International Journal of Horticulture, 2024, Vol.14, No.3, 110-116 http://hortherbpublisher.com/index.php/ijh 111 development of new breeding strategies that not only meet the demands of global food security but also align with the principles of sustainability and conservation of genetic diversity. 1 Review of Genetic Foundations in Plant Breeding 1.1 Basic principles of population and quantitative genetics in plant breeding The application of population and quantitative genetics forms the bedrock of modern plant breeding strategies. Jain (1992) elucidates that the essence of plant breeding lies in the manipulation of genetic variation through deliberate selection and breeding cycles. These cycles involve the selection of phenotypically superior plants, followed by their cross-breeding to combine desirable traits, and subsequently selecting the best progeny over successive generations. This process depends critically on the principles of population genetics, which deals with the frequencies of alleles and genotypes in a breeding population and how these frequencies change over time under the influence of forces like selection, mutation, and genetic drift. Quantitative genetics, on the other hand, focuses on traits influenced by multiple genes, known as quantitative trait loci (QTLs). Jain (1992) discusses the importance of understanding polygenic traits, which are controlled by several to many genes and are often significantly influenced by the environment. The breeding methods vary depending on the breeding system of the plant species—whether outbreeding, inbreeding, or asexual—and the specific objectives of the breeding program. Each method leverages these genetic principles to optimize the creation of new, desirable plant varieties that can contribute to increased agricultural productivity and sustainability (Jain, 1992). 1.2 The role of genetic diversity and gene flow in plant populations Gene flow, the movement of genes between populations, plays a crucial role in maintaining genetic diversity within plant populations. Ellstrand (1992) emphasizes that gene flow is one of the key mechanisms by which genetic variation can be introduced into a plant population, thus counteracting the effects of natural selection and genetic drift which might otherwise lead to a reduction in genetic diversity. High genetic diversity within a plant population is advantageous as it provides a broader base for natural and artificial selection, increasing the population's resilience to environmental stresses and diseases. According to Ellstrand (1992), gene flow in plants is mediated by various vectors, including wind, water, animals, and human activities, and can occur over varying distances, depending on the species and the ecosystem. The level of gene flow significantly impacts the genetic structure of plant populations, influencing their evolutionary potential and adaptability to changing environments. In the context of plant breeding, managing gene flow can be critical for developing new varieties that are both productive and adapted to local conditions. Enhanced understanding and manipulation of gene flow and genetic diversity are thus vital for the effective breeding of crops capable of meeting the demands of global food security (Ellstrand, 1992). 2 Evolutionary Plant Breeding 2.1 Concept and application of evolutionary breeding to enhance resilience under changing climates Evolutionary plant breeding is a dynamic approach that harnesses the natural genetic diversity within crop populations to adapt to local environmental conditions and changing climates. This method involves creating crop populations with high genetic diversity and subjecting them to the forces of natural selection through cycles of sowing and re-sowing. Plants that are most suited to the prevailing conditions thrive and contribute more to the genetic makeup of subsequent generations. Over time, this process leads to the evolution of crop populations that are more resilient to environmental stresses, including climate variability. Döring and colleagues highlight the resilience of evolving plant populations as a major advantage, particularly in the face of global climate change. This approach not only enhances crop adaptability but also reduces the reliance on chemical inputs, contributing to sustainable agriculture practices (Döring et al., 2011). 2.2 Case studies demonstrating the success of evolutionary breeding in cereals The success of evolutionary plant breeding is particularly evident in cereals, where diverse genetic populations have been developed and tested across various environmental conditions. For example, studies have shown that
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