Potentials of Selected Sweet Potato Landraces for Crop Improvement, Biodiversity Conservation and for Official Registration in Nigeria

Innocent Ifeanyi Maxwell Nwankwo, Grace Odochi Nwaigwe, Juliet Chinwendu Eluagu

An investigation was conducted at the National Root Crops Research Institute, Umudike in South eastern Nigeria involving nine sweetpotato landraces and two Check varieties TIS87/0087 and UMUSPO/3with the following objectives: to evaluate the diversity that exists in the selected sweetpotato landraces and to conserve them for future usage, to identify parents that flowers and are resistance to pests and diseases of ecological origin, to select landraces in terms of high storage root yield, high dry matter content and to build up reserve of breeding materials of native species that have nutritional and industrial potential for crop improvement programme. The results indicated that variability existed among the selected sweetpotato landraces and that the significant (P<0.01) highest fresh storage root yield of 19.6t/ha was for the landrace Kwara followed by ABCHI with 19.4t/ha and which were above the two standard check varieties (87/0087 and UMUSPO/3 which yielded 17.9 and 17.1t/ha respectively of fresh root yield) in the two years combined qualified them to be selected for registration and for commercial sweetpotato production. The landraces have high dry matter content of 33.4 and 31.2% respectively which is good for industrial and domestic utilization. They are also resistant to major field pests and diseases of sweetpotato (score 1) and could be selected for inclusion in the sweetpotato germplasm for breeding purposes. The two landraces flowers and have moderate (0.47 for ABCHI) to high (0.51 for Kwara) harvest index, although lower than the two checks (1.70 for UMUSPO/3 and 0.53 for TIS87/0087) however, it was an indication of high photosynthetic efficiency per unit area. The root morphological characters of the landrace ABCHI (and other landraces collected from Abia State) have similar root biological ranking with TIS87/0087, and may be regarded as duplicate of TIS87/0087. These landraces are quite distinct from Kwara, Ex-Igbariam, UMUSPO/3 and Buttermilk. The characterization enables for an easy and quick discrimination between the landraces. The characters discriminated upon are generally highly heritable and can easily be seen by the eyes and are equally expressed in all environments. These characters were potential attributes for recognizing them for biodiversity conservation, crop improvement and for registration as official varieties in Nigeria.