Genotype-by-environment interaction and stability of root mealiness and other organoleptic properties of boiled cassava roots

Abstract

Genetic enhancement of cassava aimed at improving cooking and eating quality traits is a major goal for cassava breeders to address the demand for varieties that are desirable for the fresh consumption market segment. Adoption of such cassava genotypes by consumers will largely rely not only on their agronomic performance, but also on end-user culinary qualities such as root mealiness. The study aimed to examine genotype × environment interaction (GEI) effects for root mealiness and other culinary qualities in 150 cassava genotypes and detect genotypes combining stable performance with desirable mealiness values across environments using GGE biplot analysis. Experiments were conducted using an alpha-lattice design with three replications for two years in three locations in Nigeria. The analysis of variance revealed a significant influence of genotype, environment, and GEI on the performance of genotypes. Mealiness scores showed no significant relationship with firmness values of boiled roots assessed by a penetration test, implying that large-scale rapid and accurate phenotyping of mealiness of boiled cassava roots remains a major limitation for the effective development of varieties with adequate mealiness, a good quality trait for direct consumption (boil-and-eat) as well as for pounding into ‘fufu’. The moderate broad-sense heritability estimate and relatively high genetic advance observed for root mealiness suggest that significant genetic gains can be achieved in a future hybridization program. The genotype main effects plus genotype × environment interaction (GGE) biplot analysis showed that the different test environments discriminated among the genotypes. Genotypes G80 (NR100265) and G120 (NR110512) emerged as the best performers for root mealiness in Umudike, whereas G13 (B1-50) and the check, G128 (TMEB693) performed best in Igbariam and Otobi. Based on the results of this study, five genotypes, G13 (B1-50), G34 (COB6-4), G46 (NR010161), the check, G128 (TMEB693), and G112 (NR110376), which were found to combine stability with desirable mealiness values, were the most suitable candidates to recommend for use as parents to improve existing cassava germplasm for root mealiness.

Definition of sensory and instrumental thresholds of acceptability for selection of cassava genotypes with improved boiling properties

“…Thanks to a standardized operating protocol for QDA, it was possible to produce comparable sensory datasets on boiled cassava from Uganda, Benin and Colombia, and to identify similar correlations between sensory and instrumental measurements in the three countries, in particular regarding the evaluation of textural attributes. Previous research works established correlations between sensory attributes and instrumental measurements of boiled cassava in Benin, 9,10 in Nigeria 3 and in Cameroon 11 but, to our knowledge, this is the first time datasets from different countries have been combined to draw robust conclusions on sensory and instrumental characterization of boiled cassava. The present study brings together hedonic, QDA and instrumental methods (WA30, texture analysis) as a demonstration of the complete approach to define acceptability thresholds for MTPP laboratory methods.…”

“…1 Cassava cooking behaviour depends not only on genotype 2 but also on genotype × environment interaction. 3 Cassava breeders are aware of these factors but are focusing on the improvement of primarily agronomic traits (yield, tolerance to pests and diseases). For instance, Akinwale et al 4 studied genetic variability among 43 cassava genotypes in three agro-ecological zones of Nigeria through the evaluation of cassava mosaic disease, plant height, root number, root weight etc.…”

“…Several studies have reported the relationship between sensory and instrumental parameters of boiled cassava but few have integrated sensory nor instrumental thresholds. 9,10 As multi-environment and multi-year field trials are necessary to comprehend genotype × environment interactions and identify varieties with the best probability of adoption, 3 it is important to employ methods for accurate screening of both agronomic criteria and consumer quality traits as early as possible in the breeding cycle, in order to minimize costs.…”

“…Boiled cassava is eaten in almost all cassava‐growing regions of Africa, Latin America and Asia 1 . Cassava cooking behaviour depends not only on genotype 2 but also on genotype × environment interaction 3 . Cassava breeders are aware of these factors but are focusing on the improvement of primarily agronomic traits (yield, tolerance to pests and diseases).…”

Varietal and environmental influences on organoleptic and cooking quality of water yam (Dioscorea alata) landraces

“…Cooking time, hardness of cooked pulp and starch content depended on location. This suggests that for some quality traits the varietal selection will have to take environment and Genotype × Environment interaction into consideration, as shown in cassava 32 …”