Chromosome doubling

The quest for sustained production of food relies to a large extent on man`s ability to continuously improve the genetic make-up of crop plants. Inbred lines and hybrids are used in a large number of agricultural species, including the major crop species. The production of doubled haploid plants represents a shortcut to obtain 100% homozygous material within one generation, serving either directly as commercial lines or being the parent lines for F1-hybrid seed production. Haploidy refers to a haploid plant having the gametic number of chromosomes of the species in the sporophyte phase. The chromosome number of a haploid plant doubles up spontaneously, albeit in an uncontrolled manner and inefficiently, or can be doubled using anti-mitotic drugs. Most of these drugs target microtubules, which are required for chromatid segregation in mitosis. The plant obtained is called a doubled haploid, which is homozygous at all loci. Thus, the major advantage of doubled haploids in plant breeding is the immediate achievement of complete homozygosity, which leads to the fixation of any genotype (allelic complement) in one generation. Doubled haploids are being used extensively in plant breeding. Haploids can be obtained by different methods; however, one of the most limiting factors in the use of doubled haploid technology is the difficulty to double their chromosome number. Unfortunately, existing drugs such as colchicine or oryzalin are rather toxic not only for plants and for the person handling them, but they are also dangerous for the environment because of their use as herbicide (e.g. oryzalin). Therefore, new, less toxic and efficient chromosome doubling technologies are extremely important in practical applications of doubled haploids, particularly when a large number of plants must be routinely treated. Hence, the main aim of this project proposal is to test novel anti-mitotic compounds with better binding to tubulins, the monomeres of microtubules, and chromosome doubling properties in order to develop an efficient chromosome doubling and doubled haploid production technology for plant breeding. Specific objectives of the project proposal are: - characterization of the novel anti-mitotic compounds, which are less toxic, with high anti-tubulin, and chromosome-doubling activities; - development of the efficient, reproducible, easy-to-use technologies for doubled haploid production in important crop plants, such as wheat and rapeseed.