Abstract

An in vitro culture protocol was established for direct regeneration of plantlets from unpollinated ovary cultures of four Ethiopian wheat varieties. Unpollinated ovaries were excised from durum wheat (Yerer and Ude varieties) and bread wheat (Simba and Galama varieties). Analysis of variance (ANOVA) has shown that genotypes, types of media, concentrations of 2,4-dichlorophenoxy acetic acid (2,4-D) and kinetin (KIN) and durations of cold pretreatment at 4°C significantly (P≤0.05) affected direct formation of embryonic tissues independently. Stage II of wheat spikes, MS medium containing 1 mg/l of each of 2,4-D and KIN and 15 days of cold pretreatment were found to be the best conditions for direct formation of embryonic tissues. The highest frequency of shoots were regenerated from the cultured embryonic tissues of Yerer (41.6% ) and Simba (41.3%) on medium containing 0.1 mg/l 2,4-D. From a total of 14,524 cultured unpollinated ovaries, 1,100 embryonic tissues (7.6 %) and 75 regenerants were obtained. The average percentage of embryonic tissues and regenerants were 9.0  and 1.1%  from 3,444;  9.8  and 0.55% from 4,732; 5.6  and 0.17% from 2,988; 4.7  and 0.12%  from 3,360 cultured unpollinated ovaries for varieties Yerer, Simba, Ude and Galama, respectively.

Key words: Embryonic tissues, Unpollinated ovaries, regenerants, wheat varieties.

Abbreviation

Abbreviations: 2,4-D, 2,4-Dichlorophenoxy acetic acid; KIN, kinetin; NAA,naphthaline acetic acid; BAP, benzyl amino purine; IAA, indole acetic acid; DZARC,Debre Zeit Agricultural Research Center; HARC, Holetta Agricultural Research Center; PGRs, plant growth regulators; ET, embryonic tissues.