Nowadays, genetic improvement is into the spotlight. However, it is not a new topic because we have done genetic improvement during years, in plants or in animals. In this article, I will discuss genetic improvement in plants, giving the corn as example, which is a plant domesticated by humans for 10,000 years.
WHAT IS GENETIC IMPROVEMENT?
Genetic improvement in plants is the process based on theoretical principles and methods for obtaining varieties of crop plants, which guarantee under high environmental conditions and production, high and stable yields of the products grown with the required quality.
AIMS OF GENETIC IMPROVEMENT
The aims of genetic improvement are:
Improvement of productivity: increasing the potential productive capacity of individuals.
Resistance improvement: obtaining genotypes resistant to pests, diseases and adverse environmental conditions.
Improvement of agronomic characteristics: obtaining new genotypes that are better adapted to the demands and application of the mechanization of agriculture.
Increase the quality: improvement of the nutritive value of the vegetal products obtained.
Extend the area of exploitation: adapting the varieties of the species already cultivated to new geographical areas with climatic characteristics or extreme soil types.
Taming new species: transforming wild species into crops with utility and profitability for man.
STEPS OF THE GENETIC IMPROVEMENT PROCESS
Before starting the process, you have to define the objectives you want to achieve and, therefore, define those characters that you want to improve in order to obtain a specific phenotype.
The steps that follow in the process of genetic improvement are:
First step: to find within the genetic variability of the collected species, or of the species that can hybridize, individuals that have these characters.
Second step: these individuals hybridize with each other and with plants with good general agronomic characteristics. The result will be a base population that will segregate for a large character name, from which individuals will be selected that are closest to the desired variety.
Third step: to verify that these individuals are better in one or more aspects than the varieties that are in the market, a fact that normally forces to carry out comparative tests.
The maize plant (Zea Mays) has been domesticated by man for 10,000 years. At this time it has become one of the three most grained cereals in the world and this increase of the crop is linked to the development of varieties that are better adapted to the needs of each place.
Maize is one of the most important staple foods since it makes many derived products (flours, oils). As it has a great value in the industry, it is a much studied plant and its genome has been sequenced.
EUROPEAN CORN BORER
Maize is affected by the European borer (Figure 1), Ostrinia nubilalis. It is a plague of cereals, particularly of corn. It is a native lepidopteran of Europe that infested the millet, before the arrival of the corn.
Its butterfly is about 2.5cm long. The female is yellowish brown with irregular bands on the wings, and the male is smaller and darker. The female lays eggs under the leaves.
The borer makes tunnels inside the corn (Figure 2) that cause the plant to break and fall to the ground. It has to be taken into account that when the maize is still immature it is not affected by the borer, thanks to the natural defenses of these plants in the growing stage.
Bt maize is a plant genetically modified by modern biotechnology to defend itself against the attack of lepidopteran insects. Using recombinant DNA technology, maize was modified by inserting a bacterium gene of Bacillus thuringensis (Bt), such that its leaves, stem and pollen express the Bt protein of bacteria. Bt maize is the importation and the new tool for the control of damages and losses caused by insect pests.
Herbicide-tolerant maize is maize that has been improved by the use of recombinant DNA technology to tolerate the use of certain types of herbicides. With the use of these technologies for the possible state deactivate or replace the sequence of susceptibility by another that confer resistance and that allow a crop plant to tolerate the use of the herbicide.
OBTAINING THE MAIZE BT
To transform a normal plant to a transgenic plant, the gene that produces a characteristic of interest is identified and separated from the rest of the gene material of a donor organism.
A donor organism can be a bacterium, fungus or any other plant. In the case of Bt maize, the donor organism is a naturally occurring soil bacterium, Bacillus thuringiensis, and the gene of interest produces a protein that kills lepidopteran larvae. This protein is called Bt delta endotoxin.
The Bt delta endotoxin was selected for the fact that it is highly effective for controlling larvae of caterpillars. It is during the larval stage when most of the damage occurs from the European corn borer. The protein is very selective, in general, it does not harm the insects in other orders (like beetles, flies, bees and wasps). Therefore, transgenics that have the Bt gene are compatible with biological control programs, since they harm predators and parasitoids less than insecticides with a broad spectrum of insects. Bt endotoxin is considered safe for humans, other mammals, fish, birds and the environment due to its selectivity.
The actual world is in turmoil. News related to terrorism, drug trafficking, coups d’état, refugees crisis or the numerous wars still present flood our screens day after day. And, in a completely understandable bias, the focus is almost exclusively on the people and countries involved. But (and it’s something I ask every time I watch the news) what happens to nature in these regions punished by violence? In this entry we review the most important armed conflicts nowadays and their consequences for the nature surrounding them.
Any human action has repercussions on natural life, and even more wars, intrinsically destructive. A series of damages on the wildlife are associated with them such as deforestation, soil degradation, pollution or hunting, among many others. The first time we really became aware of the great impact of the wars on nature was in the Vietnam War. The US army, in its fight against an invisible enemy, threw more than 75 million liters of herbicides into the jungles, in order to defoliate the trees to find their enemies. However, despite partially achieving its objective (we all know how that war ended) nature was seriously damaged. A study carried out in Vietnam in the mid-1980s found that there were only 24 birds and 5 mammals in an area where there were previously between 145 and 170 birds and between 30 and 55 mammals.
Other wars, such as the Civil War in Rwanda, apart from causing more than 500,000 deadsand displacing more than 2 million of people, left the nature of the country in a state of absolute crisis. In the Akagera National Park, one of the most emblematic environments in the country, deforestation wreaked havoc: 200,000 of the 300,000 hectares of forest were lost in just 3 years, as well as 90% of large mammals.
But what is happening today? How are the wars of today affecting the survival of nature? Here we review the most important current conflicts and their difficult coexistence with the wildlife of the region.
Israeli-Palestinian Conflict (1948-present)
Although the last war between Israel and Palestine began in 2005, violence between the two countries has been present since the creation of the state of Israel. Thousands of people have been dead for decades, and millions have been displaced against their will. And, of course, nature has not come out unscathed.
One of the most famous cases occurred in 2006. The Israeli army bombarded two oil tanksnear a power station in Jieh, Lebanon (where a terrorist group called Hezbollah was emplaced) causing a spill of 10,0000 and 15,000 cubic meters of oil in the Mediterranean sea. This black tide spread along 90 km of the coast of Lebanon, carrying the death with it. In addition, this phenomenon severely affected the habitat of the green turtle (Chelonia mydas) in one of the last well-preserved places that this species still had in the Mediterranean basis.
However, in early 2016, images that would call even more international attention came to light: dozens of animals from the Gaza zoo appeared completely mummified after suffering a terrible agony and starving.It happened twice since the zoo opened in 2007, but the strongest famine took place in 2014, following a conflict between Israel and Hamas’s Palestinian forces.It is estimated that about 80 animals died because of famine, including crocodiles, tigers, baboons or porcupines.When rescue services were able to reach the zoo, only 15 animals remained alive, many of them with severe symptoms of malnutrition.
Second Congo War (1998-2003)
This war, also known as the Great War of Africa or the African World War, has caused the death of more than 5 million people since then, which has given it the dubious honor of being the deadliest armed conflict since The Second World War. Although the war officially ended in 2003 and there is an elected government since 2006, the Democratic Republic of the Congo lives in a state of instability typical of a country at war.
The guerrillas use the country’s many natural resources to obtain money so they can continue the war. And ivory is the most precious commodity, the one that produces the most benefits. That is why African elephant populations (Loxodonta africana) have been reduced by 90% since the beginning of the conflicts. Something worse has occurred to the northern white rhinoceros (Ceratotherium simum cottoni) a subspecies of the white rhinoceros. Its last specimens, 2 males and 2 females living in the Garamba National Park, are believed to have died between 2006 and 2008 at the hands of the guerrillas, causing the extinction of this subspecies.
Bushmeat, or the food coming from wild animals, is another major problem stemming from the numerous military conflicts in the country. In the wake of extreme poverty, many villagers have been forced to hunt to survive.And the primates has been one of the most harmed groups.The populations of the great primates, once counted by millions, have been drastically reduced.It is believed that there are only 200,000 lowland gorillas, 100,000 chimpanzees and 10,000 bonobos in freedom.
Syrian Civil War (2011-present)
Undoubtedly, the most famous war at the moment. This conflict has killed more than 500,000 people and has caused one of the most important humanitarian crises of our time: it is estimated that there are more than 10 million of refugees because of the war. Those who have remained in Syria, have been displaced from the interior to the coastal zone, becoming a great threat to the forests of the region. According to Aroub Almasri, a Syrian government environmentalist, most people need food, electricity and fuel to cook and warm up, which has lead to clear the area’s forests, mostly in protected areas. Apart from the severe impact of deforestation, there are also a large number of fires that have been spreading throughout the region in recent times. A particularly affected area is the Fronlok forest on the border with Turkey. In these mountains the degree of endemism is high, and many species are at a serious risk of disappearing from the area, especially a type of oak, Quercus cerris, native to the region and which would begin to be threatened.
Due to the fragmentation of the habitat, it is believed that an iconic species of the Mediterranean zone and classified as critically endangered by IUCNhas become extinct in Syria. It is the bald ibis (Geronticus eremita), a bird of which only 500 individuals remain and is present only in three countries: Morocco, Turkey and Syria. In spite of Syria‘s enormous effort to maintain a stable population in its territory, the war wiped out the last individuals of this species in the region. Only one individual of the species remains, a female named Zenobia, who was seen for the last time in Palmyra before ISIS troops entered the city.
Second Libyan Civil War (2014-present)
After the first Libyan civil war, which ended with the fall of Colonel Gaddafi, the country entered into a spiral of violence sponsored by the numerous armed groups that control the country. The importation of meat from abroad has stopped, and the owners of sheep, goats and camels keep their animals as if they were gold because of shortages. Because of this, armed groups are heading to the south of the country, where anarchy prevails and there are a lot of wild animals to take advantage of.
One of the most harmed species has been the rhim gazelle (Gazella leptoceros), classified as threatened by IUCN and with its populations in decline. Ten years ago the population did not exceed several hundred individuals, and it is believed that today the situation is much worse.
But the gazelles are not the only ones harmed by the banditry and impunity reigning in Libya. Large numbers of migratory birds, which have to cross the African country on their way to Europe, are slaughtered by hunters. In addition, the oases that they use to rest are being opened by the hunters, which causes that hundreds of cranes, ducks, herons and flamingos are annihilated without anyone can do anything.
In addition, the effect of the Libyan war on nature does not remain within its borders.In 2015, weapons from Libya were found near elephant corpses in Mali, a heavily threatened elephant subspecies.It is believed that the ivory of the Mali elephants is serving to finance the Libyan militias.
The Colombian government against the FARC and other guerrillas (1964-2016)
Despite the peace agreement reached few months ago between the Colombian government and the FARC, both social and environmental wounds will take a long time to be closed. For a long time the militias have been financed largely from the money generated by illegal cocaine crops. Placed deep in the Colombian jungle, thousands of hectares of pristine foresthave been cleared for the construction of laboratories and coca plantations. In addition, in an attempt to stop this type of illegal crops, the government fumigated extensive forest areas withglyphosate, a herbicide that, despite being considered harmless, caused the death of birds, small mammals and insects, what in turn left without sustenance the people who live on hunt. Another added problem is that illicit crops have spread to protected areas. Thus, according to a report by the National Parks of Colombia, FARC were present in 37 protected areas of the country, and 3791 hectares of coca plantations were also detected in there.
However, the illicit activity that most threatens Colombia’s nature is illegal mining, one of the most lucrative activities for armed groups. Not for less, since while 1 kg of coca is sold at about 4.3 million pesos, 1kg of gold is sold at 85 million pesos, about 20 times more. For this reason, large areas of jungle have been destroyed by backhoes to open gold (60%), coltan (25%), charcoal (10%) and tungsten (5%) mines. Deforestation resulting from illegal mining reaches unimaginable numbers: between 1990 and 2010, an average of 310,349 hectares of forest per year were deforested, that is, 6206.000 hectares in all that time, or what is the same, 5.4% of the Colombian surface.
Finally, FARC actions against oil extraction have caused serious oil spills in areas of high environmental value. This is the case, for example, of the 492-liter oil spill in Puerto Asis, Putumayo, in June 2015. The FARC intercepted a convoy containing tanks with oil and spilled them, affecting 9 wetlandsand spreading oil along the Putumayo River.
War in Afghanistan (2001-2014)
Either the last war and the previous one had a strong impact on the region’s wildlife. It is estimated that between 1990 and 2007, more than one-third of Afghanistan’s forests were cleared, either by refugees to use wood for cooking, fuel or construction, or by logging industries, which cut down the forests of the region with impunity.
Nevertheless, the news are more optimistic than would be expected of a country plunged into war for decades. Between 2006 and 2009, the first censuses since the 1970s were carried out in the province of Nuritán, with the help of trap cameras, the study of faeces and the realization of transects. The results were encouraging: 18 black bears, 280 porcupines and many red foxes, gray wolves, golden jackals, wildcats, palm civets and rhesus macaques were observed, and even the elusive snow leopard (Panthera uncia), concretely 3 distinct individuals.
However, there are still threats for Afghan wildlife. The large number of bombsthrown during the years made a dent in the abundance of migratory birds. Many birds died directly from the impact of the bombs or poisoned when they came into contact with contaminated water. Others, however, varied their rute due to the bombing and no longer cross the country. This is the case of the Siberian crane (Grus leucogeranus), a species critically endangered by IUCN that has not been seen in Afghanistan since 1999. In addition, due to the war and the incipient Afghan economy, hundreds of hunters Are forced to catch live birds for subsequent smuggling into rich Arab countries.This has led to the fact that, in some regions of Afghanistan, migratory bird watching has declined by 85% since the start of the war.
Korean Conflict (1950-present)
The KoreanDemilitarized Zone is the proof that even something as tragic as a war can bring positive consequences. In 1953, following the peace agreement by both countries, the Korean Demilitarized Zone, a strip of land 4 km wide and 250 km long that separates both countries, was created. The area, which has a strong military presence of about 2 million soldiers, has remained virtually unchanged and sparsely populated since then.
The area is characterized by a great topographic richness and high variety of ecosystems, which allows it to contain a great diversity. Some scientific expeditions have documented more than 1,100 species of plants, 80 species of fish, 50 of mammals and hundreds of birds.In addition, it is a frequent stop for many species of migratory birds that head towards Mongolia, the Philippines or Australia.
Recently, thanks to improved relations between the two countries, the area can be visited for only about 43 euros. In addition, due to its exceptional conservation status and high diversity, somecampaigns are under way to turn the area into a protected area. One of these campaigns, the DMZ Forum, proposes to declare the area as World Heritage Site and World Park for Peace, in order to be able to protect it from a possible urban development on the day that peace between the two countries is reached.