Replacement of ammonium nitrate by alternative nitrogen sources in MS medium to enhance ginger (Zingiber officinale Rosc.) in vitro regeneration

Abstract

Ginger is an important perennial herb used for many purposes that has become a major spice crop across Ethiopia. Its production has been challenged primarily due to bacterial wilt disease eruption since 2012. The use of disease-free tissue culture generated seed rhizome as part of integrated management was considered as the best option to reduce this problem. However, attempts to produce large amounts of tissue culture plantlets were challenged by the lack of the major nitrogen source, ammonium nitrate. Hence, an experiment was designed to select potential alternative sources of nitrogen as a replacement of ammonium nitrate. The study evaluated three nitrogen salts at different levels in MS medium supplemented with 2.0 mg/l BAP and 1.0 mg/l Kinetin using ginger variety Boziab. A significant, highest mean shoot number was achieved with 1.0 g/l NH₄Cl, followed by 3.8 g/l KNO₃, and 3 g/l urea, with 9.33, 7.33 and 7.00 mean number of shoots, respectively. Shoot growth, rooting and survival after acclimatization were affected negatively at higher levels of NH₄Cl. The highest mean number of roots (19) was observed on a medium containing 1.0 g/l NH₄Cl, followed by control MS media (16). Survival after acclimatization was 98% for plants derived from medium containing 4.5 and 3.8 g/l urea and KNO₃, respectively, and 95% for plants from medium containing 1.0 g/l NH₄Cl. These findings indicate that low cost salts can be alternative potential sources of nitrogen to enhance large scale disease free ginger production in Ethiopia.

Key message

Ginger plantlets were successfully regenerated in ammonium nitrate replaced MS media. This is the first report on ginger using low-cost ammonium chloride and urea replacing ammonium nitrate as nitrogen source.