Evaluation of Performance of Introduced Yam Bean (Pachyrhizus spp.) in Three Agro-Ecological Zones of Rwanda

Abstract

The yam bean (Pachyrizhus spp) was recently introduced as a root crop with high-yield potential, considerable protein and micro-nutrient concentration to investigate its potential for food production in Rwanda. Except for Chuin types (Pachyrizhus tuberosus) which have high storage root dry matter (RDM) (26 to 36%), most accessions are consumed raw and are reported to have low RDM. The present study aimed to evaluate and identify adapted high yielding yam bean accessions in major agro-ecological zones of Rwanda. Field experiments with 22 accessions were conducted in 2012 at three research sites representing the major agro-ecologies of Rwanda. Strict reproductive pruning was followed to enhance fresh storage root yields. Across locations, ANOVA indicated highly significant differences (p < 0.01) for genotypes (G), locations (L), seasons (S) and G x L effects for storage root yield, vine yield and harvest index and accounted for 21.88%, 43.41%, 1.43% and 13.25% of the treatment sum of squares, respectively. The GGE bi-plot revealed that EC209018 is high yielding but unstable. However, genotypes, AC209034, AC209035 and EC209046, were outstanding in terms of adaptation and relative stability across the 3 locations, suggesting consistent root yields irrespective of location and environmental conditions. The GGE scatter plot showed that all genotypes formed one mega-environment for storage root yield (Karama, Musanze and Rubona) and two mega-environments for biomass yield (Karama and Rubona as one mega-environment and Musanze the second one). This study revealed that Karama is the most suitable environment for evaluation and selection of yam bean for yield components in Rwanda.

Studying the Genetic Diversity of Yam Bean Using a New Draft Genome Assembly

“…The genetic and phenotypic diversity within P. erosus could be due to geographic isolation and domestication, which is in line with previous studies showing that yam bean genotypes are associated with their respective environment [5,6,10]. P. tuberosus and P. erosus also have genotype-by-environment interactions associated with fresh storage root yield [45] and crop yield [46]. Engelmann's work [9], shows that P. erosus accessions could be divided into four groups based on RAPD analysis: a group of P. erosus that originated from Central America only; two groups that are from Central America and Mexico; and a group that was exclusively made up of accessions from Mexico.…”

Predictive genotype-phenotype relations using genetic diversity in African yam bean (Sphenostylis stenocarpa (Hochst. ex. A. Rich) Harms)

“…For instance, Zanklan [ 40 ] observed that reproductive pruning of yam bean led to a great increase in fresh tuber yield including dry matter yield and explained by avoiding the nutrient and water competition between tuber and pod formation, yet a large variation was found among accessions. Similarly, the positive impact of reproductive pruning on fresh storage root yields has been also reported in American yam bean [ 41 , 42 ]. Despite reproductive pruning is a common practice in the yam bean including Mexican and Andean yam bean, more studies are needed in AYB because there are evidences of either adverse or independent effect of pruning and genotype on tuber fresh weight but also interact for tuber dry matter [ 43 , 44 ].…”

Research Article Genotype x year interaction for agronomical traits and proximate composition in yam beans (<i>Pachyrhizus</i> spp., Fabaceae) in the Brazilian Amazon

“…Previous studies in yam bean reported that root yield ranges from 14 -108 t ha -1 (Nielsen et al, 2000;Belford et al, 2001;Silva et al, 2016;Jean et al, 2017;Vasconcelos et al 2018). In contrast, we found up to 3.53 t ha -1 .…”

“…When cooked, they serve for preparing cakes and sweets (Silva et al, 2016). Root yield in research ranges from 14 -108 t ha -1 (Nielsen et al, 2000;Belford et al, 2001;Silva et al, 2016;Jean et al, 2017) and at a commercial level 40 -80; 25-65; 24 and 7-17 t ha -1 in Mexico, Thailand, Hawaii, and the Far East, respectively (Phillips-Mora et al, 1993). Its composition ranges from 78 to 94% moisture, 1.0 to 2.2% proteins, 0.0 to 0.8% lipids, 4.6 to 14.9% carbohydrates, 0.5 to 1.4% fibers, and 0.3 to 0.8% ash (Sorensen, 1996).…”