DETECTING GENETIC DIVERSITY AMONG BARLEY LANDRACES GROWN IN THE WEST-BANK, PALESTINE IN 2010-2011

ABSTRACT Fifteen barley landraces were collected from different localities in the West-Bank,-Palestine during 2009. A field experiment was conducted at the Faculty of Agriculture-An Najah National University to evaluate several agronomical traits of these landraces in 2010-2011 growing season. Cluster analysis was performed using the complete-linkage method, genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), broad sense heritability (H 2 ), and genetic advance (GA) were calculated for the quantitative traits. Significant diversity was exhibited among the landraces regarding days to 90% heading, 100-grain weight, number of grains per spike, spike length, and awns length. The Cluster analysis showed high genetic diversity among the collected landraces with dissimilarity ranging from 0.26 to 0.75. The fifteen landraces were grouped into four clusters. Genotypic coefficient of variation ranged from 6.1 to 22.9, whereas phenotypic coefficient of variation ranged from 6.6 to 41.8 with maximum phenotypic and genotypic variability observed for number of fertile tellers, number of grains per spike and spike length. Moderate to high heritability (broad sense) estimates (70-87%) were found for most of the characters. The genetic advance was highest for number of grains per spike (39.4%), followed by spike length (37.2%). High positive significant correlations were found among the different studied traits with correlation coefficient ranging from 0.395 to 0.536. The results of this study indicated high genetic diversity among barley landraces in Palestine, which make them potential sources for selection and hybridization programmes

Characterisation of barley resistance to rhynchosporium on chromosome 6HS

Key Message: Major resistance gene to rhynchosporium, Rrs18, maps close to the telomere on the short arm of chromosome 6H in barley. Rhynchosporium or barley scald caused by a fungal pathogen Rhynchosporium commune is one of the most destructive and economically important diseases of barley in the world. Testing of Steptoe × Morex and CIho 3515 × Alexis doubled haploid populations has revealed a large effect QTL for resistance to R. commune close to the telomere on the short arm of chromosome 6H, present in both populations. Mapping markers flanking the QTL from both populations onto the 2017 Morex genome assembly revealed a rhynchosporium resistance locus independent of Rrs13 that we named Rrs18. The causal gene was fine mapped to an interval of 660 Kb using Steptoe × Morex backcross 1 S₂ and S₃ lines with molecular markers developed from Steptoe exome capture variant calling. Sequencing RNA from CIho 3515 and Alexis revealed that only 4 genes within the Rrs18 interval were transcribed in leaf tissue with a serine/threonine protein kinase being the most likely candidate for Rrs18.Max Coulter, Bianca Büttner, Kerstin Hofmann, Micha Bayer, Luke Ramsay, Günther Schweizer, Robbie Waugh, Mark E. Looseley, Anna Avrov

Search for partial resistance against Puccinia hordei in barley landraces from the Fertile Crescent

A collection of 111 barley landraces from the Fertile Crescent was screened for resistance to barley leaf rust in the field and under controlled conditions. Large variation was observed for disease severity under field conditions. Accessions with high resistance because of hypersensitivity were identified. Also segregation was observed in some accessions, with individual plants showing hypersensitive reactions (IT ≤ 6). Partial resistance due to a reduction of infection in spite of a compatible infection was commonly found (19%). Resistance of 12 accessions selected for their low disease severity and high IT, was shown to be due to a prolonged latency period and increased percentage of early aborted colonies not associated with host cell necrosis. A high correlation was observed between the microscopic and macroscopic components of partial resistance.The Spanish Agency for International Cooperation (AECI) and CICYT project AGL2005-01781 for financial support.Peer reviewe

Identification of a new pathotype of Puccinia hordei with virulence for the resistance gene Rph7

Barley leaf rust resistance gene Rph7, derived from barley accession Cebada Capa, is the most effective R-gene for resistance to Puccinia hordei. Virulence for this gene was known in the USA, Israel and Morocco but not yet in Europe. We found an unexpected leaf rust infection in the field at Córdoba, Spain in 2004 on Rph7 carrying lines. This virulence for Rph7 was confirmed in growth chamber experiments, being the first report of Rph7 virulence in European populations of P. hordei. A collection of 680 barley accessions was screened for resistance against this new isolate. Twelve accessions showed segregation with individual plants showing resistance based on hypersensitivity (low infection type). These individual resistant plants were selected and grown in the greenhouse to obtain seeds.The Spanish Agency for International Cooperation and CICYT project AGL2005-01781 for financial support.Peer reviewe

Screening for Resistance to Leaf Rust (Puccinia hordei) in a Collection of Spanish Barleys

A collection of 418 Spanish barley accessions was screened for resistance to leaf rust in the field at Córdoba, Spain during the 2002–2003 season. Six accessions displaying the lowest disease severity with no macroscopically visible necrosis were selected for further studies on components of resistance. Five of them showed a significantly higher relative latency period than the susceptible line L94 and were similar to the partially resistant Vada. All of them showed lower relative infection frequency and smaller colony size than the susceptible L94 under controlled conditions. Histological studies indicated that the resistance in four of these accessions was based on a higher percentage of early aborted colonies not associated with host cell necrosis. In the remaining two accessions, resistance was based on hypersensitivity.We gratefully acknowledge Dr. Rients Niks for critical reading of the manuscript, CRF, INIA Madrid for kindly providing the accessions used in this study, the Spanish Agency for International Cooperation and CICYT projects AGF99-1036-CO1 and AGL2005-01781 for financial support.Peer reviewe

The resistance to leaf rust and powdery mildew of recombinant lines of barley (Hordeum vulgare L.) derived from H. vulgare × H. bulbosum crosses

A set of 23 recombinant lines (RLs) of barley (Hordeum vulgare L.) derived from H. vulgare × H. bulbosum L. crosses was inoculated with barley leaf rust (Puccinia hordei) and powdery mildew (Blumeria graminis f.sp. hordei) at the seedling stage to identify their levels and mechanisms of resistance. Eight RLs were studied further in glasshouse and field tests. All three barley parents (‘Emir’, ‘Golden Promise’ and ‘Vada’) were highly susceptible to powdery mildew and leaf rust isolates. Several RLs showed partial resistance expressed as high relative latency periods and low relative infection frequencies against leaf rust. This high level of partial resistance was due to a very high level of early aborting colonies without host cell necrosis. Several RLs showed hypersensitive resistance to some or all isolates. For powdery mildew, one RL was completely resistant to the CC1 isolate and had a hypersensitive resistance to the CO-02 isolate. Three RLs derived from ‘Emir’ were completely resistant to both powdery mildew isolates, and three more RLs tested in the field had higher levels of partial resistance than their parents. The results indicate that H. bulbosum contains major and minor gene(s) for resistance to leaf rust and powdery mildew that can be transferred to cultivated barley.The authors acknowledge the Spanish Agency for International Cooperation (AECI), CICYT projects AGF99-1036-CO1 and AGL2005-01781 for financial support in Spain. R. Pickering acknowledges the financial support of the Foundation for Research, Science and Technology (New Zealand).Peer reviewe

Identification of QTLs for powdery mildew and scald resistance in barley

A population of 103 recombinant inbred lines (RILs, F9-derived lines) developed from the two-row spring barley cross L94 × ‘Vada’ was evaluated under field conditions for resistance against powdery mildew (Blumeria graminis f.sp. hordei) and scald (Rhynchosporium secalis). Apart from the major resistance gene mlo on chromosome 4 (4H), three QTLs (Rbgq1, Rbgq2 and Rbgq3) for resistance against powdery mildew were detected on chromosomes 2 (2H), 3 (3H), and 7 (5H), respectively. Rbgq1 and Rbgq2 have not been reported before, and did not map to a chromosome region where a major gene for powdery mildew had been reported. Four QTLs (Rrsq1, Rrsq2, Rrsq3 and Rrsq4) for resistance against scald were detected on chromosomes 3 (3H), 4 (4H) and 6 (6H). All four mapped to places where QTLs for scald resistance had been reported before in different populations.The authors gratefully acknowledge the Spanish Agency for International Cooperation (AECI), CICYT project AGF99-1036-CO1 and the European Cereal Atlas Foundation (ECAF) fellowship for financial support, Dr. Rajeev K. Varshney and Dr. Nils Stein of the Institute of Plant Genetics and Crop Plant Research (IPK) are gratefully acknowledged for providing primer sequences of GBM- microsatellite markers.Peer reviewe

Characterizing Palestinian snake melon (Cucumis melo var. flexuosus) germplasm diversity and structure using SNP and DArTseq markers

Abstract Background Crop landraces embody a source of beneficial genes potentially providing endurance to environmental stress and other agronomic qualities including yield. Our study included 88 snake melon accessions (Cucumis melo var. flexuosus) collected from 9 districts in the Palestinian West-Bank. These accessions represent four landraces of Palestinian snake melon: Green, and White Baladi, and Green, and White Sahouri. Results This is the first report on successful application of genotyping by sequencing in snake melon. Nine thousand seven hundred fifty single-nucleotide polymorphism (SNP) and 7400 DArTseq genetic markers were employed to evaluate genetic biodiversity and population structure of Palestinian snake melon germplasm collection. Clustering based on neighbor-joining-analysis, principle coordinate and Bayesian model implemented in Structure showed that patterns of genetic diversity of snake melon landraces depends on their geographical source and unraveled the presence of two major local landraces (Sahouri, and Baladi) with accessions from each group clustering together. A significant correlation was observed between both types of markers in Mantel correlation test. A significant association between genetic and geographic matrices (P < 0.0001) was also detected. AMOVA indicated that majority of variation (90%) was due to the difference within accessions. Conclusion The Palestinian landraces seem to have unique genes that may allow the enhancement of the global snake melon gene pool and developments of the plant production worldwide. Our subsequent objective is to detect genotypes with promising qualities and to conduct association mapping studies concentrating on Fusarium-wilt resistance, yield, and environmental stresses

Effects of crop mixtures on chocolate spot development on faba bean grown in mediterranean climates

Chocolate spot incited by Botrytis fabae is a serious faba bean disease of worldwide distribution. The increasing interest in sustainable tools for disease control, together with the lack of sufficient levels of genetic resistance triggered our interest in the use of intercropping as a tool for the management of this disease. The effect of intercropping on chocolate spot severity was studied in field experiments performed in Egypt, the Palestinian Territories, Spain and Tunisia, in which a susceptible faba bean cultivar was grown as a monocrop or with two mixed species intercrops of either barley, oat, triticale, wheat, pea or common vetch, or with three mixed species intercrops of wheat and berseem clover. Chocolate spot was significantly reduced when faba bean was intercropped with cereals, but not when intercropped with legumes. Suppressive effects can be ascribed to a combination of host biomass reduction, altered microclimate and physical barriers to spore dispersal. © 2011 Elsevier Ltd.This research was supported by EU FP6 integrated project Grain Legumes and Spanish project AGL2008-01239.Peer Reviewe

Effects of crop mixtures on rust development on faba bean grown in Mediterranean climates

Faba bean (Vicia faba) is a temperate grain legume of major importance in Mediterranean agriculture. Faba bean production can be severely constrained in the area by rust incited by Uromyces viciae-fabae. Control with fungicides is possible, but there is a growing interest on alternative control methods, compatible with organic agriculture. Intercropping faba bean with cereals has been suggested as an alternative to maximize land use and increase crop resilience, with potential beneficial effects reducing weeds and diseases. In the present work, we studied the effect of intercropping faba bean with barley, triticale or wheat on faba bean rust development. Field studies performed over two consecutive seasons in two different countries showed that faba bean rust is significantly reduced when faba bean is intercropped with cereals confirming the value of faba bean-cereal intercropping for the management of faba bean rust. These results confirm that, under our conditions, intercropping faba bean with cereals (oat, barley, wheat or triticale) could usefully contribute to the management of faba bean rust.This research was supported by EU-FP6-GLIP, PCI2020-111974-PRIMA-DiVicia projects, An-Najah National University, Palestine and RYC-2015-18961.Peer reviewe