Plant selection and breeding are crucial aspects especially when one considers the need to enhance agricultural productivity for an ever-rising global population. It is believed that in the next 50 years the human population will rise to 9.5 billion, which means that more food must be priced to meet these demands. The demand for food is what has forced specialists to continually improve the existing plants so that they can produce high quality and more yields. These specialists do not select and breed plants out of the vacuum but Gregor Mendel’s work on hybridization informs them. Out of Mendel’s work, specialists are able to produce plants with superior genes that are diseases and weather resistant plants especially in this age of climate change. Most of the modern plants are a fair reflection of the original plants owing to the continued efforts to improve the traditional plants. It is important to note that plant selection, breeding is not a new practice, and what happens today is the improvement of the previous breeding practices.
Background Information
Plant selection is an intentional action where individuals choose certain plants that have desirable qualities. It should be noted that there are several varieties of plants that individuals can choose to work within the breeding process. The plants that are selected must be economically and aesthetically desirable if they are to give desirable results. The selection is also based on the best qualities, which will make sure that the resultant plants will bear a strong genetic makeup. According to Hake and Ross-Ibarra (2015), selection first starts by controlling the mating process of the plants. Once the mating process is complete, individuals then select the best plants in the progeny. This process of controlling the mating and then selecting the best plant is repeated over and over for many generations until the value and the hereditary makeup of the plants is a far reflection of the original plants.
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Plant breeding is the intentional process of manipulating the existing plants’ heredity by crossing various plants with the required characteristics to come up with stronger plants. The resultant plant may be very different from the original plant and it may not survive in the world. Moreover, the resultant plants are improved which makes them resistant to a variety of diseases and weather changes. Plant breeding applies genetic principles to produce plants that are more useful to humans. Of importance is the fact that humans can have various varieties of the same food crops and flowers which helps meet the diverse needs of the populations.
Earliest Attempts For Plant Selection And Breeding
Human civilization rides on the ability of humans to harness their environment to meet their immediate and future needs. The earliest attempts to select and breed plants can be traced to the period when individuals started to domesticate plants for their own use. At this point, one can establish that the earliest human societies intentionally selected some plants over others to meet their unique needs. At this point, plant breeding may have occurred informally for some centuries with the farmers choosing to save only the seeds from the healthiest and high yielding plants over the generations. The main reason for this intentional selection was to ensure that they got more harvest to sustain their needs. However, it should be noted that the earliest human societies lacked scientific knowledge about inheritance and genetic hereditary to enhance deliberate breeding. Nonetheless, the efforts of these earliest plant breeders saw them develop productive cultivated species as compared to their wild relatives. As opposed to plant breeding the earliest practice can only be considered as plat husbandry as it lacked the scientific aspect associated with plant selection and breeding.
Pre-Mendelian Plant Selection And Breeding
Prior to the historic breakthrough in the scientific aspect of plant selection and breeding, humans selected and bred plants though informally. Research shows that maize is the earliest plant that was subjected to most of the breeding, as it was a staple food for many communities. The European pilgrims who established that the plant varieties that grew back in Europe would not survive in the New World conducted the earliest example of plant breeding. These pilgrims adapted the Native American varieties for their initial sustenance while adjusting their own varieties to the new environment. Slowly, the European variety became part of the existing stock paving way for interbreeding of the indigenous and exotic varieties. During these eras, the existing scientists explored more on the components of plants as well as the role of pollen in plant growth and development. Although this knowledge was scanty and unscientific, it still formed the basis of plant selection and breeding. Of importance is the fact that this information helped individuals to understand that plants are sexual in nature meaning that there must be both male and female facts. Looking closely one can establish that this sexual nature of plants has enhanced hybridization and cross-breeding witnessed today. The first attempt to work on the anatomical discoveries was in 1717 when Thomas Fairchild crossed a carnation with a sweet William resulting in a sterile flower: ‘Fairchild’s Mule’(Schlegel, 2018).
The discovery by William opened doors for more individuals to conduct an investigation into hybridization. Joseph Koelreuter performed a series of scientific experiments to determine whether plants characteristics are inherited from the father or the mother. Joseph worked with tobacco and a variety of flowers where he demonstrated that hybrid offspring inherit characteristics from both the father and the mother. Moreover, Joseph established that the offsprings could only produce seed if their parents belong to closely related species. Thomas Andrew Knight became inspired to continue with the new trend of hybridization by concentrating on fruits and vegetables. In spite of having no scientific background, Thomas created two improved strawberry varieties. Of importance, here is the fact that Thomas made a historical breakthrough when he experimented with crossing inbred sweet pea plants. One can clearly establish that by doing the experimentation Thomas was actually foreshowing Mendel’s experiments, which are highly referenced. In as much as Thomas would not offer any scientific explanation on the aspects of dominant and recessive alleles, he changed the art and science of plant selection and breeding. His work attracted the attention of Franz Achard who focused his attention on improving sugar beets sucrose content (Schlegel, 2018). Achard’s hybridization efforts saw him create a major industry concerned with the extraction of sucrose from sugar beets thus meeting the rising demand for sucrose.
Mendelian Era
Gregor Mendel (1822-1884), is one of the most celebrated individuals when it comes to the science behind plant selection and breeding that he is known as ‘the father of genetics’. Gregor Mendel worked with garden peas since he felt that it had several distinct varieties where he described that specific traits are transferred from the parents to the offsprings. These genetic factors are continually transferred to subsequent generations. Mendel tested 34 varieties of a garden pea from 1854 to 1856 testing for constancies in their specific traits. In his research, Mendel focused on seven characteristics including seed color (yellow or green) and, plant height (short or tall). Mendel referred to these distinct traits as alternatives or contrasting characteristics and then went on ahead to cross varieties that had differences in one trait. For example, Mendel would cross a tall and a short variety or yellow and agreed seeded variety. From the first experiment, Mendel derived the F 1 generation of a hybrid with this generation displaying the characteristics of only one of the varieties. From the first generation, Mendel came up with the terms recessive and dominant terms, which are still in use up to date. The second-generation F 2 contained the recessive trait in one part as compared to the three parts exhibited by the dominant trait. From The third generation (F 3) , Mendel established that 50 percent of the F 2 generation was still hybrid while the other 50 percent of the F 2 generation was true breeding (Breseghello, & Coelho, 2013). This experimentation established that a hybrid encompasses differing characteristics, which are significant in enhancing the quality of plants.
Post-Mendelian Era
Gregor Mendel set the stage for further experimentation in the field of hybridization and several other individuals picked up and improved his work. The preceding breeder focused on improving the existing crops, which then led to commercial plant breeding. In the 1890s, John Garton from England became the first person to cross-pollinate and various agricultural plants and then commercialized the new varieties. Some of the agricultural plants that John used in his experiment included cereals, herb species, and root crops. John discovered far-reaching techniques and he is credited for being the first scientist to discover that common grains and other plants are self-fertilizing (Schlegel, 2018). William Ferrer from Australia worked with Mendel’s theories for over twenty years by releasing the Federation strain of wheat, which was fungus resistant in 1903. This new strain of wheat variety brought a revolution in wheat farming, as farmers would now have increased and high-quality yields. In Italy, Nazareno Strampelli came up with various wheat breeds, which enhanced Italy’s grain production (Schlegel, 2018). Some of these varieties were even exported to other foreign countries such as China, Mexico, and Argentina. Nazareno is credited for setting the stage for modern plant selection and breeding movements including the Green Revolution.
The Green Revolution
The Green Revolution is famous for transforming the hybridization efforts that had occurred in previous centuries. The period between 1960 and 1980 is a significant one considering that it is during this time that rice and wheat production intensified to meet the rising demand. The Rockefeller Foundation and the Ford Foundation collaborated to ensure that there was a development of modern wheat and rice varieties. The emergent rice and wheat varieties were short and responded to fertilizers resulting in high and unprecedented yields. Once these varieties were developed, developing nations adopted them on a large scale to deal with food scarcity and hunger situation. Green Revolution attempted to produce better varieties at the various research centers in Mexico, Philippines. Green Revolution brought a revolution in plant breeding as it helped several nations to achieve food security over a short period (Breseghello, & Coelho, 2013). The concerned countries adopted the High Yielding rice and wheat varieties, which coupled with irrigation fertilizers and pesticides dealt with food scarcity.
Modern Plant Selection And Breeding Techniques
Climate change and global warming have continued to threaten food sources as more and more agricultural land are rendered unproductive. As a result, the world is experiencing more food shortage that it was several decades ago. Green Revolution, which had made headlines in increasing wheat and rice supply, has slowed down forcing stakeholders to come with quick and effective solutions.
Molecular Breeding
Molecular breeding is the application of molecular biology or biotechnology in the selection and breeding of plants to enhance their quality. This form of breeding allows for the molecular biology techniques in selecting and inserting desirable traits in plants. DNA fingerprinting and molecular markers are some of the tools that are used by breeders to map thousands of genes through laboratory procedures. The result of this process is the identification of phenotypes that exist within the genome that in turn leads to genome sequence Acquaah, 2015). The molecular breeding rides on the assumption that all plants have genomes that code for the different proteins. One gene can be identified in various plant species and it is this gene similarity that is harnessed to create superior plant DNA combinations. Genetic modification is a popular term, which refers to the process of adding specific genomes to plants or by deleting genes with RNAi to produce improved phenotypes. (Acquaah, 2015) Some of the methods used to transpose the genetic makeup of plants include genetic recombination, microinjection, or gene gun. As a result, one plant exhibits the desirable traits of another and which are resistant to herbicides and insect pests. Moreover, genetically modified plants have increased stress tolerance in many environments, which in turn leads to increased yields. The field of plant breeding is ripe with opportunities and it is hoped that the future holds endless opportunities to experiment with more techniques.
In conclusion, plant selection and breeding is a very significant aspect as it helps in improving the existing plants to meet the ever-rising human needs. Plant selection and breeding have a rich history dating back to the early civilizations when human societies started domesticating plants for survival. These early human societies planted only the highest quality seeds to ensure that they got better yield. Over time, individuals started breeding and crossing crop since they realized the concept of pollination. Further on, breeders realize that plant had male and female characteristics, which were responsible for fruition. The harnessing of plants has seen individuals come up with varieties of the same plant. Gregor Mendel’s experiment came as a breakthrough as individuals learned that they could improve on the existing varieties. The Green Revolution achieved much success by working with Mendelian experiments to improve food security in developing countries. Currently, breeders are tapping into the endless possibilities offered by molecular biology by capitalizing on desire traits while doing away with undesirable traits. These breeding efforts will help deal with the issue of food scarcity, which is inevitable owing to climate change and global warming.
References
Acquaah G. (2015) Conventional plant breeding principles and techniques. In: Al-Khayri J., Jain S., Johnson D. (eds) Advances in Plant Breeding Strategies: Breeding, Biotechnology and Molecular Tools . pp. 115-158. Berlin: Springer.
Breseghello, F., & Coelho, A.S.G. (2013). Traditional and modern plant breeding methods with examples in rice (Oryza sativa L.). Journal of Agricultural and Food Chemistry, 2013 (61), 8277-8286.
Hake, S., & Ross-Ibarra, J. (2015). Genetic, evolutionary and plant breeding insights from the domestication of maize. eLife, 4, e05861.
Schlegel, R. (2018). History of Plant Breeding . Boca Raton, Florida: CRC Press, Taylor & Francis Group
