stomatal density, and aperture were observed upon increasing planting density. Moreover, our experiments revealed a positive correlation between grain yield and the net photosynthetic rate (Pn) upon the hybrid release year. Compared to other cultivars, the higher grain yield obtained in DH618 resulted from a higher 1000-kernel weight (TKW), which can be explained by a longer photosynthetic duration, a higher chlorophyll content, and a lower ratio of chlorophyll a/b. Moreover, we found that a higher leaf area per plant and the leaf area index (HI) do not necessarily result in an improvement in maize yield. Taken together, we demonstrated that higher photosynthetic capacity, longer photosynthetic duration, suitable LAI, and higher chlorophyll content with lower chlorophyll a/b ratio are important factors for obtaining high-yielding maize cultivars and can be used for the improvement of maize crop yield.


1982 ◽  
Vol 18 (1) ◽  
pp. 93-100 ◽  
Author(s):  
S. U. Remison ◽  
E. O. Lucas

SUMMARYTwo maize cvs, FARZ 23 and FARZ 25, were grown at three densities (37,000, 53,000 and 80,000 plants/ha) in 1979 and 1980. Leaf area index (LAI) increased with increase in plant population and was at a maximum at mid-silk. Grain yield was highest at 53,000 plants/ha. There was no relation between LAI and grain yield but there was a positive correlation between LAI and total dry matter yield.


Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6732
Author(s):  
Haixia Qi ◽  
Bingyu Zhu ◽  
Zeyu Wu ◽  
Yu Liang ◽  
Jianwen Li ◽  
...  

Leaf area index (LAI) is used to predict crop yield, and unmanned aerial vehicles (UAVs) provide new ways to monitor LAI. In this study, we used a fixed-wing UAV with multispectral cameras for remote sensing monitoring. We conducted field experiments with two peanut varieties at different planting densities to estimate LAI from multispectral images and establish a high-precision LAI prediction model. We used eight vegetation indices (VIs) and developed simple regression and artificial neural network (BPN) models for LAI and spectral VIs. The empirical model was calibrated to estimate peanut LAI, and the best model was selected from the coefficient of determination and root mean square error. The red (660 nm) and near-infrared (790 nm) bands effectively predicted peanut LAI, and LAI increased with planting density. The predictive accuracy of the multiple regression model was higher than that of the single linear regression models, and the correlations between Modified Red-Edge Simple Ratio Index (MSR), Ratio Vegetation Index (RVI), Normalized Difference Vegetation Index (NDVI), and LAI were higher than the other indices. The combined VI BPN model was more accurate than the single VI BPN model, and the BPN model accuracy was higher. Planting density affects peanut LAI, and reflectance-based vegetation indices can help predict LAI.


2020 ◽  
Vol 15 (1) ◽  
pp. 106-122
Author(s):  
J. Alam ◽  
R. K. Panda

 Any change in climate will have implications for climate-sensitive systems such as agriculture, forestry and some other natural resources. Changes in solar radiation, temperature and precipitation will produce changes in crop yields and hence economics of agriculture. It is possible to understand the phenomenon of climate change on crop production and to develop adaptation strategies for sustainability in food production, using a suitable crop simulation model. CERES-Maize model of DSSAT v4.0 was used to simulate the maize yield of the region under climate change scenarios using the historical weather data at Kharagpur (1977-2007), Damdam (1974-2003) and Purulia (1986-2000), West Bengal, India. The model was calibrated using the crop experimental data, climate data and soil data for two years (1996-1997) and was validated by using the data of the year 1998 at Kharagpur. The change in values of weather parameters due to climate change and its effects on the maize crop growth and yield was studied. It was observed that increase in mean temperature and leaf area index have negative impacts on maize yield. When the maximum leaf area index increased, the grain yield was found to be decreased. Increase in CO2 concentration with each degree incremental temperature decreased the grain yield but increase in CO2 concentration with fixed temperature increased the maize yield. Adjustments were made in the date of sowing to investigate suitable option for adaptation under the future climate change scenarios. Highest yield was obtained when the sowing date was advanced by a week at Kharagpur and Damdam whereas for Purulia, the experimental date of sowing was found to be beneficial.


2015 ◽  
Vol 27 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Soheila Dastborhan ◽  
Kazem Ghassemi-Golezani

Abstract Borage is a valuable medicinal plant with various constituents in leaves, flowers and seeds. Hence, it is important to improve the performance of this medicinal plant under different environmental conditions. Thus, two field experiments were arranged as split-plots based on a RCB design with three replications in 2012 and 2013, to evaluate the effects of seed priming and different irrigation intervals on selected physiological properties of borage leaves. Irrigation intervals (irrigation after 60, 90, 120, 150 mm evaporation from Class A pans, respectively) and priming treatments (control, water, KNO3 and KH2PO4) were allocated to the main and sub plots, respectively. The chlorophyll content index was enhanced under limited irrigation treatments, mainly due to a decrease in leaf area index and intercepting more radiation. However, the membrane stability index was stable under different irrigation intervals. Decreased relative water content and leaf area index and increased leaf temperature under lower water availability led to some reductions in the grain yield of borage. All of the priming techniques, particularly hydro-priming, enhanced the seedling emergence rate, leaf area index and consequently grain yield per unit area. Therefore, seed hydro-priming can be used to improve the field performance of borage, particularly when sufficient water is available.


2021 ◽  
Vol 25 (01) ◽  
pp. 43-51
Author(s):  
Qinglong Yang

To better understand the accumulation and transport of substances under different planting densities, the adaptation of maize root and leaf in response to increasing planting densities was investigated. In this two-year filed study, three maize varieties, Fumin108 (FM), Xianyu335 (XY) and Dika159 (DK), were sown under three different planting densities: 15,000 (D1), 60,000 (D2) and 90,000 plants ha-1 (D3) during 2018 and 2019. Increase in planting density gradually increased leaf area index along with reduced leaf area and net photosynthetic rate of individual leaves. In the 0–20 cm soil layer, the average root dry matter decreased by 55.88 and 80.92%, and the average root number decreased by 31.18 and 38.71% under D2 and D3, respectively, compared with D1. With increase in planting density, yield and dry matter per plant of maize gradually decreased while yield and dry matter per ha was increased with increase in D1-D2 density and then flattened in D2-D3 density. Compared with D1, two-year average yield per plant was decreased by 34.10 and 51.87% under D2 and D3, respectively. The difference in the number of roots of XY, FM and DK were not significant, so change in variety did not alleviate the decrease in the number of roots. At higher planting densities (above D2), the increase in density did not increase per ha grain yield. In conclusion, the suitable plant density was about 60,000 plants ha-1 to harvest more yield of spring maize while density higher than that reduced leaf area and photosynthesis per plant. Moreover, leaf area, root number and net photosynthesis per plant was higher in lower planting density coupled with overall less yield on ha basis and thus seemed wastage of soil nutrients and light resources. © 2021 Friends Science Publishers


1975 ◽  
Vol 84 (2) ◽  
pp. 305-312 ◽  
Author(s):  
P. E. L. Thomas ◽  
J. C. S. Allison

SUMMARYOne pot and five field experiments were made to study different aspects of the competition between R. exaltata and maize.The growth of young maize plants was not inhibited by being grown together in pots with young R. exaltata plants. In the field the soil tended to be somewhat wetter when the two species were grown together than when maize was grown alone, and was wettest with R. exaltata grown alone. Maize grain and total yield decreased and shoot yield of R. exaltata increased with R. exaltata plant density on both irrigated and unirrigated blocks of land, but yields were not much affected on either block by increase in plant density of maize or in nitrogen supply; maize yield was increased by irrigation but that of R. exaltata was not. Maize plant arrangement did not greatly affect maize grain and total yield or R. exaltata shoot yield, nor did arrangement of R. exaltata plants have much influence on their depression of maize yield, but R. exaltata caused a greater decrease in the grain yield of a short than of a tall maize cultivar.R. exaltata plants germinating at the same time as the crop plants did not have much effect on maize grain yield if they were removed by 8 weeks after the seedlings emerged, but decreased it considerably if allowed to remain for 12 weeks or more; weeds sown 2 or more weeks after the maize emerged hardly grew and had little effect on maize yield. When maize and R. exaltata were grown together leaf area of the maize was little affected up to the time of flowering, but was decreased after flowering, while leaf area of the weed was greatly depressed. Up to 7–8 weeks after seedling emergence more of the ground area was covered by foliage when maize was grown with R. exaltata than when it was grown alone, but later the ground was completely covered by foliage in both cases. Dry weight of grain and shoot of maize increased and that of shoot of R. exaltata decreased when the weed plants were shortened with growth regulators.


1972 ◽  
Vol 78 (1) ◽  
pp. 73-78 ◽  
Author(s):  
B. O. Adelana ◽  
G. M. Milbourn

SUMMARYWork that has been reported from some African countries indicates a dependence of grain yield in maize on the duration of leaf area after flowering. This paper studies maize yield in south-east England and confirms work at a similar northern latitude in Canada which has shown that considerable remobilization of photosynthate from the stem to the ear takes place during the main ear fill period.A similar grain yield was obtained from two contrasting hybrids. In a short early hybrid, Kelvedon 75A, there was a low peak leaf area index (5·3) but the net assimilation rate was high due possibly to efficient light interception by leaves that maintained an erect posture. Stem dry matter was also low and hence in this hybrid the high reproductive/vegetative ratio shows that there has been economy in the production of leaves and stem, especially as a 48% stem loss occurred during the period of ear fill.In contrast, in a later hybrid, Anjou 210, the final shoot dry matter was 20% higher as the peak leaf-area index of 7·7 gave slightly higher crop growth rates than K 75A. Although the remobilization of stem dry matter was similar in both hybrids it was notable that a different partition of dry matter in the ears of Anjou 210 gave a higher grain/rachis ratio.


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