Integrating Agronomic Practices for the Mitigation of Crack Formation on Sweet Potato Roots at Umudike, South Eastern Nigeria

Onunka N.A,Ehisianya C.N,Njoku J.C

doi:10.13189/ujar.2017.050402

Abstract

Field experiment was conducted in 2013 cropping season to evaluate the effect of integrating different agronomic practices for mitigating crack formation on sweet potato (Ipomoea batatas) roots. Cracks are malformations on the edible roots of sweet potato which make them look unattractive, form portals for disease and pest invasion, lead to decay and high peeling loss, and reduce marketability and acceptability. The agronomic practices evaluated included; two nutrient sources NPK 20:10:10 and 15:15:15, four different harvest periods 3, 4, 5, and 6 months after planting (MAP) on the three varieties of sweet potato namely TIS87/0087, UMUSPO/1 and CIP440293. It was carried out at the Eastern farm of National Root Crops Research Institute Umudike Abia State which lies between latitude 40 151 and 70 N and longitude 150 291 N and 70 331 E at an elevation of 122m above sea level. The experimental design was a split plot arrangement fitted into a randomized complete block design, main plot was nutrient source, subplot was time of harvest, and sub subplot was variety. There were thirty six treatments replicated three times. The soil was classified as sandy loam. Data were collected on number of roots with cracks, total root number, total root fresh weight, and rot incidence. Results showed that the effect of the nutrient sources was not statistically significant at (P≤0.05) on crack formation more cracks were recorded on varieties UMUSPO/1 and CIP440293 (orange-fleshed) than TIS87/0087 (white-fleshed). Time of harvest was very highly significant (P<0.001) on number of roots with cracks. From this work it can be concluded that time of harvest and variety played important roles in the formation of the cracks in the tuberous roots of sweet potato which reduce the quality of the crop. The type of fertilizer used has no effect on the crack formations, root size and number while early harvest is recommended.

Highlights

Sweet potato originated from tropical Central America
The effect of some agronomic practices on the number of roots with cracks of three Sweet potato varieties is shown on Table 1
Variety 2 V2 (UMUSPO/1) had the highest mean number of roots with cracks 5.39, followed by V3 (CIP440293) 2.31, whereas the least was recorded on V1 (TIS87/0078) 1.72

Summary

Introduction

The underground part is classified as a storage root, rather than a tuber, as in the white (“Irish”) potato (Solanum tuberosum). Sweet potato is cultivated in more than 100 countries, mostly throughout tropical and subtropical Asia. The Sweet potato is a perennial, it is grown as an annual. It belongs to the morning glory family or Convolvulaceae. Fleshy, edible storage roots are formed on the underground stem nodes. Latex occurs in all parts of the plant. It is a perennial herb cultivated as an annual, with trailing or twining stems up to 4 m long, which sends roots into the soil at the nodes.

Objectives

Methods

Results

Conclusion