Advances in Legume Crops Research

Dear Colleagues,

Legumes are important crops in diversifying farming systems, being able to fix nitrogen and improving soil structure. The ability of fixing nitrogen contributes to reducing the use of chemical fertilizers, which are expensive and unfriendly for the environment. They also reduce the carbon footprint They contribute to food and nutritional security through diversified food systems. However, legume crops remain marginalized in many countries due to policy issues which favor cereals over legumes. Legumes are also affected by diverse biotic (diseases, parasitic weeds, and insects) and abiotic stresses (heat, frost, drought, salinity, soil acidity, nutrient deficiency). Conventional breeding approaches have resulted in significant genetic improvement in legume crops, and improved cultivars have been developed for cultivation in different agro-ecologies. However, low genetic gains have been reported in legume crops grown in developing countries, which indicate production gaps and low self-sufficiency. Significant research has been carried out on introgression desirables genes from crop-wide relatives, and development efforts have been made in the past decade on important legumes at advanced research institutes and in the CGIAR centers, which have led to valuable genomic resources and genomic tools such as draft genome sequence, resequencing data, large-scale genome wide markers, dense genetic maps, quantitative trait loci (QTLs), and diagnostic markers. These tools are essential to the modernization of breeding programs and accelerate the breeding cycle, which can increase genetic gains when integrated with a speed breeding approach.

Dr. Fouad S. Maalouf
Dr. Diego Rubiales
Guest Editors

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• genomics in legumes
• genetics
• molecular breeding and marker-assisted selection/breeding
• biotic and abiotic stresses
• genetic resources
• wild relatives
• genomic selection
• modern breeding methods
• G x E interaction
• rapid advancement generation
• genetic gains

Title: Selection for Phytophthora root rot resistance in chickpea crosses affects yield potential
Authors: Sean Bithell1, David Backhouse2, Andre Drenth3, Steve Harden1, and Kristy Hobson1
Affiliation: 1New South Wales Department of Primary Industries, Tamworth, New South Wales, Australia. 2University of New England, Armidale, New South Wales, Australia. 3University of Queensland, Brisbane, Queensland, Australia.
Abstract: Phytophthora root rot of chickpea (Cicer arietinum) caused by Phytophthora medicaginis is an important disease. Resistance is based on chickpeaxCicer echinospermum crosses providing quantitative and partial resistance. We tested if selection for lines with low levels of foliage symptoms in two contrasting recombinant inbred (RIL) populations of chickpeaxC. echinospermum crosses led to the selection of material that maximises yield. For the var. YorkerxC. echinospermum backcross RIL population with the highest level of resistance, in the absence of Phytophthora root rot, significant linkage drag effects were observed for later flowering, later podding, lower grain yields and 100 seed weight between low and high foliage symptom RIL groups. For the var. RupalixC. echinospermum backcross RIL population, with lower levels of resistance, the only significant difference between low and high foliage symptoms groups was for 100 seed weight. Across four P. medicaginis inoculated experiments and a natural inoculum experiment comparing low and high foliage symptom RIL groups, survival to maturity was the most consistently related foliage symptom parameter. Survival to maturity was more strongly related across experiments than grain yields. Comparison of foliage symptom parameters as grain yield predictors showed that for inoculated experiments the area under the disease progress stairs was the more consistent predictor of yield. Overall results showed foliage symptom based selection included some high yielding RIL in the most resistant population. Additional selection efforts in the absence of PRR disease will be required to identify the material with both the highest levels of PRR resistance and grain yield potential.

Title: Transcriptomic Analysis Reveals the Defense Mechanisms of Common Bean (Phaseolus vulgaris L.) Infested with Anthracnose
Authors: Zhiyuan Li1, Daping Gong1, Xu Kaiyuan2, Mingli Chen1*
Affiliation: 1. Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China 2. Harbin Institute of Technology, Weihai
Abstract: Abstract: Anthracnose (ANT), caused by the fungus Colletotrichum lindemuthianum, is one of the most destructive disease in common bean growth process. Until now, more than 100 physiologic races of Anthracnose have been identified around the world. Among them, the physiologic race No. 81 is the dominant race of anthracnose in China, which is widely distributed in bean growing areas. In this study, the expression pattern of various genes were analyzed in common bean plants that were infested by ANT for different durations (12, 24, and 48 hours). A total of 8,284 DEGs were significantly differentially expressed in response to ANT infection at all three time points. Several pathways related to defense were induced after ANT infection, such as cell wall biosynthesis, MAPK cascades, phenylpropanoid and Ca2+ influx, and some pathways related to defense reactions and signal transduction were activated in response to ANT infestation. After ANT infestation, the expression of several genes was significantly altered, including R proteins, phytohormones, transcription factors, and genes associated with secondary metabolite synthesis. At the molecular level, these findings greatly improve our understanding of the defense mechanisms of common bean plants against ANT infestation. The identification and functional characterization of the defense-related genes in this study will aid the molecular breeding of insect-resistant common bean varieties.

Title: GWAS analysis for quality traits (protein, tannin, vicine convicine content) in faba bean
Authors: Gutierrez N1, Moreno JM1, Ordóñez JL1, Pegard M2, Solis I3, Howard C4, Sokolovic D5, Torres AM1
Affiliation: 1 Área de Mejora Vegetal y Biotecnología, IFAPA Centro “Alameda del Obispo”, 14080, Córdoba, Spain 2 INRA, Centre Nouvelle-Aquitaine-Poitiers, UR4 (URP3F), 86600, Lusignan, France 3 Agrovegetal S.A., Demetrio de los Rios 15, 41003 Sevilla, Spain 5 Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth, Ceredigion SY23 3EE, UK 4 Institute for Forage Crops, 37251 Globoder, Kruševac, Serbi
Abstract: NA at this moment. Data analysis in process

Title: Negative Effects of Nitrogen Fertilizer on Fixation in Common Bean
Authors: Yarmilla Reinprecht1, Lyndsay Schram1, Samantha Keyes1, John Sulik1, Jamie Larsen2, Brett Hill3, Thomas H. Smith1, and K. Peter Pauls1
Affiliation: 1Department of Plant Agriculture, University of Guelph, Guelph, ON, Canada 2Harrow Research and Development Centre, Agriculture and Agri-Food Canada, Harrow, ON, Canada 3Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada
Abstract: Common (dry) bean (Phaseolus vulgaris L.) is the most important legume crop used for direct human consumption. Generally viewed as a poor nitrogen fixer, the crop is frequently fertilized with nitrogen in order to achieve high yields but this also inhibits nitrogen fixation. The main focus of this work is to reduce nitrogen application in common bean crop production. Initial work with genotypes from the Sanilac x Mist mapping population demonstrated variation in inhibition of nitrogen fixation by addition of nitrogen fertilizer. In some genotypes, nitrogen fixation was less affected by added nitrogen fertilizer. The objective of the current study was to evaluate a set of diverse bean genotypes for their capacity to fix atmospheric nitrogen in the presence of some nitrogen fertilizer. Twenty-one beans, including nine from the initial study, were tested under different nitrogen regimes {three sources of Rhizobium [no Rhizobium (0R) and two commercially available inoculants (OldR – strain used in the initial work and NewR - Nodulator) and three levels of nitrogen [50 kg ha-1 (50N), 100 kg ha-1 (100N) and no nitrogen (0N)]} in replicated trials using a split-split-plot design (SSPD) on N-poor land at the University of Guelph Elora Research Station over three years. In addition to the commonly collected field data, Unmanned Aerial Vehicle (UAV) based remote sensing data were recorded for trials. Genotypes were significantly different for all analyzed traits, including yield and nitrogen fixation [measured as percent nitrogen derived from atmosphere (%Ndfa)] and yield. As expected, nitrogen significantly affected most of the analyzed traits. However, averaged over three years, the effect of rhizobia on most traits was marginal. The highest yield was achieved under the OldR_50N treatment while the %Ndfa was highest in the control treatment (0R_0N). In addition to confirm the good performance of lines RIL38 and RIL119, the study also identified a few bean cultivars commonly grown in Ontario that were high yielding and good nitrogen fixers under most of the applied nitrogen regimes. These genotypes may be useful for joint improvement of both traits. Additionally, there is potential to use UAV-based vegetation indices to predict yield as indicated by significant positive correlations between the traits.