Somatic embryogenesis and plant regeneration from fragments of immature inflorescences and coleoptiles of durum wheat

Abstract

Somatic embryogenesis and plant regeneration were obtained from the culture of immature inflorescence and coleoptile fragments of ten durum wheat cultivars. The explants were cultivated on Murashige and Skoog (MS) medium with various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), 2.3 μM to 11.3 μM. After four to six weeks, both types of explants produced embryogenic and non-embryogenic calli. Embryogenic calli developed somatic embryos which produced normal fertile plants without visible abnormalities. For inflorescence fragments, the highest frequencies of embryogenic callus formation (100% for most cultivars) and regeneration (100% for `Massa' and `Isly') were obtained from 0.5 or 1-cm-long fragments incubated on media containing 6.8 μM of 2,4-D. For coleoptile explants, embryogenesis and especially regeneration, frequencies were generally lower than for inflorescence fragments. The results depended largely on the length of the coleoptile explant, where fragments of 1 mm were better than 2 to 4-mm-long segments. The 2,4-D concentration did not influence callus induction but, for regeneration, 9 μM was best. For both inflorescence and coleoptile explants, and in our culture conditions, a genotype effect on callus induction and plant regeneration was observed.