Developing mutant sunflower lines (Helianthus annuus L.) through induced mutagenesis and study of their combining ability

Abstract

Immature sunflower (Helianthus annuus L.) zygotic embryos of sunflower double haploid fertility restorer line 381 R were treated with ultrasound before planting to embryo culture medium. Some mutant plants were isolated and self-pollinated for several generations. New sunflower forms with inherited morphological, biochemical and phytopathological changes were obtained through selection and self-pollination. The genetic changes included 12 morphological and biochemical agronomic traits. In our study the plant height, leaf petiole length, 1000-seed weigh, as well as oil content in them were most unstable, based on all investigated characteristics. In comparison to the control 381 R, decreasing in the mean value of the indexes was registered for 66.7% of the total number of characteristics and vice verse, significant increasing for the number of branches and oil content in seed i.e., 16.7%. Stability after induced mutagenesis was demonstrated by the characteristic number of leaves. This index was not affected by the changes in climatic conditions. Mutation for resistance to Plasmopara halstedii (Farl.) was obtained from the susceptible Bulgarian control line 381 R. Reduction of plant height, increasing oil content in seeds, very good combining ability, resistance to Plasmopara halstedii, as well as to the parasite Orobanche cumana of the new mutant lines is a desirable combination in the breeding program of sunflower. Hybrids No. 15, No. 16 and No. 17, developed with the participation of lines No. 97, No. 100 and No. 101 considerably exceeded the mean standard (commercial hybrids San Luka, Maritza and Mura) by seed and oil yield. Ultrasound in sunflower can be successfully used to develop new mutant lines useful for heterosis breeding.