Global Crop Diversity Trust Project - Summary
The focus of GCDT-funded activities is to phenotype a representative set of wild accessions for drought tolerance, which will enhance our long-term objective of identifying genes involved in abiotic stress tolerance and their deployment in cultivated chickpea. We focus in particular on transpiration-related phenotypes that conserve soil moisture, as such phenotypes have been correlated with drought tolerance in cultivated chickpea. Water availability is critical during reproduction and grain filling, and thus is a key factor in yield. Plant traits that conserve soil moisture even when water is not limiting are indeed likely to be relevant for yield improvement under limiting water conditions, especially in chickpea where the most relevant water stress is terminal drought.
Activities under GCDT are distinct from those conducted under the USAID award, as the former emphasizes the performance of wild accessions in the Turkish environment, while the later emphasizes the performance of introgressed, i.e, cultivated x wild genotypes, in the agricultural environment. The GCDT project engages partners in Turkey at Harran University in Sanliurfa, at the Aegean Agricultural Research Institute in Izmir, at Dicle University in Diyarbakir, Turkey, from ICARDA in Morocco, from Florida International University in Miami, US, and from the University of California-Davis in the US.
The project includes the twin objectives of germplasm curation and drought phenotyping.
Germplasm. Seed and passport have been deposited to the Aegean Agricultural Research Institute (AARI) in Izmir, Turkey. Turkish partners are amplifying seed over two growing seasons (March-June, 2015-2016), which will stabilize the resource at AARI and enable distribution to other international gene banks.
Phenotyping. Increased water use efficiency (WUE) has been pursued by crop breeders as a route to drought tolerance. However, screening for WUE can be cumbersome and expensive particularly when high hundreds or thousands of lines and plants are to be assessed in a relatively short time. Surrogate traits that contribute to WUE have been used to screen for WUE, including specific leaf area (SLA), specific leaf nitrogen or SPAD chlorophyll meter readings (SCMR), and carbon isotope discrimination, but these surrogates have proven to be of limited value for breeding drought tolerant varieties (Krishnamurthy et al. 2007; Devi et al. 2011, Vadez et al., 2014). More promising is the capacity of certain genotypes to conserve soil moisture. Such physiological strategies increase the likelihood of moisture availability during flowering and pod filling, when terminal drought takes its largest share of yield in many cultivated varieties.
During the project we will evaluate a total of 4 wild accessions from each of the 9 genetically defined populations. Within each population, data on pairwise nucleotide dissimilarity among genotypes will be used to select the 4 biological accessions. These 36 wild accessions will be phenotypically evaluated in greenhouse dry-down and vapour pressure deficit experiments conducted in Diyarbakir, Turkey.
This work is undertaken as part of the initiative "Adapting Agriculture to Climate Change: Collecting, Protecting and Preparing Crop Wild Relatives" which is supported by the Government of Norway. The project is managed by the Global Crop Diversity Trust with the Millennium Seed Bank of the Royal Botanic Gardens, Kew and implemented in partnership with national and international gene banks and plant breeding institutes around the world. For further information see the project website (http://www.cwrdiversity.org/) and the published CWR Strategy Publication.