Abstract
Thirteen Egyptian bread wheat (Triticum aestivum L.) cultivars and Bobwhite were evaluated for their potential use in tissue culture studies using three different concentrations of 2,4-dicholorophenoxyacetic acid (2,4-D). Modified medium of Cheng et al (1997) supplemented with 0.5 mg/l, 1.0 mg/l, and 2.0 mg/l of 2,4-D were used. The results showed genotypes, 2,4-D concentrations and their interactions significantly affected the percentage of embryogenic calli induced, regenerable call! and regenerated green plants. The highest responding genotypes across the three concentrations of 2,4-D were Gemmieza 3 (69.6%) for embryogenic calli, Sakha 69 (88.2%) for regenerable calli and Gemmieza 3 (92.3%) for regenerated green plants. The most favorable concentration of 2,4-D, across all genotypes, was 0.5 mg/l with high frequencies of embryogenic calli (48.6%), regenerable calli (77.3%) and regenerated green plants (76.7%). Highly significant genotype by 2,4-D concentrations interactions were observed for all studied traits. The best responding genotypes at the lowest concentration of 2,4-D (0.5 mg/l) were Gemmeiza 3 (80.7%) for embryogenic calli, Giza 167 (90.1%) for regenerable calli and Gemmieza 3 (95.3%) for regenerated green plants. At the higher 2,4-D concentrations, Sakha 69 was the best cultivar for embryogenic calli (68.7%; 2.0 mg/l 2,4-D), regenerable calli (94.2%; 2.0 mg/l 2,4-D) and regenerated green plants (94.8%; 1.0 mg/l 2,4-D). The response of Gemmeiza 3, Giza 167 and Sakha 69 was better or equal to Bobwhite at different 2,4-D concentrations.