Submitted to: Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/1996
Publication Date: N/A
Interpretive Summary: Durum wheat is widely used for making pasta and semolina. In the United States alone, durum yields more than $2.98 billion worth of grain annually. Therefore, the need for improving durum cultivars and making them more suitable for pasta, semolina and other products cannot be over-emphasized. Although attempts at improving durum wheat by conventional cytogenetic techniques have yielded some fruitful results, the usefulness of biotechnological tools in genetic reprogramming of durums has not been adequately explored. A routine regeneration method of producing a large number of plantlets from embryos or parts thereof is a prerequisite for direct introduction of useful genes into agronomically desirable cultivars. We have, therefore, attempted to standardize a procedure for regenerating a large number of plantlets from immature scutellum (a shield-shaped structure of the embryo) of four improved durum wheat cultivars, viz., Renville, Medora, Monroe and Vic, that occupy more than 70% of the durum acreage in the Northern Plains of USE This manuscript describes the most suitable media and optimal culture conditions for obtaining a large number of plantlets from cultured scutella. Using this regeneration system, we are already introducing foreign genes into durum wheat and have made a substantial progress in this direction.
Technical Abstract: Four durum wheat cultivars, viz., Renville, Medora, Monroe and Vic, were selected for studies on rapid regeneration of plantlets through in vitro culture of isolated immature scutellum. Effects of two concentrations of sucrose (either 2% or 3%) and three gelling agents, viz., agar (0.8%), agarose (0.8%), and phytagel (0.4%) were studied for callus induction. All cultivars responded to the MS induction medium supplemented with 2 mg/L 2,4-D, 3% sucrose and 0.8% agar, and initiation of somatic embryogenesis was evident within 2-3 days of culture. The embryogenic calli developed into clusters of small dense globular somatic embryos within 3-4 weeks of culture and subsequently developed into distinct somatic embryos and plantlets after transfer to the regeneration medium. An average of up to 16 plantlets per cultured scutellum were recovered from two regeneration media studied, i.e. half-strength hormone-free MS medium (for cultivar Monroe) and MS medium with BA and IAA (for cultivars Renville, Medora, and Vic). The plantlets were then transferred to pots in the greenhouse, where they developed into mature, fertile plants.