Effect of genotype and genotype by environment interaction on total cyanide content, fresh root, and starch yield in farmer-preferred cassava landraces in Tanzania.

Mariam K Mtunguja,Edward Kanju,Henry S Laswai,Joseph Ndunguru,Yasinta C Muzanila

doi:10.1002/fsn3.345

Abstract

High starch yield is the most important trait for commercialized cassava starch production. Furthermore, cyanide present in cassava roots poses a health challenge in the use of cassava for food. Cassava genotypes have varying maturity periods that are also environmental dependent. This study aimed at identifying suitable cultivars and optimum time of harvest to maximize starch production across three environments. The study found significant difference between genotypes, locations, harvest period, and all the interactions (P ≤ 0.001) for all traits analyzed. Kiroba recorded high starch yields of 17.4, 12.7, and 8.2 t ha−1 at Chambezi, Amani, and Magadu, respectively. Kilusungu recorded highest cyanide content of 300–400 ppm across all locations but Kiroba recorded highest values of 800 ppm, 15 months after planting at Chambezi. Genotype by environment (GGE) biplot analysis revealed that Kiroba was a superior cultivar in terms of starch yield. Kilusungu recorded highest cyanide content and average starch yield, therefore suitable for use in starch production. The study confirmed effect of genotype and genotype by environment interaction, Kiroba cultivar was superior in terms of starch yield and maximum starch yield was obtained at 9 months after planting. Nyamkagile and Kibandameno had the lowest cyanide content across all environments.

Highlights

Starchy tuberous roots of cassava provide food for people in sub-Saharan Africa and Latin America (Nassar and Ortiz 2007)
A total of six farmer-preferred cassava landraces collected from Eastern zone of Tanzania in January 2012 were used for this study
Cation Exchange Capacity (CEC) measures the ability of soil to hold essential nutrients and its availability to plants; it was high at Amani (16.2 cmol/kg) and Chambezi had the lowest (8.2 cmol/kg)

Summary

Introduction

Starchy tuberous roots of cassava provide food for people in sub-Saharan Africa and Latin America (Nassar and Ortiz 2007). Apart from culinary requirements, cassava starch can find application in various industries such as pharmaceuticals, cosmetics, biopolymers, textile, and biofuels (Nassar and Ortiz 2007). This demand can be met by cassava farmers and the potential to fulfill the demand is available. Adequate information is required on the right cassava cultivars and appropriate harvesting period so as to maximize cassava production and increase income. Cassava has varying maturity period depending on genotype (Ceballos et al 2004). Studies have reported that definite optimal harvest time for cassava is genotype and environment dependent (Benesi et al 2008).

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Conclusion