African and Mediterranean Agricultural Journal - Al Awamia (Jun 2022)
Evaluation of the planting method, and auxin hormone for vegetative multiplication of Opuntia spp. varieties resistant to Dactylopius opuntiae (Hemiptera: Dactylopiidae) in Morocco
Abstract
Cactus Opuntia spp. is a perfectly appropriate crop for land rehabilitation in the arid and semi-arid regions of Morocco. Unfortunately, the sustainability of this extremely resilient crop has become seriously threatened by the appearance of Dactylopius opuntiae (Cockerell) (Hemiptera: Dactylopiidae), a cochineal specific to Opuntia spp cacti that was introduced in Morocco in 2014. Thus, eight Opuntia spp. varieties were identified by National Institute of Agricultural Research in Morocco as resistant to the cochineal, to provide a solid basis for the national emergency program of rehabilitating the devastated Opuntia spp. ecosystems throughout the country. To produce large quantities of planting material, a rapid Ex-situ propagation method for prickly pears have been developed. For each of the eight varieties, cladodes were harvested in march, 2019 and 2020 in the Experimental Station of the Regional Office of Agricultural Development of Doukkala (ORMVAD). They were cut into 6 pieces of about 140 cm2 with at least two bud areolas. After 25 days of drying at a temperature range from 17 to 28 °C, the cuttings were soaked for 5 min in 2.5 g/l of a Rhizogen product (containing 0.3% IBA), which represents for us the Auxin, or in talc powder or in talc powder and a rapid soaking in auxin solution (mix 1) or soaking in water then in talc powder (mix 2) or in water. The cuttings were planted in normal polarity in black plastic cylindrical containers (24.6 cm long and 14.1 cm wide), filled with a mixture of fine sand (2/3 w/w) and peat (1/3 w/w) and placed at an average ambient temperature of 28°C/17°C (day/night) in field for growth. In general, auxin (2.5 g/l) and mix 1 treatments were found to be the most effective regarding rooting (20-73 roots number) and growth of cuttings. This research has also allowed us to demonstrate that, in general, for all the varieties studied, basal cuttings planted in orientation (N-S) and normal polarity show very interesting results under optimal conditions concerning rhizogenesis and caulogenesis.
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