Effect of Provenance and Storage Agroecology on Duration of Yam (Dioscorea rotundata Poir.) Tuber Dormancy

Abstract

Abstract:Crop improvement in yam is slow due to poor understanding of tuber dormancy. Tuber provenance and storage agroecology are thought to affect the duration to sprouting in yam, but systematic studies on the role of these factors are rare. The objective of this study was to determine the effects of tuber provenance and storage agroecology on the duration to sprouting in D. rotundata. Twenty landraces [comprising 7 originating from the Guinea savanna (GS), 5 from the Forest/transition (TS), and 8 from the Humid forest (HF)] were collected and multiplied at a location in their respective agroecologies: Abuja (GS), Ibadan (TS) and Onne (HF). Thereafter, 100 tubers of each of the 20 landraces were stored at each of the three sites, and dates of the appearance of shoot bud (ASB)/ sprouting were recorded. The results showed that provenance did not significantly affect the duration from planting to sprouting or the duration from date in storage to sprouting in D. rotundata. The duration to ASB varied by up to 21 days (d) for landraces originating from HF and TS, and 37 d for landraces originating from GS. Variations among landraces within a provenance group were greater than between provenance groups. This suggests that the provenance of a landrace is not a major factor controlling the duration to ASB. All landraces responded to storage agroecology/ environment in a similar manner. There was no interaction between provenance and storage environment. Tubers stored at Onne and Ibadan sprouted about 10 d earlier than those at Abuja, and this was associated with slightly higher temperature and RH at Onne and Ibadan. Storage agroecology is an important factor controlling the duration to sprouting but provenance is not.