Plant Records: An ever increasing pot of gold

Selling corn on the cob in a street market
Selling corn on the cob in a street market

Name: Maize or Corn
Scientific name: Zea mays
Known for: Food of the Gods (or Blasphemy against them when in Corn Dogs)
Record broken: Yields

I expect most of you have limited direct experience with many of our other plant record winners this week. But you almost certainly have personal experience with my choice already today: corn

Corn bread rolls
Corn bread rolls

If you read AoBBlog over breakfast, you may be looking at your corn flakes, maize-oil margarine, perhaps corn-starch whitener, corn syrup sweetener, and if your are lucky some corn bread, not to say milk, the rashers of bacon and eggs all from animals fed on corn meal! In England, you may well have some custard from corn starch during the day (one of several made-in-the-USA products that you need to take back as a much-appreciated present on visits to that country) and you will eat popcorn and nacho chips with your bourbon or vodka distilled from corn later in the evening! In many countries, even the fuel in your car may have a few percent of corn-derived ethanol, and corn oil and starch are in many cosmetics, papers and pills. So Zea mays, maize or simply corn is my selection for the prize-winning plant of the year.

World averages for maize or corn yield, area grown and production 1961-2014
World averages for maize or corn yield, area grown and production 1961-2014

2016 marked the announcement of the highest ever yield of the crop in the worldwide statistics from 2014 from FAOStat: a world-wide average of 5.664 tonnes per ha, or in old measures 2.5 tons per acre or 90 bushels per acre. It was also the second year ever, after 2013, when total production exceeded a billion tonnes. Look again at the graphs, and you may rightly ask ‘So what is special?’ Corn has had its highest yield and production pretty much every year for the last 53 years, over the whole period nearly tripling its yield.

Maize yield across regions of the world
Maize yield across regions of the world

My argument here is that this achievement has not come from complacency or doing things like we have always done. Notably, the yield was the highest ever throughout the world: of the major regions on my graph, only South America is showing a tiny decline from the previous year. Thus the technology and genetics that are making these yields possible are being spread around all the world, from the poorest to the richest countries. The picture essay below is showing some of the many technological and genetic contributions to this ever-increasing yield: from agronomy including tillage, precision planting, fertilization, irrigation and crop protection chemicals, then genetics including use of F1 hybrids, improved harvest index, modified plant architecture, and improved yield per plant, and then since 2000 the widespread introduction of genetic modification with the Bt trait to stop insects, particularly the stem borer, and herbicide tolerance. These traits are not designed, though, to give a major uplift in yield but to increase the environmental sustainability of the crop and reduce farmers’ work by making soil tillage and other field operations unnecessary, stopping erosion, and avoiding the need for heavy and late sprays of insecticides after the leaf canopy is complete.

F1 seed production in maize. The male lines with tassels producing the pollen are taller and separated by several rows of male-sterile plants which will have the seeds planted the following year in commercial fields.
F1 seed production in maize. The male lines with tassels producing the pollen are taller and separated by several rows of male-sterile plants which will have the seeds planted the following year in commercial fields.
Another view of F1 seed production showing two rows of the male pollinator separated by 6 rows of the female parent.
Another view of F1 seed production showing two rows of the male pollinator separated by 6 rows of the female parent.
Seeding herbicide-tolerant corn into weedy grass in Brazil. Unlike adjacent cassava fields, there is no erosion of soil from tillage, wind or rain. The weeds will be sprayed off with glyphosate once the maize seedlings are established.
Seeding herbicide-tolerant corn into weedy grass in Brazil. Unlike adjacent cassava fields, there is no erosion of soil from tillage, wind or rain. The weeds will be sprayed off with glyphosate once the maize seedlings are established.
Corn-on-the-cob: the best known form we eat, but actually a tiny part of the world total production. Here we see some cobs of inbred lines with white and yellow kernels and their F2 hybrid segregating 3:1 yellow to white kernels. The colour actually represents the next generation of the plant so they do not need to be grown out to score genetic ratios.
Corn-on-the-cob: the best known form we eat, but actually a tiny part of the world total maize production. Here we see some cobs of inbred lines with white and yellow kernels and their F2 hybrid (on an F1 plant) segregating 3:1 yellow to white kernels known as Butter and Sugar Sweetcorn. The colour actually represents the next generation of the plant so they do not need to be grown out to score genetic ratios.