Posts Tagged ‘durum wheat’

Exploiting genetic diversity from landraces in wheat breeding for adaptation to climate change

Posted by gabrielamartinez on , in Journal Articles

56898Authors: Lopes, M.S., El-Basyoni, I., Baenziger, P.S., Sukhwinder-Singh, Royo, C., Ozbek, K., Aktas, H., Ozer, E., Ozdemir, F., Manickavelu, A., Ban, T., Vikram, P.

Published in: Journal of Experimental Botany, In press.


 

Climate change has generated unpredictability in the timing and amount of rain, as well as extreme heat and cold spells that have affected grain yields worldwide and threaten food security. Sources of specific adaptation related to drought and heat, as well as associated breeding of genetic traits, will contribute to maintaining grain yields in dry and warm years. Increased crop photosynthesis and biomass have been achieved particularly through disease resistance and healthy leaves. Similarly, sources of drought and heat adaptation through extended photosynthesis and increased biomass would also greatly benefit crop improvement. Wheat landraces have been cultivated for thousands of years under the most extreme environmental conditions. They have also been cultivated in lower input farming systems for which adaptation traits, particularly those that increase the duration of photosynthesis, have been conserved. Landraces are a valuable source of genetic diversity and specific adaptation to local environmental conditions according to their place of origin. Evidence supports the hypothesis that landraces can provide sources of increased biomass and thousand kernel weight, both important traits for adaptation to tolerate drought and heat. Evaluation of wheat landraces stored in gene banks with highly beneficial untapped diversity and sources of stress adaptation, once characterized, should also be used for wheat improvement. Unified development of databases and promotion of data sharing among physiologists, pathologists, wheat quality scientists, national programmes, and breeders will greatly benefit wheat improvement for adaptation to climate change worldwide.

Durum wheat (Triticum durum L.) quality and yield as affected by tillage-straw management and nitrogen fertilization practice under furrow-irrigated conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Field Crops Research 164 : 166-177, 2014

Grahmann, K.Verhulst, N.Peña-Bautista, R.J.Buerkert, A.;Vargas-Rojas, L.Govaerts, B.

Little is documented about the effect of different tillage and residue management practices on durum wheat (Triticum durum L.) quality. This study aims at examining the effect of tillage–residue management systems on wheat yield and quality in two cropping cycles, 19 years after establishment of tillage–residue management systems in 1992. Wheat grain samples were collected in an experiment with a durum wheat-maize (Zea mays L.) rotation and furrow-irrigation, conducted in the arid Yaqui Valley of north-western Mexico. Main plots had five tillage–crop residue management treatments: conventionally tilled raised beds (CTB) with straw incorporated and permanent raised beds (PB) with straw burned, removed, partly retained or fully retained. Split plots had seven nitrogen (N) fertilizer treatments with different rate (0, 150 or 300 kg N ha−1) and timing of application (basal, 1st node and split between both). Highest yields were obtained with PB-straw partly retained and 300 kg N ha−1 split application in 2010/11 (7.48 t ha−1) and with PB-straw removed and 300 kg N ha−1 applied at 1st node in 2011/12 (8.26 t ha−1). Permanent beds with full residue retention had high yellow berry (YB, opaque and starchy endosperm) incidence, even with 300 kg N ha−1; 19.5% in 2010/11 and 9.4% in 2011/12 of the grain kernels were affected by YB. Four groups of tillage–straw systems with different characteristics in relation to the durum wheat quality and yield were distinguished with a principal component analysis: PB-partly retained with high yields and acceptable quality, PB-straw retained with low quality and acceptable yields, CTB with intermediate quality results and lower yields and PB-straw burned with high quality and low yields. Results indicate a significant effect of timing of N application on durum wheat grain quality in PB. For both cycles and both N rates, the application of mineral N resulted in higher grain quality when all N was applied near 1st node. Grain quality was highest in PB-straw burned, but this practice had the lowest yields. For PB-straw fully retained, 1st node application of N fertilizer is recommended to minimize N immobilization. To obtain stable yields and desirable quality, alternative tillage practices such as PB with full or partial residue retention require adjusted, site-specific N management. Further research is required to identify fertilization strategies in tillage systems with full or partial residue retention that include fertilizer applications after first node to improve grain quality.

Lr72 confers resistance to leaf rust in durum wheat cultivar Atil C2000

Posted by Carelia Juarez on , in Journal Articles

Published in Plant Disease 98 (5) : 631-635, 2014

Herrera-Foessel, S.A.Huerta-Espino, J.;Calvo-Salazar, V.Lan, C.X.Singh, R.P. 

Leaf rust, caused by Puccinia triticina (Pt), has become a globally important disease for durum wheat (Triticum turgidum subsp. durum) since the detection of race group BBG/BN, which renders ineffective a widely deployed seedling resistance gene present in several popular cultivars including Mexican cultivars Altar C84 and Atil C2000. The resistance gene continues to play a key role in protecting durum wheat against bread wheat–predominant races since virulence among this race group has not been found. We developed F3 and F5 mapping populations from a cross between Atil C2000 and the susceptible line Atred #1. Resistance was characterized by greenhouse seedling tests using three Pt races. Segregation tests indicated the presence of a single gene, which was mapped to the distal end of 7BS by bulk segregant analysis. The closest marker, wmc606, was located 5.5 cM proximal to the gene. No known leaf rust resistance genes are reported in this region; this gene was therefore designated as Lr72. The presence of Lr72 was further investigated in greenhouse tests in a collection of durum wheat using 13 Pt races. It was concluded that at least one additional gene protects durum wheat from bread wheat–predominant Pt races.

Evaluation of macroscopic and microscopic components of partial resistance to leaf rust in durum wheat

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Phytopathology, 2013

Soleiman, N.H.; Solis, I.; Sillero, J.C.; Herrera-Foessel, S.A.; Ammar, K.; Martinez, F.

Leaf rust, caused by the fungus Puccinia triticina, is considered one of the most important foliar diseases in durum wheat. Hypersensitive resistance (HR) may be rapidly overcome by the pathogen when resistant cultivars are grown on a large acreage or following changes in virulence in the pathogen population. Prolonging the durability of the resistance requires uses of other types of resistance such as partial resistance (PR). In this study, six durum wheat lines provided by the International Center for Corn and Wheat Improvement (CIMMYT) with a high level of PR to leaf rust were studied in monocyclic tests in a growth chamber. Inoculations were performed on both primary and fifth leaves using the Spanish race DGB/BN. UV fluorescence microscopy was employed to determine microscopic components of the resistance, such as the number of early aborted infection units not associated with plant cell necrosis (EA−) and relative colony size (RCS) of the established infection units. Macroscopic components of PR such as latency period, infection frequency and uredinium size were measured as well. All six resistant lines were characterized by a higher EA− and smaller RCS respect to the susceptible control ‘Don Rafael’. Line 3 showed the highest level of PR. It had 22% of EA− compared with 4% in the susceptible control, and the smallest RCS (17% respect to RCS of ‘Don Rafael’) at adult plant stage. Both EA− and RCS had a high heritability (more than 97%) and the correlation with macroscopic parameters (latency period and uredinium size) was also high (significant at 0.001 level). Hence, PR to leaf rust in these durum wheat genotypes has been revealed at microscopic level (higher EA− and smaller RCS).

High genetic diversity of Mycospaherella graminicola (Zymoseptoria tritici) from a single wheat field in Tunisia as revealed by SSR markers

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Biotechnology 12 (12) : 1344-1349, 2013

Samia Berraies, Mohamed Salah Gharbi, François Belzile, Amor Yahyaoui, Mohamed Rebah Hajlaoui, Mokhtar Trifi, Martine Jean and Salah Rezgui

Microsatellite markers were used to assess genetic diversity of Mycosphaerella graminicola at a micro geographical scale in Tunisia. Forty five (45) isolates were sampled and assessed using seven pairs of single-locus microsatellite primers not previously tested on populations of M. graminicola in Tunisia. Genetic diversity of the field population ranged from 0.403 to 0.555 with an average of 0.484. A high level of genetic diversity was found at a sharp scale throughout the pathogen population tested. Among 45 isolates sampled, 39 different multi locus genotypes (MLG) were identified. Cluster analysis (UPGMA) showed that 86% of the isolates tested were distinct. The high degree  of DNA polymorphism, the large number of different molecular genotypes and the pattern of cluster analysis suggest that sexual ascospores and/or asexual spores of a highly mutable local population could have contributed to the genetic diversity of M. graminicola in Tunisia.

Heat and drought stress on durum wheat: Responses of genotypes, yield, and quality parameters

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Cereal Science 57 (3) : 398-404, 2013

Yun-Fang Li, Yu Wu, Nayelli  Hernandez-Espinosa and Roberto J. Peña

Heat and/or drought stress during cultivation are likely to affect the processing quality of durum wheat (Triticum turgidum L. ssp. durum). This work examined the effects of drought and heat stress conditions on grain yield and quality parameters of nine durum wheat varieties, grown during two years (2008–09 and 2009–10). Generally, G and E showed main effects on all the parameters whereas the effects of G × E were relatively small. More precipitation in Y09–10 may account for the large differences in parameters observed between crop cycles (Y08–09 and Y09–10). Combined results of the two crop cycles showed that flour protein content (FP) and SDS sedimentation volume (SDSS) increased under both stress conditions, but not significantly. In contrast the gluten strength-related parameters lactic acid retention capacity (LARC) and mixograph peak time (MPT) increased and decreased significantly under drought and heat stress, respectively. Drought and heat stress drastically reduced grain yield (Y) but significantly enhanced flour yellowness (FY). LARC and the swelling index of glutenin (SIG) could be alternative tests to screen for gluten strength. Genotypes and qualtiy parameters performed differently to drought and heat stress, which justifies screening durum wheat for both yield and quality traits under these two abiotic stress conditions.

 

Variability in glutenin subunit composition of Mediterranean durum wheat germplasm and its relationship with gluten strength

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Agricultural Science, 2013

R. Nazco, R.J. Peña, K. Ammar, D. Villegas, J. Crossa, M. Moragues and C. Royo

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.

 

 

Physical mapping of puroindoline b-2 genes and molecular characterization of a novel variant in durum wheat (Triticum turgidum L.)

Posted by Carelia Juarez on , in Journal Articles

Published in Molecular Breeding  28 (2) : 153-161, 2012

F. Chen, H.-X. Xu, F.-Y. Zhang, X.-C. Xia, Z.-H. He, D.-W. Wang, Z.-D. Dong, K.-H. Zhan, X.-Y. Cheng and D.-Q. Cui

The puroindoline genes (Pina and Pinb) are the functional components of the common or bread wheat (Triticum aestivum L.) grain hardness locus that are responsible for kernel texture. In this study, four puroindoline b2 variants were physically mapped using nulli-tetrosomic lines of bread wheat cultivar Chinese Spring and substitution lines of durum wheat (Triticum turgidum L.) cultivar Langdon. Results indicated that Pinb2v1 was on 7D of Chinese Spring, Pinb2v2 on 7B of Chinese Spring, Pinb2v3 on 7B of Chinese Spring and Langdon, and Pinb2v4 on 7A of Chinese Spring and Langdon. A new puroindoline b2 variant, designated Pinb2v5, was identified at the puroindoline b2 locus of durum wheat cultivar Langdon, with a difference of only five single nucelotide polymorphisms compared with Pinb2v4. Sequencing results indicated that, in comparison with the Pinb2v3 sequence (AM99733 and GQ496618 with one base-pair modification of G to T at 6th position, designated Pinb2v3a) in bread wheat cultivar Witchta, the coding region of Pinb2v3 in 12 durum wheat cultivars had a single nucleotide change from T to C at the 311th position, resulting in a corresponding amino acid change from valine to alanine at the 104th position. This new allele was designated Pinb2v3b. The study of puroindoline b2 gene polymorphism in CIMMYT and Italian durum wheat germplasm and discovery of a novel puroindoline b2 variant could provide useful information for further understanding the molecular and genetic basis of kernel hardness and illustrating gene duplication events in wheat.

Genomic prediction of breeding values when modeling genotype × environment interaction using pedigree and dense molecular markers

Posted by Carelia Juarez on , in Journal Articles

Published in Crop Science 52 (2) : 707-719, 2012

Juan Burgueño, Gustavo de los Campos, Kent Weigel and José Crossa

Genomic selection (GS) has become an important aid in plant and animal breeding. Multienvironment (multitrait) models allow borrowing of information across environments (traits), which could enhance prediction accuracy. This study presents multienvironment (multitrait) models for GS and compares the predictive accuracy of these models with: (i) multienvironment analysis without pedigree and marker information, and (ii) multienvironment pedigree or/and marker-based models. A statistical framework for incorporating pedigree and molecular marker information in models for multienvironment data is described and applied to data that originate from wheat (Triticum aestivum L.) multienvironment trials. Two prediction problems relevant to plant breeders are considered: (CV1) predicting the performance of untested genotypes (“newly” developed lines), and (CV2) predicting the performance of genotypes that have been evaluated in some environments but not in others. Results confirmed the superiority of models using both marker and pedigree information over those based on pedigree information only. Models with pedigree and/or markers had better predictive accuracy than simple linear mixed models that do not include either of these two sources of information. We concluded that the evaluation of such trials can benefit greatly from using multienvironment GS models.

 

 

Allelic Variants at the Psy-A1 and Psy-B1 Loci in Durum Wheat and Their Associations with Grain Yellowness

Posted by on , in Journal Articles

Published in Crop Science 49(6): 2058-2064, 2009

Allelic Variants at the Psy-A1 and Psy-B1 Loci in Durum Wheat and Their Associations with Grain Yellowness

Xinyao He, Jianwu Wang, Karim Ammar, Roberto Javier Peña, Xianchun Xia  and Zhonghu He

Phytoene synthase (PSY) genes are involved in the biosynthesis of carotenoid pigments in durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.], significantly influencing grain yellowness. This study was conducted to identify new allelic variants at the Psy-A1 and Psy-B1 loci in durum wheat, and to evaluate the applicability of functional markers developed from common wheat (Triticum aestivum L.) for durum wheat breeding. Two new allelic variants, Psy-A1d and Psy-A1e, were identified at the Psy-A1 locus, and both the codominant markers YP7A and YP7A-2 can be used to discriminate the two haplotypes, yielding 194- and 231-bp polymerase chain reaction (PCR) products with YP7A and 1001- and 1684-bp fragments with YP7A-2, respectively. At the Psy-B1 locus, three allelic variants were identified. Psy-B1e was also found in common wheat, whereas Psy-B1f and Psy-B1g were detected only in durum wheat. The codominant marker YP7B-1 can be used to distinguish Psy-B1f and Psy-B1g, generating 151- and 153-bp PCR fragments, respectively, and the dominant marker YP7B-4 was specific to haplotype Psy-B1e, producing a 717-bp PCR product. In a set of 100 CIMMYT durum wheat lines with widely variable grain yellowness, the frequencies of Psy-A1d, Psy-A1e, Psy-B1e, Psy-B1f, and Psy-B1g were 99, 1, 0, 67, and 33%, respectively, and the genotype Psy-B1f showed a significant association with higher grain yellowness, whereas the presence of Psy-B1g led to lower yellowness. A phylogenetic tree generated from the gene sequences of the allelic variants at Psy-A1 and Psy-B1 loci indicated two parallel lineages of durum–common wheat, suggesting that more than one tetraploid T. turgidum L. subsp. dicoccon (Schrank) Thell. genotypes were involved in the origin of common wheat. Our results suggested that Psy-B1f should be paid more attention in durum breeding programs for its association with elevated grain yellowness