CALLOGENESIS AND REGENERATIVE CAPACITY OF WHEAT’S MATURE EMBRYO IN RESPONSE TO HORMONAL COMBINATIONS AND INCUBATION PERIOD EFFECTS

A study was conducted to assess the effect of auxin 2,4-D (2,4-dichlorophenoxyacetic) alone or combined to cytokinin BAP (6-benzylaminopurine) on callus induction in wheat (Triticum aestivum L.) and to consider the effect of incubation period on regeneration capacity. Mature embryos of five wheat varieties (Nassim, Wissam, Wafia, Rajae and Tigre) were cultured on medium (MS) supplemented with different hormonal combinations for six weeks in darkness. The obtained calli were transferred on three types of media to regenerate for six weeks in photoperiod. The achieved results showed a significant callogenesis rate (66.66% to 83.33%) recorded by four varieties Nassim, Wafia, Rajae and Tigre on the M4 medium, while medium M1 appears to be optimum for callus induction in Wissam (77.08%). However, the importance of callogenesis depends not only on the nature of the plant growth regulator but also on its concentration in the base media. This has been shown in high rates of fresh and dry matters obtained on M4 media for Nassim, Rajae, Wissam and Tigre, also on M5 for Wafia. For regeneration, six weeks old calli were strongly influenced by the accumulation of growth regulators in all medium and were not able to develop any Vitroplants. Statistically, the use of the auxin 2,4-D alone has proved to be the most suitable hormone to induce calli in wheat. However, concentration applied and the long period of incubation has been inhibitory and preventing plants regeneration. Nevertheless, they only promote the production of roots which shows the strong accumulation of auxin.