Using Lens lamottei to transfer anthracnose resistance to lentil varieties

Non-Peer ReviewedAnthracnose is a serious fungal disease of lentil that can cause severe yield loss. It is now widespread in Saskatchewan and can be devastating in years with warm wet weather. Producers are limited to controlling this disease by crop rotation, foliar spray or development of varieties with resistance to anthracnose. Pathology research shows that we have two major strains of lentil anthracnose. Varieties like CDC Robin have resistance to one of the strains, but after exhaustive screening of cultivated lentil germplasm, no resistance was found to the second strain of anthracnose. One of the newly discovered wild species of lentil, Lens lamottei, has recently been discovered to have resistance to a combination of both strains of anthracnose when grown under field conditions in an inoculated disease nursery. The objective of this project is to determine if L. lamottei can be by crossed with L. culinaris in order to transfer anthracnose resistance into lentil varieties

RAPD and AFLP markers linked to anthracnose resistance gene in PI 320937 lentil (Lens culinaris Medik.)

Non-Peer ReviewedColletotrichum truncatum (Schwein.) Andrus & W.D. Moore is the causal fungus for anthracnose disease in lentils. A germplasm accession, ‘PI 320937’, is among the lines used as a resistance source to develop cultivars in the breeding program. A cross of Eston (susceptible) and PI 320937 (resistant) was used to develop 147 recombinant inbred lines (RILs) to study the genetics of resistance and identify markers associated to the resistance gene. The F5:6 RILs were inoculated with C. truncatum isolate 95B36 at 105 conidia ml-1 and scored for anthracnose reactions over 2 replications in the greenhouse. About 600 RAPD and 10 AFLP primers were screened. We used bulk segregant analysis to construct contrasting DNA bulks, one containing only resistant and the other only susceptible plants based on the greenhouse tests. These polymorphic markers between parental lines were used to genotype RILs and make linkage analysis. Segregation data indicated that a single major gene (LCt-2) confers resistance. Minor genes also modified the level of resistance. Two RAPD markers; namely, OPE O61250 and UBC 704700 were linked in repulsion and coupling at 6.4 and 10.8 cM, respectively, to the resistance gene. Also, 3 AFLP markers were identified within 30 cM distance from the resistance locus. These markers will be useful in lentil breeding via marker-assisted selection towards developing cultivars with anthracnose resistance

Genetic study of Ascochyta blight resistance in chickpea and lentil

Non-Peer ReviewedAscochyta blight is responsible for severe crop losses in most chickpea and lentil production areas around the world. The research was conducted to study the genetic basis for Ascochyta blight resistance in chickpea and lentil by means of QTL analysis, and PCR-based approaches to identify resistance gene analogues (RGA) sequences in the lentil genome. An AFLP and three SSR markers were linked to the gene(s) for Ascochyta resistance in a chickpea population derived from a cross between CDC Chico and CDC Marengo. Two QTL that explained 36 % and 29 % of the disease reaction variability were identified in a lentil RI population derived from a cross between ILL5588 and L692-16-1. These markers were converted into SCAR markers to simplify their use for marker-assisted selection

Genetic improvement of chickpea for western Canada

Non-Peer ReviewedThe chickpea crop has experienced a roller-coaster ride over the past decade in western Canada. Production rose rapidly in the late 1990’s, followed by dramatic declines in the past two years. Instability can be attributed to many factors including commodity prices, erratic weather patterns, Ascochyta blight and late maturity. This paper summarizes current research on genetic improvement of chickpea at the University of Saskatchewan, with particular emphasis on efforts to improve Ascochyta blight resistance and to develop varieties with earlier maturity. Under ‘average’ weather conditions, chickpea remains an excellent nitrogen-fixing crop for the Brown and Dark Brown soil zones

Revisiting strategies for breeding anthracnose resistance in lentil: the case with wild species

Non-Peer ReviewedBreeders at the Crop Development Centre (CDC) have up to now only used germplasm resources available in the cultivated lentil to develop new varieties with resistance to diseases. Based on recent studies, the available cultivated germplasm does not offer sufficient genetic variation for resistance to anthracnose and ascochyta diseases. Lentil crop is attacked by two major diseases (anthracnose and ascochyta) that can cause 100% loss in the worst scenarios. Since anthracnose is only a major lentil disease in North America, no work has been done to improve resistance to this disease elsewhere. Wild species of many crops are known to carry many disease resistance genes lacking in the cultivated crop. We began the search for anthracnose resistance in the six wild species of lentil (world collection), of which two can be easily crossed with the cultivated type. Two strains of anthracnose (race 1 and race 2) with varying degrees of virulence were reported. The 2002 field data suggested that some of the Lens ervoides and Lens lamottei accessions exhibited no lesions at all when exposed to the combination of the two anthracnose strains. The cultivated types that show resistance to the less virulent strain were severely affected by anthracnose. In the greenhouse study the wild species were inoculated with the two strains separately and results indicate that no accession is immune to the more virulent type. However, some of the L. ervoides and L. lamottei accessions had good resistance compared to their cultivated counterparts. As a long term strategy, the lentil breeding program at CDC, University of Saskatchewan has a goal of fully utilizing the available resistance sources. However, these two species cannot be easily crossed with the cultivated types using the conventional/manual crossing techniques. A tissue culture procedure involving embryo rescue is used to facilitate crossing. We have been able to successfully rescue some embryos from crosses with Lens ervoides. The hybrid plants produce some fertile seeds which will be evaluated for resistance to both anthracnose and ascochyta. The selected resistant lines will then be backcrossed to the adopted backgrounds in order to deploy resistance genes

Horizontal transmission of the symbiont Microsporidia MB in Anopheles arabiensis

<jats:p>The recently discovered <jats:italic>Anopheles</jats:italic> symbiont, <jats:italic>Microsporidia MB</jats:italic>, has a strong malaria transmission-blocking phenotype in <jats:italic>Anopheles arabiensis</jats:italic>, the predominant <jats:italic>Anopheles gambiae</jats:italic> species complex member in many active transmission areas in eastern Africa. The ability of <jats:italic>Microsporidia MB</jats:italic> to block <jats:italic>Plasmodium</jats:italic> transmission together with vertical transmission and avirulence makes it a candidate for the development of a symbiont-based malaria transmission blocking strategy. We investigate the characteristics and efficiencies of <jats:italic>Microsporidia MB</jats:italic> transmission between <jats:italic>An. arabiensis</jats:italic> mosquitoes. We show that <jats:italic>Microsporidia MB</jats:italic> is not transmitted between larvae but is effectively transmitted horizontally between adult mosquitoes. Notably, <jats:italic>Microsporidia MB</jats:italic> was only found to be transmitted between male and female <jats:italic>An. arabiensis</jats:italic>, suggesting sexual horizontal transmission. In addition, <jats:italic>Microsporidia MB</jats:italic> cells were observed infecting the <jats:italic>An. arabiensis</jats:italic> ejaculatory duct. Female <jats:italic>An. arabiensis</jats:italic> that acquire <jats:italic>Microsporidia MB</jats:italic> horizontally are able to transmit the symbiont vertically to their offspring. We also investigate the possibility that <jats:italic>Microsporidia MB</jats:italic> can infect alternate hosts that live in the same habitats as their <jats:italic>An. arabiensis</jats:italic> hosts, but find no other non-anopheline hosts. Notably, <jats:italic>Microsporidia MB</jats:italic> infections were found in another primary malaria African vector, <jats:italic>Anopheles funestus s.s</jats:italic>. The finding that <jats:italic>Microsporidia MB</jats:italic> can be transmitted horizontally is relevant for the development of dissemination strategies to control malaria that are based on the targeted release of <jats:italic>Microsporidia MB</jats:italic> infected <jats:italic>Anopheles</jats:italic> mosquitoes.</jats:p&gt

The GCP molecular marker toolkit, an instrument for use in breeding food security crops

Crop genetic resources carry variation useful for overcoming the challenges of modern agriculture. Molecular markers can facilitate the selection of agronomically important traits. The pervasiveness of genomics research has led to an overwhelming number of publications and databases, which are, nevertheless, scattered and hence often difficult for plant breeders to access, particularly those in developing countries. This situation separates them from developed countries, which have better endowed programs for developing varieties. To close this growing knowledge gap, we conducted an intensive literature review and consulted with more than 150 crop experts on the use of molecular markers in the breeding program of 19 food security crops. The result was a list of effectively used and highly reproducible sequence tagged site (STS), simple sequence repeat (SSR), single nucleotide polymorphism (SNP), and sequence characterized amplified region (SCAR) markers. However, only 12 food crops had molecular markers suitable for improvement. That is, marker-assisted selection is not yet used for Musa spp., coconut, lentils, millets, pigeonpea, sweet potato, and yam. For the other 12 crops, 214 molecular markers were found to be effectively used in association with 74 different traits. Results were compiled as the GCP Molecular Marker Toolkit, a free online tool that aims to promote the adoption of molecular approaches in breeding activities

Genomics-assisted breeding in four major pulse crops of developing countries: present status and prospects

The global population is continuously increasing and is expected to reach nine billion by 2050. This huge population pressure will lead to severe shortage of food, natural resources and arable land. Such an alarming situation is most likely to arise in developing countries due to increase in the proportion of people suffering from protein and micronutrient malnutrition. Pulses being a primary and affordable source of proteins and minerals play a key role in alleviating the protein calorie malnutrition, micronutrient deficiencies and other undernourishment-related issues. Additionally, pulses are a vital source of livelihood generation for millions of resource-poor farmers practising agriculture in the semi-arid and sub-tropical regions. Limited success achieved through conventional breeding so far in most of the pulse crops will not be enough to feed the ever increasing population. In this context, genomics-assisted breeding (GAB) holds promise in enhancing the genetic gains. Though pulses have long been considered as orphan crops, recent advances in the area of pulse genomics are noteworthy, e.g. discovery of genome-wide genetic markers, high-throughput genotyping and sequencing platforms, high-density genetic linkage/QTL maps and, more importantly, the availability of whole-genome sequence. With genome sequence in hand, there is a great scope to apply genome-wide methods for trait mapping using association studies and to choose desirable genotypes via genomic selection. It is anticipated that GAB will speed up the progress of genetic improvement of pulses, leading to the rapid development of cultivars with higher yield, enhanced stress tolerance and wider adaptability