Application of Embryo Rescue Technique in Juglans regia L. x J. nigra L. Hybridization

Abstract

Embryo culture were used to produce inter specific walnut hybrid plants between <em>Juglans nigra </em>L. and <em>J. regia</em> L. Developed ovaries were collected from <em>J. rejia</em> female flowers which were pollinated with <em>J. nigra</em> pollen grain by high dusting on a mature tree. In order to isolate embryos, exocarps were aseptically removed. Isolated embryos from ovules at different developmental stages were transferred to the different kind of growth-regulators hormone free media (MS, Half-MS, MS and Half-MS supplemented with 1 mg/l BA +0.1 mg/l NAA) for embryo development and germination. There was a significant difference between media for embryo germination α= 0.05 level. Highest percentage of embryo germination was observed in MS hormone free medium (13.7%). Because of long period required for embryo development, isolation of embryo less than 45 days old embryos were impractical. There were a highly significant difference between age of embryos for embryo germination α= 0.01 level. Embryo with more than 45 days old germinated and produced plants on all applied media. Highest germination rate were observed on cross-pollinated embryos which was isolated from 90 old ovaries. Before being transferred to the potting soil and green-house, plantlets sub cultured in the same medium within jars. Thirteen successful acclimatized plantlets were transferred to the field.