Growth performance of the neglected crop Telfairia pedata across elevation and climate gradients in Northern Tanzania

Abstract

Herbaceous vines, including the neglected crop Telfairia pedata, play a key role in small-holder livelihoods of Eastern Africa. Despite this species’ importance in enhancing agro-biodiversity, little is known about its distribution and growth performance in relation to environmental variables. We collected biophysical and environmental data, i.e., on climate and elevation, for 346 T. pedata vines across four districts of Northern Tanzania from September, 2019, to February, 2020. The four sites included Same, Lushoto, Muheza and Arumeru districts. We found that plants of T. pedata were mainly grown in elevations ranging between 900 to 1800 m above sea level with annual rainfall regimes of 1000 to 1400 mm. We recorded large abundance of T. pedata in Lushoto (46%) and Arumeru (28%) and observed that the number of fruits and fruit diameter were both positively correlated with elevation across the study districts. There was a significant effect of elevation on number of seeds, with Same district having more seeds across the studied districts. Rainfall had a significant effect on fruit diameter and number of seeds in the study districts. Furthermore, the tree species Albizia schimperiana was most commonly (in 40% of the cases) associated with T. pedata, followed by Persea americana (14%), and Croton macrostachyus (9%). We highlight that mountainous regions are ideal for this highly nutritious crop, and that native trees are of high importance for enriching this vine to current agro-ecosystems. Our findings will increase awareness on the importance of raising T. pedata crop, livelihood diversification, and increasing biodiversity through production of this orphan crop in small-holder farms.