However, this is not the only kind of intensification available. More productive crop phenotypes, with traits such as more resistance to biotic and abiotic stresses and shorter crop cycles, are possible through modifications in the management of rice plants, soil, water, and nutrients, reducing rather than increasing material inputs. Greater factor productivity can be achieved through the application of new knowledge and more skill, and (initially) more labor, as seen from the System of Rice Intensification (SRI), whose practices are used in various combinations by as many as 1. The highest yields achieved with these management methods have come from hybrids and improved rice varieties, confirming the importance of making genetic improvements. However, unimproved varieties are also responsive to these changes, which induce better growth and functioning of rice root systems and more abundance, diversity, and activity of beneficial soil organisms. Some of these organisms as symbiotic endophytes can affect and enhance the expression of rice plants' genetic potential as well as their phenotypic resilience to multiple stresses, including those of climate change. SRI experience and data suggest that decades of plant breeding have been selecting for the best crop genetic endowments under suboptimal growing conditions, with crowding of plants that impedes their photosynthesis and growth, flooding of rice paddies that causes roots to degenerate and forgoes benefits derived from aerobic soil organisms, and overuse of agrochemicals that adversely affect these organisms as well as soil and human health. This review paper reports evidence from research in India and Indonesia that changes in crop and water management can improve the expression of rice plants' genetic potential, thereby creating more productive and robust phenotypes from given rice genotypes. Data indicate that increased plant density does not necessarily enhance crop yield potential, as classical breeding methods suggest. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 2011 6, No. 032 Review Plant mutation breeding in agriculture Ranjith.A SRI-Rice, 624 Bradfield Hall, Cornell University, Ithaca, NY 14853, USA; b Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Athens, GA. FAO's Plant Production and Protection Division (AGP) promotes Sustainable Intensification of Crop Production. This approach requires the integration and harmonization. Developing cultivars that can achieve their higher productivity under a wide range of plant densities—breeding for density- neutral cultivars using alternative selection strategies—will enable more effective exploitation of available crop growth resources. Density- neutral cultivars that achieve high productivity under ample environmental growth resources can also achieve optimal productivity under limited resources, where lower densities can avert crop failure due to overcrowding. This will become more important to the extent that climatic and other factors become more adverse to crop production. Focusing more on which management practices can evoke the most productive and robust phenotypes from given genotypes is important for rice breeding and improvement programs since it is phenotypes that feed our human populations. Keywords. Expression of genetic potential; Rice phenotypes; Selection criteria for plant breeding; Selection efficiency; System of Rice Intensification. Introduction. There is certainly need for continued improvement in the genetic potentials of rice varieties, as such potentials can yield greater returns on the land, labor, capital, seeds, water, and other inputs that farmers invest in their rice production. Also, plant breeding can increase the range of options available to farmers. Mutagenesis in Plant Breeding for Disease and Pest Resistance . Authors: Petra Kozjak and Vladimir Megli Host Plant Resistance Genes for Fusarium Head Blight: Sources, Mechanisms, and Utility in Conventional Breeding Systems J. FiBLDOSSIER No.2 September 2001 1 st edition Plant Breeding Techniques An Evaluation for Organic Plant Breeding In cooperation with. Easac building science into EU policy Risks to plant health: European Union priorities for tackling emerging plant pests and diseases EASAC policy report 24. GMO seeds are sold on the grounds that they're taking over where conventional plant breeding left off. But breeding might actually be a better tool in the climate battle. Michael Kantar examines a perennial sunflower that is part of the perennial sunflower breeding program designed to produce food and ecosystem services. The fundamental discoveries of Darwin and Mendel established the scientific basis for plant breeding and genetics at the turn of the 20th century. However, we suggest here that more attention be given to ways in which rice varieties (genotypes) can be managed more beneficially, to induce the fuller phenotypic expression of their genetic potentials and obtain more robust and more productive plants. This suggestion reframes somewhat the tasks of plant breeding for proved rice performance, given that observed phenotypes do not map directly to genotypes, reflecting environmental influences as much as genetic endowments. When breeders use phenotypic expression and yield performance under test- site conditions for their screening and selection, their efforts will be more efficient and successful to the extent that these decisions are informed by a fuller understanding of environmental influences on phenotypic expression and of the associated mechanisms of such influences. We need to double the world's rice production by 2. Achieving this ambitious goal will require realizing more effective agronomic expression of the genetic potentials that exist in rice cultivars, beyond the gains that can still be made in raising rice potentials through various methods of plant breeding. Data presented in Table 1 show the increases in rice yields at the national level that have been achieved over the past five decades in 1. Bangladesh, Brazil, China, India, Indonesia, Myanmar, Pakistan, Philippines, Vietnam and Thailand, calculated from FAO and USDA sources available on IRRI's website.
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