Optimization of regeneration and transformation system in finger millet (Eleucine coracana L.)

Abstract

A proficient in vitro regeneration protocol and transformation system is a requisite for genetic improvement of finger millet. Finger millet (Eleucine coracana L.) GN-4 was used for optimization of regeneration protocol. Using seed as a explants, highest frequency of callus induction was observed on MS supplemented with 2,4-D (1.0 mg.L-1), Proline (500 mg.L-1) and Casein enzyme hydrolysate (300 mg.L-1). Among the different combinations used for shoot initiation, MS with kinetin (1.50 mg.L-1) and BAP (0.50 mg.L-1) produced maximum number of shoots (11.00) having highest shoot length (11.2 cm). Within six days, maximum numbers of roots (12.3) were obtained on half strength MS basal media fortified with NAA (1 mg.L-1). In hardening process, maximum survival (44.51%) of plantlets with minimum days for new sprouting (4.4 days) was reported in vermicompost: sand: cocopeat (1:1:1 v.v-1) mixture. Agrobacterium tumefaciens mediated genetic transformation system was optimized and putative transgenic plants were confirmed by PCR. When the effect of the age of the callus and co-cultivation duration were evaluated, forty five days old co-cultivated callus for five days yielded 1.33% frequency of transformation.