Download Free Use Of Induced Mutations In Connection With Haploids And Heterosis In Cereals Book in PDF and EPUB Free Download. You can read online Use Of Induced Mutations In Connection With Haploids And Heterosis In Cereals and write the review.

China was the first country to use cytoplasmic male sterility to develop hybrid rice for commercial use in 1973. In 1986 more than 8 million hectares of hybrid rice were planted in China, which is one fourth of the total rice area and produces one third of the total rice in the country. Hybrids usually out yield the leading commercial varieties by -20-30%, giving an average yield advantage of 1 to 1. 5 t/ha, because of their better morphological traits, higher physiological efficiency, better resistance to major diseases and insects, and wide adaptability to various agro-ecological stresses. IMPROVEMENT OF HYBRID RICE A. Mutation techniques Almost all of the cultivated F1 rice hybrids in China are developed from cytoplasmic male sterile and restorer lines. According to surveys made in recent years, more than 30 sources of cytoplasmic male sterility in rice can be identified, among which only six are being commercially used (Table 1). Wild rice with aborted pollen (WA) cytosterility system is the most popular one in use to develop male sterile lines (MS line) in China. The main technique available for developing stable MS lines is sUbstitution backcrossing of the genome of one species into alien cytoplasm of another. Sufficient backcrosses are required to eliminate all nuclear genes derived from the cytoplasm donor species. A number of studies have shown that using interspecies crosses, such as the cross of wild rice (Q. perennis, Q. sativa, f.
This book summarizes the research done on preharvest sprouting during recent years. Naturally, whenever needed, earlier findings are also considered. Both publishers and the authors hope that his publication will provide researchers and students with a convenient source of up-to-date information in this expanding field.
This volume has been produced for the XI 11th EUCARPIA Congress. EUCARPIA (the European Association for Plant breeding) currently has 1.200 members, including scientists and staff of both publ ic and private organizations. Its aim is to promote scientific and technical research and cooperation In the field of plant breeding, and thereby to contribute to the development of agriculture. Every three years, EUCARPIA organizes a scientific congress. In 1992, the Xilith EUCARPIA Congress will be held In ANGERS (Fran ce) and the theme Is "Reproductive biology and plant breeding". Reproduction of plant material Is central to selection. The geneti cist, the plant breeder and the seed grower all use sexual and ve getative reproduction during the various stages of plant breeding and creation of variety. The possibility of unlimited interspecific reproduction, the use of gametogenesis dysfunction, the creation of auto and allogamy, and the cloning of the best genotypes are the challenges before the plant breeder. To understand how the reproductive system conditions the genetic structure of a population, and to Investigate the relation ships between the reproductive mode and the organization of varia bility Is a central key to genetic progress. The articles presented In this book review the current state of knowledge of reproductive biology, and Its impact on variety crea tion.
Genetic variability is an important parameter for plant breeders in any con ventional crop improvement programme. Very often the desired variation is un available in the right combination, or simply does not exist at all. However, plant breeders have successfully recombined the desired genes from cultivated crop gerrnplasm and related wild species by sexual hybridization, and have been able to develop new cultivars with desirable agronomie traits, such as high yield, disease, pest, and drought resistance. So far, conventional breeding methods have managed to feed the world's ever-growing population. Continued population growth, no further scope of expanding arable land, soil degradation, environ mental pollution and global warrning are causes of concern to plant biologists and planners. Plant breeders are under continuous pressure to improve and develop new cultivars for sustainable food production. However, it takes several years to develop a new cultivar. Therefore, they have to look for new technologies, which could be combined with conventional methods to create more genetic variability, and reduce the time in developing new cultivars, with early-maturity, and improved yield. The first report on induced mutation of a gene by HJ. Muller in 1927 was a major mi1estone in enhancing variation, and also indicated the potential applica tions of mutagenesis in plant improvement. Radiation sources, such as X-rays, gamma rays and fast neutrons, and chemical mutagens (e. g. , ethyl methane sulphonate) have been widely used to induce mutations.
Proceedings of a symposium jointly organized by the IAEA and FAO, Vienna, 18-22 June 1990. The technology of mutation induction has been accepted by plant breeders as a valuable additional tool for creating improved cultivars for agriculture and horticulture. It was amply demonstrated at the symposium that this technique has been applied with great success in many annual seed propagated crops such as rice, barley, wheat, cotton, soybean and pea. The technological problems identified primarily concerned vegetatively propagated crops and, in general, the logistic difficulties in identifying desirable mutants in large mutagenized populations.