Exploitation of epigenetic variation of crop wild relatives for crop improvement and agrobiodiversity preservation

Crop wild relatives (CWRs) are recognized as the best potential source of traits for crop improvement. However, successful crop improvement using CWR relies on identifying variation in genes controlling desired traits in plant germplasms and subsequently incorporating them into cultivars. Epigenetic diversity may provide an additional layer of variation within CWR and can contribute novel epialleles for key traits for crop improvement. There is emerging evidence that epigenetic variants of functional and/or agronomic importance exist in CWR gene pools. This provides a rationale for the conservation of epigenotypes of interest, thus contributing to agrobiodiversity preservation through conservation and (epi)genetic monitoring. Concepts and techniques of classical and modern breeding should consider integrating recent progress in epigenetics, initially by identifying their association with phenotypic variations and then by assessing their heritability and stability in subsequent generations. New tools available for epigenomic analysis offer the opportunity to capture epigenetic variation and integrate it into advanced (epi)breeding programmes. Advances in -omics have provided new insights into the sources and inheritance of epigenetic variation and enabled the efficient introduction of epi-traits from CWR into crops using epigenetic molecular markers, such as epiQTLs

Locating stable across environment QTL involved in the determination of agronomic characters in wheat

The International Triticeae Mapping Initiative (ITMI) recombinant inbred line (RIL) population was used to detect quantitative trait loci (QTL) underlying some key agronomic characters in bread wheat ( Triticum aestivum L.). Trait measurements were taken from five independent field experiments performed in Serbia. Stable across environment QTL involved in the determination of heading/flowering time and ear morphology/grain yield were detected on, respectively, chromosome arms 2DS and 4AL. These map locations are consistent with those obtained where the same population has been grown in contrasting geographical sites. However, as a result of QTL × environment interactions, not all these QTL are expressed in all environments. Nevertheless the (pleiotropic) effect on ear morphology appears to be expressed in almost all environments, and so represents a high value target for wheat improvement

Locating Stable Across Environment QTL Involved in the Determination of Agronomic Characters in Wheat

The International Triticeae Mapping Initiative (ITMI) recombinant inbred line (RIL) population was used to detect quantitative trait loci (QTL) underlying some key agronomic characters in bread wheat ( Triticum aestivum L.). Trait measurements were taken from five independent field experiments performed in Serbia. Stable across environment QTL involved in the determination of heading/flowering time and ear morphology/grain yield were detected on, respectively, chromosome arms 2DS and 4AL. These map locations are consistent with those obtained where the same population has been grown in contrasting geographical sites. However, as a result of QTL x environment interactions, not all these QTL are expressed in all environments. Nevertheless the ( pleiotropic) effect on ear morphology appears to be expressed in almost all environments, and so represents a high value target for wheat improvement

Improvement of Wheat Quality in Cultivars Released in Serbia during the 20(th) Century

Twenty wheat varieties were analyzed to assess the contribution of 40-year breeding process to the advancement of wheat technological quality. A trial using a randomized block design with three replications was carried out during five growing seasons (2001-2005) that varied in temperature and rainfall conditions. Changes of quality were analyzed in the varieties from different breeding periods using linear regression analysis. Changes of quality indicators were expressed by regression coefficients. The studied varieties were released at 3-4-year intervals. The annual changes in genetic potentials were as follows: protein content - -0.03%, wet gluten - -0.14%, farinograph absorption -0.04%, dough energy - 1.53 cm(2), loaf volume 2.94 ml, and baking score - 0.07. The decreases in the protein and wet gluten contents were compensated for by an improvement in protein quality. The increase in gluten structure stability and appropriate combinations of high molecular weight glutenin subunits have contributed to the improvement of other quality indicators

Strategy for exploiting exotic germplasm using genetic, morphological, and environmental diversity: the Aegilops tauschii Coss. example

Hexaploid bread wheat evolved from a rare hybridisation, which resulted in a loss of genetic diversity in the wheat D-genome with respect to the ancestral donor, Aegilops tauschii. Novel genetic variation can be introduced into modern wheat by recreating the above hybridisation; however, the information associated with the Ae. tauschii accessions in germplasm collections is limited, making rational selection of accessions into a re-synthesis programme difficult. We describe methodologies to identify novel diversity from Ae. tauschii accessions that combines Bayesian analysis of genotypic data, sub-species diversity and geographic information that summarises variation in climate and habitat at the collection point for each accession. Comparisons were made between diversity discovered amongst a panel of Ae. tauschii accessions, bread wheat varieties and lines from the CIMMYT synthetic hexaploid wheat programme. The selection of Ae. tauschii accessions based on differing approaches had significant effect on diversity within each set. Our results suggest that a strategy that combines several criteria will be most effective in maximising the sampled variation across multiple parameters. The analysis of multiple layers of variation in ex situ Ae. tauschii collections allows for an informed and rational approach to the inclusion of wild relatives into crop breeding programmes