Relationship Of Morphogenetic Processes In Wheat Tissue Culture
L. P. Khlebova, E. D. Nikitina, A. V. Matsyura, O. V. Bychkova
Relationship of different morphogenetic processes in immature embryo cultures from 15 spring bread wheat varieties of different ecological and geographical origin was studied. Embryos (14–16 days post anthesis with 1.3–1.5 mm in size) were placed with the sculletum upwards on a solid agar medium containing the inorganic components of Linsmaier & Skoog (LS), 3 % sucrose, 2.0 mg l-1 2,4-dichlorophenoxyacetic acid (2,4-D). Induced calli were subcultured after 25–30 days interval in fresh medium supplemented with 0.5 mg l-1 2,4-D and 0.5 mg l-1 kinetin. Embryogenic calli were transferred to LS medium containing 0.2 mg l-1 indole-3-acetic acid (IAA). Varietal polymorphism was revealed in relation to callusogenesis, morphogenesis and plant regeneration. The frequency of callusogenesis made 94.3 % with variation from 76.6 % to 100 % depending on a genotype. An active morphogenic process was revealed in 72 % of the varieties tested. The regeneration level depended on the type of morphogenesis (embryoidogenesis, hemmorhizogenesis and rhizogenesis). On average across all varieties it was not high and made 97.9 %; that is one morphogenic line produced about one plant. Organogenesis in 80.2 % of morphogenic calluses did not reach the development stage of the whole plant and stopped with root production. Plant regeneration by embryoido- and hemmorhizogenesis occurred in 19.8 % of morphogenic calluses. For the study of theoretical aspects of embryoido- and organogenesis as well as genetic transformation of plants the varieties with high regeneration potential are proposed as model objects (Spektr, Skala, Leones, and Zhnitsa). Positive correlation of embryoido-, hemmorhizogenesis and plant regeneration was revealed (r = 0.777), and it proves that there is a common genetic system responsible for those processes. When factorial trait shifted by 1 %, the resultant trait (regeneration) increases by 3.59 %. Negative correlation was found between rhizogenesis and regeneration level (r = -0.749). The rise in rhizogenesis frequency by 1 % results in regeneration decrease by 1.1 %. There is no correlation of calluso- and morphogenesis indicating that they are genetically independent. The analysis of multiple correlations between calluso-, morphogenesis and plant regeneration revealed the dominant factors determining regenerant output. They were the processes of the embryoido- and hemmorhizogenesis. Their contribution to the variability of plant regeneration level was about 51 %. The effect of rhizogenesis was about 12 %. Possible reasons of the revealed correlations between different morphogenetic processes are discussed.