Genetic variability and genotype by environment interaction of two major cassava processed products in multi-environments

Abstract

Conversion of cassava (Manihot esculenta) roots to processed products such as gari and fufu before consumption is a common practice worldwide by cassava end-user for detoxification, prolonged shelf life or profitability. Fresh root and processed product yield are supposed to be equivalent for each genotype, however, that is not the case. Developing genotypes with high product conversion rate is an important breeding goal in cassava as it drives the adoption rates of new varieties. The objective of this study was to quantify the contribution of genetic and genotype-by-environment interaction (GEI) patterns on cassava root conversion rate to gari and fufu. Sixty-seven advanced breeding genotypes from the International Institute of Tropical Agriculture (IITA) were evaluated across eight environments in Nigeria. Root conversion rate means across trials ranges from 14.72 to 22.76% for gari% and 16.96–24.24% for fufu%. Heritability estimates range from 0.17 to 0.74 for trial bases and 0.71 overall environment for gari% and 0.03–0.65 for trial bases and 0.72 overall environment for fufu% which implies that genetic improvement can be made on these traits. Root conversion rate for both gari and fufu% showed a negative but insignificant correlation with fresh root yield and significant positive correlation to Dry Matter content. For all fitted models, environment and interaction had explained more of the phenotypic variation observed among genotypes for both product conversion rates showing the presence of a strong GEI. Wrickle ecovalence (Wi) stability analysis and Geometric Adaptability index (GAI) identified G40 (TMS14F1285P0006) as part of top 5 genotypes for gari% but no overlapping genotype was identified by both stability analysis for fufu%. This genotypic performance across environments suggests that it is possible to have genotype with dual-purpose for high gari and fufu conversion rate.

Drivers of consumer acceptability of cassava gari‐eba food products across cultural and environmental settings using the triadic comparison of technologies approach (tricot)

“…Public breeding programs have been assessing improved genotypes on-station for genetic variability, heritability and stability of the food product yield and quality traits of interest. 9,10 Assessment of clones for food product traits at the last breeding stage using multi-disciplinary methodologies 4,11,12 provided evidence of the need for a deliberate shift in breeding priorities to user-focused, inclusive and gender-responsive approach. [11][12][13] Recent breeding activities have incorporated the assessment and inclusion of the post-harvest processing and consumer acceptability aspects, 4,14 informing breeders' selection accuracy and definition of genetic gains.…”

“…This is crucial to facilitate the selection of genotypes for specific, dual or multipurpose food uses. 9 It is also essential to overcome the paucity of information regarding the stability of acceptability traits of cassava-eba food across cultural and environmental settings among its diverse consumers. Earlier research 4,6,15,16,18 has established that processor and consumer preferences are mainly related to the texture and color of the food products, which informed our focus on laboratory parameters related to these.…”

“…Consistent efforts in the last 10 years through funded projects such as Nextgen cassava (https://www.nextgencassava.org) and RTBfoods (https://rtbfoods.cirad.fr) have led to the assessment of improved cassava genotypes to meet identified demand and preferences of diverse crop users. Public breeding programs have been assessing improved genotypes on‐station for genetic variability, heritability and stability of the food product yield and quality traits of interest 9,10 . Assessment of clones for food product traits at the last breeding stage using multi‐disciplinary methodologies 4,11,12 provided evidence of the need for a deliberate shift in breeding priorities to user‐focused, inclusive and gender‐responsive approach 11‐13 .…”

Exploring genetic variability, heritability, and trait correlations in gari and eba quality from diverse cassava varieties in Nigeria

“…Different genotypes exhibit variations in both the quantity and quality of the final product. 19,20 As a result, it is unclear what proportion of the phenotypic variation in gari yield and quality is due to genetics, environment, or/and processing factors and their interactions. For genetic improvements, breeders are interested in the proportion of variation attributed to genotype effect.…”

“…Previous studies on genotypic variation of genotypes on traits related to gari/eba quality were mainly descriptive, and assessment was done using a limited number of varieties. 9,10,[20][21][22][23][24][25][26][27][28] For example, Almazan 25 screened 35 genotypes in two replications to study the influence of genotypes on gari quality. Though the study revealed a significant genetic variation for gari quality, it did not elucidate the nature and extent of genetic variation, heritability, and correlations with fresh root quality-related traits.…”