Crop Centre in Print
Please find the latest journal publications from the Crop Centre listed below.
Read our articles in the Vegetable Farmer
For a full list of publications from the School of Life Sciences please visit the Latest Journal Publications
Genetic structure and domestication of carrot (Daucus carota subsp. sativus) (Apiaceae)
Massimo Iorizzo, Douglas A. Senalik , Shelby L. Ellison, Dariusz Grzebelus, Pablo F. Cavagnaro, Charlotte Allender, Johanne Brunet, David M. Spooner, Allen Van Deynze and Philipp W. Simon
Analyses of genetic structure and phylogenetic relationships illuminate the origin and domestication of modern crops. Despite being an important worldwide vegetable, the genetic structure and domestication of carrot (Daucus carota) is poorly understood. We provide the first such study using a large data set of molecular markers and accessions that are widely dispersed around the world.
Genetic regulation of glucoraphanin accumulation in Beneforté® broccoli
Maria H Traka, Shikha Saha, Stine Huseby, Stanislav Kopriva, Peter G Walley, Guy C Barker, Jonathan Moore, Gene Mero, Frans van den Bosch, Howard Constant, Leo Kelly, Hans Schepers, Sekhar Boddupalli and Richard F Mithen
Diets rich in broccoli (Brassica oleracea var italica) have been associated with maintenance of cardiovascular health and reduction in risk of cancer. These health benefits have been attributed to glucoraphanin that specifically accumulates in broccoli. The development of broccoli with enhanced concentrations of glucoraphanin may deliver greater health benefits.
Three high-glucoraphanin F1 broccoli hybrids were developed in independent programmes through genome introgression from the wild species Brassica villosa. Glucoraphanin and other metabolites were quantified in experimental field trials. Global SNP analyses quantified the differential extent of B. villosa introgression.
This study illustrates the translation of research on glucosinolate genetics from Arabidopsis to broccoli, the use of wild Brassica species to develop cultivars with potential consumer benefits, and the development of cultivars with contrasting concentrations of glucoraphanin for use in blinded human intervention studies.
New Phytologist Apr 2013 (online)
A strong immune response in young adult honeybees masks their increased susceptibiliity to infection compared to older bees
In this study, the researchers infected house and forager bees with an insect pathogen. They measured bee survival rate and the expression of genes that regulate the immune system. More immune genes were up regulated in house bees than foragers in response to infection, but foragers were more resistant to the pathogen than house bees.
Development of best practices for ex situ conservation of radish germplasm in the context of the crop genebank knowledge base
I. Thormann, Q. Yang, C. Allender, N. Bas, G. Campbell, M. E. Dulloo, A. W. Ebert, U. Lohwasser, C. Pandey and L. D. Robertson et al
Information about crop-specific best practices for ex situ conservation of plant genetic resources has been difficult to find until recently. The CGIAR, together with national and regional partners, started to fill that gap by publishing best practices on the crop genebank knowledge base (CGKB -http://cropgenebank.sgrp.cgiar.org/), a website specifically developed and officially launched in 2010 to provide easy access to knowledge about all aspects of ex situ conservation of specific crops to genebank managers and ex situ conservation researchers. A collaborative study, undertaken by Bioversity International with eight national and international genebanks, utilized the framework provided by the CGKB to develop and publish radish conservation best practices.
This paper focuses on two aspects of this study: (1) Differences in procedures and practices in radish conservation currently applied in five key genebank activities, namely, acquisition of germplasm, viability testing and monitoring, seed drying, seed storage, and regeneration. While in a few cases genebanks agreed on a specific best practice to recommend, in others it was not desirable to identify one practice as superior to another, therefore a range of existing practices is described as a variety of equivalent options. The results highlight the importance of proactive genebank management aimed at meeting the standards within the specific context in which a genebank operates. (2) The framework and template provided by the CGKB in guiding the development of genebank best practices, and the CGKB as an excellent resource to widely and freely share best practices with the global community to support the effective management of crop genebanks.
Evolved polygenic herbicide resistance in Lolium rigidum by low-dose herbicide selection within standing genetic variation
Roberto Busi, Paul Neve , Stephen Powles
The interaction between environment and genetic traits under selection is the basis of evolution. In this study, we have investigated the genetic basis of herbicide resistance in a highly characterized initially herbicide-susceptible Lolium rigidum population recurrently selected with low (below recommended label) doses of the herbicide diclofop-methyl. We report the variability in herbicide resistance levels observed in F1 families and the segregation of resistance observed in F2 and back-cross (BC) families. The selected herbicide resistance phenotypic trait(s) appear to be under complex polygenic control. The estimation of the effective minimum number of genes (NE), depending on the herbicide dose used, reveals at least three resistance genes had been enriched. A joint scaling test indicates that an additive-dominance model best explains gene interactions in parental, F1, F2 and BC families. The Mendelian study of six F2 and two BC segregating families confirmed involvement of more than one resistance gene. Cross-pollinated L. rigidum under selection at low herbicide dose can rapidly evolve polygenic broad-spectrum herbicide resistance by quantitative accumulation of additive genes of small effect. This can be minimized by using herbicides at the recommended dose which causes high mortality acting outside the normal range of phenotypic variation for herbicide susceptibility.
Herbicide cycling has diverse effects on evolution of resistance in Chlamydomonas reinhardtii
Mato Lagator, Tom Vogwill, Nick Colegrave, Paul Neve
Cycling pesticides has been proposed as a means of retarding the evolution of resistance, but its efficacy has rarely been empirically tested. We evolved populations of Chlamydomonas reinhardtii in the presence of three herbicides: atrazine, glyphosate and carbetamide. Populations were exposed to a weekly, biweekly and triweekly cycling between all three pairwise combinations of herbicides and continuously to each of the three herbicides. We explored the impacts of herbicide cycling on the rate of resistance evolution, the level of resistance selected, the cost of resistance and the degree of generality (cross-resistance) observed. Herbicide cycling resulted in a diversity of outcomes: preventing evolution of resistance for some combinations of herbicides, having no impacts for others and increasing rates of resistance evolution in some instances. Weekly cycling of atrazine and carbetamide resulted in selection of a generalist population. This population had a higher level of resistance, and this generalist resistance was associated with a cost. The level of resistance selected did not vary amongst other regimes. Costs of resistance were generally highest when cycling was more frequent. Our data suggest that the effects of herbicide cycling on the evolution of resistance may be more complex and less favourable than generally assumed.