IMPACT OF VIRUS INFECTION ON YAM (Dioscorea rotundata POIR) PERFORMANCE IN NIGERIA

  • S.W. Asala Department of Crop Protection, Faculty of Agriculture, University of Abuja, Abuja, Nigeria
Keywords: Incidence, severity, virus, yam yield, and Guinea Savanna

Abstract

Yam is important for food security in Nigeria. The trial was laid out in Randomized Complete Block Design
(RCBD) with seven treatments (seven local varieties), and three replications to assess the impact of virus
incidence and severity on performance of yam varieties in the field during three growing seasons (2014, 2015 and
2016). The performance indicator that was studied was yam yield and virus symptoms used for evaluation were
mosaic and mottling, vein-clearing, and vein-banding. Plants that grew from virus-negative seed yams expressed
the presence of virus symptoms on the field. Germination percentage was lowest in Gbakumo yam variety and
played a greater role in the determination of yam yield in all yam varieties. The presence or absence of virus in the
seed yam before planting affected the level of yam germination and yam yield. Virus incidence, which increased
yearly, was negatively correlated to germination and yield. Average tuber weight was positively correlated to
germination count (%) in some varieties. For the three years, the varieties; Mailemu, Bangwasi and Allushe
showed evidence of tolerance to virus infection with high performance in terms of germination and yield. New
local yam varieties therefore need to be further investigated for inclusion in food security staples in Nigeria.

Published
2020-08-30

Journal Identifiers


eISSN: 0300-368X