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Bapela T, Shimelis H, Tsilo TJ, Mathew I. Genetic Improvement of Wheat for Drought Tolerance: Progress, Challenges and Opportunities. Plants (Basel) 2022; 11:1331. [PMID: 35631756 PMCID: PMC9144332 DOI: 10.3390/plants11101331] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/27/2022] [Accepted: 05/04/2022] [Indexed: 06/01/2023]
Abstract
Wheat production and productivity are challenged by recurrent droughts associated with climate change globally. Drought and heat stress resilient cultivars can alleviate yield loss in marginal production agro-ecologies. The ability of some crop genotypes to thrive and yield in drought conditions is attributable to the inherent genetic variation and environmental adaptation, presenting opportunities to develop drought-tolerant varieties. Understanding the underlying genetic, physiological, biochemical, and environmental mechanisms and their interactions is key critical opportunity for drought tolerance improvement. Therefore, the objective of this review is to document the progress, challenges, and opportunities in breeding for drought tolerance in wheat. The paper outlines the following key aspects: (1) challenges associated with breeding for adaptation to drought-prone environments, (2) opportunities such as genetic variation in wheat for drought tolerance, selection methods, the interplay between above-ground phenotypic traits and root attributes in drought adaptation and drought-responsive attributes and (3) approaches, technologies and innovations in drought tolerance breeding. In the end, the paper summarises genetic gains and perspectives in drought tolerance breeding in wheat. The review will serve as baseline information for wheat breeders and agronomists to guide the development and deployment of drought-adapted and high-performing new-generation wheat varieties.
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Affiliation(s)
- Theresa Bapela
- African Centre for Crop Improvement, University of Kwa-Zulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa; (H.S.); (I.M.)
- Agricultural Research Council—Small Grain, Bethlehem 9700, South Africa;
| | - Hussein Shimelis
- African Centre for Crop Improvement, University of Kwa-Zulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa; (H.S.); (I.M.)
| | - Toi John Tsilo
- Agricultural Research Council—Small Grain, Bethlehem 9700, South Africa;
| | - Isack Mathew
- African Centre for Crop Improvement, University of Kwa-Zulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa; (H.S.); (I.M.)
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Nkhata W, Shimelis H, Melis R, Chirwa R, Mzengeza T, Mathew I, Shayanowako A. Genome-wide association analysis of bean fly resistance and agro-morphological traits in common bean. PLoS One 2021; 16:e0250729. [PMID: 33914796 PMCID: PMC8084209 DOI: 10.1371/journal.pone.0250729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 04/12/2021] [Indexed: 11/19/2022] Open
Abstract
The bean fly (Ophiomyia spp) is a key insect pest causing significant crop damage and yield loss in common bean (Phaseolus vulgaris L., 2n = 2x = 22). Development and deployment of agronomic superior and bean fly resistant common bean varieties aredependent on genetic variation and the identification of genes and genomic regions controlling economic traits. This study's objective was to determine the population structure of a diverse panel of common bean genotypes and deduce associations between bean fly resistance and agronomic traits based on single nucleotide polymorphism (SNP) markers. Ninety-nine common bean genotypes were phenotyped in two seasons at two locations and genotyped with 16 565 SNP markers. The genotypes exhibited significant variation for bean fly damage severity (BDS), plant mortality rate (PMR), and pupa count (PC). Likewise, the genotypes showed significant variation for agro-morphological traits such as days to flowering (DTF), days to maturity (DTM), number of pods per plant (NPP), number of seeds per pod (NSP), and grain yield (GYD). The genotypes were delineated into two populations, which were based on the Andean and Mesoamerican gene pools. The genotypes exhibited a minimum membership coefficient of 0.60 to their respective populations. Eighty-three significant (P<0.01) markers were identified with an average linkage disequilibrium of 0.20 at 12Mb across the 11 chromosomes. Three markers were identified, each having pleiotropic effects on two traits: M100049197 (BDS and NPP), M3379537 (DTF and PC), and M13122571 (NPP and GYD). The identified markers are useful for marker-assisted selection in the breeding program to develop common bean genotypes with resistance to bean fly damage.
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Affiliation(s)
- Wilson Nkhata
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
- * E-mail:
| | - Hussein Shimelis
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Rob Melis
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Rowland Chirwa
- Alliance of Biodiversity International and CIAT, Chitedze Agricultural Station, Lilongwe, Malawi
| | - Tenyson Mzengeza
- Department of Agricultural Research Service, Chitedze Agricultural Research Station, Lilongwe, Malawi
| | - Isack Mathew
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
| | - Admire Shayanowako
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Scottsville, Pietermaritzburg, South Africa
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Gerrano AS, Mathew I, Shayanowako AI, Amoo S, Mellem JJ, Van Rensburg WJ, Bairu MW, Venter SL. Variation in mineral element composition of landrace taro ( Colocasia esculenta) corms grown under dryland farming system in South Africa. Heliyon 2021; 7:e06727. [PMID: 33869880 PMCID: PMC8045039 DOI: 10.1016/j.heliyon.2021.e06727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/07/2021] [Accepted: 04/01/2021] [Indexed: 11/01/2022] Open
Abstract
Taro [Colocasia esculenta (L.) Schott] has the potential to address food and nutrition insecurity in sub-Saharan Africa. However, the nutrient content of taro is yet to be fully elucidated. The objective of this study was to evaluate mineral element content as a proxy for nutritional value of different taro genotypes. The study evaluated 14 taro accessions at Roodeplaat and Umbumbulu in South Africa based on their calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorous (P) and zinc (Zn) content. The accessions were planted in a randomized complete block design, replicated three times under field conditions. The mineral element content varied significantly (p < 0.05) among the genotypes. Genotypes Amad7-2, Umbu8 and Amad101 exhibited high Ca (≥432 mg kg-1), Fe (≥32 mg kg-1) and Mg (≥229 mg kg-1) across the locations. The first principal component (PC) accounted for 33.7% of the variation and was strongly associated with Zn (r = 0.94, p < 0.001) and P (r = 0.89, p < 0.001). The second PC explained 29.7% of the variation and was associated with Na (r = 0.83, p < 0.001), Mg (r = 0.76, p < 0.001) and K (r = 0.55, p < 0.05). Fe and Mn contributed below the 12.5% threshold to the PCs and were considered as less discriminatory among the accessions. The negative correlations among some of the mineral elements would be a challenge for selection and breeding of nutritious taro accessions. This information is essential to select superior local accessions based on their mineral element content for developing breeding populations and lines for improving nutrition quality among poor households in sub-Saharan Africa.
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Affiliation(s)
- Abe Shegro Gerrano
- Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa.,Faculty of Natural and Agricultural Sciences, School of Agricultural Sciences, Crop Science Department, North-West University, Private Bag X2046, Mmabatho, 2790, South Africa
| | - Isack Mathew
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
| | - Admire It Shayanowako
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
| | - Stephen Amoo
- Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa.,Department of Botany and Plant Biotechnology, Faculty of Science, University of Johannesburg, Auckland Park Kingsway Campus, South Africa.,Indigenous Knowledge Systems Centre, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2790, South Africa
| | - John Jason Mellem
- Department of Biotechnology and Food Technology, Durban University of Technology, PO Box 1334, Durban 4000, South Africa
| | - Willem Jansen Van Rensburg
- Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa
| | - Michael Wolday Bairu
- Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa
| | - Sonja Louise Venter
- Agricultural Research Council-Vegetables, Industrial and Medicinal Plants, Private Bag X293, Pretoria 0001, South Africa
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Kisten L, Tolmay VL, Mathew I, Sydenham SL, Venter E. Genome-wide association analysis of Russian wheat aphid (Diuraphis noxia) resistance in Dn4 derived wheat lines evaluated in South Africa. PLoS One 2020; 15:e0244455. [PMID: 33370360 PMCID: PMC7769470 DOI: 10.1371/journal.pone.0244455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/09/2020] [Indexed: 11/18/2022] Open
Abstract
Russian wheat aphid (RWA; Diuraphis noxia Kurdjumov) resistance on the 1D chromosome of wheat has been the subject of intensive research. Conversely, the deployment of the Dn4 derived RWA resistant varieties diminished in recent years due to the overcoming of the resistance it imparts in the United States of America. However, this resistance has not been deployed in South Africa despite reports that Dn4 containing genotypes exhibited varying levels of resistance against the South African RWA biotypes. It is possible that there may be certain genetic differences within breeding lines or cultivars that influence the expression of resistance. The aim of this study was to identify single nucleotide polymorphism (SNP) markers associated with resistance to South African RWA biotypes. A panel of thirty-two wheat lines were phenotyped for RWA resistance using four South African RWA biotypes and a total of 181 samples were genotyped using the Illumina 9K SNP wheat chip. A genome wide association study using 7598 polymorphic SNPs showed that the population was clustered into two distinct subpopulations. Twenty-seven marker trait associations (MTA) were identified with an average linkage disequilibrium of 0.38 at 10 Mbp. Four of these markers were highly significant and three correlated with previously reported quantitative trait loci linked to RWA resistance in wheat. Twenty putative genes were annotated using the IWGSC RefSeq, three of which are linked to plant defence responses. This study identified novel chromosomal regions that contribute to RWA resistance and contributes to unravelling the complex genetics that control RWA resistance in wheat.
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Affiliation(s)
- Lavinia Kisten
- Germplasm Development, ARC-Small Grain, Bethlehem, Free State, South Africa
- Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, Gauteng, South Africa
- * E-mail: (LK); (VLT)
| | - Vicki L. Tolmay
- Germplasm Development, ARC-Small Grain, Bethlehem, Free State, South Africa
- * E-mail: (LK); (VLT)
| | - Isack Mathew
- School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, KwaZulu-Natal, South Africa
| | - Scott L. Sydenham
- LongReach Plant Breeders Management Pty Ltd, York, Western Australia, Australia
| | - Eduard Venter
- Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, Gauteng, South Africa
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Nkhata W, Shimelis H, Melis R, Chirwa R, Mzengeza T, Mathew I, Shayanowako A. Population structure and genetic diversity analyses of common bean germplasm collections of East and Southern Africa using morphological traits and high-density SNP markers. PLoS One 2020; 15:e0243238. [PMID: 33338076 PMCID: PMC7748271 DOI: 10.1371/journal.pone.0243238] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/18/2020] [Indexed: 11/19/2022] Open
Abstract
Knowledge of genetic diversity in plant germplasm and the relationship between genetic factors and phenotypic expression is vital for crop improvement. This study's objectives were to understand the extent of genetic diversity and population structure in 60 common bean genotypes from East and Southern Africa. The common bean genotypes exhibited significant (p<0.05) levels of variability for traits such as days to flowering (DTF), days to maturity (DTM), number of pods per plant (NPP), number of seeds per pod (NSP), and grain yield per hectare in kilograms (GYD). About 47.82 per cent of the variation among the genotypes was explained by seven principal components (PC) associated with the following agronomic traits: NPP, NFF (nodes to first flower), DTF, GH (growth habit) and GYD. The SNP markers revealed mean gene diversity and polymorphic information content values of 0.38 and 0.25, respectively, which suggested the presence of considerable genetic variation among the assessed genotypes. Analysis of molecular variance showed that 51% of the genetic variation were between the gene pools, while 49% of the variation were within the gene pools. The genotypes were delineated into two distinct groups through the population structure, cluster and phylogenetic analyses. Genetically divergent genotypes such as DRK57, MW3915, NUA59, and VTTT924/4-4 with high yield and agronomic potential were identified, which may be useful for common bean improvement.
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Affiliation(s)
- Wilson Nkhata
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Hussein Shimelis
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Rob Melis
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Rowland Chirwa
- International Centre for Tropical Agriculture, Chitedze Agricultural Research Station, Lilongwe, Malawi
| | - Tenyson Mzengeza
- Department of Agricultural Research Service, Chitedze Agricultural Research Station, Lilongwe, Malawi
| | - Isack Mathew
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Admire Shayanowako
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
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Nkhoma N, Shimelis H, Laing MD, Shayanowako A, Mathew I. Assessing the genetic diversity of cowpea [Vigna unguiculata (L.) Walp.] germplasm collections using phenotypic traits and SNP markers. BMC Genet 2020; 21:110. [PMID: 32948123 PMCID: PMC7501654 DOI: 10.1186/s12863-020-00914-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/31/2020] [Indexed: 02/08/2023] Open
Abstract
Background Productivity of cowpea [Vigna unguiculata (L.) Walp] in sub-Sahara Africa is curtailed by a lack of farmer-preferred and improved cultivars and modern production technologies. The objectives of the study were to determine the extent of genetic diversity present among a collection of cowpea accessions from Zambia and Malawi using phenotypic traits and single nucleotide polymorphism (SNP) markers and, to select distinct and complementary parental lines for cultivar development. One hundred cowpea genotypes were evaluated for agronomic traits in two selected sites in Zambia, using a 10 × 10 alpha lattice design with two replications. Ninety-four of the test genotypes were profiled with 14,116 SNP markers. Results Number of pods plant− 1 (NPP), pod length (PDL), and number of seeds pod− 1 (NSP), were significantly (p < 0.05) affected by genotype × environment interaction effects. Genotypes such as CP411, CP421, CP645, CP732, Chimponongo, and MS1–8–1-4 exhibited higher grain yield of > 1200 kg/ha with excellent performance in yield components such as NSP, PDL, HSW and GYD. Grain yield had significant (p < 0.05) associations with NPP (r = 0.50), NSP (r = 0.46) and PDL (r = 0.42) useful for simultaneous selection for yield improvement in cowpea. The SNP markers revealed gene diversity and polymorphic information content of 0.22 and 0.17, respectively, showing that the tested cowpea accessions were genetically diverse. Test genotypes were classified into four genetic groups irrespective of source of collection allowing selection and subsequent crosses to develop breeding populations for cultivar development. Conclusions Genotypes Bubebe, CP411, CP421, CP645, Chimponogo and MS1–8–1-4 were identified to be the most genetically divergent and high yielding making them ideal parental lines for breeding. This study provided a baseline information and identified promising cowpea genetic resources for effective breeding and systematic conservation.
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Affiliation(s)
- Nelia Nkhoma
- African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.,Seed Control and Certification Institute, P. O. Box 350199, Chilanga, Lusaka, Zambia
| | - Hussein Shimelis
- African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Mark D Laing
- African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Admire Shayanowako
- African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
| | - Isack Mathew
- African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa.
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Daudi H, Shimelis H, Mathew I, Oteng‐Frimpong R, Ojiewo C, Varshney RK. Genetic diversity and population structure of groundnut ( Arachis hypogaea L.) accessions using phenotypic traits and SSR markers: implications for rust resistance breeding. Genet Resour Crop Evol 2020; 68:581-604. [PMID: 33505123 PMCID: PMC7811514 DOI: 10.1007/s10722-020-01007-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 08/30/2020] [Indexed: 05/27/2023]
Abstract
Groundnut (Arachis hypogaea L.) is a multi-purpose legume serving millions of farmers and their value chain actors globally. Use of old poor-performing cultivars contributes to low yields (< 1 t/ha) of groundnut in sub-Saharan Africa including Tanzania. The objectives of this study were to determine the extent of genetic variation among diverse groundnut collections using phenotypic traits and simple sequence repeat (SSR) markers to select distinct and complementary genotypes for breeding. One hundred and nineteen genotypes were evaluated under field conditions for agronomic traits and susceptibility to rust and leaf spot diseases. The study was conducted in two locations across two seasons. In addition, the 119 accessions were profiled with 13 selected SSR markers. Genotype and genotype by environment interaction effects were significant (p < 0.05) for days to flowering (DTF), late leaf spot score at 85 and 100 days after planting, pod yield (PDY), kernel yield (KY), hundred seed weight (HSW) and shelling percentage (SP). Principal components analysis revealed that plant stand, KY, SP, NPP (number of pods per plant), late leaf spot and rust disease scores accounted for the largest proportion of the total variation (71.9%) among the tested genotypes. Genotypes ICGV-SM 08587 and ICGV-SM 16579 had the most stable yields across the test environments. Moderate genetic variation was recorded with mean polymorphic information content of 0.34 and gene diversity of 0.63 using the SSR markers. The majority (74%) of genotypes showed high membership coefficients to their respective sub-populations, while 26% were admixtures after structure analysis. Much of the variation (69%) was found within populations due to genotypic differences. The present study identified genotypes ICGV-SM 06737, ICGV-SM 16575, ICG 12725 and ICGV-SM 16608 to be used for development of mapping population, which will be useful for groundnut improvement. This study provided a baseline information on characterization and selection of a large sample of groundnut genotypes in Tanzania for effective breeding and systematic conservation.
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Affiliation(s)
- Happy Daudi
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa
- Tanzania Agricultural Research Institute-Naliendele, P.O. Box 509, Mtwara, Tanzania
| | - Hussein Shimelis
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Isack Mathew
- African Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | | | - Chris Ojiewo
- International Crops Research Institute for the Semi-Arid Tropics, Nairobi, Kenya
| | - Rajeev K. Varshney
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
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Mathew I, Shimelis H, Shayanowako AIT, Laing M, Chaplot V. Genome-wide association study of drought tolerance and biomass allocation in wheat. PLoS One 2019; 14:e0225383. [PMID: 31800595 PMCID: PMC6892492 DOI: 10.1371/journal.pone.0225383] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/04/2019] [Indexed: 11/18/2022] Open
Abstract
Genome wide association studies (GWAS) are important in discerning the genetic architecture of complex traits such as biomass allocation for improving drought tolerance and carbon sequestration potential of wheat. The objectives of this study were to deduce the population structure and marker-trait association for biomass traits in wheat under drought-stressed and non-stressed conditions. A 100-wheat (Triticum aestivum L.) genotype panel was phenotyped for days to heading (DTH), days to maturity (DTM), shoot biomass (SB), root biomass (RB), root to shoot ratio (RS) and grain yield (GY). The panel was sequenced using 15,600 single nucleotide polymorphism (SNPs) markers and subjected to genetic analysis using the compressed mixed linear model (CMLM) at false discovery rate (FDR < 0.05). Population structure analysis revealed six sub-clusters with high membership ancestry coefficient of ≤0.65 to their assigned sub-clusters. A total of 75 significant marker-trait associations (MTAs) were identified with a linkage disequilibrium threshold of 0.38 at 5cM. Thirty-seven of the MTAs were detected under drought-stressed condition and 48% were on the B genome, where most quantitative trait loci (QTLs) for RB, SB and GY were previously identified. There were seven pleiotropic markers for RB and SB that may facilitate simultaneous selection. Thirty-seven putative candidate genes were mined by gene annotation on the IWGSC RefSeq 1.1. The significant MTAs observed in this study will be useful in devising strategies for marker-assisted breeding for simultaneous improvement of drought tolerance and to enhance C sequestration capacity of wheat.
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Affiliation(s)
- Isack Mathew
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
- * E-mail:
| | - Hussein Shimelis
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
| | - Admire Isaac Tichafa Shayanowako
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
| | - Mark Laing
- African Centre for Crop Improvement, University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
| | - Vincent Chaplot
- University of KwaZulu-Natal, School of Agricultural, Earth and Environmental Sciences, Pietermaritzburg, South Africa
- Sorbonne Universities, UPMC, IRD, CNRS, MNHN, Laboratoire d’Océanographie et du Climat: Expérimentations et approches numériques (LOCEAN), IPSL, Paris, France
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Mathew I, Hassan KM. Disseminated tuberculosis with ocular tuberculoma and disseminated candidiasis in acquired immunodeficiency syndrome. J Assoc Physicians India 2001; 49:841-2. [PMID: 11837479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
A 39 years man presented with painless progressive loss of vision and proptosis of left eye associated with constitutional symptoms. He was diagnosed to have acquired immunodeficiency syndrome (AIDS) with disseminated tuberculosis (TB) and invasive candidiasis. The proptosis was due to a retrobulbar mass. The uncommon occurrence of retrobulbar tuberculoma and invasive candidiasis is discussed and relevant literature is reviewed.
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Affiliation(s)
- I Mathew
- Department of Medicine, Armed Forces Medical College, Pune
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Mathew I, Hassan KM. Neurocysticercosis presenting as reversible parkinsonian syndrome. J Assoc Physicians India 2001; 49:288-9. [PMID: 11225151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- I Mathew
- Department of Medicine, Armed Forces Medical College, Pune 411 040
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Hassan KM, Mathew I. Guillain Barre' syndrome--in an HIV seropositive subject. J Assoc Physicians India 2000; 48:1214. [PMID: 11280235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Affiliation(s)
- K M Hassan
- Department of Medicine, AFMC, Pune-411 040
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Mathew I, Hassan KM. Tuberculous peritonitis--an uncommon presentation. J Assoc Physicians India 2000; 48:1135. [PMID: 11310407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Mathew I, Sharma SK. Human leptin deficiency and resistance. J Assoc Physicians India 2000; 48:1032. [PMID: 11200911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Hassan KM, Mathew I. Neurocysticercosis presenting as chronic meningitis. J Assoc Physicians India 2000; 48:940. [PMID: 11198809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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Kashyap AS, Mathew I. ACE inhibitors and angioedema. Postgrad Med J 1999; 75:189. [PMID: 10448511 PMCID: PMC1741165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Abstract
Poly(N,N-disubstituted) acrylamides with both hydrophilic and hydrophobic groups as substituents were synthesized. Different degrees of hydrophilicity were achieved by varying the bulk of the hydrophobic substituent. N-alkyl, N-(2-hydroxyethyl) acrylamides with alkyl substituents propyl (PROPAAm), octyl (OCTAAm) and benzyl (BENAAm) were synthesized. The swelling capacity of the polymers decreased with increase in bulk of the hydrophobic substituent. In vitro studies showed that the surfaces of these polymers did not induce platelet aggregation. Cell compatibility of these polymers was assessed by following the growth of human umbilical cord fibroblast cells. Pronounced cell growth and spreading was observed on the surfaces of polyOCTAAm and polyBENAAm. The relatively low cell growth on polyPROPAAm was ascribed to its high water content.
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Affiliation(s)
- I Mathew
- Department of Bio-engineering, Research Institute for Polymers and Textiles, Ibaraki, Japan
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