Francis Chuks Ogbonnaya
Grains Research and Development Corporation

Achieving sustainable wheat yield improvement has been a major objective of wheat breeding programs worldwide. Incorporation of genetic diversity from synthetic hexaploid wheat into elite wheat is seen as pivotal in improving wheat productivity and securing global wheat supply. Of recent, yield improvement of wheat in rain-fed environment have plateaued accentuated by the repeated occurrences of drought, heat and sporadic outbreak of fungal disease because of break down in major gene resistances giving impetus to the exploitation of natural diversity in synthetic hexaploids as a means of improving productivity. As a consequence, since the early 2000, there have been significant national and international interests in the utilisation of synthetic hexaploids as sources of germplasm aimed at developing adapted, stress resistant, high yielding and disease resistant wheat cultivars.
Synthetic backcross-derived lines (SBLs, i.e., when SHW is crossed to adapted local bread varieties) showed significant yield increases with the magnitude of yield improvement over the recurrent parent ranging from 32 to 58% depending on the environment and thus, enhanced yield performance across a diverse range of environments, demonstrating their potential for improving wheat productivity worldwide. Similarly, we had previously shown that synthetic hexaploid wheat possess resistance to several different diseases. Using a combination of bi-parental mapping and whole genome association mapping, we identified loci contributing to such enhanced yield performance in addition to novel loci that confers multiple disease and insect pest resistance aimed at elucidating the genetic architecture of multiple diseases and insect resistances in synthetic hexaploid wheat.
Clusters of disease resistance QTLs were located at multiple distinct genomic locations. Similarly, novel QTLs that are involved in the control of multiple root diseases in wheat were also identified. The dataset provides valuable new information on the feasibility of using association genetics to position loci controlling agronomically important traits in synthetic hexaploid wheat and accelerate the incorporation of useful genes into elite locally adapted cultivars.