International Maize and Wheat Improvement Center

About: International Maize and Wheat Improvement Center is a nonprofit organization based out in Texcoco, Mexico. It is known for research contribution in the topics: Population & Agriculture. The organization has 1976 authors who have published 4799 publications receiving 218390 citations.

Genetic Yield Gains of the CIMMYT International Semi-Arid Wheat Yield Trials from 1994 to 2010

Abstract: Genetic progress for yield has been assessed globally in the semi-arid wheat yield trials (SAWYTs) of the International Maize and Wheat Improvement Center (CIMMYT) over a 17-yr period. Grain yield expressed as a percentage of the long-term check cultivar Dharwar Dry has increased at approximately 1% yr −1 between 1994 and 2010. In real terms, yield has been increased at a rate of 31 kg ha −1 yr −1 . The rate of yield increase in high-yielding environments was twice that of low-yielding environments. The average yield of low-yielding sites are signifi cantly correlated with the average yield of high-yielding sites (p < 0.001), and many of the highest-yielding lines of the various SAWYT performed well at both low- and high-yielding sites. The key parents Attila and Pastor were consistently high yielding in several of the early SAWYT. In later trials their derivatives were also high yielding. The line Vorobey, developed by crossing Pastor with a synthetic derivative, showed outstanding yield in SAWYT 11 and 12. The performance of CIMMYT lines compared to local check cultivars was relatively stable over time. A success rate was calculated as the ratio of the number of sites where a given line is superior to the local check divided by the total number of sites. On average, the success rate of the 10% best lines was 61% in low-yielding sites and 62% in high-yielding sites.

Genetic dissection of drought and heat-responsive agronomic traits in wheat.

Abstract: High yield and wide adaptation are principal targets of wheat breeding but are hindered by limited knowledge on genetic basis of agronomic traits and abiotic stress tolerances. In this study, 277 wheat accessions were phenotyped across 30 environments with non-stress, drought-stressed, heat-stressed, and drought-heat-stressed treatments and were subjected to genome-wide association study using 395 681 single nucleotide polymorphisms. We detected 295 associated loci including consistent loci for agronomic traits across different treatments and eurytopic loci for multiple abiotic stress tolerances. A total of 22 loci overlapped with quantitative trait loci identified by biparental quantitative trait loci mapping. Six loci were simultaneously associated with agronomic traits and abiotic stress tolerance, four of which fell within selective sweep regions. Selection in Chinese wheat has increased the frequency of superior marker alleles controlling yield-related traits in the four loci during past decades, which conversely diminished favourable genetic variation controlling abiotic stress tolerance in the same loci; two promising candidate paralogous genes colocalized with such loci, thereby providing potential targets for studying the molecular mechanism of stress tolerance-productivity trade-off. These results uncovering promising alleles controlling agronomic traits and/or multiple abiotic stress tolerances, providing insights into heritable covariation between yield and abiotic stress tolerance, will accelerate future efforts for wheat improvement.