Modelling climatic risks of aflatoxin contamination in maize

2008 ◽  
Vol 48 (3) ◽  
pp. 358 ◽  
Author(s):  
Y. S. Chauhan ◽  
G. C. Wright ◽  
N. C. Rachaputi
Keyword(s):  
Risk Index ◽  
Grain Filling ◽  
Aflatoxin Contamination ◽  
Climatic Data ◽  
Seasonal Temperature ◽  
Sowing Time ◽  
Wide Range ◽  
Climatic Risks ◽  
Grain Filling Period ◽  
Lower Temperature

Aflatoxins are highly carcinogenic mycotoxins produced by two fungi, Aspergillus flavus and A. parasiticus, under specific moisture and temperature conditions before harvest and/or during storage of a wide range of crops including maize. Modelling of interactions between host plant and environment during the season can enable quantification of preharvest aflatoxin risk and its potential management. A model was developed to quantify climatic risks of aflatoxin contamination in maize using principles previously used for peanuts. The model outputs an aflatoxin risk index in response to seasonal temperature and soil moisture during the maize grain filling period using the APSIM’s maize module. The model performed well in simulating climatic risk of aflatoxin contamination in maize as indicated by a significant R2 (P ≤ 0.01) between aflatoxin risk index and the measured aflatoxin B1 in crop samples, which was 0.69 for a range of rainfed Australian locations and 0.62 when irrigated locations were also included in the analysis. The model was further applied to determine probabilities of exceeding a given aflatoxin risk in four non-irrigated maize growing locations of Queensland using 106 years of historical climatic data. Locations with both dry and hot climates had a much higher probability of higher aflatoxin risk compared with locations having either dry or hot conditions alone. Scenario analysis suggested that under non-irrigated conditions the risk of aflatoxin contamination could be minimised by adjusting sowing time or selecting an appropriate hybrid to better match the grain filling period to coincide with lower temperature and water stress conditions.

scholarly journals Influence of Drought and Sowing Time on Protein Composition, Antinutrients, and Mineral Contents of Wheat

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sondeep Singh ◽  
Anil K. Gupta ◽  
Narinder Kaur
Keyword(s):  
Protein Content ◽  
Protein Composition ◽  
Thermal Conditions ◽  
Grain Filling ◽  
Mineral Contents ◽  
Sowing Time ◽  
Fe Content ◽  
Meal Quality ◽  
Grain Filling Period ◽  
Lower Temperature

The present study in a two-year experiment investigated the influence of drought and sowing time on protein composition, antinutrients, and mineral contents of wheat whole meal of two genotypes differing in their water requirements. Different thermal conditions prevailing during the grain filling period under different sowing time generated a large effect on the amount of total soluble proteins. Late sown conditions offered higher protein content accompanied by increased albumin-globulin but decreased glutenin content. Fe content was increased to 20–23%; however, tannin decreased to 18–35% under early sown rain-fed conditions as compared to irrigated timely sown conditions in both the genotypes. Activity of trypsin inhibitor was decreased under rain-fed conditions in both genotypes. This study inferred that variable sowing times and irrigation practices can be used for inducing variation in different wheat whole meal quality characteristics. Lower temperature prevailing under early sown rain-fed conditions; resulted in higher protein content. Higher Fe and lower tannin contents were reported under early sown rain-fed conditions however, late sown conditions offered an increase in phytic acid accompanied by decreased micronutrients and glutenin contents.

scholarly journals Physiological Traits Determining Yield Tolerance of Wheat to Foliar Diseases

2017 ◽  
Vol 107 (12) ◽  
pp. 1468-1478 ◽  
Author(s):  
F. van den Berg ◽  
N. D. Paveley ◽  
I. J. Bingham ◽  
F. van den Bosch
Keyword(s):  
Carbon Assimilation ◽  
Grain Filling ◽  
Specific Weight ◽  
Water Soluble ◽  
Strong Positive Correlation ◽  
Area Index ◽  
Disease Tolerance ◽  
Wide Range ◽  
Mechanistic Basis ◽  
Grain Filling Period

Tolerance is defined as the ability of one cultivar to yield more than another cultivar under similar disease severity. If both cultivars suffer an equal loss in healthy (green) leaf area duration (HAD) over the grain filling period due to disease presence, then the yield loss per unit HAD loss is smaller for a more tolerant cultivar. Little is understood of what physiological and developmental traits of cultivars determine disease tolerance. In this study, we use a mathematical model of wheat to investigate the effect of a wide range of wheat phenotypes on tolerance. During the phase from stem extension to anthesis, the model calculates the assimilate source and sink potential, allowing for dynamic changes to the source–sink balance by partitioning assimilates between ear development and storage of water-soluble carbon (WSC) reserves, according to assimilate availability. To quantify tolerance, rates of epidemic progress were varied on each phenotype, leading to different levels of HAD loss during the postanthesis, grain-filling period. Model outputs show that the main determinant of tolerance is the total amount of assimilate produced per grain during the rapid grain-fill period, leading to a strong positive correlation between HAD per grain and tolerance. Reductions in traits that affect carbon assimilation rate and increases in traits that determine the amount of structural biomass in the plant increase disease tolerance through their associated reduction in number of grains per ear. Some of the most influential traits are the canopy green area index, carbon use efficiency, and leaf specific weight. Increased WSC accumulation can either increase or decrease tolerance. Furthermore, a cultivar is shown to be maximally tolerant when a crop is able to just fill its total sink size in the presence of disease. The model has identified influential functional traits and established that their associations with tolerance have a mechanistic basis.

Effects of light, temperature, and rate of desiccation on translucency in wheat grain

1968 ◽  
Vol 19 (3) ◽  
pp. 365 ◽  
Author(s):  
JA Parish ◽  
NJ Halse
Keyword(s):  
Low Temperatures ◽  
Dry Weight ◽  
Grain Filling ◽  
Wheat Grain ◽  
Low Light ◽  
Wide Range ◽  
Grain Drying ◽  
Drying Techniques ◽  
Laboratory Results ◽  
Grain Filling Period

Wheat grain was harvested at maximum dry weight and dried under various conditions in the laboratory. Results showed that opaque grain was produced by fast drying; translucency developed with slow drying. The effect of various temperatures when drying rate was constant was also measured. It was found that translucency developed more at high temperatures than at low temperatures. There was little "mottling" despite the wide range between treatments from entirely opaque to fully translucent grain. Drying techniques were found whereby grain samples different in texture but identical in other respects can be prepared. In other experiments wheat plants were grown in controlled light and temperature conditions during the grain-filling period. Results showed that at this stage low temperature and low light intensity favoured the development of translucency.

scholarly journals Using Satellite Data to Optimize Wheat Yield and Quality under Climate Change

2021 ◽  
Vol 13 (11) ◽  
pp. 2049
Author(s):  
Shilo Shiff ◽  
Itamar M. Lensky ◽  
David J. Bonfil
Keyword(s):  
Land Surface ◽  
Wheat Yield ◽  
Grain Filling ◽  
High Temperature Stress ◽  
Climatic Conditions ◽  
Google Earth ◽  
Sowing Time ◽  
Wheat Field ◽  
Yield And Quality ◽  
Grain Filling Period

Climatic conditions during the grain-filling period are a major factor affecting wheat grain yield and quality. Wheat in many semi-arid and arid areas faces high-temperature stress during this period. Remote sensing can be used to monitor both crops and environmental temperature. The objective of this study was to develop a tool to optimize field management (cultivar and sowing time). Analysis of 155 cultivar experiments (from 10 growth seasons) representing different environmental conditions revealed the required degree-days for each Israeli spring wheat cultivar to reach heading (from emergence). We developed a Google Earth Engine (GEE) app to analyze time series of gap-filled 1 km MODIS land surface temperature (LSTcont). By changing the cultivar and/or emergence date in the GEE app, the farmer can “expose” each wheat field to different climatic conditions during the grain-filling period, thereafter enabling him to choose the best cultivar to be sown in the field with the right timing. This approach is expected to reduce the number of fields that suffer from heat stress during the grain-filling period. The app can be also used to assess the effects of different global warming scenarios and to plan adaptation strategies in other regions too.

scholarly journals Night-Warming Priming at the Vegetative Stage Alleviates Damage to the Flag Leaf Caused by Post-anthesis Warming in Winter Wheat (Triticum aestivum L.)

2021 ◽  
Vol 12 ◽  
Author(s):  
Yonghui Fan ◽  
Zhaoyan Lv ◽  
Ting Ge ◽  
Yuxing Li ◽  
Wei Yang ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Winter Wheat ◽  
Grain Filling ◽  
Membrane Lipid ◽  
Control Treatment ◽  
Seasonal Temperature ◽  
Membrane Lipid Peroxidation ◽  
Flag Leaves ◽  
Grain Filling Period ◽  
Night Warming

The asymmetric warming in diurnal and seasonal temperature patterns plays an important role in crop distribution and productivity. Asymmetric warming during the early growth periods of winter wheat profoundly affects its vegetative growth and post-anthesis grain productivity. Field experiments were conducted on winter wheat to explore the impact of night warming treatment in winter (Winter warming treatment, WT) or spring (Spring warming treatment, ST) on the senescence of flag leaves and yield of wheat plants later treated with night warming during grain filling (Warming treatment during grain filling, FT). The results showed that FT decreased wheat yield by reducing the number of grains per panicle and per 1,000-grain weight and that the yield of wheat plants treated with FT declined to a greater extent than that of wheat plants treated with WT + FT or ST + FT. The net photosynthetic rate, chlorophyll content, and chlorophyll fluorescence parameters of the flag leaves of wheat plants treated with WT + FT or ST + FT were higher than those under the control treatment from 0 to 7 days after anthesis (DAA) but were lower than those under the control treatment and higher than those of wheat plants treated with FT alone from 14 to 28 DAA. The soluble protein and Rubisco contents in the flag leaves of wheat plants treated with WT + FT or ST + FT were high in the early grain-filling period and then gradually decreased to below those of the control treatment. These contents were greater in wheat plants treated with WT + FT than in wheat plants treated with ST + FT from 0 to 14 DAA, whereas the opposite was true from 21 to 28 DAA. Furthermore, WT + FT and ST + FT inhibited membrane lipid peroxidation by increasing superoxide dismutase and peroxidase activities and lowering phospholipase D (PLD), phosphatidic acid (PA), lipoxygenase (LOX), and free fatty acid levels in the early grain-filling period, but their inhibitory effects on membrane lipid peroxidation gradually weakened during the late grain-filling period. Night-warming priming alleviated the adverse effect of post-anthesis warming on yield by delaying the post-anthesis senescence of flag leaves.

scholarly journals Application of a model to assess aflatoxin risk in peanuts

2010 ◽  
Vol 148 (3) ◽  
pp. 341-351 ◽  
Author(s):  
Y. S. CHAUHAN ◽  
G. C. WRIGHT ◽  
R. C. N. RACHAPUTI ◽  
D. HOLZWORTH ◽  
A. BROOME ◽  
...  
Keyword(s):  
Large Scale ◽  
Production Systems ◽  
Risk Index ◽  
Temperature Response ◽  
Decision Support Tool ◽  
Fold Increase ◽  
Climatic Conditions ◽  
Aflatoxin Contamination ◽  
Climatic Data ◽  
Support Tool

SUMMARYWhen exposed to hot (22–35°C) and dry climatic conditions in the field during the final 4–6 weeks of pod filling, peanuts (Arachis hypogaeaL.) can accumulate highly carcinogenic and immuno-suppressing aflatoxins. Forecasting of the risk posed by these conditions can assist in minimizing pre-harvest contamination. A model was therefore developed as part of the Agricultural Production Systems Simulator (APSIM) peanut module, which calculated an aflatoxin risk index (ARI) using four temperature response functions when fractional available soil water was <0·20 and the crop was in the last 0·40 of the pod-filling phase. ARI explained 0·95 (P⩽0·05) of the variation in aflatoxin contamination, which varied from 0 toc. 800 μg/kg in 17 large-scale sowings in tropical and four sowings in sub-tropical environments carried out in Australia between 13 November and 16 December 2007. ARI also explained 0·96 (P⩽0·01) of the variation in the proportion of aflatoxin-contaminated loads (>15 μg/kg) of peanuts in the Kingaroy region of Australia during the period between the 1998/99 and 2007/08 seasons. Simulation of ARI using historical climatic data from 1890 to 2007 indicated a three-fold increase in its value since 1980 compared to the entire previous period. The increase was associated with increases in ambient temperature and decreases in rainfall. To facilitate routine monitoring of aflatoxin risk by growers in near real time, a web interface of the model was also developed. The ARI predicted using this interface for eight growers correlated significantly with the level of contamination in crops (r=0·95,P⩽0·01). These results suggest that ARI simulated by the model is a reliable indicator of aflatoxin contamination that can be used in aflatoxin research as well as a decision-support tool to monitor pre-harvest aflatoxin risk in peanuts.

EFFECTS OF PHOTOPERIOD AND TEMPERATURE ON VEGETATIVE AND REPRODUCTIVE GROWTH OF A MAIZE (ZEA MAYS) HYBRID

1977 ◽  
Vol 57 (4) ◽  
pp. 1127-1133 ◽  
Author(s):  
R. B. HUNTER ◽  
M. TOLLENAAR ◽  
C. M. BREUER
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Dry Weight ◽  
Grain Filling ◽  
Temperature Treatment ◽  
Limiting Factor ◽  
Grain Filling Period ◽  
Temperature Interaction ◽  
Lower Temperature ◽  
Vegetative And Reproductive Growth

A single-cross maize (Zea mays L.) hybrid was grown to maturity in the four combinations of two temperatures, 20 and 30 C, and two photoperiods, 10 and 20 h, in controlled-environment growth cabinets. Measurements of dry weights of plant components were made at tassel initiation, mid-anthesis, mid-anthesis plus 16 days, and maturity. The longer photoperiod and cooler temperature treatment produced the highest final plant dry weight. Average daily dry matter (DM) production was greater for plants grown at the longer photoperiod. This could largely be attributed to a higher leaf area per plant. The duration of DM production was longer at the cooler temperature. Grain yields were higher under the lower temperature because of an increase in the length of the grain-filling period and because a greater proportion of the post-anthesis DM was allocated to the grain. The results of this study showed a significant photoperiod × temperature interaction for length of the grain-filling period, kernel number and grain yield. Post-anthesis DM accumulation did not appear to be a limiting factor for grain yield. The effects of temperature and photoperiod on length of the grain-filling period and grain yield may have been partly mediated through the size of the grain sink.

scholarly journals In-Depth Field Characterization of Teff [Eragrostis tef (Zucc.) Trotter] Variation: From Agronomic to Sensory Traits

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1107
Author(s):  
Lianne Merchuk-Ovnat ◽  
Jajaw Bimro ◽  
Noga Yaakov ◽  
Yaarit Kutsher ◽  
Orit Amir-Segev ◽  
...  
Keyword(s):  
Grain Filling ◽  
Eragrostis Tef ◽  
Early Type ◽  
Important Food ◽  
Lodging Resistance ◽  
Pollen Donor ◽  
Wide Range ◽  
Grain Filling Period ◽  
Sensory Parameters

Teff is an important food crop that serves to prepare Injera-flat-bread. It is cultivated worldwide and is particularly susceptible to lodging. A diverse collection of teff [Eragrostis tef (Zucc.) Trotter] populations was characterized for a wide range of traits, ranging from agronomic to final Injera sensory parameters, under well-irrigated Mediterranean spring conditions. The populations tested were collected from single plants presenting lodging resistance at the site of collection and their traits were characterized herein. An early type of lodging was observed, which was most likely triggered by a fast and sharp inflorescence weight increase. Other populations were ‘strong’ enough to carry the inflorescence during most of the grain-filling period, up to a point where strong lodging occurred and plants where totally bent to the ground. Three mixed color seed populations were established from a single plant. These were separated into ‘white’ and ‘brown’ seeds and were characterized separately under field conditions. The newly ‘brown’ populations appear to be the result of a rather recent non-self (external) airborne fertilization from a dark pollen donor. Some of these hybrids were found to be promising in terms of Injera sensory traits. The population of these studies might serve as breeding material. Integration between a wide range of parameters and the correlations obtained between agronomic and sensory traits might improve our ability to breed towards a “real world” better end-product.

HERITABILITIES AND RELATIONSHIPS AMONG GRAIN-FILLING PERIOD, SEED WEIGHT AND QUALITY IN FORTY ITALIAN VARIETIES OF CORN (ZEA MAYS L.)

1980 ◽  
Vol 60 (4) ◽  
pp. 1101-1107 ◽  
Author(s):  
M. PERENZIN ◽  
F. FERRARI ◽  
M. MOTTO
Keyword(s):  
Zea Mays ◽  
Seed Weight ◽  
Zea Mays L ◽  
Grain Filling ◽  
Kernel Weight ◽  
Genotypic Differences ◽  
Dry Matter Accumulation ◽  
Grain Moisture ◽  
Wide Range ◽  
Grain Filling Period

Forty Italian open-pollinated varieties of corn (Zea mays L.), selected to represent a wide range of plant maturity and grain weight, were evaluated in 1977 and 1978 to determine genetic variances and heritabilities for length and rate of grain-filling period, kernel weight and three seed-quality traits and to examine relationships among these traits. The results showed highly significant genotypic differences and high heritability estimates for most of the traits studied. Moreover, kernel weight and rate of grain filling were found to be closely associated, although this relationship could not be statistically tested. A relatively high correlation was also detected between kernel weight and length of the grain-filling period. The increase in seed weight obtained through a delay in black-layer formation was associated with a higher grain moisture content and a decreased grain protein percentage. A further noteworthy finding of this study was the identification of two varieties which attained a large seed weight in a relatively short time through a very high rate of dry matter accumulation. The implications of these findings are discussed from a physiological and breeding point of view.

Influence of Canopy Temperature (CT) During Grain-Filling Period on Yield and Effects of Several CT-Associated SSR Loci

2015 ◽  
Vol 41 (4) ◽  
pp. 548 ◽  
Author(s):  
Dong-Ling ZHANG ◽  
Hong-Na ZHANG ◽  
Chen-Yang HAO ◽  
Lan-Fen WANG ◽  
Tian LI ◽  
...  
Keyword(s):  
Canopy Temperature ◽  
Grain Filling ◽  
Ssr Loci ◽  
Grain Filling Period
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