Pea Accessions Research Articles

Investigation of IRAP transposon-based molecular markers for analysis of genetic diversity in pea germplasm

Retrotransposons diversity has been extensively studied in monocots, but it is not well documented in dicot species. Transposition activity of transposons creates DNA polymorphism and their abundant presence in genomes is making transposons a promising marker system for varietal identification and fingerprinting. In this study, four transposon-based markers (two DNA- and two RNA-transposons) were employed to evaluate the effectiveness of Inter-Retrotransposon Amplified Polymorphism (IRAP) transposon system in assessing genetic diversity in pea germplasm accessions. A total of 28 alleles were detected across the 35 pea accessions with number of alleles per locus ranged from 5 (Mutator) to 9 (Cyclops). RNA transposons produced a higher number of polymorphic alleles (Ogre: 8, Cyclops: 9) than DNA transposon markers (Mutator: 5, MITE: 6). Overall mean PIC value and D values for these transposon markers were 0.810 and 0.817 respectively. Genetic similarity values ranged from 0.143 to 0.823 with a mean similarity value of 0.403. Cluster analysis classified pea genotypes into six major groups that were somewhat consistent with their geographical origins. The molecular analyses differentiated all the 35 accessions and generated higher PIC and D values that can be useful for MAS-based breeding programs in pea.

Population structure analysis and determination of neurotoxin content in a set of grass pea (Lathyrus sativus L.) accessions of Bangladesh origin

Grass pea (Lathyrus sativus L.) is a crop that is considered one of the more resilient to climate change. With protein-rich seeds and leaves, it has strong potential as human food as well as animal feed and fodder. However, genetic improvement in this crop remains stagnant owing to the poor characterization of its genetic resources. In this study, we characterized 118 accessions of grass pea with 18 EST-SSR markers. A total of 118 accessions, 101 of L. sativus (100 cultivated accessions from Bangladesh and one wild accession) and 17 wild accessions of other Lathyrus species, were used. A total of 67 alleles were detected, with an average of 3.72 alleles per locus and average polymorphism information content of 0.52. A dissimilarity matrix was formed and hierarchical cluster analysis performed using the UPGMA method grouped genotypes into four main clusters. Cluster analysis based on the genetic dissimilarity revealed a clear grouping of the 100 cultivated and 18 wild accessions into four main groups. Group I consisted of 20 accessions with high β-N-oxalyl-l-α,β-diaminopropionic acid (β-ODAP) concentration. Of these 20 accessions, 17 were wild accessions. Only one wild accession (L. cicera) was clustered in group II, which contained 35 accessions. Most of the group II accessions contained low β-ODAP. Group III was represented by 34 accessions, many of them with high β-ODAP. Group IV consisted of 29 accessions, a few of which had very high β-ODAP concentrations. Analysis of molecular variance of the microsatellite data showed significantly higher values of molecular variance between (83%) than within (17%) populations. These characterized accessions will be useful in grass pea breeding programs.

Physical and Chemical Barriers in Root Tissues Contribute to Quantitative Resistance to Fusarium oxysporum f. sp. pisi in Pea.

Fusarium wilt caused by Fusarium oxysporum f. sp. pisi (Fop) is one of the most destructive diseases of pea worldwide. Control of this disease is difficult and it is mainly based on the use of resistant cultivars. While monogenic resistance has been successfully used in the field, it is at risk of breakdown by the constant evolution of the pathogen. New sources of quantitative resistance have been recently identified from a wild relative Pisum spp. collection. Here, we characterize histologically the resistance mechanisms occurring in these sources of quantitative resistance. Detailed comparison, of the reaction at cellular level, of eight pea accessions with differential responses to Fop race 2, showed that resistant accessions established several barriers at the epidermis, exodermis, cortex, endodermis and vascular stele efficiently impeding fungal progression. The main components of these different barriers were carbohydrates and phenolic compounds including lignin. We found that these barriers were mainly based on three defense mechanisms including cell wall strengthening, formation of papilla-like structures at penetration sites and accumulation of different substances within and between cells. These defense reactions varied in intensity and localization between resistant accessions. Our results also clarify some steps of the infection process of F. oxysporum in plant and support the important role of cell wall-degrading enzymes in F. oxysporum pathogenicity.

Pisatin involvement in the variation of inhibition of Fusarium oxysporum f. sp. pisi spore germination by root exudates of Pisum spp. germplasm

Fusarium wilt caused by Fusarium oxysporum f. sp. pisi (Fop) is one of the major constraints of pea worldwide. Its control is difficult and is mainly based on the use of resistant cultivars. This study aimed to identify and characterize resistance mechanisms interfering with Fop spore germination, as an additional pre‐penetration resistance mechanism little explored so far. For this, root exudates were collected from 12 pea accessions with differential responses to the disease, from resistant to susceptible, and their effects on Fop germination and growth were determined. While root exudates from most accessions stimulated Fop germination, the root exudates of three accessions, JI 1412, JI 2480 and P42, did not stimulate, or even inhibited, Fop germination. Although some additional compounds might be involved, the analysis showed that the most active metabolite was the pea phytoalexin pisatin. Pisatin was identified in the active fraction of pea root exudate extracts and its amount in the root exudates was negatively correlated with the extent of Fop germination. This suggests an important role of pisatin in the constitutive defence of pea against F. oxysporum.

High-Throughput RNA-Seq Data Analysis of the Single Nucleotide Polymorphisms (SNPs) and Zygomorphic Flower Development in Pea (Pisum sativum L.).

Pea (Pisum sativum L.) is a model plant that has been used in classical genetics and organ development studies. However, its large and complex genome has hindered research investigations in pea. Here, we generated transcriptomes from different tissues or organs of three pea accessions using next-generation sequencing to assess single nucleotide polymorphisms (SNPs), and further investigated petal differentially expressed genes to elucidate the mechanisms regulating floral zygomorphy. Eighteen samples were sequenced, which yielded a total of 617 million clean reads, and de novo assembly resulted in 87,137 unigenes. A total of 9044 high-quality SNPs were obtained among the three accessions, and a consensus map was constructed. We further discovered several dorsoventral asymmetrically expressed genes that were confirmed by qRT-PCR among different petals, including previously reported three CYC-like proliferating cell factor (TCP) genes. One MADS-box gene was highly expressed in dorsal petals, and several MYB factors were predominantly expressed among dorsal, lateral, and/or ventral petals, together with a ventrally expressed TCP gene. In sum, our comprehensive database complements the existing resources for comparative genetic mapping and facilitates future investigations in legume zygomorphic flower development.

Development and validation of breeder-friendly KASPar markers for er1, a powdery mildew resistance gene in pea (Pisum sativum L.)

Powdery mildew of pea is caused by Erysiphe pisi DC and is a serious threat to pea (Pisum sativum L.) production throughout much of the world. Development and utilization of genetic resistance to powdery mildew is considered an effective and sustainable strategy to manage this disease. One gene, er1, conferring powdery mildew resistance, was previously cloned and sequenced, and the functional markers for each resistance allele were reported. Allele-specific DNA markers are efficient and powerful tools to facilitate crop improvement and new cultivar development in breeding programs. However, extensive application of these markers is limited by gel-associated obstacles. In this study, eight breeder-friendly kompetitive allele-specific PCR (KASPar) markers were developed to overcome the problems of gel-based markers and increase the efficiency of genotypic screening. In order to identify additional pea germplasm with powdery mildew resistance, these KASPar markers were deployed and used to genotype a pea collection derived from the USDA pea single-plant (PSP) collection. Simultaneously, a phenotypic screening and a genotypic validation using the corresponding gel-based functional markers were conducted on the PSP collection. One pea accession, PI 142775, was identified by both phenotyping and genotyping to carry the allele er1-1 for powdery mildew resistance, indicating that the KASPar assay is an efficient and robust tool for breeding for powdery mildew resistance.

Evaluation of the green pea (Pisum sativum L.) collection for presence of carriers of r and rb mutations

Objective. To evaluate the green pea (Pisum sativum L.) collection in order to identify carriers of r and rb mutations in it. Methods. Pea accessions were grown in the field, and seeds were produced under controlled pollination. The starch granule shape was determined in micrographs taken with a computer digital microscopic camera DMC-300 through a Biolam-15 microscope (object lens × 40). The starch content was determined polarimetrically by the Evers method and the amylase content colorimetrically — by the BO Juliano method. The data were statistically processed using analysis of variance. Results. The effect of r and rb mutations on the starch content and fractional composition in pea seeds was confirmed. In smooth-seed accessions the average starch content was 39,9 %, and the amylose content in starch was 45,9 %, while in r mutation carriers these contents were 31 ,2 % and 67,6 %, respectively, and in rb mutation carriers — 26,9 % and 28,2 %, respectively. An accession with marrowfat seeds, roundish starch granules and a low content of amylose in starch was identified. It was established that this accession was a carrier of a recessive mutation that is not allelic to r mutation and coincides with rb mutation by the effect type. Conclusions. A new genetic source of starchmodifying monogenic rb mutation of pea was identified. It was involved hybridization with sources of r mutation to expand the genetic basis of pea cultivar breeding.Keywords: peas, Pisum sativum, genetic diversity, r, rb, seed phenotype, starch grain shape, starch content, amylose content.

Marker-trait association analysis of frost tolerance of 672 worldwide pea (Pisum sativum L.) collections

Frost stress is one of the major abiotic stresses causing seedling death and yield reduction in winter pea. To improve the frost tolerance of pea, field evaluation of frost tolerance was conducted on 672 diverse pea accessions at three locations in Northern China in three growing seasons from 2013 to 2016 and marker-trait association analysis of frost tolerance were performed with 267 informative SSR markers in this study. Sixteen accessions were identified as the most winter-hardy for their ability to survive in all nine field experiments with a mean survival rate of 0.57, ranging from 0.41 to 0.75. Population structure analysis revealed a structured population of two sub-populations plus some admixtures in the 672 accessions. Association analysis detected seven markers that repeatedly had associations with frost tolerance in at least two different environments with two different statistical models. One of the markers is the functional marker EST1109 on LG VI which was predicted to co-localize with a gene involved in the metabolism of glycoproteins in response to chilling stress and may provide a novel mechanism of frost tolerance in pea. These winter-hardy germplasms and frost tolerance associated markers will play a vital role in marker-assisted breeding for winter-hardy pea cultivar.

Genetic Diversity in Pigeon Pea ( Cajanuscajan (L.) Millspaugh Germplasm Revealed by Gel Electrophoresis of the Seed Proteins

Ten accessions of Pigeon pea (Cajanuscajan) obtained from National Centre for Genetic Resources and Biotechnology (NACGRAB), Ibadan, Oyo state, were assessed for their genetic and phylogenetic relatedness through electrophoretic analysis of the seed proteins. 0.2g of the seeds were weighed and macerated with mortar and pestle in 0.2M phosphate buffer containing 0.133M of acid (NaH2PO4) and 0.067 of base (Na2HPO4) at pH 6.5. Protein characterization with standard marker revealed that the seeds of the ten accessions contained proteins (B.S.A, Oval Albumin, Pepsinogen, Trypsinogen and Lysozyme) with molecular weights ranging from 66kda and above, 45 – 65 kDa, 44 – 33 kda, 32-24 kDa and 23-14 kDa, respectively. The student T-test revealed that accessions PP2, PP3, PP5, PP6, PP8 and PP9 have molecular weights not significantly different from one another (P 0.05). All the accessions had at least two proteins and two major bands in common. The study revealed intra-specific similarities and genetic diversity in protein contents among the ten accessions of pigeon pea (Cajanuscajan).

Genetic diversity and structure of the zombi pea (Vigna vexillata (L.) A. Rich) gene pool based on SSR marker analysis.

Zombi pea (Vigna vexillata (L.) A. Rich) is an underutilized legume species and a useful gene source for resistance to biotic and abiotic stresses, although there is little understanding on its genetic diversity and structure. In this study, 422 (408 wild and 14 cultivated) accessions of zombi pea from diverse origins (201 from Africa, 126 from America, 85 from Australia, 5 from Asia and 5 from unknown origin) were analyzed with 20 simple sequence repeat (SSR) markers to determine its genetic diversity and genetic structure. The SSR markers detected 273 alleles in total with a mean of 13.6 alleles per locus. Polymorphism information content values of the markers varied from 0.58 to 0.90 with an average of 0.76. Overall gene diversity was 0.715. Gene diversity and average allelic richness was highest in Africa (0.749 and 8.08, respectively) and lowest in America (0.435 and 4.10, respectively). Nei's genetic distance analysis revealed that the highest distance was between wild Australia and cultivated Africa (0.559), followed by wild West Africa and wild Australia (0.415). STRUCTURE, neighbor-joining (NJ), and principal coordinate analyses consistently showed that these zombi pea accessions were clustered into three major groups, viz. America, Africa and Asia, and Australia. NJ tree also suggested that American and Australian accessions are originated from East African zombi peas, and that the cultivated accessions from Africa and Asia were genetically distinct, while those from America were clustered with some cultivated accessions from Africa. These results suggest that Africa is the center of origin and diversity of zombi pea, and that domestication of this pea took place more than once in different regions.

Genotyping of Pigeon Pea [Cajanus cajan (L.) Millsp.] Accessions Obtained from International Institute of Tropical Agriculture (IITA) Germplasm Using Random Amplified Polymorphic DNA

Genotyping of crop plants, especially pigeon pea is very strategic in the global quest for crops that will be suitable for the precarious climate change as it provides genotypes for introgression. 22 pigeon pea accessions obtained from IITA germplasm were evaluated for genetic diversity. Genomic DNA was extracted using SDS protocol from young leaves of each accession and quantification was done. 12 RAPD primers were used for PCR DNA amplification and bands were visualized under UV light using ethidium bromide. Data analyses were computed using power marker version 3.25 and GenAlex 6.41 software. Results obtained revealed that the polymorphic information content ranged from 0.6458-0.9436 while percentage polymorphism ranged from 71.4- 100. Average percentage polymorphism was 88.6%. UPGMA- based cluster generated two major clusters with 12 and 10 accessions, respectively. Principal coordinates (PCoA) contributed 20.75% to the total diversity. Though showing two clusters, it was not population-dependent. AMOVA result gave 0.00% to variation among the population while variation within population was 100%. Additionally, genetic diversity parameters such as heterozygosity, mean Nei unbiased genetic distance, genetic identity were 0.015, 0.006 and 0.994, respectively. However, Shannon’s information index, diversity and unbiased diversity were 1.858±0.02, 0.648±0.005 and 0.503±0.005. Pigeon pea accessions used in this present study revealed very narrow genetic diversity suggesting that they came from one population. The little variability observed may have been contributed by the accession TCc CITA 3. The implication of the results taking together is that further genotyping should be carried out using other DNA markers before explicit conclusion can be made.

Evaluation of field pea accessions for root-knot nematode resistance and possible role of NADP dependent malic enzyme gene in host resistance

The present study was undertaken to evaluate resistance of different field pea accessions to RKN, Meloidogyne javanica under microplots and pot culture conditions. Three hundred accessions of field pea were screened initially using sick soil and evaluated after 2 months of sowing using root gall index of 1–5 scale. Based on galling index eleven accessions showing resistant reaction were further screened under controlled condition. All eleven acessions were consistent in their response to RKN infection under pot culture experiment. The partial sequence of NADPdependent malic enzyme (ME) gene was PCR amplified, sequenced and used to screen field pea accessions showing resistant and susceptible reaction against RKN using PCR amplification. PCR screening using ME specific primers showed PCR amplification only in accessions showing resistant reaction. There was no amplification of ME gene from susceptible field pea accessions. The partial sequence of putative NADP dependent Malic enzyme gene from resistant accessions of field pea has been cloned and characterized. The results indicate possible link between ME and resistance against RKN in field pea. Role of malate metabolism in generating resistance reaction against RKN is discussed.

Abyssinian pea (Lathyrus schaeferi Kosterin nom. nov. pro Pisum abyssinicum A. Br.) is a problematic taxon

The Abyssinian pea (Pisum abyssinicum A. Br.), concerned in this review, is known from Ethiopia and Yemen, where it is cultivated along with the common pea (Pisum sativum L. subsp. sativum). The continuously reproduced notion of its possible spontaneous occurrence in the wild ascends to suppositions made in the XIX century and is not based on any actual data. P. abyssinicum is of practical interest owing to its extra early ripening and resistance to bacterial blight. Morphologically it is very similar to P. sativum but its crossability with it is bad as either seed or pollen parent. Traditionally this reproductive barrier was associated with karyological differences. The Abyssinian pea karyotype is variable as 1–2 reciprocal translocations were reported. At the same time there are accessions not differing from the standard karyotype of P. sativum with respect to reciprocal translocations, yet their crossability with the latter is very low and the pollen fertility of F1 and F2 hybrids is lowered. Data were reported on influence of the region of Linkage Group III, containing a gene known to participate in the conflict of nucleus and plastids in remote crosses of peas, on the pollen fertility of hybrids with abyssinian pea. With their karyological variability, the known accessions of the Abyssinian pea are very close to each other genetically, as they diverged just about 4000 years ago. The presence of alleles of molecular markers common with Pisum fulvum Sibth. et Smith on the one hand and P. sativum L. subsp. elatius (Bieb.) Schmalh. on the other hand evidences in favour of an old hypotheses by L.I. Govorov that the Abyssinian pea originated from their spontaneous hybrid. This spontaneous cross may have taken place under cultivation, in Yemen or Afar Depression. A representative of P. sativum subsp. elatius was revealed, the F1 hybrids of which with the Abyssinian pea as a seed parent had fully fertile pollen. P. abyssinicum× P. fulvum crosses provide the best hybrid seed outcome among remote crosses conducted, so that P. abyssinicum can be used as a ‘bridge’ for gene introgression from P. fulvum to P. sativum. Rather a high evel of reproductive isolation of the Abyssinian pea from other representatives of the genus conforms the biological species concept, however the disposition of P. abyssinicum accessions as a small cluster among accessions of P. sativum subsp. elatius on molecular phylogeny reconstructions violates the phylogenetic species concept. Most authors assume the Abyssinian pea as a species, Pisum abyssinicum, some as a subspecies, P. sativum subsp. abyssinicum (A. Br.) Berger. Perhaps it would be most correct to consider it as a hybridogenic species. Because of the recent subsuming of the genus Pisum L. into the genus Lathyrus and with respect to the existing name Lathyrus abyssinicus A. Br. (a synonym of L. sativus L.), the Abyssinian pea is given a new name Lathyrus schaeferi (A. Braun) Kosterin nomen novum pro Pisum abyssinicum A. Braun), in honour of Hanno Schaefer, who substantiated the revision of tribe Fabeae by molecular reconstruction of its phylogeny. New combinations of Lathyrus sectio Pisum (L.) Kosterin combinatio nova and Lathurus fulvus (Sibthrop et Smith) Kosterin combinatio nova are proposed.

Fatty acid characteristics of grass pea (Lathyrus sativus) in an East Mediterranean environment

AbstractLathyrus sativus L., (grass pea) is an annual plant widely grown as a pulse crop and its dried seeds are harvested and consumed as human food since ancient times. This plant is also commonly grown for animal feed and forage. Grass pea seeds may represent a potential source of several important nutrients for human and animal nutrition. Fatty acid compositions of 173 different grass pea accessions have been studied. Present results indicate that total saturated fatty acids, total monounsaturated fatty acids, total polyunsaturated fatty acids, and total fatty acids ranged from 295.72 to 436.94, 113.19 to 170.78, 127.39 to 179.39, 538.04 to 778.98 mg 100 g−1, respectively. In addition, unsaturated fatty acids, oleic acid, linoleic acid, γ-linolenic acid, and α-linolenic acid that are the main components of fatty acids ranged from 109.22 to 163.95,59.57 to 82.98, 16.18 to 30.38, and 45.56 to 71.59 mg 100 g−1, respectively.

Effect of seed treatment on germination and flavonoids diversity in accessions of butterfly pea (Clitoria ternatea)

Effect of seed treatment on germination and flavonoids diversity in accessions of butterfly pea (Clitoria ternatea)

Genetic Diversity and Structure of Pea (Pisum sativum L.) Germplasm Based on Morphological and SSR Markers

The pea (Pisum sativum L.) is one of the oldest domesticated, highly valued and extensively cultivated pulse crops throughout the world. We studied genetic structure, diversity and inter-relationships in a worldwide collection of 151 pea accessions using 21 morphological descriptors and 20 simple sequence repeat (SSR) primers. Among quantitative traits, seed yield per plant followed by seed weight and pod length have shown significant variation. SSR primers showed a high level of diversity and amplified a total of 179 alleles with an average of 8.95 alleles per primer in a size range of 95–510 bp. Primer AA-122 amplified the maximum (21) alleles while primer AB-64 amplified the minimum (4) alleles. Mean polymorphism information content (PIC) was 0.72. Observed heterozygosity (Ho) varied from 0.10 to 0.99 in primers AB-64 and AD-160, respectively, with a mean value of 0.46. Expected heterozygosity (He) ranged from 0.47 to 0.94 in primers C-20 and AA-122, with a mean of 0.75. Genetic relationships inferred from a neighbour-joining tree separated accessions into 3 groups. Bayesian model-based STRUCTURE analysis detected 3 gene pools for the analysed pea germplasm and showed a high admixture within individual accessions. Furthermore, STRUCTURE analysis showed that these 3 gene pools co-existed in accessions belonging to different geographic regions indicating frequent transference and exchange of pea germplasm during its domestication history. The results of the present study will be useful in understanding the pea’s genetic structure and in the selection of suitable diverse accessions for future improvement programmes in the pea.

Refinement of the collection of wild peas (Pisum L.) and search for the area of pea domestication with a deletion in the plastidic psbA-trnH spacer

The plastidic psbA-trnH spacer was sequenced in 78 accessions representing the genus Pisum L. A nucleotide substitution C64T in the spacer was found to be specific for Pisum abyssinicum A. Br.; a substitution T75G occurred in five accessions of the wild pea [Pisum sativum L. subsp. elatius (Bieb.) Schmalh.], one from France, three from Greece and one from Turkey, and also in a primitive landrace from Afghanistan with signs of contamination. A 7-bp tandem duplication was found in two P. sativum subsp. elatius accessions, from Turkey and Georgia. All (except for the probably contaminated Afghan accession) of the cultivated subspecies P. sativum L. subsp. sativum had a deletion of one copy of a tandem 8-bp repeat. The same deletion was found in two wild pea (P. sativum subsp. elatius) accessions, from Bulgaria and Georgia, belonging to the same earlier defined lineage B as the cultivated pea. They are supposed to represent the ancestral evolutionary lineage of the cultivated pea. It is noteworthy that accessions from the proposed Core Area of the Near East founder crop domestication in south-eastern Turkey do not have the deletion. Most of wild representatives of lineage B have a scarcely pigmented flower with almost non-opening standard, but those from Transcaucasia have a normal flower. The revealed area of co-existence of the earlier defined wild pea lineages A and B (differing in alleles of three molecular markers from different cellular genomes) was extended from Turkey to include Georgia and probably North Africa. Accessions claimed to represent wild peas were tested for spontaneous pod dehiscing and 14 of them were disproved as such. They are enriched with ‘recombinant’ marker combinations and most probably resulted from hybridisation of wild and cultivated peas, either in nature or while reproducing in germplasm collections.

Clarification on Host Range of Didymella pinodes the Causal Agent of Pea Ascochyta Blight.

Didymella pinodes is the principal causal agent of ascochyta blight, one of the most important fungal diseases of pea (Pisum sativum) worldwide. Understanding its host specificity has crucial implications in epidemiology and management; however, this has not been clearly delineated yet. In this study we attempt to clarify the host range of D. pinodes and to compare it with that of other close Didymella spp. D. pinodes was very virulent on pea accessions, although differences in virulence were identified among isolates. On the contrary, studied isolates of D. fabae, D. rabiei, and D. lentil showed a reduced ability to infect pea not causing macroscopically visible symptoms on any of the pea accessions tested. D. pinodes isolates were also infective to some extend on almost all species tested including species such as Hedysarum coronarium, Lathyrus sativus, Lupinus albus, Medicago spp., Trifolium spp., Trigonella foenum-graecum, and Vicia articulata which were not mentioned before as hosts of D. pinodes. On the contrary, D. lentil and D. rabiei were more specific, infecting only lentil and chickpea, respectively. D. fabae was intermediate, infecting mainly faba bean, but also slightly other species such as Glycine max, Phaseolus vulgaris, Trifolium spp., Vicia sativa, and V. articulata. DNA sequence analysis of the nuclear ribosomal internal transcribed spacer region (ITS) was performed to confirm identity of the isolates studies and to determine phylogenetic relationship among the Didymella species, revealing the presence of two clearly distinct clades. Clade one was represented by two supported subclusters including D. fabae isolates as well as D. rabiei with D. lentil isolates. Clade two was the largest and included all the D. pinodes isolates as well as Phoma medicaginis var. pinodella. Genetic distance between D. pinodes and the other Didymella spp. isolates was not correlated with overall differences in pathogenicity. Based on evidences presented here, D. pinodes is not specialized on pea and its host range is larger than that of D. fabae, D. lentil, and D. rabiei. This has relevant implications in epidemiology and control as these species might act as alternative hosts for D. pinodes.

Comparative Productivity and Adaptive ability of Forage Pea (Pisum sativum L.) and Vetch (Vicia sativa L.) Cultivars

<p>Adaptive potential of forage pea and vetch accessions was estimated based on seed yield and yield components. А varietal-specific reaction of the studied accessions to environmental conditions was established. The conducted assessment of selective value of genotypes gave accurate data for breeding of highly productive forms. Among studied pea varieties the following were characterized to possess adaptive ability and selective value - Glyans for numbers of seeds (1000 seed weight and seed yield), Kamerton for plant height, and Svit for seed yield. In terms of general adaptive ability and stability in plant height with the greatest value as a starting material was vetch variety Vilena. Moldovskaya was of interest in terms of 1000 seed weight. Liya is preferred vetch genotype for improving the number of seeds per plant and for selection of new forms for improving grain yield.</p>

Evaluation of pea accessions and commercial cultivars for fusarium root rot resistance

Fusarium root rot caused by Fusarium solani f. sp. pisi (Fsp) can result in major yield losses in pea (Pisum sativum L.). Currently no fungicides effectively manage this disease. Previous studies evaluated the Pisum germplasm collection for resistance to Fsp, however, evaluations of commercial market classes of pea cultivars grown in the US, and elsewhere, have not been reported. This study evaluated pea accessions and commercial cultivars for Fsp resistance under greenhouse conditions. Accessions evaluated included pigmented lines with high levels of partial resistance to Fsp. Based on root disease severity (RDS) values, the most Fsp-resistant Austrian winter, green fresh, green dry, yellow dry, green winter and yellow winter pea were: PI 125673, 5003, ‘Banner’, ‘Carneval’, PS 05300234, and ‘Whistler’, respectively. Genotypes with a RDS value of 3.05, on a 0–6 scale with 6 being severe, or less had no significant (P ≤ 0.05) reductions in plant height, shoot dry weight, and root dry weight, compared to non-inoculated controls, establishing an important disease threshold value for pea breeders. Plant height, more than shoot dry weight or root dry weight, was the most highly negatively correlated growth parameter related to RDS in repeated tests based on Pearson’s Correlation coefficients. However, root dry weight was also a highly sensitive growth parameter affected by Fsp since 14 of 33 genotypes had significant (P ≤ 0.05) reductions in root dry weight compared to non-inoculated controls, while only 5 of 33 genotypes had significant reductions in plant height and/or shoot dry weight in combined tests.