No abstract

A majority of sunflower lines and hybrids were based on starting material obtained by traditional methods; so the issues of developing new trends in extending the genetic diversity of this crop require constant attention of scientists. At present, induced mutagenesis along with hybridization has become a leading method for generating new forms of crops. Their success depends largely on availability and assortment of starting material. Induction of mutations is a way to create it. The main value of induced mutagenesis for breeding is determined by opportunities to solve problems that are impossible or difficult to solve by traditional methods. The choice of an effective concentration (dose) of a mutagen is very important, since the frequency and range of mutations depend not only on the mutagen itself but also on its dose and exposure. In addition, it is relevant to search for new mutagens with reduced harmful effects at the same level of mutability. Cytological analysis of chromosomal aberrations is an important method of evaluation and identification of mutagenic effects. In this section, studies into chemical and physical mutagenesis in breeding, exemplified by new modern homozygous self-pollinated sunflower lines, are summarized; methodical recommendations on the use of induced mutagenesis in sunflower breeding are presented; and methods of generation, investigation, and further use of mutations are rationalized.