This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.
Breeding for increased drought tolerance in wheat: a review
Drought being a yield limiting factor has become a major threat to international food security. It is a complex trait and drought tolerance response is carried out by various genes, transcription factors, microRNAs, hormones, proteins, co-factors, ions, and metabolites. This complexity has limited the development of crop cultivars for drought tolerance. Breeding for drought tolerance is further complicated since several types of abiotic stress, such as high temperatures, high irradiance, and nutrient toxicities or deficiencies can challenge crop plants simultaneously. Although marker-assisted selection is now widely deployed in wheat, it has not contributed significantly to cultivar improvement for adaptation to low-yielding environments and breeding has relied largely on direct phenotypic selection for improved performance in these difficult environments. Advances in crop plant breedingscience to produce improved and higher-performing wheat cultivars are key to making dryland food production systems more efficient and more resistant to pressure from drought, extremes of cold and heat, unpredictable rainfall, and new pests and diseases. For optimal performance, varieties wheat cultivars can be targeted to specific farming systems, depending on local conditions and stresses. Genetic gain in wheat yield potential during the last cCentury achieved by plant breeding and has been well documented for wheat species. It has been studied by comparing in the same ﬁeld trial the yield of cultivars characterized by different years of release. Genomic selection (GS) and high-throughput phenotyping (HTP) have recently been captivating the interest of the plant breeders and both approaches promise to revolutionize the prediction of complex traits, including growth, yield and adaptation to stress. A linear relation between yield and year of release was found in wheat, which gives an estimate of the genetic improvement. In Tthis review, we describes the impact of drought on yield, trends in yield for boosting crop yields to meet the projected demands from rising population in the world by 2050, genetic gain achived by plant breeding in the last decades; and gathering any known functional information on the genes, metabolites and traits and their direct involvement in conferring drought tolerance in wheat. In addition, recent developments techniques i.e., genome selection (GS) and high throughput phenotyping (HTP) in integrated with current approaches such as breeding, genetics, genomics, and agronomic strategies for improving resistance against drought in wheat are discussed.
CP17387 Accepted 21 November 2017
© CSIRO 2017