Response of Four Lemon (Citrus limon L. Burm) Cultivars Cultured in vitro toBAP, KIN and 2,4- D Combinations

The present study was carried out in the lab. of plant tissue culture at King Abdulaziz University to test the response of four lemon cultivars to micro-propagation using BAP, Kin and 2,4D combinations. The used explants in this study were intermodal segments and collected from the one year old lemon seedlings which obtained from the Citrus Research Center, Najran, Saudi Arabia. The experiments were laid out in a split plot design using 4 replicates. The results revealed that there were significant differences due to genotypic and growth regulators effects and their interaction for all measured parameters except no of days to buds sprouting. Explants of ‘Shehri’ registered maximum values of no. of days to buds sprouting with 0.5mg/l Kin +0.5mg/l 2,4-D, % sprouted buds with 0.5mg/l BAP, % dead shootlets with 2mg/l BAP+0.5mg/l 2-,4D and length of primary shoots (mm) 1mg/l BAP+0.5mg/l 2-,4D. Shoots of ‘AlnEurka’ formed the highest no. of leaves with 0.5mg/l BAP+1mg/l 2-,4D. Low responses were observed for explants from ‘Shaary’, ‘Banzahir’ and ‘Aln-Eurka’ on culture medium supplemented with high concentration of BAP alone or with combination of 2,4D. There were observed no sprouted buds for explants of ‘Shehri’ on culture medium complemented with high concentrations of Kin in combinations with 2,4D. Lemon explants were successfully in vitro propagated using intermodal segments and combinations of BAP, Kin and 2,4D at low concentrations.