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51. Identification of QTLs Controlling Resistance to Anthracnose Disease in Water Yam (Dioscorea alata)

Author

Agre, Paterne Angelot, primary, Darkwa, Kwabena, additional, Olasanmi, Bunmi, additional, Kolade, Olufisayo, additional, Mournet, Pierre, additional, Bhattacharjee, Ranjana, additional, Lopez-Montes, Antonio, additional, De Koeyer, David, additional, Adebola, Patrick, additional, Kumar, Lava, additional, Asiedu, Robert, additional, and Asfaw, Asrat, additional

Published
2022
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52. Diversity of Water Yam (Dioscorea alata L.) Accessions from Côte d’Ivoire Based on SNP Markers and Agronomic Traits

Author

Bakayoko, Lassana, primary, Pokou, Désiré N’Da, additional, Kouassi, Abou Bakari, additional, Agre, Paterne A., additional, Kouakou, Amani Michel, additional, Dibi, Konan Evrard Brice, additional, Nzue, Boni, additional, Mondo, Jean M., additional, Adebola, Patrick, additional, Akintayo, Oluyemi T., additional, Asfaw, Asrat, additional, and N’Guetta, Assanvo Simon Pierre, additional

Published
2021
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56. Diversity of white Guinea yam (Dioscorea rotundataPoir.) cultivars from Benin as revealed by agro-morphological traits and SNP markers

Author

Agre, Paterne A., primary, Dassou, Anicet G., additional, Loko, Laura E. Y., additional, Idossou, Roger, additional, Dadonougbo, Eric, additional, Gbaguidi, Anicet, additional, Mondo, Jean M., additional, Muyideen, Yusuf, additional, Adebola, Patrick O., additional, Asiedu, Robert, additional, Dansi, Alexandre A., additional, and Asfaw, Asrat, additional

Published
2021
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58. Cytological and Molecular Characterization for Ploidy Determination in Yams (Dioscorea spp.)

Author

Gatarira, Cobes, primary, Sládeková, Lucia, additional, Němečková, Alžběta, additional, Šimoníková, Denisa, additional, Paliwal, Rajneesh, additional, Asfaw, Asrat, additional, Abberton, Michael, additional, Badara, Gueye, additional, Asiedu, Robert, additional, Čížková, Jana, additional, Hřibová, Eva, additional, Doležel, Jaroslav, additional, DeKoeyer, David, additional, Adetimirin, Victor, additional, and Bhattacharjee, Ranjana, additional

Published
2021
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59. Biomass production and nutrient use efficiency in white Guinea yam (Dioscorea rotundata Poir.) genotypes grown under contrasting soil mineral nutrient availability.

Author

Ryo Matsumoto, Asfaw, Asrat, Haruki Ishikawa, Kanako Takada, Hironobu Shiwachi, and Asiedu, Robert

Subjects
BIOMASS production, SOIL mineralogy, YAMS, GENOTYPES, SOIL fertility, SHIFTING cultivation, FERTILIZERS
Abstract

Yam (Dioscorea spp.) is of great importance to food security, especially in West Africa. However, the loss of soil fertility due to dwindling fallow lands with indigenous nutrient supply poses a challenge for yam cultivation. This study aimed to determine shoot and tuber biomass and nutrient use efficiency of white Guinea yam (Dioscorea rotundata) grown under low- and high-NPK conditions. Six white Guinea yam genotypes were used in field experiments conducted at Ibadan, Nigeria. Experiments were conducted with low soil NPK conditions with zero fertilizer input and high soil NPK conditions with mineral fertilizer input. Differences in response to soil NPK conditions, nutrient uptake, and nutrient use efficiency (apparent nutrient recovery efficiency) were observed among the tested genotypes. The genotypes TDr1499 and TDr1649, with high soil fertility susceptibility index (SFSI>1) and an increase in shoot and tuber biomass with fertilizer input, were recognized as susceptible to soil NPK conditions. There was a marked difference in apparent nutrient recovery efficiency; however, there was no varietal difference in physiological efficiency. Differences in apparent nutrient recovery efficiency among genotypes affected the fertilizer response (or susceptibility to soil NPK conditions) and the nutrient uptake. In contrast, the genotype TDr2029, with SFSI<1 and low reduction in shoot and tuber production between non-F and +F conditions, was recognized as a less susceptible genotype to soil NPK status. It was revealed that NPK fertilization did not reduce tuber dry matter content, regardless of genotype differences in susceptibility to soil NPK conditions. Hence, this could be helpful to farmers because it implies that yield can be increased without reducing tuber quality through a balanced application of soil nutrients. Our results highlight genotypic variation in sensitivity to the soil NPK availability, nutrient uptake, and nutrient use efficiency white Guinea yam. Differences in susceptibility to soil NPK conditions could be due to the genotypic variations in nutrient recovery efficiency white Guinea yam. Our findings could contribute to breeding programs for the development of improved white Guinea yam varieties that enhance productivity in low soil fertility conditions with low and high-input farming systems. [ABSTRACT FROM AUTHOR]

Published
2022
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62. sj-docx-1-oag-10.1177_00307270211058209 - Supplemental material for Yam seed system characteristics in Nigeria: Local practices, preferences, and the implications for seed system interventions

Author

Stuart, Esm��, Asfaw, Asrat, Adebola, Patrick, Maroya, Norbert, Edemodu, Alex, Adeosun, Tunde, Asiedu, Robert, and Almekinders, Conny

Subjects
Geography
Abstract

Supplemental material, sj-docx-1-oag-10.1177_00307270211058209 for Yam seed system characteristics in Nigeria: Local practices, preferences, and the implications for seed system interventions by Esm�� Stuart, Asrat Asfaw, Patrick Adebola, Norbert Maroya, Alex Edemodu, Tunde Adeosun, Robert Asiedu and Conny Almekinders in Outlook on Agriculture

Published
2021
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63. Additional file 1 of Identification of quantitative trait nucleotides and candidate genes for tuber yield and mosaic virus tolerance in an elite population of white guinea yam (Dioscorea rotundata) using genome-wide association scan

Author

Agre, Paterne A., Norman, Prince E., Asiedu, Robert, and Asfaw, Asrat

Abstract

Additional file 1: Supplementary Table 1. Description of trait progenitors utilized for the study. Supplementary Table 2. BLUP values of tuber yield per plant (TYP) and yam mosaic virus (YMV) among 406 clones of white yam. Supplementary Table 3. Cluster membership of 406 genotypes of white yam based on structure and phylogeny tree analyses. Supplementary Table 4. Single nucleotide polymorphism (SNP) markers associated with the yield per plant (TYP) and yam mosaic virus (YMV) and putative genes identified in chromosomes of 406 clones of white yam

Published
2021
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64. Yam seed system characteristics in Nigeria : Local practices, preferences, and the implications for seed system interventions

Author

Stuart, Esmé, Asfaw, Asrat, Adebola, Patrick, Maroya, Norbert, Edemodu, Alex, Adeosun, Tunde, Asiedu, Robert, Almekinders, Conny, Stuart, Esmé, Asfaw, Asrat, Adebola, Patrick, Maroya, Norbert, Edemodu, Alex, Adeosun, Tunde, Asiedu, Robert, and Almekinders, Conny

Abstract

Yam is an important food and cash crop in Nigeria. The seed system is mostly farmer-based and its challenges and opportunities are not well documented. This study reports results of surveys, interviews, focus group discussions and participant observations that describe local practices characterizing yam cultivation and the farmer-based seed system in five states in Nigeria. Our findings show that ware and seed yam are dynamic and highly commercialized goods in Nigeria. There is a high demand for, and a high turn-over of, seed yam. The reasons for the high demand are the low multiplication rate and degeneration of seed yam which lead farmers to frequently acquire fresh seeds and replace varieties, investing significantly in the seed of ware yam. The study found some farmers specializing in seed yam production but less than expected for such a highly commercial crop. The market is the major source for off-farm sourced seed yam, and although completely informal, the seed yam sector is vibrant and well organized. The identification of strategically positioned farmers and traders can offer opportunities and entry points for introduction of new varieties and improved seed production techniques. Building on the existing farmer-based system is a more logical strategy than replacing it with formal structures and legislative regulation.

Published
2021

68. Chromosome evolution and the genetic basis of agronomically important traits in greater yam

Author

Bredeson, Jessen V., primary, Lyons, Jessica B., additional, Oniyinde, Ibukun O., additional, Okereke, Nneka R., additional, Kolade, Olufisayo, additional, Nnabue, Ikenna, additional, Nwadili, Christian O., additional, Hřibová, Eva, additional, Parker, Matthew, additional, Nwogha, Jeremiah, additional, Shu, Shengqiang, additional, Carlson, Joseph, additional, Kariba, Robert, additional, Muthemba, Samuel, additional, Knop, Katarzyna, additional, Barton, Geoffrey J., additional, Sherwood, Anna V., additional, Lopez-Montes, Antonio, additional, Asiedu, Robert, additional, Jamnadass, Ramni, additional, Muchugi, Alice, additional, Goodstein, David, additional, Egesi, Chiedozie N., additional, Featherston, Jonathan, additional, Asfaw, Asrat, additional, Simpson, Gordon G., additional, Doležel, Jaroslav, additional, Hendre, Prasad S., additional, Van Deynze, Allen, additional, Kumar, Pullikanti Lava, additional, Obidiegwu, Jude E., additional, Bhattacharjee, Ranjana, additional, and Rokhsar, Daniel S., additional

Published
2021
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70. Sample Preservation and Plant Sex Prediction in White Guinea Yam (Dioscorea rotundata Poir.) Seedlings

Author

Asfaw, Asrat, Agre, Paterne, Nwachukwu, Chidinma, Olasanmi, Bunmi, Obidiegwu, Jude, Nwachukwu, Emmanuel, Adebola, Patrick, and Koeyer, David De

Subjects
fungi, food and beverages, plant_sciences
Abstract

Methods for high-quality DNA extraction and knowledge of sex expression and flowering time are essential for applying genomic-assisted breeding and improve the success with hybridization in Guinea yam. A dioecious or monoecious pattern of flowering and sometimes non-flowering is a common phenomenon within and between the Dioscorea species. The flowering in yam plants raised from botanical seeds often takes an extended period, mostly till the first clonal generation after propagation from the tubers. The prolonged process of testing required to identify plant sex and flowering intensity in yam breeding often poses a challenge to realize reduced breeding cycle and apply genomic selection. This study assessed sample preservation methods for DNA quality during extraction and potential of DNA marker to diagnose plant sex at the early seedling stage in white Guinea yam. The predicted sex at the seedling stage was further validated with the visual score for the sex phenotype at the flowering stage. DNA extracted from leaf samples preserved in liquid nitrogen, silica gel, dry ice, and oven drying methods was similar in quality with a high molecular weight than samples stored in ethanol solution. Yam plant sex diagnosis with the DNA marker (sp16) identified a higher proportion of ZW genotypes (female or monoecious phenotypes) than the ZZ genotypes (male phenotype) in the studied materials with 74% prediction accuracy. The results from this study provided valuable insights on suitable sample preservation methods for quality DNA extraction and the potential of DNA marker sp16 to predict sex in white Guinea yam.

Published
2020

78. Genome analyses reveal the hybrid origin of the staple food crop white Guinea yam

Author

Sugihara, Yu, primary, Darkwa, Kwabena, additional, Yaegashi, Hiroki, additional, Natsume, Satoshi, additional, Shimizu, Motoki, additional, Abe, Akira, additional, Hirabuchi, Akiko, additional, Ito, Kazue, additional, Oikawa, Kaori, additional, Tamiru-Oli, Muluneh, additional, Ohta, Atsushi, additional, Matsumoto, Ryo, additional, Paterne, Agre, additional, De Koeyer, David, additional, Pachakkil, Babil, additional, Yamanaka, Shinsuke, additional, Muranaka, Satoru, additional, Takagi, Hiroko, additional, White, Ben, additional, Asiedu, Robert, additional, Innan, Hideki, additional, Asfaw, Asrat, additional, Adebola, Patrick, additional, and Terauchi, Ryohei, additional

Published
2020
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79. A SNP-Based Linkage Map and QTL Identification for Resistance to Yam Anthracnose Disease (YAD) in Water Yam (Dioscorea alata)

Author

Darkwa, Kwabena, primary, AGRE, Paterne, additional, Olasanmi, Bunmi, additional, Kolade, Olufisayo, additional, Mournet, Pierre, additional, Lopez-Montes, Antonio, additional, Dekoeyer, David, additional, Adebola, Patrick, additional, Kumar, Lava P., additional, Asiedu, Robert, additional, and Asfaw, Asrat, additional

Published
2020
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83. Production of hybrid seeds by intraspecific crossing in yam Dioscorea alata L

Author

Ehounou, Adou Emmanuel, Kouakou, A.M., N'zi, J.C., Dibi, K.B.E., Bakayoko, Y., Essis, B.S., N'Zue, Boni, Arnau, Gemma, Maledon, Erick, Asfaw, Asrat, Adebola, P., and N'Guetta, Assanvo Simon-Pierre

Subjects
clone, Graine, food and beverages, F30 - Génétique et amélioration des plantes, Dioscorea alata, Fruit, Hybridation intraspécifique, Croisement
Abstract

Manual crosses were carried out over two successive years on Dioscorea alata for the production of hybrid seeds between five females and seven males' parents with contrasting characteristics. A total of 22951 flowers were manually pollinated in both years (14145 in 2016 and 8806 in 2017) in 33 parental combinations. The ploidy levels of the parents were determined by flow cytometry. The crossed parents were all diploids except the female OA49 which was triploid. In both years the fruiting and seed rates were comparable (25.06% and 22.82%; 30.05% and 30.18%). A significant variation in fruiting rates was observed between the different parental combinations. Analysis of variance have shown that there is both a male effect on the fruit setting. The lowest rates were observed in combinations involving male clones 23 and Ma01 (2.04% and 2.77%) and the highest rates involved males TDa00/00128 and TDa00/00095 (48.25% and 33.91%). The triploid female OA49 is sterile. Females TDa01/00003, TDa01/00018, TDa99/00240 and TDa01/00295 gave comparable fruiting rates which are respectively (37.87%, 29.38%, 24.70% and 20.92%). For seeds production, there is no male and female effect. The fruiting rate according to the time slot depends on each male variety involved. For some males, the fruiting rate is influenced by the time slot of pollination while for others, there is no time slot effect on the fruiting rate.

Published
2019

84. Diversity of white Guinea yam (Dioscorea rotundata Poir.) cultivars from Benin as revealed by agro-morphological traits and SNP markers.

Author

Agre, Paterne A., Dassou, Anicet G., Loko, Laura E. Y., Idossou, Roger, Dadonougbo, Eric, Gbaguidi, Anicet, Mondo, Jean M., Muyideen, Yusuf, Adebola, Patrick O., Asiedu, Robert, Dansi, Alexandre A., and Asfaw, Asrat

Subjects
YAMS, SINGLE nucleotide polymorphisms, GENETIC variation, CULTIVARS, GERMPLASM, PHENOTYPIC plasticity
Abstract

White Guinea yam (Dioscorea rotundata Poir.) is indigenous to West Africa, a region that harbours the crop's tremendous landrace diversity. The knowledge and understanding of local cultivars' genetic diversity are essential for properly managing genetic resources, conservation, sustainable use and their improvement through breeding. This study aimed to dissect phenotypic and molecular diversity of white yam cultivars from Benin using agro-morphological and single nucleotide polymorphism (SNP) markers. Eighty-eight Beninese white Guinea yam cultivars collected through a countrywide ethnobotanical survey were phenotyped with 53 traits and genotyped with 9725 DArT-SNP. Multivariate analysis using phenotypic traits revealed 30 traits as most discriminative and explained up to 80.78% of cultivars' phenotypic variation. Assessment of diversity indices such as Shannon–Wiener (H′), inverse Shannon (H.B.), Simpson's (λ) index and Pilou evenness (J) based molecular and phenotypic data depicted a moderate genetic diversity in Beninese white Guinea yam cultivars. Genetic differentiation of cultivars among country production zones was low due to the high exchange of planting materials among farmers of different regions. However, there was high genetic diversity within regions. Hierarchical clusters (HCs) on phenotypic data revealed the presence of two groups while HCs based on the SNP markers and the combined analysis identified three genetic groups. Our result provided valuable insights into the Beninese white Guinea yam diversity for its proper conservation and improvement through breeding. [ABSTRACT FROM AUTHOR]

Published
2021
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85. Yam Cropping System in Cote d’Ivoire: Current Practices and Constraints

Author

Kouakou, Amani Michel, primary, Yao, Guy Fernand, additional, Brice Dibi, Konan Evrard, additional, Mahyao, Adolphe, additional, Lopez-Montes, Antonio, additional, Essis, Brice Sidoine, additional, N’zue, Boni, additional, Kouamé, Brou, additional, Adebola, Patrick Olusanmi, additional, Asfaw, Asrat, additional, and Asiedu, Robert, additional

Published
2019
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89. Genetic parameters, prediction, and selection in a white Guinea yam early‐generation breeding population using pedigree information.

Author

Asfaw, Asrat, Aderonmu, Dotun Samuel, Darkwa, Kwabena, De Koeyer, David, Agre, Paterne, Abe, Ayodeji, Olasanmi, Bunmi, Adebola, Patrick, and Asiedu, Robert

Subjects
*YAMS, *MOSAIC viruses, *GENOTYPES, *GENEALOGY, *FORECASTING, *TUBERS
Abstract

Better understanding of the genetic control of traits in breeding populations is crucial for the selection of superior varieties and parents. This study aimed to assess genetic parameters and breeding values for six essential traits in a white Guinea yam (Dioscorea rotundata Poir.) breeding population. For this, pedigree‐based best linear unbiased prediction (P‐BLUP) was used. The results revealed significant nonadditive genetic variances and medium to high (.45–.79) broad‐sense heritability estimates for the traits studied. The pattern of associations among the genetic values of the traits suggests that selection based on a multiple‐trait selection index has potential for identifying superior breeding lines. Parental breeding values predicted using progeny performance identified 13 clones with high genetic potential for simultaneous improvement of the measured traits in the yam breeding program. Subsets of progeny were identified for intermating or further variety testing based on additive genetic and total genetic values. Selection of the top 5% progenies based on the multi‐trait index revealed positive genetic gains for fresh tuber yield (t ha−1), tuber yield (kg plant−1), and average tuber weight (kg). However, genetic gain was negative for tuber dry matter content and Yam mosaic virus resistance in comparison with standard varieties. Our results show the relevance of P‐BLUP for the selection of superior parental clones and progenies with higher breeding values for interbreeding and higher genotypic value for variety development in yam. [ABSTRACT FROM AUTHOR]

Published
2021
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90. Review of empirical and emerging breeding methods and tools for yam (Dioscorea spp.) improvement: Status and prospects.

Author

Darkwa, Kwabena, Olasanmi, Bunmi, Asiedu, Robert, Asfaw, Asrat, and Léon, Jens

Subjects
YAMS, TUBER crops, FUNCTIONAL foods, NUCLEOTIDE sequencing, TUBERS, TECHNOLOGICAL innovations
Abstract

Yam (Dioscorea spp.) is an important tuber crop with tremendous potential as a functional food in the tropics and subtropics. However, the crop has not shown progressive productivity gain over decades due to various production constraints. This paper reviews the progress achieved in empirical breeding endeavours and the development, status and application of emerging breeding tools and technologies to translate genetic gains in yam improvement. Significant progress has been made in yam genetic improvement over the years which has led to the identification and development of several improved clones and sources of variability for various economically important traits. Substantial efforts have also been made to develop diverse molecular markers, transcriptome and metabolome profiles of crucial traits, trait mapping and generate reference genome sequences of the key species. However, there seems to be a slow translation of research improvements into widespread applications. These advances and the integration of empirical and emerging methods and technologies into the breeding process will enhance yam breeding efforts and ensure the quick delivery of improved varieties that possess superior agronomic and quality traits. [ABSTRACT FROM AUTHOR]

Published
2020
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92. Genomics-Assisted Breeding in the CGIAR Research Program on Roots, Tubers and Bananas (RTB)

Author

Friedmann, Michael, primary, Asfaw, Asrat, additional, Anglin, Noelle, additional, Becerra, Luis, additional, Bhattacharjee, Ranjana, additional, Brown, Allan, additional, Carey, Edward, additional, Ferguson, Morag, additional, Gemenet, Dorcus, additional, Lindqvist-Kreuze, Hanele, additional, Rabbi, Ismail, additional, Rouard, Mathieu, additional, Swennen, Rony, additional, and Thiele, Graham, additional

Published
2018
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