Evaluation of polycross sweetpotato seedlings for root yield potential, flesh roots colour and response to major sweetpotato diseases
The study aimed at determining the root yield potential of the sweetpotato seedlings, the variation in storage root flesh colour and response of the storage roots to major pests and diseases attacking sweetpotato in the field .The experiment was carried out in the screen house and at the Eastern experimental field of National Root Crops Research Institute Umudike, Abia State, Nigeria. The result indicated that total number of seedlings from various families that produced storage/ enlarged roots ranging from 1 - 10 per stand were of high percentage (95.23%) when compared with those seedlings without storage/enlarged roots (4.87%). It showed evidence of yield potential of the seedlings and adaptability of the seedlings to the field conditions. The result from the study also identified the family MUSG 0608-61with superior root yield potential of 0.63kg per stand equivalent to 21.0t/ha of fresh root yield to other families and was rated as the highest top yielder according to National Agricultural Research Organization (NARO) classification. However, a total of 66.19% of colour variation among the seedlings in the families were orange fleshed genotypes with the 84.3% from the family MUSG 066-6-15 and 70.18% from the family NCPP573, 50-17-02 which indicated that majority of the seedlings from various families were mainly Orange fleshed genotypes. Farmers who wish to incorporate orange fleshed sweetpotato genotypes in their farming systems should do so especially from these two families that have high percentage of orange fleshed seedlings. All the 739 sweetpotato seedlings from the five families responded negatively to field viral and nematode infection. The 6.2% of the storage roots seedlings from the family MUSG 0614-22 responded moderately to the attack of Sweetpotato root weevil (score rate 3) while only 3.6% of seedlings in the family of MUSG 066-6-15 showed mild symptom (score rate 2) of attack of Sweetpotato root weevil. This result indicated that the seedlings in the two families were not totally resistant to the attack of Sweetpotato root weevil
Keywords: sweetpotato seedlings, yield potential, variation in flesh colour, major pests and diseases.