تعيين بهترين زمان براي نجات جنين هاي زايشي از بذور چند جنين (پلي امبريون ) پايه هاي مركبات

Determination of the best time of zygotic embryo rescue from the polyembryony seeds of citrus root stocks

The maturity of adventive embryos in aspect of time was studied in five citrus rootstocks. Two GA3 concentrations of Murashige and Tuker (MT) medium were selected and used (1 mg/I and 5mg/I). Ovules were collected at 35, 50, 65, 80, 95, 110, and 125 days after pollination (DAP) and cultured on the medium. The experimental design was factorial on basis of randomized complete-blocks with three replications. Each replication consisted of one petri- dish with ten seeds. Overall, 2100 seeds were cultured and the germinated plantlets were counted. Results showed that genotype, seed age, gibberellin concenteration and their interactions significantly affected the embryo number and plantlet formation. None of the seeds, (harvested at 35 and 50 DAP) was germinated, and in most of genotypes the best time for zygotic embryo rescue was between 65-80 DAP. Gibberellin at 5 mg/l was better than 1 mg/I and mean number of plantlets produced in each genotype in petri-dish was at the order of: Soure Orange (19.48), Flying Dragon (16.4), Citromelo (13.21), Citrange (11.17) and Shell MohalIe (10.26).