Stephen smith, ed buckler and john doebley,1 department of statistics, north carolina state university, raleigh, north carolina 27695, department of crop science, north carolina. This type of hybrid maize is used for specialty products of the wetmilling starch industry. Drought tolerance in maize is influenced by timing of drought. Unesco eolss sample chapters soils, plant growth and crop production vol. Farhad hassanpour 1, hamid reza mobasser 1, hamid reza ganjali 1 department of agronomy, islamic azad university, zahedan branch, zahedan, iran article published on july 27, 2014 key words. Screening relevant genes of tolerance to low phosphorus in. Annotation csv files for the exon arrays are split into a probeset level annotation file and a transcript cluster level annotation file. The tolerant germplasm accessions, like those identified in this study, are essential materials for breeding drought andor heattolerant maize hybrids. The 4114 maize is a new maize line that combines genes and traits from two maize lines that had previously been given nonregulated status. Maize with a high percentage of translucent of hard endosperm is preferred by the dry milling industry, because it produces more of the popular highquality and highvalue products sought after than does soft maize. To understand the response of maize to abiotic and biotic stresses and its mechanism of stress tolerance, highthroughput omics approaches have been used in.
Genetic structure and diversity among maize inbred lines. Furthermore, we assessed the effect of this fungicide on i foliar disease severity and stalk health, ii incidence of green leaves in the upper leaf. Transgenic foodmaize has been detectedalbeit in variable proportionsdeep in the. On a daily basis, we can access from maize about 66. Maize is the most important food crop in the w orld for people and animal due to its high quality nutrition. Association mapping for cold tolerance in two large maize inbred. Evaluation of variety and plant density on grain yield. Maize kernels of another colour in white maize bloody butcher not defective. Genotype dependent tolerance to herbicides of maize zea. Biotechnological approaches to manage abiotic stress tolerance in maize will be discussed. This supports the widely held view that technology adoption increases household incomes. Obtaining ideal plant populations in maize is necessary in order to maximize grain yields.
Alternatively click here to download the full set in pdf. However, in maize, a major effect of water stress is a delay in silk. In doing this, some 84 mexican ethnic groups are also acting as stewards of maize genetic diversity. Maize is thought to have originated at least 5000 years ago in the highlands of mexico, peru, ecuador, andor bolivia because of the great density of native forms found in the region. Identification of drought, heat and combined drought and heat. Lown agronomic efficiency lnae, absolute grain yield gy at lown conditions, and the ratio between gy. Evaluation of different maize varieties zea mays l. It is considered a standard method for evaluation of plant responses to drought.
Quantifying the effect of pyraclostrobin on grain fill. The root elongation was the single most significant index in ranking the genotypes against al tolerance. Since corn is grown in climatically diverse regions and under different production conditions, assuming that high salinity in the substrate affect. Maize is a staple food crop for millions of africans. Breeding for cold tolerance in maize promises to allow increasing growth. Department of agriculture, agricultural research service, university of nebraska, lincoln, ne 68583, usa. It spread to the rest of the world after european contact with the americas in the late 15th and early 16th century. Maize zea mays l is one of the most important cereal crops grown in africa and rank the third most cultivated crop in nigeria ayeni, 1987. Nafziger encyclopedia of life support systems eolss 1. Response of maize zea mays lvarieties to planting densities. Low water availability is one of the major causes for maize yield reductions affecting the majority of the farmed regions around the world. According to an estimate the application of nitrogen fertilizer will increase maize yield by 6070 percent in year 2025 and twothird of this will be applied in developing world 7.
Insect pests cause major damage to stored maize grain thereby reducing its weight, quality and germination vigour. Growing maize in nigeria choice of land any well drained sandy loam or loamy soil can be used for planting maize but if in doubt, contact your nearest extension office or agroservice center. Land preparation use any method mechanical, chemical and manual that can adequately remove weeds and keep the soil loose for good seedbed. Population improvement in maize for corn rootworm tolerance. Influence of row spacing reduction on maize grain yield in. To unveil this information, a panel of 189 diverse maize inbred lines was evaluated under contrasting levels of n availability over 2 years. Influence of plant height and of leaf number on maize production at high plant densities1 luis sangoi2 and ricardo jonathan salvador3 abstract this experiment was conducted in ames, iowa, us, with the purpose of verifying if reduction in plant height, through the use of dwarfing genes, or leaf number, by growing short season. Maize yield and fertilizer n rate as observed symbols and simulated with the spherical function used in the maizen model solid line.
Drought, like many other environmental stresses, has adverse effects on crop yield including maize zea mays l. Influence of row spacing reduction on maize grain yield in regions with a short summer. First of all, due to homozygous, maize lines have often smaller habitus, with uneven growth than hybrid maize. Abstract the interest in reducing maize row spacing in the short growing season regions of brazil is increasing due to potential advantages such as higher radiation use efficiency. Since there was ahigh degreeofconcordanceamong replicateassays,inferred. The seeding stage of maize is especially sensitive to drought stress. Evaluation of variety and plant density on grain yield, number of seed per cob and 100 grain weight in maize zea mays l. We tested the hypothesis that reduced root cortical cell file number ccfn would improve drought tolerance in maize zea mays by reducing. Identification of drought, heat and combined drought and heat tolerant donors in maize zea mays l. Approaches to mitigate yield loss include developing drought. The performance of ten early open pollinated varieties opvs and their f 1 hybrids for grain yield and nitrogen use efficiency nue was assessed, and productive cultivars under low n fertilizer regimes were also quantified. Root cortical cells as a tool to screen for salt tolerance 117. Furthermore, we assessed the effect of this fungicide on i foliar disease severity and stalk health, ii incidence of green leaves in the upper leaf canopy stay green. Maize responses to drought drought is a multidimensional stress, affecting plants at various levels of their organization over space and time, so that the physiological responses to it are complex and often unpredictable.
The production of this crop has been transformed from that of a minor crop being grown around the homestead to a major or. Developing drought and low n tolerant maize cimmyt repository. Screening drought tolerance criteria in maize agecon search. However, tropical maize has been shown to have stable yields across a narrower range of temperatures than temperate maize lafitte et al.
The high cost of inorganic fertilizer in west and central africa has necessitated an investigation into the nitrogen optimum fertilizer rate for profitable maize production. There have been four principal and several minor theories regarding the origin of maize. Furthermore, genetic and phenotypic analysis showed that maize hybrids made from inbred lines with superior heat tolerance inherited an enhanced tolerance to elevated temperatures. For instance, yield of maize has stagnated at about 1. The absence of resistance or tolerance in the local maize varieties to the american rust shaped the first approach towards an improvement of the maize crop and introduction of maize materials from all over the world. Maize yield and components as influenced by environment. This waxy maize is composed entirely of amyl pectin, in contrast with common maize which contains approximately 78 percent of starch and 22 percent of amylose. Drought tolerance in maize is influenced by timing of. Notill processes are soilconserving, but highly challengingin organic farm. Identification of drought, heat, and combined drought and heat. Technology adoption is often countered by the uncertainty of the timing when positive impacts start to be realized.
Breeding for drought tolerance in maize zea mays l. In general, maize showed steady progress in terms of area expansion and production figure 2. Influence of row spacing reduction on maize grain yield 863 dropped per hill to assure the desired stand on each treatment. Information on the gross chemical composition of maize is. Characterization of maize inbred lines for drought and heat. These farmers grow their own seed and depend on maize as their main source of food. Magnavaca, national com and sorghum research center, embrapa. Hamish cheetham1 james millner2 and allan hardacre3 1corson grain ltd, gisborne. Photosynthesis can be roughly separated into biochemical and photochemical processes. Chemical composition of the maize kernel components % carbohydrates 84,0 protein 10,9 fat 4,5 minerals 1,3 table 1. In the case of the sweet maize, the sugary gene retards the normal conversion of sugar within. The chilling tolerance of six genetically different maize inbred lines with different degrees of chilling tolerance and that of four hybrids produced from four of these lines using line 156 as the. The effect of nitrogen fertilisation on maize grain.
Reduced root cortical cell file number improves drought. Gianessi 1 international pesticide benefit case study 107 september, 2014 introduction traditionally, maize was grown in south and southeast asia primarily as a subsistence food crop. Identification of drought, heat, and combined drought and. Identification of drought tolerant mechanisms in maize.
Importance of pesticides for growing maize in south and southeast asia leonard p. The reasons for low yield of maize in nigeria are associated with a number of biotic and abiotic. University of groningen the determinants of salinity. Three experiments were conducted in minnesota to compare drought. We also conclude that simple nutrient solution can be effectively used for screening crops for al tolerance. Extraearly maize inbreds and hybrids that are resistant to striga, tolerant of low nitrogen n and drought at flowering and grain filling periods, and that combine tolerance for these three stresses are now available in subsaharan africa as a result of the painstaking research under the maize improvement program at iita. Despite this fact, african farmers have been harvesting average grain yield of not more than.
Gas exchange, which mainly assesses the first process, has welldefined protocols. Tilling the maize crop leads to soil compaction and reduces soil quality, which can have a negative impact upon the growing conditions of subsequent crops. Consequently, the exploration and utilization of lptolerant genes are of great significance in plants. There have been four principal and several minor theories regarding the origin of. Maize is widely cultivated throughout the world, and a greater weight of maize is produced each year than any other grain. Article pdf available in american journal of plant sciences 0714.
Importance of pesticides for growing maize in south and. Low maize yields and the impacts of climate change on maize production highlight the need to improve yields in eastern and southern africa. Comparisons of maize populations for aluminum tolerance in. Maize yield and components as influenced by environment and. The current status of tropical maize transformation.
Other droughttolerant maize varieties are under development. Nitrogen use efficiency and grain yield in a diallelic. Mar 16, 2011 limited information is available on genetic variation in lownitrogen lown stress tolerance and nuse efficiency nue among maize inbreds. Climate projections suggest higher temperatures within droughtprone areas. Comparisons of maize populations for aluminum tolerance in nutrient solution r.
Limited information is available on genetic variation in lownitrogen lown stress tolerance and nuse efficiency nue among maize inbreds. Consequently, grain yield was higher in the first than in the second growing season, regardless of hybrid, planting date and row spacing figure 3. The experiment reveals genotypic variation in plant genotypes in al tolerance that can be exploited for target breeding in acid soils. Click the below thumbnails to view the deviations enlarged. Molecular improvement of tropical maize for drought stress. Affymetrix is dedicated to developing stateoftheart technology for acquiring, analyzing, and managing complex genetic information for use in biomedical research. Given the diversity of ecosystems in which maize can be grown, it is highly likely that there is genetic variability in the tolerance of tropical and subtropical maize to heat stress.
Marked strings were used during planting to position the seeds properly on each. Introduction maize zea mays l is the most important and most widely distributed cereal in the world after wheat and rice. Genetic structure and diversity among maize inbred lines as inferred from dna microsatellites kejun liu, major goodman, spencer muse, j. Pdf breeding for drought tolerance in maize zea mays l. To characterize how maize seedling respond to drought stress at the transcriptional level, we. The space between two adjacent hills within each row was 26. Low water availability is one of the major causes for maize yield reductions affecting the majority of the farmed regions around the wor l d. Ammonium tolerance and carbohydrate status in maize cultivars. Characterization of maize inbred lines for drought and. Affymetrix support by product for genechip maize genome array. Yield increases over that time period have been shown to be largely due to hybrids with greater crowding stress tolerance combined with increased plant populations duvick 2005. Omics of maize stress response for sustainable food production. The fundamental approach to solving this problem is to screen new genes of low phosphorous lp tolerance.
Both are affected by drought and can be assessed by noninvasive standard methods. Response of maize to nitrogen levels and seed priming. Genetic variation was found between the genotypes for yield potential yp stress yield ys, tolerance index tol, geometric mean productivity gmp, harmonic. Five open pollinated maize varieties zm401, zm309, zm521, zm421 and hickory king and one hybrid maize variety sc709 were evaluated for tolerance and their effects on progeny development against the maize weevil, sitophilus zeamais motsch. The maize inbred line 178 is an inbred lptolerant line. Agronomic and physiological approaches article pdf available in crop and pasture science 606. Drought tolerant varieties developed through biotechnology enable farmers to protect their harvest and minimize losses in times of severe drought by using water more efficiently. The project of maize breeding for tolerance to low n was established at nsw fcrc in 1995 with the objectives of developing inbred lines, hybrids and populations tolerant to low n.
O notill cultivation of maize in rolled forage peas n. Identification of drought, heat and combined drought and. Effect of irrigation and preplant nitrogen fertilizer. In recent years, the consumption of maize as a food crop has declined while the. Twumasiafriyie2 1international maize and wheat improvement center cimmyt, mexico 2 cimmyt, ethiopia introduction maize zea mays l. Inputs, processes, and outputs of the maizen model to determine the economically optimum n rate eonr. In this study we evaluated 300 maize inbred lines testcrossed to cml539. Since corn has been classified as one of the most sensitive crops to soil salinity, the evaluation of nacl tolerance of a hybrid of zea mays ssp. Maize yields have improved drastically over the last 40 years. Therefore, the development of droughttolerant lines becomes increasingly more important. Subsequently, organized approach towards a systematic corresponding author. Maize set more grains per ear and filled heavier grains in 199697 than in 199798 figures 1 and 2. The observed data are from the calibration data set from clay center, ne, in 2002. Salt tolerance of corn genotypes zea mays l during.
Genetic structure and diversity among maize inbred lines as. Research in model species suggests that tolerance to combined drought and heat stress is genetically distinct from tolerance to either stress alone, but this has not been confirmed in maize. While the usa produces almost half of the worlds harvest, other top producing countries are as widespread as china, brazil, france, indonesia, and south africa. Agbiz grain supports and promotes the interests of its members through representation and liaison with major role players in agriculture such as formal grain industry bodies, government, semigovernment. Effects of drought stress and water recovery on physiological. Researcharticle effect of irrigation and preplant nitrogen fertilizer source on maize in the southern great plains jacobt.