Person: Peña, Roberto
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
Peña
First Name
Roberto
Name
Peña, Roberto
36 results
Search Results
Now showing 1 - 10 of 36
- Uso de marcadores moleculares en el mejoramiento de la calidad de trigo II: marcadores moleculares en variedades de trigo harinero mexicanas(CIMMYT, 2015) Guzman, C.; Dreisigacker, S.; Autrique, E.; Gonzalez-Santoyo, H.; Villaseñor Mir, H.E.; Peña, RobertoEl trigo es el cuarto mayor cultivo a nivel mundial, con una producción cercana a las 716 millones de toneladas. La calidad del trigo es un carácter altamente complejo, controlado principalmente por factores genéticos, pero influido por factores ambientales, tales como el suelo, el clima, las técnicas de cultivo y almacenamiento.
Publication - Durum wheat (Triticum durum Desf.) Mediterranean landraces as sources of variability for allelic combinations at Glu-1/Glu-3 loci affecting gluten strength and pasta cooking quality(Springer Nature, 2014) Ruyman, N.; Peña, Roberto; Ammar, K.; Villegas, D.; Crossa, J.; Royo, C.With the aim of identifying durum wheat landraces (LR) with a potential use in breeding programs for gluten strength enhancement, the allelic combinations present at five glutenin loci were determined in a collection of 155 LR from 21 Mediterranean countries. A set of 18 modern cultivars (MC) was used for comparison. Gluten strength was determined by SDS-sedimentation test on grain samples from field experiments conducted during 3 years. A total number of 131 different allelic/banding pattern combinations were found. Taking together high (HMW-) and low (LMW-) molecular weight glutenin subunit loci resulted in 126 combinations in LR, but only nine in MC, which are characterized for having strong gluten. Two LMW-2 type models were identified in the collection and LMW-1 types were absent. LMW-2 was present in 78 % of MC, including the only three with outstanding gluten strength (Ocotillo, Claudio and Meridiano), while 14 % of the LR had LMW-2 and 6 % LMW-2−. In the LR a known combination LMW-2 (aaa) and three new ones had a positive effect on the gluten strength. LMW-2 models were found in high frequency in LR from Italy and the three Maghreb countries; from medium to low frequencies in genotypes from Turkey, Jordan, Lebanon, Portugal and Spain, and were absent in the remaining countries. The large variability found in LR proved their potential value in breeding to broaden the genetic basis of gluten quality improvement. Genotypes interesting for breeding purposes are identified.
Publication - Variability in glutenin subunit composition of Mediterranean durum wheat germplasm and its relationship with gluten strength(Cambridge University Press, 2013) Nazco, R.; Peña, Roberto; Ammar, K.; Villegas, D.; Crossa, J.; Moragues, M.; Royo, C.The allelic composition at five glutenin loci was assessed by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS–PAGE) on a set of 155 landraces (from 21 Mediterranean countries) and 18 representative modern varieties. Gluten strength was determined by SDS-sedimentation on samples grown under rainfed conditions during 3 years in north-eastern Spain. One hundred and fourteen alleles/banding patterns were identified (25 at Glu-1 and 89 at Glu-2/Glu-3 loci); 0·85 of them were in landraces at very low frequency and 0·72 were unreported. Genetic diversity index was 0·71 for landraces and 0·38 for modern varieties. All modern varieties exhibited medium to strong gluten type with none of their 13 banding patterns having a significant effect on gluten-strength type. Ten banding patterns significantly affected gluten strength in landraces. Alleles Glu-B1e (band 20), Glu-A3a (band 6), Glu-A3d (bands 6 + 11), Glu-B3a (bands 2 + 4+15 + 19) and Glu-B2a (band 12) significantly increased the SDS-value, and their effects were associated with their frequency. Two alleles, Glu-A3b (band 5) and Glu-B2b (null), significantly reduced gluten strength, but only the effect of the latter locus could be associated with its frequency. Only three rare banding patterns affected gluten strength significantly: Glu-B1a (band 7), found in six landraces, had a negative effect, whereas banding patterns 2 + 4+14 + 15 + 18 and 2 + 4+15 + 18 + 19 at Glu-B3 had a positive effect. Landraces with outstanding gluten strength were more frequent in eastern than in western Mediterranean countries. The geographical pattern displayed from the frequencies of Glu-A1c is discussed.
Publication - Breeding-assisted genomics: applying meta- GWAS for milling and baking quality in CIMMYT wheat breeding program(Public Library of Science, 2018) Battenfield, S.D.; Sheridan, J.L.; Silva, L.D.C.E.; Miclaus, K.J.; Dreisigacker, S.; Wolfinger, R.D.; Peña, Roberto; Singh, R.P.; Jackson, E.W.; Fritz, A.; Guzman, C.; Poland, J.One of the biggest challenges for genetic studies on natural or unstructured populations is the unbalanced datasets where individuals are measured at different times and environments. This problem is also common in crop and animal breeding where many individuals are only evaluated for a single year and large but unbalanced datasets can be generated over multiple years. Many wheat breeding programs have focused on increasing bread wheat (Triticum aestivum L.) yield, but processing and end-use quality are critical components when considering its use in feeding the rising population of the next century. The challenges with end-use quality trait improvements are high cost and seed amounts for testing, the latter making selection in early breeding populations impossible. Here we describe a novel approach to identify marker-trait associations within a breeding program using a meta-genome wide association study (GWAS), which combines GWAS analysis from multiyear unbalanced breeding nurseries, in a manner reflecting meta-GWAS in humans. This method facilitated mapping of processing and end-use quality phenotypes from advanced breeding lines (n = 4,095) of the CIMMYT bread wheat breeding program from 2009 to 2014. Using the meta-GWAS we identified marker-trait associations, allele effects, candidate genes, and can select using markers generated in this process. Finally, the scope of this approach can be broadly applied in ‘breeding-assisted genomics’ across many crops to greatly increase our functional understanding of plant genomes.
Publication - Strategies for selecting crosses using genomic prediction in two wheat breeding programs(Crop Science Society of America, 2017) Lado, B.; Battenfield, S.D.; Guzman, C.; Quincke, M.; Singh, R.P.; Dreisigacker, S.; Peña, Roberto; Fritz, A.; Silva, P.; Poland, J.; Gutiérrez, L.The single most important decision in plant breeding programs is the selection of appropriate crosses. The ideal cross would provide superior predicted progeny performance and enough diversity to maintain genetic gain. The aim of this study was to compare the best crosses predicted using combinations of mid-parent value and variance prediction accounting for linkage disequilibrium (VLD) or assuming linkage equilibrium (VLE). After predicting the mean and the variance of each cross, we selected crosses based on mid-parent value, the top 10% of the progeny, and weighted mean and variance within progenies for grain yield, grain protein content, mixing time, and loaf volume in two applied wheat (Triticum aestivum L.) breeding programs: Instituto Nacional de Investigación Agropecuaria (INIA) Uruguay and CIMMYT Mexico. Although the variance of the progeny is important to increase the chances of finding superior individuals from transgressive segregation, we observed that the mid-parent values of the crosses drove the genetic gain but the variance of the progeny had a small impact on genetic gain for grain yield. However, the relative importance of the variance of the progeny was larger for quality traits. Overall, the genomic resources and the statistical models are now available to plant breeders to predict both the performance of breeding lines per se as well as the value of progeny from any potential crosses.
Publication - Anti-Wheat fad diets undermine global food security efforts: wheat consumption healthy despite claims in self-help publications(CIMMYT, 2014) Peña, Roberto; Braun, H.J.; Mollins, J.A recent review paper released by Britain’s University of Warwick (Lillywhite and Sarrouy 2014) addresses two fundamental questions regarding wheat: “Are whole grain products good for health?”; and “What is behind the rise in popularity of glutenand wheat-free diets?” The paper was commissioned by cereal-maker Weetabix to address reports in the news media that wheat products are the cause of health problems, resulting in an increasing number of consumers switching to low-carbohydrate grain- and wheat- free diets. For many health professionals this is a worrying trend because wheat not only supplies 20 percent of the world’s food calories and protein, but has important benefits beyond nutrition, the authors state. The Warwick paper provides a scientific assessment of the benefits of whole grain consumption, information that the authors note seems to have been lost in media headlines and the reporting of “pseudo-science.” The paper concludes that whole grain products are good for human health, apart from the 1 percent of the population who suffer from celiac disease and another 1 percent who suffer from sensitivity to wheat (Lillywhite and Sarrouy 2014). Eating wholegrain wheat products is positive, improves health and can help maintain a healthy body weight, the authors report. Scientific evidence regarding wheat- and carbohydrate-free diets is thin and selectively used, they state, and a low cereal and carbohydrate diet “may cost more but deliver less.” Additionally, an economically viable industry has developed around so-called “free-from” diets and may be persuading consumers to switch from staple foods to specialist foods created especially for those who need to avoid gluten, a protein found in wheat and other grains, they add. This Wheat Discussion Paper serves as a foundation upon which the authors hope further conversation will develop. It aims to highlight unsubstantiated nutritional claims about wheat and shine a spotlight on the important role of wheat and fiber in human diets. It also seeks to encourage discussion about how non-scientific claims about wheat could affect poor consumers and global food security.
Publication - Wheat quality improvement at CIMMYT and the use of genomic selection on it(Elsevier, 2016) Guzman, C.; Peña, Roberto; Singh, R.G.; Autrique, E.; Dreisigacker, S.; Crossa, J.; Rutkoski, J.; Poland, J.; Battenfield, S.D.The International Center for Maize and Wheat Improvement (CIMMYT) leads the Global Wheat Program, whose main objective is to increase the productivity of wheat cropping systems to reduce poverty in developing countries. The priorities of the program are high grain yield, disease resistance, tolerance to abiotic stresses (drought and heat), and desirable quality. The Wheat Chemistry and Quality Laboratory has been continuously evolving to be able to analyze the largest number of samples possible, in the shortest time, at lowest cost, in order to deliver data on diverse quality traits on time to the breeders for making selections for advancement in the breeding pipeline. The participation of wheat quality analysis/selection is carried out in two stages of the breeding process: evaluation of the parental lines for new crosses and advanced lines in preliminary and elite yield trials. Thousands of lines are analyzed which requires a big investment in resources. Genomic selection has been proposed to assist in selecting for quality and other traits in breeding programs. Genomic selection can predict quantitative traits and is applicable to multiple quantitative traits in a breeding pipeline by attaining historical phenotypes and adding high-density genotypic information. Due to advances in sequencing technology, genome-wide single nucleotide polymorphism markers are available through genotyping-by-sequencing at a cost conducive to application for genomic selection. At CIMMYT, genomic selection has been applied to predict all of the processing and end-use quality traits regularly tested in the spring wheat breeding program. These traits have variable levels of prediction accuracy, however, they demonstrated that most expensive traits, dough rheology and baking final product, can be predicted with a high degree of confidence. Currently it is being explored how to combine both phenotypic and genomic selection to make more efficient the genetic improvement for quality traits at CIMMYT spring wheat breeding program.
Publication - Genomic selection for processing and end-use quality traits in the CIMMYT spring bread wheat breeding program(Crop Science Society of America, 2016) Battenfield, S.D.; Guzman, C.; Gaynor, R.C.; Singh, R.P.; Peña, Roberto; Dreisigacker, S.; Fritz, A.; Poland, J.Wheat (Triticum aestivum L.) cultivars must possess suitable end-use quality for release and consumer acceptability. However, breeding for quality traits is often considered a secondary target relative to yield largely because of amount of seed needed and expense. Without testing and selection, many undesirable materials are advanced, expending additional resources. Here, we develop and validate whole-genome prediction models for end-use quality phenotypes in the CIMMYT bread wheat breeding program. Model accuracy was tested using forward prediction on breeding lines (n = 5520) tested in unbalanced yield trials from 2009 to 2015 at Ciudad Obregon, Sonora, Mexico. Quality parameters included test weight, 1000-kernel weight, hardness, grain and flour protein, flour yield, sodium dodecyl sulfate sedimentation, Mixograph and Alveograph performance, and loaf volume. In general, prediction accuracy substantially increased over time as more data was available to train the model. Reflecting practical implementation of genomic selection (GS) in the breeding program, forward prediction accuracies (r) for quality parameters were assessed in 2015 and ranged from 0.32 (grain hardness) to 0.62 (mixing time). Increased selection intensity was possible with GS since more entries can be genotyped than phenotyped and expected genetic gain was 1.4 to 2.7 times higher across all traits than phenotypic selection. Given the limitations in measuring many lines for quality, we conclude that GS is a powerful tool to facilitate early generation selection for end-use quality in wheat, leaving larger populations for selection on yield during advanced testing and leading to better gain for both quality and yield in bread wheat breeding programs.
Publication - Genomic prediction of gene bank wheat landraces(Genetics Society of America, 2016) Crossa, J.; Jarquin, D.; Franco, J.; Pérez-Rodríguez, P.; Burgueño, J.; Saint Pierre, C.; Vikram, P.; Sansaloni, C.; Petroli, C.; Akdemir, D.; Sneller, C.; Reynolds, M.P.; Tattaris, M.; Payne, T.S.; Guzman, C.; Peña, Roberto; Wenzl, P.; Singh, S.This study examines genomic prediction within 8416 Mexican landrace accessions and 2403 Iranian landrace accessions stored in gene banks. The Mexican and Iranian collections were evaluated in separate field trials, including an optimum environment for several traits, and in two separate environments (drought, D and heat, H) for the highly heritable traits, days to heading (DTH) and days to maturity (DTM). Analyses accounting and not accounting for population structure were performed. Genomic prediction models include genotype × environment interaction (G×E). Two alternative prediction strategies were studied: (1) random cross-validation of the data in 20% training (TRN) and 80% testing (TST) (TRN20-TST80) sets, and (2) two types of core sets, “diversity” and “prediction”, including 10% and 20%, respectively, of the total collections were formed. Accounting for population structure decreased prediction accuracy by 15%-20% as compared to prediction accuracy obtained when not accounting for population structure. Accounting for population structure gave prediction accuracies for traits evaluated in one environment for TRN20-TST80 that ranged from 0.407 to 0.677 for Mexican landraces and from 0.166 to 0.662 for Iranian landraces. Prediction accuracy of the 20% diversity core set was similar to accuracies obtained for TRN20-TST80, ranging from 0.412 to 0.654 for Mexican landraces and from 0.182 to 0.647 for Iranian landraces. The predictive core set gave similar prediction accuracy as the diversity core set for Mexican collections but slightly lower for Iranian collections. Prediction accuracy when incorporating G×E for DTH and DTM for Mexican landraces for TRN20-TST80 was around 0.60, which is greater than without the G×E term. For Iranian landraces, accuracies were 0.55 for the G×E model with TRN20-TST80. Results show promising prediction accuracies for potential use in germplasm enhancement and rapid introgression of exotic germplasm into elite materials.
Publication - Anti-wheat fad diets undermine global food security efforts: wheat consumption healthy despite claims in self-help publications(CIMMYT, 2014) Peña, Roberto; Braun, H.J.; Mollins, J.A recent review paper released by Britain’s University of Warwick (Lillywhite and Sarrouy 2014) addresses two fundamental questions regarding wheat: “Are whole grain products good for health?”; and “What is behind the rise in popularity of glutenand wheat-free diets?” The paper was commissioned by cereal-maker Weetabix to address reports in the news media that wheat products are the cause of health problems, resulting in an increasing number of consumers switching to low-carbohydrate grain- and wheat- free diets. For many health professionals this is a worrying trend because wheat not only supplies 20 percent of the world’s food calories and protein, but has important benefits beyond nutrition, the authors state. The Warwick paper provides a scientific assessment of the benefits of whole grain consumption, information that the authors note seems to have been lost in media headlines and the reporting of “pseudo-science.” The paper concludes that whole grain products are good for human health, apart from the 1 percent of the population who suffer from celiac disease and another 1 percent who suffer from sensitivity to wheat (Lillywhite and Sarrouy 2014). Eating wholegrain wheat products is positive, improves health and can help maintain a healthy body weight, the authors report. Scientific evidence regarding wheat- and carbohydrate-free diets is thin and selectively used, they state, and a low cereal and carbohydrate diet “may cost more but deliver less.” Additionally, an economically viable industry has developed around so-called “free-from” diets and may be persuading consumers to switch from staple foods to specialist foods created especially for those who need to avoid gluten, a protein found in wheat and other grains, they add. This Wheat Discussion Paper serves as a foundation upon which the authors hope further conversation will develop. It aims to highlight unsubstantiated nutritional claims about wheat and shine a spotlight on the important role of wheat and fiber in human diets. It also seeks to encourage discussion about how non-scientific claims about wheat could affect poor consumers and global food security.
Publication