Adaptability assessment of cactus species (Opuntia Ficus Indica and Opuntia Stricta) to local environmental conditions in Uganda

Abstract

Cactus plants are gaining increasing interest globally, in particular cactus pear (Opuntia ficus indica), because of its resilience to harsh climatic conditions while at the same time provide nutrients to man and animals. In some other countries e.g. Brazil, Mozambique and Italy, some elite varieties have been evaluated for their potential to produce fodder. Despite the importance of cactus, little has been done to compare the adaptability of different cactus species to the local growing conditions in Uganda hence limiting evaluation of their production and utilization potential. This study evaluated the adaptability and production potential of cactus under Ugandan conditions. The objectives of this study were a) to determine the growth rates of two cactus species Opuntia stricta and Ficus indica under screen house conditions, and b) to assess the growth rates of Opuntia stricta and Ficus indica and their biomass accumulation under the field conditions. The experiment was set up at Makerere University Agricultural Research Institute Kabanyolo (MUARIK) to assess the growth rate of two cactus species under screen house and field conditions. In the screen house experiment, three sizes (small, medium and large) of the varieties were used. In the screen house data was collected on growth rate and biomass accumulation in terms of fresh weight. Plants from each variety were selected and planted in a Randomized Complete Block Design with three replications. Each variety was represented by three rows (ridges) consisting of the sizes small, medium and large, respectively, with each row having double lines of 19 plants. In the screen house, significant variation (p<0.001) was observed for different sizes (small, medium and large), species and weeks of data collection. In O. stricta, highest increase in growth rate was observed with small sized plantlets whereas highest growth rate in F. indica occurred where large plantlets were used. Biomass accumulation in terms of fresh weight was highest in F. indica as compared to O. stricta. Growth rates for the two species under field conditions varied significantly (p<0.001). F. indica had the highest (53.67 cm) growth rate compared to O. stricta (46.56 cm). The fresh weight of the two cactus species differed significantly (p = 0.035) whereas dry weight did not differ significantly (p = 0.274). O. stricta had the highest biomass accumulation for both fresh and dry weight showing more adaptability to natural environment. A few pests (caterpillars) where observed to attack the two cactus species on station. More studies need to be carried out in semi-arid areas on adaptability of cactus species.