Propagation of cochineal scale insect free cactus (Opuntia ficus-indica) by in vitro regeneration culture technique in Tigray, Ethiopia

Cactus in northern Ethiopia is an endangered plant due to the attack by cochineal scale insect (Dactylopius coccus). The aim of this study was to micro propagate disease-free and cochineal resistance cactus pear by in vitro regeneration culturing technique. The study started with young cladodes carefully removed from mother plants. The surface-sterilized 1 cm2 cladode with one areole was cultured on shoot initiation MS media supplemented with 0, 0.5, 1.0, and 1.5 mg/l BAP alone. The already established explants were cultured on shoot multiplication media fortified with BAP at 0, 1.0, 2.0, and 3.0 mg/l. The proliferated cultures were inoculated for rooting on half-strength MS media supplemented with NAA alone at 0, 0.5, 1.0 and 1.5 mg/l. The MS medium appended with 0.5 mg/l BAP produced significantly the highest shoot number per explant (3 ± 1) and highest micro shoot length (3.27 ± 0.40). The highest multiplication factor (9.93 ± 2.25) was observed on a medium containing 1 mg/l BAP while the highest shoot lengths or elongation (3.03 ± 0.26) were observed on the medium containing 2 mg/l BAP. The best highest root number (6.06 ± 0.92) was recorded on the half MS Basal medium containing 0.5 mg/l NAA and highest root length (3.03 ± 0.27) was verified on the half MS Basal medium containing 1.0 mg/l NAA. The well-rooted plantlets were transferred for acclimatization purposes using coco peat substrate and 100% of the plants survived and established as vigorous plants under modern greenhouse conditions. The creation of a successful micro propagation method that allows for the production of more than 10,000 rooted plantlets from a single longitudinally divided shoot explant in just short period of time.