Bromoxynil tolerance during the seedling phase is associated with genetic grain yield improvement in maize

1991 ◽  
Vol 71 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
M. Tollenaar ◽  
M. Mihajlovic

Genetic grain yield improvement of maize (Zea mays L.) in Ontario during the past three decades can be attributed, in part, to increased tolerance to environmental stresses. We have observed a differential response of field-grown old and new hybrids after application of the photosystem II inhibiting herbicide bromoxynil (4-hydroxy-3,5-dibromobenzonitrile). Studies were conducted to test whether tolerance to bromoxynil is associated with stress tolerance and grain yield in maize hybrids representing three decades of yield improvement in Ontario. Experiments were carried out with seedlings of eight maize hybrids grown in pots in controlled-environment growth cabinets and, in one experiment, with seedlings grown in pots outside during the months of July and August at Guelph, Ontario. Bromoxynil was applied to the youngest fully-expanded leaf of plants at the 6- to 8-leaf stage and chlorophyll fluorescence of the treated leaves was measured in the 2- to 24-h period after bomoxynil application. Results showed that the chlorophyll fluorescence ratio Fv/Fm, an indicator of photosynthetic efficiency, declined after bromoxynil application until 4 h after application and, subsequently, recovered slightly during the next 20 h. Large differences in the Fv/Fm ratio were apparent among hybrids in the response to bromoxynil. The Fv/Fm ratio was significantly higher for hybrids released in the 1980s than for hybrids released in the 1970s, and the Fv/Fm ratio of the latter group was significantly higher than that of the four oldest hybrids. Chlorophyll fluorescence ratios Fv/Fm after bromoxynil application in the seedling phase were highly correlated with grain yield of the hybrids in field experiments conducted during 1987 and 1988 (r = 0.91). Results of this study support the contention that maize genotypes that are less sensitive to bromoxynil are less susceptible to environmental stresses. Key words: Zea mays L., stress tolerance, bromoxynil, chlorophyll fluorescence, Fv/Fm ratio, detoxifying agents

Scientifica ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Seyed Habib Shojaei ◽  
Khodadad Mostafavi ◽  
Ali Omrani ◽  
Saeed Omrani ◽  
Seyed Mohammad Nasir Mousavi ◽  
...  

The present study investigated the stability and adaptability of maize (Zea mays L.) hybrids. In this study, 12 maize hybrids were planted and examined considering the grain yield. The experiment was arranged in a randomized complete block design (RCBD) with three replications in four research stations in Iran during two crop years. The combined analysis of variance showed that genotype-environment interactions were significant at one percent probability level. The grain yield can stabilize, and hybrids with specific adaptability are recommended to each environment. Hybrids with specific adaptability can be recommended to all types of the environment. Means comparison yield of the genotypes identified DC370 as a high-yield genotype. Regarding AMMI analysis, genotype × environment interactions (GEIs) and two first components were found significant. The SC647 genotype was identified as the most stable genotype. Regarding the stability parameters, SC647 and KSC705 genotypes were selected as the most stable genotypes. From AMMI1 and AMMI2 graphs, the SC647 genotype was identified as the most stable genotype compared with other hybrids.


2010 ◽  
Vol 61 (9) ◽  
pp. 700 ◽  
Author(s):  
Saeed Safari Dolatabad ◽  
Rajab Choukan ◽  
Eslam Majidi Hervan ◽  
Hamid Dehghani

Adapted maize (Zea mays L.) hybrids should be identified and chosen based on multi-environment trials analysing several traits. The objectives of this study were to identify mega-environments and suitable adapted maize hybrids based on both mean grain yield and grain yield stability and were to evaluate the 14 maize hybrids based on several desirable traits. Biplot analysis determined one mega-environment and two sectors that consist of one location in each sector for maize in Iran. The mega-environment included Kerman (KRM), Kermanshah (KSH), Moghan (MGN), Dezfol A (DZF A), Karaj (KRJ), Darab (DRB), Dezfol B (DZF B), Shiraz B (SHZ B), and Esfahan (ESF), where hybrid OSSK 602 was the best performing hybrid. The first sector included Khoramabad (KHM) where BC 678 was the best hybrid, and the second sector included Shiraz A (SHZ A) where ZP 599 was the hybrid with the highest performance. OSSK 602 was the best hybrid among all of the studied hybrids followed by ZP 677 and ZP 684. The genotype × trait biplot indicated that ZP 677 and OSSK 602 had greater thousand-kernel weight and grain number, whereas ZP 684 had longer day to maturity and larger cob diameter. KSC 700, KSC 704, and BC 678 had higher ear height and more days to tasseling than other hybrids. The genotype × trait biplot graphically displayed the interrelationships among traits and it was used in identifying hybrids that are good for some particular traits.


2018 ◽  
Vol 10 (8) ◽  
pp. 72
Author(s):  
S. Lamptey ◽  
Lingling Li ◽  
Junhong Xie

Water is one of the most important limiting factor of rainfed continuous maize (Zea mays L.) cropping systems in northwest of China. A three continuous year field experiments were conducted to study the influence of different nitrogen time of application on grain yield and water use efficiency of maize (Zea mays L.) in the Western Loess plateau. The experiment was laid in a randomized complete block design with two treatments and three replicates. Treatments were; (one-third application of N at sowing + two-third application at pre-flowering) and (one-third application of N at sowing + one-third pre-flowering + one-third at milking) as T1 and T2 respectively. The results showed that, T1 significantly increased grain yield by 9% in 2014 and 2016; and WUE by 11% in 2016 compared to T2. T1 increased AE by 43% compared to T2. Our results indicate that ⅓ application of Nitrogen at sowing and ⅔ application of Nitrogen at pre–flowering (T1) for maize is more appropriate for sustainable maize production in terms of satisfactory grain-N recoveries and low environmental losses of N fertilizer.


2021 ◽  
Vol 66 (3) ◽  
pp. 231-245
Author(s):  
Adesike Kolawole ◽  
Ibrahim Raji ◽  
Solomon Oyekale

Maize (Zea mays L.) is a staple food for millions of people across the globe, and it supplies more than 30% of total dietary calories. However, the normal endosperm lacks a sufficient quantity of the nutritive precursor of vitamin A. To achieve food security and avert malnutrition, there is a need to adopt the cultivation of the early multiple stress-tolerant pro-vitamin A maize hybrid. The objective of this study was to assess the agronomic performance and yield of the newly developed maize hybrids. Fifteen improved maize hybrids and one commercial hybrid used as a local check were evaluated in a randomized complete block design with two replications for two years at the Ladoke Akintola University of Technology Teaching and Research farm in Ogbomoso, Nigeria. Hybrids exhibited significant variation (P < 0.01) for grain yield, number of days to anthesis and silking, ear height and husk cover. Across the years, the grain yield of hybrids ranged between 4,780.8 kg ha?1 (PVAEH-19) and 7,886.9 kg ha?1 (PVAQEH-1), with a mean of 6,354.2 kg ha?1. PVAEH-15 ranks the best on the basis of superiority in grain yield, early flowering and tight husk cover. Fourteen hybrids out-yielded the local check (4,947.2 kg ha-1), and five hybrids had a significant (P < 0.05) yield advantage of > 26% over the local check. The consistent performance of PVAEH-15 and PVAEH-16 in the two years of evaluation indicates potential for the adaptability of the hybrids to the agro-ecology. Farmers? adoption of these maize hybrids will boost maize production and prevent malnutrition in the derived savanna agro-ecology of Nigeria.


Author(s):  
M. Mohamed Amanullah

Field experiments were conducted at Maize Research Station, Vagarai, Palani Taluk, Tamilnadu during rabi 2018-19 and 2019-20 to find out the influence of detopping on green fodder, grain yield and economics of rainfed maize (Zea mays L.). The experiments were laid out in a factorial randomized block design with three stages and three heights of detopping. Three stages of detopping viz., D1-10 days after 50% silking, D2 -20 days after 50% silking and D3-30 days after 50% silking were tested with three heights of detopping viz., L1 - detopping tassel + 2 leaves, L2 - detopping tassel + 4 leaves and L3 - detopping tassel + 6 leaves with a control (No detopping) replicated thrice. The results of the experiments revealed that detopping 10 days after 50% silking with tassel + 6 leaves recorded higher green fodder yield Regarding grain yield, among the days of detopping, detopping 30 days after 50% silking and detopping 20 days after 50% silking recorded higher yield which were comparable with control (no detopping) (6460 kg / ha). Among the number of leaves, detopping tassel + two leaves recorded higher yield followed by tassel + 4 leaves and both were comparable. Among the treatment combinations, higher grain yield was recorded under detopping 20 days after 50% silking with tassel + 4 leaves followed by detopping 30 days after 50% silking with tassel + 4 leaves and detopping 30 days after 50% silking with tassel + 2 leaves. Regarding economics, higher net return and BC ratio were recorded under the treatment combination of detopping 20 days after 50% silking with tassel + 4 leaves followed by control and detopping 30 days after 50% silking with tassel + 4 leaves.


1996 ◽  
Vol 76 (3) ◽  
pp. 365-371 ◽  
Author(s):  
Thamir Alkanani ◽  
Angus. F. MacKenzie

The use of urea in corn (Zea mays L.) production is common. Under current N fertilizer recommendations for corn, urea may have adverse effects on corn growth when applied in a band. The effects of ammonium lignosulfonate (LS) on corn growth and on N uptake from the banded application of urea and diammonium phosphate (DAP) mixtures were investigated on two soils from eastern Quebec. Field experiments were initiated in the first week of May 1991 on an Ormstown silty clay and a Ste. Rosalie clay soils (fine, mixed, nonacid, mesic Typic Humaquepts). Treatments were two rates of urea (30 and 90 kg urea-N ha−1) in combination with DAP (14 kg N ha−1), with or without banded fertilizer solutions of LS (8 kg N ha−1) applied at planting 5 cm to the side and 3 cm below the seed. A no treatment control was included. The low rate of urea and DAP (no LS added) resulted in a 19 and 24% increase in grain yield at the Ste. Rosalie and Ormstown, respectively, when compared with the unfertilized plots. When compared with the unfertilized treatment, the high rate of urea and DAP (no LS added) caused 10% increase in grain yield. However, addition of LS to the high rate of urea and DAP increase grain yield by band 20%. In general, LS significantly increased corn N uptake from urea on both soils. Separate 15N field experiments were initiated in June 1991. Mean recovery of 15N in total dry matter (grain and stover) was 51.9% in Ormstown and 47.9% in Ste. Rosalie soil. Denitrification estimates, calculated as 15N not accounted for, were not affected by LS and the rate of banded urea-N. Immobilization of 15N ranged from 17.8% to 30.9% of the applied labelled urea. The rate of urea-N banded had no significant effect on immobilization, but LS resulted in significantly less 15N immobilized. These observations suggest that LS can reduce the biological immobilization of urea-N and increase the efficiency of urea fertilizer by reducing the negative effects of banding high levels of urea, while attaining benefits of band placement. Key words: Lignosulfonate, corn, urea, 15N


2017 ◽  
Vol 16 (1) ◽  
pp. 72
Author(s):  
RENATO BARBOSA CAMARGOS ◽  
JOÃO CANDIDO DE SOUZA ◽  
EDUARDO ALVES ◽  
CARLOS EDUARDO CAIXETA DE CASTRO ◽  
PAULO EDUARDO RODRIGUES PRADO ◽  
...  

 ABSTRACT - The objectives of this study were to identify maize hybrids which have high grain yield and resistance to Phaeosphaeria leaf spot, gray leaf spot and common rust, as well as to estimate the most efficient period for measuring the reaction of the hybrids to the pathogens. Two experiments were set up in Lavras, MG, Brazil, assessing 30 hybrids in the season of 2011/2012. The experimental design was a 6 x 5 lattice arrangement with three replications. Grain yield was evaluated and five assessments of disease severity were performed at ten-day intervals as of 60 days after maize emergence. After that, the area under the disease progress curve (AUDPC) and the Spearman correlations between the diseases and the various assessment periods for each disease were estimated. It was found that the hybrids GNZ9626 PRO and GNZ9501 PRO have high grain yield and a satisfactory level of resistance to Phaeosphaeria leaf spot, gray leaf and common rust, and that assessment of the level of resistance to these diseases should be performed in the period from 80 to 100 days after plant emergence, which provides results similar to AUDPC.Keywords: Zea mays L., Leaf diseases, Genetic resistance.AVALIAÇÃO DE HÍBRIDOS DE MILHO À MANCHA BRANCA, CERCOSPORIOSE E FERRUGEM COMUM E À PRODUTIVIDADERESUMO - Os objetivos deste trabalho foram identificar híbridos de milho que apresentem alta produtividade de grãos e resistência à mancha-branca, cercosporiose e ferrugem comum, bem como estimar a época de avaliação mais eficiente para mensurar a reação dos híbridos aos patógenos causadores dessas doenças. Para isso, foram instalados dois experimentos no município de Lavras, MG e avaliados 30 híbridos no ano agrícola de 2011/2012. O delineamento experimental utilizado foi o látice 6 x 5 com três repetições. Foi avaliada a produtividade de grãos e realizadas cinco avaliações da severidade dessas enfermidades, em intervalos de 10 dias, a partir de 60 dias da emergência das plantas. Posteriormente, estimou-se a área abaixo da curva de progresso das doenças (AACPD) e a correlação de Sperman entre as mesmas com as diversas épocas de avaliação de cada doença. Constatou-se que os híbridos GNZ9501 PRO e GNZ9626 PRO apresentam alta produtividade de grãos e satisfatório nível de resistência à mancha-branca, cercosporiose e ferrugem comum e que para a avaliação do nível de resistência a essas enfermidades deve-se optar pela avaliação no período que compreende 80 a 100 dias após a emergência das plantas, o qual fornece resultados semelhantes à AACPD.Palavras-chave: Zea mays L., Doenças foliares, Resistência genética.


2003 ◽  
Vol 83 (2) ◽  
pp. 241-247 ◽  
Author(s):  
B. L. Ma ◽  
L. M. Dwyer ◽  
C. Costa

Conflicting reports have led to a renewed interest in the effects of narrow row spacing and high plant population densities on maize (Zea mays L.) grain yield. Field experiments were conducted to evaluate maize response to row spacing and N fertility over a 4-yr period (1997–2000). A randomized complete block design, arranged in a split plot was used with four replications each year with modifications of treatments over years. Row spacings of 0.51 m, 0.76 m and 0.76 m paired row alone or in combination with hybrid were tested in the subplot whereas combination of fertilizer N by population density (1997 and 1998) or N alone was assigned to the main plot. In 1997 and 1998, combinations of N by density consisted of 0 , 60, 120, 180 and 240 kg N ha-1 at 89 000 plants ha-1, and 60 and 180 kg N ha-1 at 69 000 plants ha-1 using a single hybrid, Pioneer 3893. In 1999 and 2000, N fertility levels of 0, 80 and 180 kg N ha-1 >were the main plots and six combinations of hybrids (Pioneer 3893 and Pioneer 38P06 Bt) by row spacing were grown in the subplots at 69 000 plants ha-1. Row spacing and fertility levels showed no significant interaction for any parameter at any developmental stage. In both 1997 and 1998, row spacing had no significant effect on yield (yield differed by 5% among row spacing treatments) or harvest index (varied from 0.45 to 0.53). For Pioneer 38P06 Bt in 1999, grain yield of the 0.51 m row spacing with the 80 kg N ha-1 fertilizer rate was 14.6% higher than the conventional 0.76 m row spacing. In 2000, the substantially lower (11%) yield of the 0.76 m paired row spacing than the other row spacing treatments was more likely the result of an exceptionally cool and wet season. In 1997 and 1998, plant density showed no effect on shoot or root DM. The lower density (69 000 plants ha-1) did, however, show a higher root to shoot ratio than the higher density. Shoot DM, root DM and root to shoot ratio did not differ between the 60 and 180 kg N ha-1 fertility treatments. While higher N levels increased above- and below-ground crop N contents, row spacing showed no consistent effects on maize plants at the early stages. Under the conditions of this study, narrow rows did not result in higher yield or N use efficiency even plant density and N fertility varied. Key words: Maize (Zea mays L.), nitrogen use, population density, root/shoot ratio, row spacing


Author(s):  
Iliyasu Audu

Field experiments to study the performance of maize varieties (Zea mays L.) under different rates of nitrogen fertilizer and cow dung in Mubi, Adamawa State, Nigeria were conducted in 2014 and 2015 cropping seasons at the Food and Agricultural Organization/Tree Crops Plantation (FAO/TCP) Farm of the Faculty of Agriculture, Adamawa State University Mubi. A split plot design was adopted for the study with two maize varieties assigned to the main plots and nitrogen with cow dung assigned to the subplots in a factorial combination. Nitrogen rates of 0, 60 and 120 kg N ha-1 and cow dung 0, 1 and 2 ton ha-1 were used. Data were collected on number of cobs per plant, cob length, 100 grain weight and grain yield per hectare. Data collected were subjected to analysis of variance using SAS system for windows 9.2 version 2005 and treatment means were separated using Duncan Multiple Range Test. Result showed that the effect of nitrogen fertilizer on the yield and yield parameters increased significantly with the use of 120 kg N per ha-1 recording the highest for cob length (17.68 cm) 100 grain weighs (32.89 g) and grain yield (5658.3 kg). The control plot produced the least. Application of 2 ton ha-1 cow dung exhibited the highest yield. there was an interaction of variety with nitrogen on cob length and grain yield. Application of 120 kg N ha-1 significantly increased the yield of Quality Protein Maize (QPM) along with 2 ton ha-1 cow dung.


Crop Science ◽  
1969 ◽  
Vol 9 (3) ◽  
pp. 265-267 ◽  
Author(s):  
T. P. Singh ◽  
M. S. Zuber ◽  
G. F. Krause

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