In vitro shoot regeneration and genetic differentiation of Baladi cauliflower (Brassica oleracea var. botrytis) in Hebron

Abstract

Cauliflower exhibits a transition from vegetative to flowering growth triggered by low temperature (vernalization) which controls late or early flowering. FLC gene homologs in Brassica species controls flowering response. In this study, integrated molecular and tissue culture approaches were used to explore genetic variation in the flowering genes and to improved cauliflower crop. In the molecular approach, part of the BoFLC.HP gene was sequenced in hybrid and local "Baladi" cauliflower using the F7R7 primer to characterize early or late FLC gene in cauliflower. Sequenced BoFLC.HP region showed a point mutation at position 91 and an indel at position 212 to 219 in intron number 2 between Baladi and F1- hybrid cauliflower which controls flowering time. In the tissue culture approach, hypocotyl and cotyledon explants from four-day-old seedlings were cultured on Murashige and Skoog (MS) salts supplemented with BA, KIN and TDZ alone or in combination with IBA or NAA. The highest shoot regeneration response (80%) was observed in hypocotyl explants on full strength MS media supplemented 0.5 mg/L BA and 0.5 mg/L IBA. Cotyledon explants, showed 26% shoot regeneration on full strength MS media supplemented 2.0 mg/L BA and 0.1 mg/L NAA. One of the most important tools in crop improvement is the process of genetic transformation with the Agrobacterium, which requires an efficient in vitro shoot regeneration protocol from explants. These two aspects will be a prerequisite in cauliflower crop development in the future. Keywords: Brassica oleracea var. botrytis, flowering time, vernalization, BoFLC.HP gene, in vitro shoot regeneration, Hypocotyl, Cotyledon.