Successful introduction of dwarfing and semi-dwarfing traits into wheat varieties resulted in fantastic increased yield during green revolution. However, their negative effects on important agronomic traits such as grain yield, coleoptile length, early vigour, grain size and grain weight have also been reported, and the benefits of Rht-B1b and Rht-D1b semidwarf alleles are likely restricted in hot and dry rainfed conditions, such as Kazakhstan where average wheat yield has not changed from 1 t/ha in the last half century. There is the potential to apply genomic breeding methodologies to increase grain yield. The main reasons for unchanging wheat yields in Kazakhstan are i) breeders might have reached the limits of yield using only traditional plant breeding methodologies, ii) weather conditions, with extreme cold in winter and constant drought and heat in summer. Taller plants mostly outweigh their shorter counterparts in such harsh wheat growing environments.

So, what if we look for appropriate fixed allelic combinations of Iht genes? What if we stack several Iht genes to act together? As increased plant height is mostly suppressed in hot rainfed environments, is it possible that those Iht genes provide wheat with better adaptation characteristics?

To address the questions, we developed a segregating population, specially RILs, using two different wheat cultivars representing the two countries, UK and Kazakhstan, with completely different eco-geographical and climatic conditions. So far, RILs were assessed in controlled environment as well as in the field trails in both countries and genotyped with 15K Illumina iSelect. Important QTL underpinning central agronomic traits of wheat were found as a result of phenotypic and genotypic data integration using two different widely-employed software packages: WinQTLCart 2.5 and R-QTL. Consequently, two reliable and stable major QTLs, on two wheat chromosomes, for increased plant height have been identified in both glass house and across multiple field trials. We hypothesise that phenology and crop height are likely to be important adaptive traits. Therefore, two height increasing alleles have been used to develop NILs carrying that specific section of the genome of one parent in the background of second. To see the isolated effect of those genes on wheat adaptation, NILs have been sown in the UK and have been sent to Kazakhstan to be sown in spring 2019. Alongside with NILs, recombinants for two QTL regions are being developed and the exomes of parents are captured so as to identify candidate genes and putative causal polymorphisms.