Growth and Yield Potential of Wild Blackberry (Rubus spp.) under Conventional Production Practices in Kenya

Wild Blackberry (Rubus L. sub-genus Rubus Watson) species were evaluated for their growth and yield potential under conventional production practices at the Horticulture Research and Teaching Farm, Egerton University, Njoro, Kenya between January 2016 and July 2017. A randomized complete block design (RCBD) with three replications and five treatments (species) were used. The treatments included four wild blackberry species Rubus volkensis, Rubus steundneri, Rubus apetalus, Rubus pinnatus and one cultivar “Ruben” (Rubus fruiticosus). Growth and yield potential were determined by their respective components i.e. cane height, cane diameter, number of canes per plant emerging from ground, number of laterals per cane, lateral length, internode length, number of flowers per lateral and cane, fruit number per lateral, fruit size (length and width), fresh and dry fruit weight. Analysis of the data showed that wild species Rubus apetalus had the highest growth in terms of cane height (143.53 cm), cane diameter (19.37 mm), number of canes emerging from the ground (9 canes), number of flowers per lateral (58) and cane (581) and number of fruits per lateral (56), while Rubus pinnatus had the longest internodes of 8.47 cm and lateral length of 80.02 cm, however, R. volkensis was second to the cultivar “Ruben” (Rubus fruiticosus) in terms of, fruit size (length 22.84 mm and width 21.10 mm) and fruit fresh and dry weights of 3.7 vs 5.4 and 1.6 vs 2.4 g respectively. It is concluded that wild blackberry had growth and yield potential under conventional production practices. Adoption of Rubus volkensis under conventional production and the incorporation of growth vigour characteristics of wild species in breeding programs of the already cultivated species is recommended.