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MATERIALS AND METHODS.
| • | Size/shape (small/round, small/flat, medium/round, medium/flat, large/round and large/flat) |
|---|---|
| • | Planting depth (2, 4 and 6 cm) |
| • | Temperature (20, 25 and 30°C) |
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What is the arrangement of maize leaf?
The eight to 20 leaves that may form are arranged spirally on the stem. The maize leaf is a typical grass leaf and consists of a sheath and a blade. The leaf blade is long, narrow and undulating, and tapers towards the tip. It is supported by a prominent mid-rib along its entire length.
What type of leaf does maize have?
The maize plant possesses a simple stem of nodes and internodes. A pair of large leaves extend off of each internode and the leaves total 8–21 per plant. The leaves are linear or lanceolate (lance-like) with an obvious midrib (primary vein) and can grow from 30 to 100 cm (11.8–39.4 in) in length.
What is the stem structure of maize?
The system providing strength to a maize stem is described as consisting of thick-walled, lignified cells located in three distinct stem tissues: hypodermis; peripheral bundle sheaths; and sclerified ground parenchyma.
Does maize have strap shaped leaves?
The strap-like foliar leaf, a lateral appendage positioned at each node on the stem, has two distinct parts--the distal blade and the proximal sheath that encircles the stem at its insertion. Shoot-borne crown and brace roots are formed from consecutive basal nodes.
What are characteristics of maize plant?
Plant Characteristics Maize (Zea mays) is a tall, deep-rooted, warm weather annual grass. A single long stalk will develop from seed. Long smooth leaves are attached at the stem nodes. Seed producing shoots originate from the base of the main stem.
Which part of plant is maize?
The leafy stalk of the plant produces pollen inflorescences (or "tassels") and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are fruits....MaizeClade:TracheophytesClade:AngiospermsClade:MonocotsClade:Commelinids11 more rows
What is maize root?
The root system of maize can be divided into an embryonic root system (Abbe and Stein, 1954) consisting of a single primary root and a variable number of seminal roots, and a post‐embryonic root system which is made up by shoot‐borne roots.
What is maize flower?
Maize is a monoecious plant that produces male flowers on a terminal tassel (Fig. 1A) and female flowers on lateral ears (Fig. 1B), which arise in the axils of vegetative leaves. The tassel initiates several long, indeterminate branches at the base while the ear consists of a single spike with no long branches.
How tall is a maize plant?
Structure and physiology. The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk.
Where was maize found?
Plant fragments dated to 4200 BC found in the Guilá Naquitz Cave in Oaxaca, Mexico, showed maize had already been domesticated from teosinte. Ancient Mesoamerican engraving, National Museum of Anthropology of Mexico. Maize is a cultigen; human intervention is required for it to propagate.
What is maize used for?
In addition to being consumed directly by humans (often in the form of masa ), maize is also used for corn ethanol, animal feed and other maize products, such as corn starch and corn syrup. The six major types of maize are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn.
How much maize was grown in 2014?
In 2014, total world production was 1.04 billion tonnes. Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States alone in 2014. Genetically modified maize made up 85% of the maize planted in the United States in 2009.
What is the name of the plant that produces seeds?
The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits. Maize has become a staple food in many parts of the world, with the total production of maize surpassing that of wheat or rice.
When was maize first grown?
Around 4,500 ago, maize began to spread to the north; it was first cultivated in what is now the United States at several sites in New Mexico and Arizona, about 4,100 ago.
Did the Spanish eat maize?
After the arrival of Europeans in 1492, Spanish settlers consumed maize, and explorers and traders carried it back to Europe and introduced it to other countries. Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for communion bread, since in Christian belief only wheat could undergo transubstantiation and be transformed into the body of Christ. Some Spaniards worried that by eating indigenous foods, which they did not consider nutritious, they would weaken and risk turning into Indians. "In the view of Europeans, it was the food they ate, even more than the environment in which they lived, that gave Amerindians and Spaniards both their distinctive physical characteristics and their characteristic personalities." Despite these worries, Spaniards did consume maize. Archeological evidence from Florida sites indicate they cultivated it as well.
Determining seed size: Production
Seed sizes from hybrid production will vary field to field, and year to year due to many factors. These include specific hybrid characteristics, parent tendencies and growing conditions, especially during the pollination and fill period. Seed from a single cob falls into many size/shape categories.
Effect on Emergence & Early Growth
There have been minor differences in emergence noted under adverse planting conditions. Large seed can have slightly decreased emergence rates in dry soil conditions as the amount of moisture needed for germination and emergence is relative to the size of the seed.
Importance of Planter Settings
This is where seed size and shape matters. Planter settings should be adjusted for accurate seed positioning, placement, and the intended population. When set properly for the seed size, a planter can more accurately singulate and deliver the seed.
Summary
Overall, seed size does not affect genetic yield potential. Having a planter set properly can improve your opportunity to achieve an optimal stand by minimising skips, doubles, and triples.
How tall is a maize stem?
Stem: The maize stem varies in height from less than 0.6 m to more than 5.0 m in extreme cases and ranges from 1.5 to 3 m in general. The stem is cylindrical; solid filled with pith and is clearly divided into nodes and internodes. Internodes are somewhat flattened or grooved the side next to the leaf sheath.
What is a maize leaf?
The maize leaf is a typical grass leaf and consist s of a sheath, ligules, auricles and a blade. The sheath surrounds the internodes above the node to which it is attached. The leaf blade is long, narrow, undulating and tapers towards the tip and is glabrous to hairy.
How many internodes are there in a sage plant?
The numbers of the internodes varied from 8 to 21 internodes with an average of 14. The internodes directly below the first four leaves do not lengthen, whereas those below the sixth, seventh and eighth leaves lengthen to approximately 25, 50 and 90 mm, respectively.
What is the dent in maize?
The protein, hulls and soluble part of the maize kernel are used in animal and poultry feed. e. Kernels can be of the dent or flint (round) types. Dent kernels have a dented crown, which is formed during drying when the softer starch in the middle of the kernel shrinks faster than the outer more translucent sides.
What are the parts of a maize kernel?
The maize kernel consists of an endosperm, embryo, a pericarp and tip cap (Fig. 1). The endosperm contains the main carbohydrates. The embryo contains the parts that give rise to the next generation, while the pericarp and tip cap enclose the entire kernel. b.
How deep are the roots of a plant?
If root growth is not restricted, the root system of a mature plant extends approximately 1.5 m laterally and downwards to approximately 2.0 more even deeper. The permanent root system has adventitious and prop roots.
What is the axis of a pistillate?
ê The pistillate spikelets are borne on a thick axis called a cob. Each pistillate produces two flower one of which is abortive and the second bear glume, palea, an ovary, style and stigma. The styles are long coming out of the husk known as silk. The stigma is branched, hairy and is the receptive part of the style.
Why is my maize turning purple?
Cold conditions after establishment will slow the growth of seedling maize, often causing it´s foliage to turn purple. This is probably due to reduced phosphorus availability at lower soiltemperatures.However, once temperatures begin to rise again, the crop continues to grow normally.
What is the size of seed?
Seed details. Seed has both size and shape gradings. Size varies from 4400 seed/kg (small) to 2500 seed/kg (large). Seed shape consists of rounds or flats. Flat seed is generally best in plate seeders, while round seed is preferred by air seeders. There is no difference between the crops produced by these seed shapes.
How long does it take for maize to flush?
If conditions are hot and dry, a quick flush 2 - 3 weeks after emergence may be required.
What is the best pH for maize?
A pH range of 5 - 8 can be tolerated but best growth is achieved in the range of pH 5.6 - 7.5.
When to plant maize in Queensland?
December provides another suitable opportunity, especially for dryland crops. In Moreton, maize is often successfully planted as early as mid- August. Latest plantings in these areas would occur in early to mid-January, due tolikelihoodof disease development in late summer/autumn.
Can a mid season hybrid produce moreyieldper megalitres of water?
However, where irrigation is limited, a mid-season hybrid may produce moreyieldper megalitre of water. This may also be the case in fully irrigated situations where it is desired to limit the number of irrigations for economic reasons or to plant a following crop to obtain maximum utilisation of seasonal conditions.
Is there a variety of maize?
Maize varieties. There are a multitude of maize varieties available. The choice of variety will depend on market requirements, environmental conditions, whether the crop is irrigated and the level of disease resist ance required. Varieties are continually changing so ensure you have up-to-date varietal information.
Where is maize grown?
Maize was domesticated around 12,000 years ago in Mesoamerica and is now the largest crop in the Americas. The United States is the largest producer of maize in the world, with China, Brazil, and South Africa also growing significant areas. In the United States only 2.5% of maize is grown for human consumption; the majority being used for livestock feed. An estimated 29% of the total 2007 maize production in the United States was used for biofuels, and this is expected to increase in the future (Dhugga, 2007). Two major pests of maize in the United States and Canada are the lepidopteran European corn borer (ECB; Ostrinia nubilalis) and the coleopteran western corn rootworm (WCR; Diabrotica virgifera virgifera ). It is estimated that the WCR alone is responsible for $1 billion in lost revenue each year in the United States, which includes $800 million in yield loss and $200 million in insect control costs. The ECB larvae live hidden within the maize stalk and the WCR larvae bore into the maize roots, making both pests extremely difficult to control with conventional pesticides. Since the release of Bt maize targeted to ECB in 1996, the area planted with genetically modified maize had increased to over 35 million hectares by 2008 ( James, 2008 ).
Where does maize stripe live?
Maize stripe was discovered in Florida in 1974 and is now known to occur in Africa, the Americas, Australia, and Asia, with its distribution overlapping that of maize mosaic and its vector P. maidis ( Ammar, Gingery, & Madden, 1995; Falk & Tsai, 1998 ). The disease can cause large losses in Africa and is caused by Maize stripe virus (MSpV; genus Tenuivirus ), a nonenveloped single-stranded RNA virus with five ambisense genome segments (Falk & Tsai, 1998 ). It is transmitted in a persistent propagative manner, and natural hosts include maize, sorghum, and itchgrass, similar to MMV. Maize stripe is easily confused with maize mosaic, because of similarities in symptoms, hosts, and vector species ( Greber, 1981 ).
What is the most produced cereal crop in the world?
Maize is the most produced cereal crop in the world and the most adapted to different ecosystems. Ancient Mesoamerican farmers started to select and manipulate teosinte ( Zea mexicana) and in a couple of centuries transformed this native grass into several pre-Columbian maize races. Today, plant breeders recognize more than 300 races that evolved from these prehistoric ethnic groups. The Mesoamericans created maize by transforming a tiny two-rowed ear of teosinte of about 3 cm long into the first small maize ears with four ranks of paired female spikelets. This transformation took perhaps only 100–200 years. The maize crop produces under irrigation and in dryland conditions; however, the plant is highly susceptible to frosts. Among commercial cereals, maize is the only one that has the male and female flowers separated. The staminate or male inflorescence is borne in the tassel and the pistillate or female inflorescence on the ears. These are located in the top and middle parts of the plant, respectively. Maize is classified according to color into white or yellow and kernel configuration into dent or corneous or flinty. The main specialty types are popcorn, waxy, high-amylose or amylomaize, sweet, blue, Cuzco, and quality protein.
How does Zea mays reproduce?
Maize plants contain both male and female reproductive structures and reproduce by both cross-pollination and self-pollination. In most commercially viable maize genotypes, the female structure (the ear) projects outward from a central stalk, while the male structure (the tassel) projects out the top of the stalk. Pollen from the tassel is carried by the wind to other maize plants, where fertilization of the individual kernels on the ear occurs. The ears of maize may range in size from about 2.5 to over 45 cm long. The kernel size, shape, and color also vary widely.
What causes streaks on maize?
Maize streak symptoms are characterized by the development of chlorotic spots and streaks in longitudinal lines on leaves. There is a progressive increase in the number and length of streaks that occur on new leaf tissue. The streaks often fuse laterally, resulting in narrow broken chlorotic stripes, which can in some cases cover the entire leaf. In very susceptible maize cultivars, severe chlorosis occurs leading to stunted plant and premature death. MSV is transmitted by several species of leafhoppers in the genus Cicadulin a, with C. mbila (Naudé) being the most common vector. It transmits MSV in a circulative nonpropagative manner. Streak symptoms have been described in numerous species of wild grasses. Late plantings are generally more severely infected than early ones. The major source of MSV infection on maize is a previously infected maize field. Therefore, planting of maize close to a previous maize field must be avoided. Carbamate insecticides (such as carbofuran) can effectively prevent MSV transmission but prices of chemicals and equipment for spraying are often prohibitive for smallholder farmers. The development of insect resistant plants is under study.
Is maize a model organism?
Maize (Zea mays) has been a model organism for genetics and molecular bi ology for more than a 100 years. It is well studied in genetic mapping, cytogenetics, and epigenetics ( Freeling and Walbot, 1996). As with any other multicellular eukaryote, normal growth, development, and environmental response in maize is dependent upon a carefully orchestrated program of gene expression. This program is regulated by a number of overlapping and interdependent mechanisms, including genetic and epigenetic pathways. Maize is an excellent model for studying epigenetic regulation of gene expression, because it has a large genome with a high percentage of transposable elements (TEs), it exhibits known types of epigenetic regulation of gene expression, and there are many reported epigenetic phenomena to focus mechanistic studies on. This review considers the role that epigenetic regulatory mechanisms play in influencing gene expression in maize, starting with the earliest examples through recent studies that take advantage of major technological advances in genomics.
Overview
Names
The word maize derives from the Spanish form of the indigenous Taíno word for the plant, mahiz. It is known by other names including corn in some English speaking countries.
The word "corn" outside the US, Canada, Australia, and New Zealand refers to any cereal crop, its meaning understood to vary geographically to refer to the l…
History
Maize is a cultigen; human intervention is required for it to propagate. Whether or not the kernels fall off the cob on their own is a key piece of evidence used in archaeology to distinguish domesticated maize from its naturally-propagating teosinte ancestor. Genetic evidence can also be used to determine when various lineages split.
Structure and physiology
The maize plant is often 3 m (10 ft) in height, though some natural strains can grow 13 m (43 ft), and the tallest recorded plant reached 45 feet (14 m). The stem is commonly composed of 20 internodes of 18 cm (7 in) length. The leaves arise from the nodes, alternately on opposite sides on the stalk, and have entire margins.
Genetics
Maize is an annual grass in the family Gramineae, which includes such plants as wheat, rye, barley, rice, sorghum, and sugarcane. There are two major species of the genus Zea (out of six total): Zea mays (maize) and Zea diploperennis, which is a perennial type of teosinte. The annual teosinte variety called Zea mays mexicana is the closest botanical relative to maize. It still grows in the wild as …
Evolution
As with many plants and animals, Z. mays has a positive correlation between effective population size and the magnitude of selection pressure. Z. m. having an EPS of ~650,000, it clusters with others of about the same EPS, and has 79% of its amino acid sites under selection.
Recombination is a significant source of diversity in Z. mays. (Note that this finding supersedes previous studies which showed no such correlation.)
Breeding
Maize reproduces sexually each year. This randomly selects half the genes from a given plant to propagate to the next generation, meaning that desirable traits found in the crop (like high yield or good nutrition) can be lost in subsequent generations unless certain techniques are used.
Maize breeding in prehistory resulted in large plants producing large ears. Modern breeding began with individuals who selected highly productive varieties in their fields and then sold seed to oth…
Origin
Maize is the domesticated variant of teosinte. The two plants have dissimilar appearance, maize having a single tall stalk with multiple leaves and teosinte being a short, bushy plant. The difference between the two is largely controlled by differences in just two genes, called grassy tillers-1 (gt1, A0A317YEZ1) and teosinte branched-1 (tb1, Q93WI2).