International Center for Maize and Wheat Improvement

El Barrancón del Tío Blas (El Barrancón), Mexico

International Center for Maize and Wheat Improvement

El Barrancón del Tío Blas (El Barrancón), Mexico
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Trucillo Silva I.,Iowa State University | Abbaraju H.K.R.,DuPont Pioneer | Abbaraju H.K.R.,Fountain | Fallis L.P.,DuPont Pioneer | And 5 more authors.
Theoretical and Applied Genetics | Year: 2017

Key message: Aside from the identification of 32 QTL for N metabolism in the seedling leaves of a maize testcross population, alanine aminotransferase was found to be a central enzyme in N assimilation. Abstract: Excessive application of nitrogen (N) fertilizer to grow commercial crops like maize is a cause of concern because of the runoff of excess N into streams and rivers. Breeding maize with improved N use efficiency (NUE) would reduce environmental pollution as well as input costs for the farmers. An understanding of the genetics underlying N metabolism is key to breeding for NUE. From a set of 176 testcrosses derived from the maize IBMsyn10 population grown in hydroponics, we analyzed the youngest fully expanded leaf at four-leaf stage for enzymes and metabolites related to N metabolism. Three enzymes, along with one metabolite explained 24% of the variation in shoot dry mass. Alanine aminotransferase (AlaAT) stood out as the key enzyme in maintaining the cellular level of glutamate as it alone explained 58% of the variation in this amino acid. Linkage mapping revealed 32 quantitative trait loci (QTL), all trans to the genomic positions of the structural genes for various enzymes of N assimilation. The QTL models for different traits accounted for 7–31% of the genetic variance, whereas epistasis was generally not significant. Five coding regions underlying 1-LOD QTL confidence intervals were identified for further validation studies. Our results provide evidence for the key role of AlaAT in N assimilation likely through homeostatic control of glutamate levels in the leaf cells. The two QTL identified for this enzyme would help to select desirable recombinants for improved N assimilation. © 2017 Springer-Verlag Berlin Heidelberg

Alo F.,International Center for Agriculture in the Dry Areas | Furman B.J.,University of California at Davis | Furman B.J.,International Center for Maize and Wheat Improvement | Akhunov E.,University of California at Davis | And 3 more authors.
Journal of Heredity | Year: 2011

Advances in comparative genomics have provided significant opportunities for analysis of genetic diversity in species with limited genomic resources, such as the genus Lens. Medicago truncatula expressed sequence tags (ESTs) were aligned with the Arabidopsis thaliana genome sequence to identify conserved exon sequences and splice sites in the ESTs. Conserved primers (CPs) based on M. truncatula EST sequences flanking one or more introns were then designed. A total of 22% of the CPs produced polymerase chain reaction amplicons in lentil and were used to sequence amplicons in 175 wild and 133 domesticated lentil accessions. Analysis of the sequences confirmed that L. nigricans and L. ervoides are well-defined species at the DNA sequence level. Lens culinaris subsp. odemensis, L. culinaris subsp. tomentosus, and L. lamottei may constitute a single taxon pending verification with crossability experiments. Lens culinaris subsp. orientalis is the progenitor of domesticated lentil, L. culinaris subsp. culinaris (as proposed before), but a more specific area of origin can be suggested in southern Turkey. We were also able to detect the divergence, following domestication, of the domesticated gene pool into overlapping large-seeded (megasperma) and small-seeded (microsperma) groups. Lentil domestication led to a loss of genetic diversity of approximately 40%. The approach followed in this research has allowed us to rapidly exploit sequence information from model plant species for the study of genetic diversity of a crop such as lentil with limited genomic resources. © 2011 The American Genetic Association. All rights reserved.

Mujeeb-Kazi A.,National Institute for Biotechnology and Genetic Engineering NIBGE | Kazi A.G.,National University of Sciences and Technology | Dundas I.,University of Adelaide | Rasheed A.,Quaid-i-Azam University | And 9 more authors.
Advances in Agronomy | Year: 2013

Genetic diversity is paramount for cultivated crops genetic improvement, and for wheat this resides in three gene pools of the Triticeae. In wheat, access to this diversity and its exploitation is based upon the genetic distance of the wild species relatives from the wheat genomes. For several decades, these wide crosses have been a reservoir of novel variation for wheat improvement. Among these, close relatives of the primary gene pool have been preferred since this ensures successful gene transfer as they permit homologous genetic exchanges to occur between related genomes, as exemplified by the A and D genome diploid progenitors. One strategy has been based upon first producing genetic stocks that capture the potential of the diploids via bridge crossing where the D genome synthetic hexaploid wheats (2n=6x=42, AABBDD) are exploited. The synthetics are products of crosses between elite durum wheat cultivars (Triticum turgidum) and various Aegilops tauschii accessions. Similarly, the diversity of the A and B genomes has also been assembled as AABBAA (T. turgidum/A genome diploids Triticum boeoticum, Triticum monococcum, Triticum urartu) and AABBBB (SS) (T. turgidum/Aegilops speltoides). The utilization of these useful diversity for various biotic/abiotic stresses including in the development of molecular tools for enhancing breeding efficiency has been in the forefront of wheat improvement over the past two decades. Additional strategy employed includes the direct crosses between parental diploids and recipient wheat cultivars extended to give even swifter products by top- or backcrossing the F1 combinations with either durum or bread wheats. Relatively less progress has been made in the use of genes from tertiary gene pool often involving "intergeneric crosses." The potency of potentially useful diversity in tertiary gene pool warrants further exploitation of this resource. Presented here are major facets of intergeneric hybridization embracing a taxonomic consideration of genetic diversity within the Triticeae, the exploitation protocols, prebreeding strategies, and some of the outputs from distant hybridization with a major focus on wheat/alien chromosomal exchanges classed as "translocations" such as T1BL.1RS and to a lesser degree the T1AL.1RS Robertsonian translocations. This chapter also attempts to relate the exploitation of the Triticeae genetic diversity with wheat productivity as a means of addressing diverse stress constraints that if pursued will provide yield enhancing outputs necessary for overriding environmental limitations of climate change, unpredictable incidences of biotic stresses, and catalyzing gains for food security with wheat. © 2013 Elsevier Inc.

Abate T.,International Crops Research Institute for the Semi Arid Tropics ICRISAT | Shiferaw B.,International Center for Maize and Wheat Improvement | Gebeyehu S.,Ethiopian Institute of Agricultural Research EIAR | Amsalu B.,Ethiopian Institute of Agricultural Research EIAR | And 5 more authors.
Outlook on Agriculture | Year: 2011

In spite of the availability of several improved agricultural technologies generated by the research system in Ethiopia over the last four decades, adoption of these innovations by smallholder farmers has been very low. This has led to stagnation of agricultural productivity and low crop yields, exposing the country to recurrent food shortfalls and national food insecurity. The old approach to agricultural research emphasized developing new technologies mainly through onstation research that were then supposed to reach farmers through the public-sector extension system. The Ethiopian Institute of Agricultural Research (EIAR) has in recent years introduced a shift in agricultural research for development, which is based on the innovation systems approach that involved cultivating partnerships with several actors along the value chain, especially farmers, farmers' cooperatives and input suppliers. This paper presents the methodology used to facilitate agricultural innovations and the diffusion of new technologies and illustrates the outcomes of this initiative with regard to technology adoption, productivity growth and the market orientation of production. The authors use examples from experiences in scaling up three grain legumes. Compared to the three-year baseline average (2003-05), crop output increased nationally by 89%, 85% and 97% in 2008 for common bean, chickpea and lentil respectively. Nationally, 53-59% of the output growth is attributable to yield growth due to technological change, while the balance is due to area expansion. These results affirm that the new approach has led to accelerated adoption of new and high-yielding or low-risk varieties.

Kienzler K.M.,International Center for Agricultural Research in the Dry Areas | Lamers J.P.A.,Center for Development Research | McDonald A.,International Center for Maize and Wheat Improvement | Mirzabaev A.,International Center for Agricultural Research in the Dry Areas | And 4 more authors.
Field Crops Research | Year: 2012

Rainfed and irrigated agricultural systems have supported livelihoods in the five Central Asian countries (CAC) for millennia, but concerns for sustainability and efficient use of land and water resources are long-standing. During the last 50 years, resource conserving technologies were introduced in large parts of the rainfed areas while the irrigated areas were expanded largely without considering resource conservation. In more recent years, the use of conservation agriculture (CA) practices has been reported for the different agricultural production (AP) zones in CAC, albeit centering on a single AP zone or on single factors such as crop yield, implements or selected soil properties. Moreover, conflicting information exists regarding whether the current practices that are referred to as 'CA' can indeed be defined as such. Overall information on an application of CA-based crop management in Central Asia is incomplete. This discussion paper evaluates experimental evidence on the performance of CA and other resource conserving technologies in the three main AP zones of CAC, provides an overview of farmer adoption of production practices related to CA, and outlines technical and non-technical challenges and opportunities for the future dissemination of CA practices in each zone. Agronomic (e.g. implements, crop yields, duration, and crop residues), institutional (e.g. land tenure) and economic (e.g. short vs. long-term profitability) perspectives are considered. At present, adoption of CA-based agronomic practices in the rainfed production zone is limited to partial crop residue retention on the soil surface or sporadically zero tillage for one crop out of the rotation, and hence the use of single CA components but not the full set of CA practices. In the irrigated AP zones, CA is not commonly practiced and many of the pre-conditions that typically encourage the rapid spread of CA practices appear to be absent or limiting. Further, our analysis suggests that given the diversity of institutional, socio-economic and agro-ecological contexts, a geographically differentiated approach to CA dissemination is required in the CAC. Immediate priorities should include a shift in research paradigms (e.g. towards more participatory approaches with farmers), development of commercially available reduced and no-till seeders suitable for smaller-scale farm enterprises, and advocacy so that decision makers understand how different policies may encourage or discourage innovations that lead towards more sustainable agricultural intensification in the CAC. © 2011 Elsevier B.V.

Singh M.,Punjab Agricultural University | Sidhu H.S.,Borlaug Institute for South Asia BISA | Humphreys E.,International Rice Research Institute | Thind H.S.,Punjab Agricultural University | And 4 more authors.
Field Crops Research | Year: 2015

In intensive rice-wheat systems of north-west (NW) India, surface retention of rice residues in wheat has been recommended instead of burning. Optimum nitrogen (N) management for zero till (ZT) wheat sown into rice residues may to differ from that of conventional practice (in-situ burning of residues followed by intensive tillage prior to sowing). Therefore, we conducted several on-farm and on-station field experiments in 2007-2008 to 2012-2013 to evaluate N management practices for ZT wheat sown into rice residues using the Happy Seeder. The optimum N rate for wheat planted into rice residues in fields with no or only a short history of rice residue retention was 120kgNha-1, the current recommendation for conventional practice. Short-term (up to 20 d) soil N mineralization was lower in undisturbed soil than disturbed soil, while the total amount of N mineralization was similar after 40d, suggesting that over the crop season, total soil N mineralization may be similar in tilled and non-tilled soil. Ammonia volatilization loss from urea broadcast over the residue covered surface, followed by irrigation, was low (<2kgha-1) regardless of time of urea application. Band placement of 20% of the fertilizer N as diammonium phosphate at seeding, and topdressing of the remaining 80% as urea in two equal doses before first and second irrigations produced higher grain yield and N use efficiency than other treatments. However, surface residue retention reduces the rate of soil drying and in some situations this delays the time of the second irrigation and thus N fertilizer application beyond the optimum time. Therefore, the effect of banding various proportions of the urea N between the rows at sowing was investigated. The results showed that, on a loam soil, up to 75% of the recommended N fertilizer can be applied at sowing, 24kgNha-1 as DAP with the seed and 66kgNha-1 as urea drilled between every second wheat row, without loss of yield. In conclusion, a better applied N management strategy for ZT wheat than currently practiced is drilling of 24kgNha-1 as diammonimum phosphate into the soil at seeding followed by two top-dressings of 48kgNha-1 each just prior to first and second irrigations. © 2015 Elsevier B.V.

Rattu A.R.,Pakistan National Agricultural Research Center | Ahmad I.,Pakistan National Agricultural Research Center | Singh R.P.,International Center for Maize and Wheat Improvement | Fayyaz M.,Pakistan National Agricultural Research Center | And 3 more authors.
Pakistan Journal of Botany | Year: 2010

Seventy six bread wheat (Triticum aestivum L.) candidate lines and commercial cultivars from Pakistan were postulated for their leaf rust genes resistance. Since limited information available on the genes, the main objective of the study was to postulate the known Lr genes conferring low seedling reactions to 14 pathotypes of Puccinia triticina in 76 Pakistani wheats. Eleven leaf rust resistance genes were present either singly or in combination: Lr1 (in 12 lines), Lr3 (4), Lr9 (2), Lr10 (28), Lr13 (27), Lr14a (2), Lr16 (9), Lr17 (8), Lr23 (18), Lr26 (36), Lr27+31 (5) in the tested material among which Lr26 was the most frequent while Lr9 was the least frequent.

PubMed | International Center for Maize and Wheat Improvement and ENEA
Type: Journal Article | Journal: PloS one | Year: 2016

Phenylalanine Ammonia Lyase (PAL) gene which plays a key role in bio-synthesis of medicinally important compounds, Rutin/quercetin was sequence characterized for its efficient genomics application. These compounds possessing anti-diabetic and anti-cancer properties and are predominantly produced by Fagopyrum spp. In the present study, PAL gene was sequenced from three Fagopyrum spp. (F. tataricum, F. esculentum and F. dibotrys) and showed the presence of three SNPs and four insertion/deletions at intra and inter specific level. Among them, the potential SNP (position 949th bp G>C) with Parsimony Informative Site was selected and successfully utilised to individuate the zygosity/allelic variation of 16 F. tataricum varieties. Insertion mutations were identified in coding region, which resulted the change of a stretch of 39 amino acids on the putative protein. Our Study revealed that autogamous species (F. tataricum) has lower frequency of observed SNPs as compared to allogamous species (F. dibotrys and F. esculentum). The identified SNPs in F. tataricum didnt result to amino acid change, while in other two species it caused both conservative and non-conservative variations. Consistent pattern of SNPs across the species revealed their phylogenetic importance. We found two groups of F. tataricum and one of them was closely related with F. dibotrys. Sequence characterization information of PAL gene reported in present investigation can be utilized in genetic improvement of buckwheat in reference to its medicinal value.

PubMed | International Center for Maize and Wheat Improvement
Type: Journal Article | Journal: TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik | Year: 2013

Thirteen maize (Zea mays L.) populations including five adapted, five adapted x exotic, two composites of adapted and exotic, and one exotic selected for adaptability were crossed in a diallel mating system. The parents and 78 crosses and nine check hybrids were evaluated for grain yield and plant height in five environments. The Gardner-Eberhart model Analysis II indicated that additive and nonadditive gene effects accounted for 60 and 40% of the total variation among populations, respectively, for grain yield and 86% and 14% of the total variation, respectively, for plant height. Components of heterosis were significant in the combined analysis for both traits. Adapted Corn Belt populations tended to have higher performance in crosses and greater values of variety heterosis than 50% adapted populations. Nebraska Elite Composite, Corn Belt x Mexican, and Corn Belt x Brazilian showed high mean yields in crosses, however, they were not among those with high estimates of variety heterosis. One exotic population (Tuxpeno x Antigua Grupo 2) and three adapted populations [307 Composite, NB(S1)C-3, and NK(S1)C-3] might be combined together to form a high-yielding population. It may be possible to synthesize two useful populations for reciprocal recurrent selection by grouping Tuxpeno x Antiqua Grupo 2, NB(S1)C-3, and NS(FS)LFW-8 into one population and NK(S1)C-3, KrugxTabloncillo, and 307 Composite in the other one.

PubMed | International Center for Maize and Wheat Improvement
Type: Journal Article | Journal: TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik | Year: 2013

Maize was crossed with sorghum, Tripsacum and millet with the aim of introgressing desirable alien characteristics into maize. The products of crosses were analyzed as to their level of differentiation following pollination; their further development on artificial culture medium was compared. In spite of a stimulation rate close to 5%, no evidence of hybridization between maize and sorghum or millet could be obtained. The plants recovered proved to be of maternal origin. However, with an appreciable frequency, stimulation leading to hypertrophic growth of nucellar tissue was observed. This phenomenon is bound to pollination, never occurring in non-pollinated ears. In crosses involving Tripsacum, more than 140 true hybrids were isolated. The influence of the genotypes used as well as factors such as climatic conditions or in vitro techniques are discussed. Except for one haploid maize plant, all the plants recovered proved to be classical hybrids, most of them showing the expected complement of chromosomes from each parent (10 + 36 chromosomes), a few others being slightly hyperploid (2n = 47 to 50 chromosomes). No non-classical hybrids constituted by a nonreduced female gamete and a reduced male gamete were obtained.

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