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The combined problems of climate change, population growth, and increased demands on a declining natural resource base force scientists to push crop performance to its limits. A powerful strategy is to explore genetic resources to identify promising material that can be used directly in breeding, for gene discovery, and to further understand the mechanisms of adaptation. Initially traits must be defined for stress targets using conceptual models, examples being better root systems to access subsoil deep water and the ability to store and remobilize water soluble carbohydrates from storage tissue. New sources of diversity for such traits can be found in collections such as the World Wheat Collection housed at CIMMYT; for example, Mexican landraces provide good sources of both of these traits. Being a polyploid, wheat has a useful secondary gene pool that can be used to re-synthesize hexaploid wheat, while transgenic approaches remove all taxonomic limits to plant improvement. To efficiently explore genetic resources, for crop improvement and to identify genetic and mechanistic bases, requires high throughput phenotyping approaches. For example, an airborne remote sensing platforms is used to determine spectral indices associated with temperature, water content, and pigment composition of leaves via thermal and multispectral imagery. Using the above approaches, best lines are used directly in pre-breeding to combine favorable combinations of traits and their alleles. These approaches have already delivered a new generation of drought adapted lines where cumulative gene action on yield is observed through strategic combination of stress adaptive traits many coming from landraces or products of wide crossing with wheat wild relatives.

In the last years there has been enormous progress in the molecular understanding of fungal disease resistance in plants. Research on effector-based immunity which is mediated by major resistance () genes has been greatly stimulated by the molecular isolation of plant resistance genes as well as the first fungal effectors. In addition, the first genes underlying QTLs or partial disease resistance have been cloned. However, much of this work is still in a phase of basic research and there is a need for translational approaches to realize the globally needed improvements of disease resistance in wheat. In particular, it is essential that future strategies are aiming at achieving durable resistance against pathogens. Durable resistance has been defined by Johnson (Genetic background of durable resistance. In: Lamberti F, Waller JM, Van der Graaff NA (eds) Durable resistance in crops. Plenum, New York, pp 5–24, 1983) as a resistance which remains effective in cultivars that are widely grown for long periods and in environments favorable to the disease. In this article we will discuss different molecular strategies towards achieving durable disease resistance in wheat. In particular, our group focuses on the allelic series of race-specific powdery mildew genes and the race non-specific multi-pathogen resistance gene.

Since 1956, our group has been working on the wide hybridization between wheat and tall wheatgrass ( Liu & Wang, 2n = 70). During the past 56 years, we developed a set of partial amphiploids (octoploids), addition lines, substitution lines, translocation lines. A series of wheat cultivars named as Xiaoyan, such as Xiaoyan 4, 5, 6, 54, 60 and 81 were released. They generally have multiple disease resistance and good adaptability to various environments. These traits might derive from tall wheatgrass, especially with respect of resistance to biotic and abiotic stresses. In this paper, we briefly review the history of this study focusing on research background, alien parental selection, establishment of breeding procedure, new germplasms and their application, as well as the newest varieties and their performance to biotic and abiotic stresses.

The International Wheat Improvement Network (IWIN), an alliance of national agricultural research systems (NARSs), International Maize and Wheat Improvement Center (CIMMYT), International Center for Agricultural Research in the Dry Areas (ICARDA), and advanced research institutes (ARIs), continues to deploy cutting-edge science alongside practical multi-disciplinary applications, resulting in the development of germplasm that has made major contributions during the Green Revolution. The continuous supply of improved germplasm for nearly half a century has also enabled developing countries to have a sustained increase of wheat production and productivity and thereby improving food security and farmers’ livelihoods. Wheat production levels have increased from 235 million tons in 1961 to 691 million tons in 2012. Yet, global food consumption has exceeded production for 6 of the last 11 years (2004–2010), and food reserves are now ‘dangerously low,’ particularly for staple grains such as wheat and maize. Changing diets, urbanization, and other factors mean that demand for wheat is likely to only multiply further, and therefore wheat yields must increase from the current global average of 3 t per hectare. According to some estimates, the global wheat production must increase at least by 1.6 % annually to meet a projected yearly wheat demand of 760 million tons by 2020. In the year 2050, the world population is estimated to be nine billion and the demand for wheat reaches more than 900 million tons. Fulfilling this demand is very challenging with the current scenario of climate change, increasing drought/water shortage, soil degradation, reduced supply & increasing cost of fertilizers, increasing demand for bio-fuel, and emergence of new virulent diseases and pests. This paper presents a review and insight about the past and current contributions of IWIN, breeding progresses and genetic gains, and its future role in offsetting the major global challenges of wheat production.

Genotyping-by-sequencing technology is rapidly reducing marker costs and increasing genome coverage allowing the widespread use of molecular markers and methods in plant breeding. Marker assisted selection (MAS) and recurrent selection are based on the selection of statistically significant, marker-trait associations. However, MAS strategies are not well suited for complex traits controlled by many genes. Genomic selection (GS) incorporates genome-wide marker information in a breeding value prediction model, thereby minimizing biased marker effect estimates and capturing more of the variation due to small effect QTL. In GS, a training population related to the breeding germplasm is genotyped with genome-wide markers and phenotyped in a target set of environments. That data is used to train a prediction model that is used to estimate the breeding values of lines in a population using only the marker scores. Prediction models can incorporate performance over multiple environments and assess G x E effects to identify a highly predictive subset of environments. Because of reduced selection cycle time, annual genetic gain for GS is predicted to be two to threefold greater than for a conventional phenotypic selection program. We have developed a new methodology for using genome-wide marker effects to group environments and identify outliers. In addition, environmental covariates can be identified that increase prediction accuracy and facilitate performance prediction in climate change scenarios. This new approach to crop improvement will facilitate a better understanding of the dynamic genome processes that generate and maintain new genetic variation.

Dietary fibre (DF) has been shown to be a vital component of diet for human health, decreasing the risk of cardiovascular disease, type II diabetes and possibly bowel cancer. DF in wheat flour is derived from the cell walls of the starchy endosperm, which is principally composed (~70 %) of the polysaccharide arabinoxylan (AX). Diversity screens of elite wheat germplasm have established that variation in total and water-extractable AX within flour exists and has high heritability. Identification of genes which determine AX content will assist in introduction of high DF alleles into appropriate backgrounds. We identified candidate genes for the synthesis and feruloylation of AX from bioinformatics approaches. Using RNAi suppression of genes in wheat endosperm, we have shown that a glycosyl transferase (GT) family 61 gene is responsible for nearly all mono-substitution of xylose by arabinose on AX, and that genes in GT43 and GT47 families are responsible for the synthesis of the xylan backbone in AX. Using mapping populations derived from crosses of high AX x normal AX varieties, we are also seeking to identify QTLs for high AX. This combination of forward and reverse genetics will accelerate the introduction of the high fibre alleles into modern commercial wheat varieties.