scholarly journals Changes in plant density dependence of leaf photosynthesis of maize (Zea mays L.) hybrids, 1959 to 1988

1991 ◽  
Vol 71 (1) ◽  
pp. 1-11 ◽  
Author(s):  
L. M. Dwyer ◽  
D. W. Stewart ◽  
M. Tollenaar
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Zea Mays L ◽  
Plant Density ◽  
Leaf Photosynthesis ◽  
Area Index ◽  
Photosynthetic Rates ◽  
Plant Densities

Understanding of the physiological basis for increased maize (Zea mays L.) yields over the last three decades may contribute to future genetic improvement. Recent maize production systems have tended to increase plant densities to maximize grain yield. The objective of this field study was to determine if there were changes in the response of leaf photosynthetic rates to increasing plant densities in four hybrids grown in Ontario from 1959 to 1989. The four hybrids, numbered from the oldest to most recent hybrid ((1) Pride 5, (2) United 106, (3) Pioneer 3978 and (4) Pioneer 3902) were grown at 20 000, 80 000 and 130 000 plants ha−1. Leaf photosynthetic response to irradiance (PRI) and crop growth rate (CGR) were measured near silking and during late grainfilling, leaf area index (LAI) was measured near silking and total grain yield was measured after maturity. The LAIs of recent hybrids tended to be larger than for old hybrids at comparable plant densities. Leaf photosynthetic rates declined in all hybrids at increasing densities, but the decline occurred at lower LAIs in the older hybrids. As a result, despite the higher LAIs of recent hybrids, they showed an equal or higher PRI at all plant densities. The higher PRI of recent hybrids was correlated with higher CGRs and grain yields. These results suggest that increases in optimum plant density for grain and increases in yield may be attributable, in part, to higher PRI at elevated LAIs in recent hybrids. Key words: Leaf area index, plant density, leaf photosynthesis, Zea mays L.

scholarly journals Narrow and twin-row plantings do not increase maize yield

2020 ◽  
Vol 38 (3) ◽  
pp. 342-349
Author(s):  
Luís Sangoi ◽  
Amauri Schmitt ◽  
Marcos Cardoso Martins Júnior ◽  
Hugo François Kuneski ◽  
Antonio Eduardo Coelho
Keyword(s):  
Grain Yield ◽  
Leaf Area Index ◽  
Nitrogen Content ◽  
Leaf Area ◽  
Plant Density ◽  
Block Design ◽  
Plant Distribution ◽  
Area Index ◽  
Plant Densities ◽  
Row Space

Reducing row space and sowing in twin rows of maize (Zea mays L.) allow more equidistant plant distribution at the same density. The objective of this research was to evaluate the effect of these two management practices on the nitrogen content of the index leaf, the leaf area index at silking, and the grain yield of maize at different plant densities. The experiment was carried out in Lages, Santa Catarina State University, in southern Brazil during the growing seasons 2016-2017 and 2017-2018. A split-plot arrangement of a randomized complete block design was used. Two plant densities (7 and 9 plants m-2) were distributed in the main plot, and five row spaces (0.4, 0.6, 0.8, 1.0 m and twin rows 0.6 m apart with 0.18 m between rows) were evaluated in split-plots. Physiological traits and grain yield were determined on the maize hybrid P30R50YH. The experiments were sown on 10/20/2016 and 10/21/2017. Kernel yields were higher at the plant density of 9 plants m-2 than at 7 plants m-2. The row space did not affect the nitrogen content of the index leaf, the crop leaf area index at silking, and the maize grain yield. The increment of plant density was more effective than the use of narrow and twin rows to enhance P30R50YH  hybrid grain yield.

RESPOSTAS MORFOAGRONÔMICAS DE MILHO SUBMETIDO A DESFOLHA ARTIFICIAL

2017 ◽  
Vol 16 (3) ◽  
pp. 460
Author(s):  
EMERSON TROGELLO ◽  
LUAN FERREIRA BORGES ◽  
FÁBIO ARAÚJO DE OLIVEIRA ◽  
QUÉZIA SANCHES MUTAGUTI ◽  
INGRID GOMIDES BARROS ◽  
...  
Keyword(s):  
Zea Mays ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Analysis Of Variance ◽  
Zea Mays L ◽  
Grain Weight ◽  
Area Index ◽  
Plant Removal ◽  
And Control ◽  
Different Levels

RESUMO - O objetivo deste estudo foi avaliar as características morfoagronômicas do híbrido simples de milho em função da aplicação de diferentes intensidades de desfolha artificial, realizadas no estádio R1 de desenvolvimento. O experimento foi conduzido na área experimental do Instituto Federal Goiano,em Morrinhos-GO, na safra 2015/2016. Foi aplicado o delineamento de blocos completamente casualizados, com oito tratamentos e quatro repetições, sendo eles: remoção de uma folha acima e uma abaixo da espiga; remoção de duas folhas acima e abaixo da espiga; remoção de três folhas acima e abaixo da espiga; remoção de todas as folhas da planta; remoção de todas as folhas acima da espiga; remoção de todas as folhas abaixo da espiga; remoção da folha da espiga; e testemunha sem desfolha. Os caracteres avaliados foram: estande de plantas, número de plantas acamadas, prolificidade, densidade de colmo, comprimento e diâmetro de espiga, comprimento de grão, massa de mil grãos, massa de grãos espiga-1 e produtividade. Os dados foram submetidos à análise de variância pelo teste F a 5% de probabilidade, observando que todas as variáveis avaliadas foram influenciadas quanto aos efeitos dos tratamentos empregados. O enchimento dos grãos esteve intimamente relacionado à fotossíntese. Sem as folhas, esta fase ficou plenamente comprometida.Palavras-chave: Zea mays, fotoassimilados, translocação, índice de área foliar, rendimento. MORPHOAGRONOMIC CHARACTERISTICS OF MAIZE AS A FUNCTION OF DIFFERENT LEVELS OF ARTIFICIAL DEFOLIATION  ABSTRACT - The objective of this study was to evaluate of morphoagronomic characteristics of simple hybrids of maize, depending on the application of different intensities of artificial defoliation, carried out in R1, when the style-stigma were fertilized. The experiment was conducted in an experimental area of the Instituto Federal Goiano, Campus Morrinhos, State of Goiás, Brazil, during the agricultural year 2015/2016. We applied the design of completely randomized block with eight treatments, in four replications: removal of a leaf above and one below the ear; removal of two leaves above and below the ear; removal of three leaves above and below the ear; removal of all leaves of the plant; removal of all leaves above the ear; removal of all leaves below the ear; removal of the leaf of the ear; and control without defoliation. The traits evaluated were stand of plants, number of plant lodging, prolificacy, density, length and diameter of the cob, length of a grain, weight of a thousand grains, grain mass cob-1 and productivity. The data obtained were subjected to analysis of variance by F test at 5% probability, noting that all variables were influenced as to the effects of the treatments used. The filling of grains is closely related to photosynthesis. Without the leaves, this phase was fully damaged.Keywords: Zea mays L., photoassimilates, translocation, leaf area index, yield.

scholarly journals Evaluating the effect of plant population densities and nitrogen application on the leaf area index of maize in a reclaimed wetland in Kenya

2016 ◽  
Vol 8 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Catherine Waithira Njuguna ◽  
Hellen Wangechi Kamiri ◽  
John Robert Okalebo ◽  
Wilson Ngetich ◽  
Syphilline Kebeney
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Density ◽  
Block Design ◽  
Nitrogen Application ◽  
Maize Production ◽  
Area Index ◽  
High Plant Density ◽  
Plant Densities ◽  
Set Up

Abstract Maize is the main staple food in Kenya with over 90% of Kenyans relying on it. While the annual national consumption is increasing, the production of this crop has been on the decline in the last two decades. Maize production in Kenya fell by 33.4% in 2013 with Nyeri among the counties said to be grappling with the production of this crop. Land pressure is one of the major causes of decreased availability of food as well as soil depletion and encroachment upon fragile ecosystems such as wetlands. Nitrogen is a key nutrient in the production of maize, and its deficiency is a major factor limiting its production. This study investigated the effect of N application at 120 kg N/ha and maize density on the Leaf Area Index in reclaimed wetland soils in an experimental set-up comprising a randomized complete block design with three replications. The research was carried out in Nyeri County, Kenya. Leaf Area Index (LAI) was determined using the given SunScan formula. Measurements were done continuously until crop physiological maturity. Results indicated that the leaf area index increased with nitrogen application and reduced with spacing for most treatments. There were no significant differences between the two methods (Copy Method and SunScan). Leaf Area Index (LAI) was high in treatments containing nitrogen and high plant density. It was concluded that high plant density gives high LAI. 50 cm * 12.5 cm (-N) and 50 cm * 12.5 cm (+N) are the recommended plant densities for the site.

COMPARISON OF INBRED AND HYBRID CORN GRAIN YIELD MEASURED AT EQUAL LEAF AREA INDEX

1972 ◽  
Vol 52 (3) ◽  
pp. 315-319 ◽  
Author(s):  
D. J. MAJOR ◽  
R. B. HUNTER ◽  
L. W. KANNENBERG ◽  
T. B. DAYNARD ◽  
J. W. TANNER
Keyword(s):  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Density ◽  
Area Index ◽  
Wide Range ◽  
The Mean ◽  
Common Plant ◽  
Single Cross Hybrids ◽  
Corn Grain

Grain yield of 44 single crosses and their component inbreds of corn (Zea mays L.) was determined over a wide range of plant populations. Yield was determined for inbreds and single cross hybrids at unit intervals of leaf area index (LAI) of 1–4. Mean inbred yield was no greater than 60% of the mean hybrid yield, regardless of whether yields were compared at a common plant density or LAI. Optimum LAI (LAI where grain yield was at its maximum) was higher for the hybrids than for the inbreds.

scholarly journals Growth and Yield Stability of Maize Varieties (Zea mays L.) as Affected by Different Rates of Nitrogen Fertilizer and Cow Dung in Mubi, Adamawa State, Nigeria

2020 ◽  
pp. 94-103
Author(s):  
I. Audu ◽  
R. Idris
Keyword(s):  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Nitrogen Fertilizer ◽  
Zea Mays L ◽  
Growth And Yield ◽  
Cow Dung ◽  
Area Index ◽  
Maize Varieties

A field experiment to study the growth and yield stability of maize varieties (Zea mays L.) to different rates of nitrogen fertilizer and cow dung in Mubi Adamawa State, Nigeria was conducted in 2014 and 2015 cropping seasons at the Food and Agricultural Organization/Tree crops Plantation (FAO/TCP) Farm of Faculty of Agriculture, Adamawa State University Mubi. Two maize varieties; viz. Quality Protein Maize (QPM) and Extra Early White (EEW) were selected for sowing. They were assigned to the main plots and nitrogen with cow dung assigned to the subplots in a factorial combination with nitrogen at the rates of 0, 60 and 120 kg N ha-1 and cow dung at 0, 1- and 2-ton ha-1 in split plot design. Data were collected on plant height, leaf area per plant, leaf area index and grain yield per hectare. Data collected were subjected to analysis of variance and treatment means were separated using Duncan Multiple Range Test. The result showed that EEW had the highest plant height (190.77 cm), higher leaf area per plant (535.6 cm2) and leaf area index (0.40 cm) than QPM. The effect of nitrogen fertilizer on the growth and yield parameters increased as the nitrogen fertilizer was increased. 120kg N ha-1 gave the highest plant height (195.68 cm) and grain yield (5658.3 kg). The control plot produced the least; 164.77 cm (plant height) and 2662.50 kg ha-1 (grain yield). Application of 1ton ha-1 cow dung exhibited the highest plant height, (95.00 cm), leaf area per plant (518.91 cm2) and leaf area index (0.37 cm). There was an interaction of variety with nitrogen on plant height and grain yield. High interaction of variety with cow dung on plant height and leaf area per plant was recorded. There was an interaction of nitrogen with cow dung on plant height, leaf area per plant and leaf area index. However, there was an interaction of variety with nitrogen and cow dung on plant height, leaf area per plant and leaf area index. Application of 120 kg N ha-1 significantly increased the yield of QPM maize along with 2-ton ha-1 of cow dung.

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