CIMMYT's use of synthetic hexaploid wheat in breeding for adaptation to rainfed environments globally.

2008 ◽  
Vol 59 (5) ◽  
pp. 461 ◽  
Author(s):  
J. Lage ◽  
R. M. Trethowan
Keyword(s):  
Hexaploid Wheat ◽  
Wheat Breeding ◽  
Trial Data ◽  
Emmer Wheat ◽  
Yield Potential ◽  
Synthetic Hexaploid Wheat ◽  
Interspecific Hybridisation ◽  
Coefficient Of Parentage ◽  
Yield Trial ◽  
Synthetic Hexaploid

The International Maize and Wheat Improvement Center (CIMMYT) has had significant impact on wheat production in rainfed regions of the developing world. During the last decade, yield potential has increased in drought-prone areas partly due to the use of synthetic hexaploid wheat (SHW), produced through interspecific hybridisation of Triticum turgidum spp. and Aegilops tauschii, followed by chromosome doubling. The objectives of this study were to document the use of SHW in wheat breeding at CIMMYT and quantify its potential effect on global wheat adaptation. The first SHW-derived lines targetted at rainfed conditions appeared in the 5th Semi-Arid Wheat Yield Trial (SAWYT) representing 8% of the lines, increasing to 46% by the 15th SAWYT. During the same period the average coefficient of parentage of SHW in all synthetically derived crosses decreased from 75 to 19%. Average yield rank of genotypes across locations and years was used as a performance indicator of the SHW-derived lines in SAWYT 5–12. In the 5th SAWYT the average rank of the SHW-derived lines was 30 (out of 50) increasing to 25 by the 12th SAWYT. SAWYT 11 was the first trial to include SHW-derived lines bred exclusively for rainfed environments, using directed selection for drought tolerance. International trial data from SAWYT 11 and 12 showed that the SHW-derived line Vorobey was a top-performing line. Vorobey performed well across all environments compared with the best locally adapted check cultivar at each location; trial means ranged from 1 to 8 t/ha. To further exploit genetic diversity for adaptation to drought, SHW has been produced using emmer wheat (T. turgidum L. subsp. dicoccon) as the tetraploid parent. Yield trial data from Mexico show that SHW derivatives based on emmer wheat improved yield performance under drought compared with their drought-tolerant recurrent parents. The use of SHW in wheat breeding for rainfed environments at CIMMYT has increased significantly over the past 10–15 years and the performance and effect of the derived lines have improved with time.

scholarly journals Transferring diversity of goat grass to farmers’ fields through the development of synthetic hexaploid wheat

Food Security ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1017-1033
Author(s):  
Hafid Aberkane ◽  
Thomas Payne ◽  
Masahiro Kishi ◽  
Melinda Smale ◽  
Ahmed Amri ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Crop Improvement ◽  
Aegilops Tauschii ◽  
Crop Wild Relatives ◽  
Wheat Breeding ◽  
Yield Potential ◽  
High Yield ◽  
Synthetic Hexaploid Wheat ◽  
Global Food Security ◽  
Synthetic Hexaploid

Abstract Genetic variation in wheat is needed to address global food security challenges, particularly as climates change. Crop wild relatives are unique reservoirs of useful alleles for crop improvement and are important components of genebank collections. We analyzed how the derivatives of ‘goat grass’ (Aegilops tauschii) have been used to widen the genetic base for wheat breeding and surveyed wheat breeders to elicit adoption estimates. Synthetic hexaploid wheat (SHW) is derived by crossing goat grass with durum wheat, serving as a bridge to transfer desirable traits into modern varieties of bread wheat. Our data show that wheat scientists used 629 unique accessions from 15 countries for pre-breeding, producing 1577 primary SHWs. These derivatives represented 21% of the germplasm distributed by the genebank of the International Maize and Wheat Improvement Center between 2000 and 2018. Over the period, more than 10,000 samples of SHW were sent to 110 institutions in 40 countries, with rising numbers of synthetic hexaploid-derived lines (SHDL) included in international nurseries. Lines were screened for major diseases of wheat. At least 86 varieties have been selected from SHDL and released in 20 countries. Survey estimates indicate the highest scale of adoption in southwest China and India, with 34% and 7% of reported wheat area, respectively. These varieties demonstrate resistance to pests and pathogens, high yield potential, good quality attributes, and suitability for biofortified wheat.

scholarly journals Genetic Contribution of Synthetic Hexaploid Wheat to CIMMYT’s Spring Bread Wheat Breeding Germplasm

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Umesh Rosyara ◽  
Masahiro Kishii ◽  
Thomas Payne ◽  
Carolina Paola Sansaloni ◽  
Ravi Prakash Singh ◽  
...  
Keyword(s):  
Bread Wheat ◽  
Hexaploid Wheat ◽  
Wheat Breeding ◽  
Synthetic Hexaploid Wheat ◽  
Genetic Contribution ◽  
Spring Bread Wheat ◽  
Synthetic Hexaploid ◽  
Breeding Germplasm

Increasing Hard Winter Wheat Yield Potential via Synthetic Hexaploid Wheat: II. Heritability and Combining Ability of Yield and its Components

Crop Science ◽  
2013 ◽  
Vol 53 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Jessica K. Cooper ◽  
Amir M. H. Ibrahim ◽  
Jackie Rudd ◽  
Dirk Hays ◽  
Subas Malla ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Hexaploid Wheat ◽  
Combining Ability ◽  
Wheat Yield ◽  
Yield Potential ◽  
Synthetic Hexaploid Wheat ◽  
Winter Wheat Yield ◽  
Synthetic Hexaploid

scholarly journals Additive genetic variance and covariance between relatives in synthetic wheat crosses with variable parental ploidy levels

Genetics ◽  
2021 ◽  
Vol 217 (2) ◽  
Author(s):  
L E Puhl ◽  
J Crossa ◽  
S Munilla ◽  
P Pérez-Rodríguez ◽  
R J C Cantet
Keyword(s):  
Hexaploid Wheat ◽  
Variance Components ◽  
Bayesian Model ◽  
Synthetic Hexaploid Wheat ◽  
Data Sets ◽  
Hierarchical Bayesian Model ◽  
Additive Variance ◽  
Ploidy Levels ◽  
Breeding Values ◽  
Synthetic Hexaploid

Abstract Cultivated bread wheat (Triticum aestivum L.) is an allohexaploid species resulting from the natural hybridization and chromosome doubling of allotetraploid durum wheat (T. turgidum) and a diploid goatgrass Aegilops tauschii Coss (Ae. tauschii). Synthetic hexaploid wheat (SHW) was developed through the interspecific hybridization of Ae. tauschii and T. turgidum, and then crossed to T. aestivum to produce synthetic hexaploid wheat derivatives (SHWDs). Owing to this founding variability, one may infer that the genetic variances of native wild populations vs improved wheat may vary due to their differential origin and evolutionary history. In this study, we partitioned the additive variance of SHW and SHWD with respect to their breed origin by fitting a hierarchical Bayesian model with heterogeneous covariance structure for breeding values to estimate variance components for each breed category, and segregation variance. Two data sets were used to test the proposed hierarchical Bayesian model, one from a multi-year multi-location field trial of SHWD and the other comprising the two species of SHW. For the SHWD, the Bayesian estimates of additive variances of grain yield from each breed category were similar for T. turgidum and Ae. tauschii, but smaller for T. aestivum. Segregation variances between Ae. tauschii—T. aestivum and T. turgidum—T. aestivum populations explained a sizable proportion of the phenotypic variance. Bayesian additive variance components and the Best Linear Unbiased Predictors (BLUPs) estimated by two well-known software programs were similar for multi-breed origin and for the sum of the breeding values by origin for both data sets. Our results support the suitability of models with heterogeneous additive genetic variances to predict breeding values in wheat crosses with variable ploidy levels.

Effects of drought and high temperature stress on synthetic hexaploid wheat

2012 ◽  
Vol 39 (3) ◽  
pp. 190 ◽  
Author(s):  
Gautam P. Pradhan ◽  
P. V. Vara Prasad ◽  
Allan K. Fritz ◽  
Mary B. Kirkham ◽  
Bikram S. Gill
Keyword(s):  
High Temperature ◽  
Temperature Stress ◽  
Hexaploid Wheat ◽  
High Temperature Stress ◽  
Synthetic Hexaploid Wheat ◽  
Combined Stress ◽  
Wheat Genotypes ◽  
Synthetic Hexaploid ◽  
Effects Of Drought ◽  
Days After Anthesis

Drought and high temperature often occurs simultaneously, causing significant yield losses in wheat (Triticum aestivum L.). The objectives of this study were to: (i) quantify independent and combined effects of drought and high temperature stress on synthetic hexaploid wheat genotypes at anthesis and at 21 days after anthesis; and (ii) determine whether responses to stress varied among genotypes. Four synthetic hexaploid and two spring wheat genotypes were grown from emergence to anthesis (Experiment I) and emergence to 21 days after anthesis (Experiment II), with full irrigation and 21/15°C day/night temperature. Thereafter, four treatments were imposed for 16 days as (a) optimum condition: irrigation + 21/15°C, (b) drought stress: withhold irrigation + 21/15°C, (c) high temperature stress: irrigation + 36/30°C and (d) combined stress: withhold irrigation + 36/30°C. Results indicated a decrease in leaf chlorophyll, individual grain weight and grain yield in an increasing magnitude of drought < high temperature < combined stress. There were 69, 81 and 92% grain yield decreases in Experiment I and 26, 37 and 50% in Experiment II under drought, high temperature and combined stress respectively. Synthetic hexaploid wheat genotypes varied in their response to stresses. Genotypes ALTAR 84/AO’S’ and ALTAR 84/Aegilops tauschii Coss. (WX 193) were least affected by combined stress in Experiments I and II respectively. Overall, combined effect of drought + high temperature stress was more detrimental than the individual stress and the interaction effect was hypo-additive in nature.

Registration of Four Synthetic Hexaploid Wheat Germplasm Lines with Resistance to Fusarium Head Blight

Crop Science ◽  
2004 ◽  
Vol 44 (4) ◽  
pp. 1500-1501 ◽  
Author(s):  
W.A. Berzonsky ◽  
K.D. Hartel ◽  
S.F. Kianian ◽  
G.D. Leach
Keyword(s):  
Fusarium Head Blight ◽  
Hexaploid Wheat ◽  
Synthetic Hexaploid Wheat ◽  
Head Blight ◽  
Wheat Germplasm ◽  
Synthetic Hexaploid
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