Synergy of storage management with varietal productivity improvement: the case of maize in Timor-Leste

Abstract

SUMMARYMaize (Zea mays L.) is the major staple crop in Timor-Leste, but yields are low, averaging 1·0–1·7 t/ha, and losses during storage are high from maize weevil (Sitophilus zeamais Motschulsky) damage. The current research, assessing both weevil damage and management options, studied household storage of traditional and introduced maize varieties in 18 farmer groups for 33 weeks, and then evaluated the weevil damage in cobs stored for 9 months of 19 populations from different multi-location yield trials in 2007 and 2010. Storage of shelled grain in airtight containers for 33 weeks had no weevil damage on-farm. In contrast, storing shelled maize in a woven sack was the worst storage method with an average of 0·96 of grain attacked by weevils by Week 33, with local and introduced varieties damaged similarly. Shelled grain stored in a woven sack were infested significantly more than in traditional storage methods husked on the cob – above a fireplace, in a tree or an elevated house. Importantly, modern varieties were damaged more extensively by weevils than local maize types when the husked maize was stored using traditional methods. In the yield trials, grain weevil damage averaged 0·39 in both years after storage in the husk for 9 months. Varietal and location effects were significant for proportion of weevil damage, but the interaction effect was not significant in either year. The broadsense heritabilities were intermediate/high for proportion of weevil-damaged grain (H2=0·81 in 2007 and 0·59 in 2010), and there is potential that populations can be found combining a substantial yield increase with no increase in weevil susceptibility for households using traditional storage methods. For those households with access to airtight storage systems, the results emphasize the need to exploit the interaction of variety with storage method to benefit from the yield advantage of introduced varieties through the concurrent dissemination of improved seed with subsidized, airtight storage drums.