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Pea (Pisum sativum L.) is an annual cool-season legume crop. Owing to its role in sustainable agriculture as both a rotation and a cash crop, its global market is expanding and increased production is urgently needed. For both technical and regulatory reasons, neither conventional nor transgenic breeding techniques can keep pace with the demand for increased production. In answer to this challenge, CRISPR/Cas9 genome editing technology has been gaining traction in plant biology and crop breeding in recent years. However, there are currently no reports of the successful application of the CRISPR/Cas9 genome editing technology in pea. We developed a transient transformation system of hairy roots, mediated by Agrobacterium rhizogenes strain K599, to validate the efficiency of a CRISPR/Cas9 system. Further optimization resulted in an efficient vector, PsU6.3-tRNA-PsPDS3-en35S-PsCas9. We used this optimized CRISPR/Cas9 system to edit the pea phytoene desaturase (PsPDS) gene, causing albinism, by Agrobacterium-mediated genetic transformation. This is the first report of successful generation of gene-edited pea plants by this route. [ABSTRACT FROM AUTHOR]

Salinity stress has become an important limiting factor for plant growth and productivity. To evaluate the effect of salinity on plant and root development three pea genotypes were grown under different concentrations of NaCl (50, 100 and 200 mM NaCI) in an in vitro and in vivo conditions. After two weeks of cultivation in culture medium the seedling emergence rate was not significantly affected by 50 mM NaCl. In culture medium containing 200 mM NaCl only in variety Prometei over 50% of the seeds developed to the plants. The data indicated that increasing NaCl level significantly reduced shoot and root lengths, and plant fresh weight. Six weeks (42 days) after sowing in vivo, a reduction in plant height and weight was observed at 200 mM NaCl concentration. A proven differences of the root traits were established only in variety Prometei. On the bases of the obtained results it can be concluded that variety Prometei was the most tolerant to applied salt stress [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Breeders and farmers did not agree completely on priority traits to select for. • A farmer selection index outperformed a breeder index for yield gain and acceptability of cultivars. • Selection based on a farmer acceptability score performed at least as well as yield-based selection. • Genome-wide predictive accuracy was high for yield and very high for a farmer acceptability score. • Genomic selection for a farmer score ranked first in a preliminary comparison of selection criteria. Abstract Participatory plant breeding (PPB) has gained increasing importance in developing countries, but its value for market-oriented breeding programmes of countries with developed agriculture that are committed to pure line selection (as needed to comply with DUS requirements) is unknown. This study aimed to compare PPB vs. conventional plant breeding of pea (Pisum sativum L.) targeted to organic systems of Italy, exploring phenotypic and genome-enabled selection approaches. Priority values assigned on a 0–5 scale to 14 traits by 18 farmers from Northern and Central Italy and six breeders were used to define weights of farmer and breeder selection indexes. Farmers and breeders attributed outmost importance to a visual acceptability score assigned a few weeks before crop maturity on a 1–9 scale, followed in importance by grain yield and tolerance to lodging. However, breeders and farmers differed (P < 0.05) for trait importance in a few cases. Five phenotypic selection criteria (farmer selection index; breeder selection index; average of farmer and breeder selection indexes; grain yield; farmer acceptability score) were applied onto 306 lines evaluated in two researcher-managed experiments of Northern and Central Italy under organic crop management, selecting overall nine lines per criterion that were tested in four organically-managed environments of the same regions and one conventionally-managed site. The farmer selection index exhibited greater selection efficiency (+23% based on yield gains over elite commercial cultivars under organic farming) and farmer's acceptability of selected material than the breeder selection index. Breeding values based on the farmer selection index or the farmer acceptability score exhibited greater correlation with grain yields in independent environments than those from breeder selection criteria. Compared with grain yield-based selection, selection for the farmer acceptability score performed comparably in terms of yield gains, and somewhat better according to correlations of its breeding values with line grain yields in independent environments. The accuracy of genome-enabled predictions issued by a Bayesian Lasso model with 3443 SNP markers generated by genotyping-by-sequencing, estimated by averaging cross-environment correlations between predicted and observed values over two locations, was very high for the farmer acceptability score (r Ac = 0.77), and high for grain yield (r Ac = 0.59). Genomic selection for the farmer acceptability score ranked first in a preliminary comparison of eight genome-enabled or phenotypic selection criteria based on correlations of breeding values with grain yields in independent environments, suggesting its adoption for preliminary screening of genotype sets that are too numerous for field-based evaluation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Studied 22 garden-pea genotypes for phenolics, flavonoids, antioxidants and horticultural traits. • Genotypes, EC9485 and VRP233 recorded maximum phenolics, flavonoids and antioxidant potential. • Phenolics recorded positive correlation with TEAC, CUPRAC and DPPH assays and negative with yield. • Combining high-antioxidants with high-yield will be the major future goal for green-pea breeding. Abstract Food legumes cater the basic nutritional requirement of humans by providing the protein, carbohydrate, minerals, and vitamins, along with several secondary metabolites having antioxidant activities. In this investigation, diverse pea genotypes belonging to different maturity groups, flower color, seed-coat color, and seed-shapes were assessed for their total phenolics and total flavonoids contents including antioxidant activities. In addition, these were also evaluated for various horticultural traits. A number of in vitro antioxidant assays including CUPRAC, FRAP, DPPH, and TEAC were compared for their relative antioxidants potential in different pea genotypes. The purple-flowered and dark seed-coat colored genotypes, EC-9485 and VRP-233 were found having highest total phenolics (128 and 104 mg GAE/100 g fw) and total flavonoids contents (45.8 and 36.8 mg CE/100 g fw) respectively, along with strong antioxidant potential, when compared to white-flowered and light seed-coat colored genotypes. However, pod-yield in these two genotypes was recorded low (22.7 g/plant and 69.2 g/plant) attributed mainly due to their lowest pod-weight (2.5 g/pod and 3.4 g/pod), respectively. At genotypic level, total phenolics content was found highly correlated with TEAC (rG = 0.987), CUPRAC (rG = 0.979) and DPPH (rG = 0.976) assays, while negatively correlated with yield per plant (rG =-0.305). Furthermore, positive correlation between total phenolics, total flavonoids with antioxidant activities indicated that the phenolics including flavonoids as the main component for antioxidant activity in pea genotypes. Principal component analysis (PCA) and UPGMA cluster analysis grouped the genotypes having a strong antioxidant capacity and high yield in distinct clusters. The results will help the breeders to combine both high-yield and high-antioxidant activity traits in a single genotype, thereby help in achieving the long-term goal of ensuring the nutritional security of the consumers. [ABSTRACT FROM AUTHOR]

Ectoapyrases (ecto‐NTPDases) function to decrease levels of extracellular ATP and ADP in animals and plants. Prior studies showed that ectopic expression of a pea ectoapyrase, psNTP9, enhanced growth in Arabidopsis seedlings and that the overexpression of the two Arabidopsis apyrases most closely related to psNTP9 enhanced auxin transport and growth in Arabidopsis. These results predicted that ectopic expression of psNTP9 could promote a more extensive root system architecture (RSA) in Arabidopsis. We confirmed that transgenic Arabidopsis seedlings had longer primary roots, more lateral roots, and more and longer root hairs than wild‐type plants. Because RSA influences water uptake, we tested whether the transgenic plants could tolerate osmotic stress and water deprivation better than wild‐type plants, and we confirmed these properties. Transcriptomic analyses revealed gene expression changes in the transgenic plants that helped account for their enhanced RSA and improved drought tolerance. The effects of psNTP9 were not restricted to Arabidopsis, because its expression in soybeans improved the RSA, growth, and seed yield of this crop and supported higher survival in response to drought. Our results indicate that in both Arabidopsis and soybeans, the constitutive expression of psNTP9 results in a more extensive RSA and improved survival in drought stress conditions. Ectopic expression of psNTP9, a pea apyrase in Arabidopsis, and soybean showed enhanced resistance to drought stress through its promotion of more extensive root system architecture (RSA). The expanded RSA occurred without negatively affecting shoot growth parameters or other phenotypic traits evaluated. The transgenic Arabidopsis and soybean plants had a higher survival rate when compared with wild‐type plants when subjected to water‐deficit conditions. The seed yield of transgenic soybean plants was significantly higher than that of wild‐type plants when subjected to drought stress. [ABSTRACT FROM AUTHOR]

Waterlogging causes germination failure in pea (Pisum sativum L.). Three genotypes (BARI Motorshuti‐3, Natore local‐2 [NL‐2], and Kaspa) contrasting in ability to germinate in waterlogged soil were exposed to different durations of waterlogging. Whole genome RNAseq was employed to capture differentially expressing genes. The ability to germinate in waterlogged soil was associated with testa colour and testa membrane integrity as confirmed by electrical conductivity measurements. Genotypes Kaspa and NL‐2 displayed different mechanisms of tolerance. In Kaspa, an energy conserving strategy was indicated by a strong upregulation of tyrosine protein kinsase and down regulation of linoleate 9S‐lipoxygenase 5, a fat metabolism gene. In contrast, a faster energy utilization strategy was suggested in NL‐2 by the marked upregulation of a subtilase family protein and peroxisomal adenine nucleotide carrier 2, a fat metabolizing gene. Waterlogging susceptibility in germinating seeds of genotype BARI Motorshuti‐3 was linked to upregulation of a kunitz‐type trypsin/protease inhibitor that blocks protein metabolism and may lead to excessive lipid metabolism and the membrane leakage associated with waterlogging damage. Pathway analyses based on gene ontologies showed seed storage protein metabolism as upregulated in tolerant genotypes and downregulated in the sensitive genotype. Understanding the tolerance mechanism provides a platform to breed for adaptation to waterlogging stress at germination in pea. Waterlogging is a major problem in cropping that is becoming more severe with increasing climatic variability. Three pea genotypes contrasting in ability to germinate in waterlogged soil were exposed to differing durations of waterlogging, and whole genome RNAseq was used to capture differentially expressing genes. We found testa membrane integrity following seed leakage strongly associated with waterlogging tolerance. Differential gene expression under waterlogging stress showed excessive lipid metabolism and membrane leakage in the sensitive genotype, whereas two tolerant genotypes displayed contrasting mechanisms of tolerance—quiescence or escape by regulating metabolism under stress. [ABSTRACT FROM AUTHOR]

In the current study, the effects of heavy metals on pea (Pisum sativum L.), which were exposed to 150 mg L-1 and 300 mg L-1 Cd, Pb and Cu treatments for 12 days, were investigated by using population parameters and Random Amplified Polymorphic DNA (RAPD) assay in the roots and leaves. In RAPD assay, 17 RAPD primers generated polymorphic band profiles, and a total of 110 bands were produced in the leaves and roots of the control seedlings. Changes were detected in the RAPD patterns of the roots and leaves of the pea plants that subjected to heavy metal treatment in terms of band intensities, appearance of new bands and disappearance of bands. The changes in the RAPD patterns were found to be more in roots when compared leaves. The results of germination, shoot and primary root length showed a correlation with the genomic template stability (GTS) values. Determination of the DNA damage by using the RAPD assay together with different biomarkers may be a practical eco-genotoxicological tool in the biomonitoring of chemical contaminants. [ABSTRACT FROM AUTHOR]

Legumes fix atmospheric nitrogen through a symbiotic relationship with bacteroids in root nodules. Following fixation in pea (Pisum sativum L.) nodules, nitrogen is reduced to amino acids that are exported via the nodule xylem to the shoot, and in the phloem to roots in support of growth. However, the mechanisms involved in amino acid movement towards the nodule vasculature, and their importance for nodule function and plant nutrition, were unknown. We found that in pea nodules the apoplasmic pathway is an essential route for amino acid partitioning from infected cells to the vascular bundles, and that amino acid permease PsAAP6 is a key player in nitrogen retrieval from the apoplasm into inner cortex cells for nodule export. Using an miRNA interference (miR) approach, it was demonstrated that PsAAP6 function in nodules, and probably in roots, and affects both shoot and root nitrogen supply, which were strongly decreased in PsAAP6 -miR plants. Further, reduced transporter function resulted in increased nodule levels of ammonium, asparagine, and other amino acids. Surprisingly, nitrogen fixation and nodule metabolism were up-regulated in PsAAP6 -miR plants, indicating that under shoot nitrogen deficiency, or when plant nitrogen demand is high, systemic signaling leads to an increase in nodule activity, independent of the nodule nitrogen status. [ABSTRACT FROM AUTHOR]

The seven parents and their 21 F1s were grown in randomized block design with 3 replications during rabi 2015-16. In the field experiment, observations on 12 quantitative characters were recorded for genetic analysis. The analysis of variance for combining ability revealed significant differences among crosses for all the characters studied except for days to first flowering. In case of general combining ability effects, RLS 3004-5 and Pusa 24 were identified as the most promising parents for involving in hybridization programme. On the basis of specific combining ability effects, five crosses exhibited highly significant SCA effects for seed yield plant-1 with two to six other yield components. Among cross combinations, Prateek×RLS 3009-2, DLY 13-7×Pusa 24, DLY 13-7×RLS 3004-5 and RLS 3004-5×Bio L 212 were identified as the most promising crosses for improvement of seed yield per plant and three to six of its component traits. The manifestation of heterosis for seed yield was evidenced by superiority of hybrids over better parent and over standard check variety (Bio L 212). Out of 21 cross combinations, 5 crosses exhibited significant heterosis over their better parent as well as standard check. Overall on the basis of results of mean performance, including GCA and SCA effects and standard heterosis, Prateek×RLS 3009-2, DLY 13-7×Pusa 24 and DLY 13- 7×RLS 3004-5 were identified as the most promising cross combinations for improvement of seed yield in grasspea. [ABSTRACT FROM AUTHOR]

Elucidation of mechanisms underlying plant tolerance to cadmium, a widespread toxic soil pollutant, and accumulation of Cd in plants are urgent tasks. For this purposes, the pea (Pisum sativum L.) mutant SGECdt (obtained by treatment of the laboratory pea line SGE with ethylmethane sulfonate) was reciprocally grafted with the parental line SGE, and four scion/rootstock combinations were obtained: SGE/SGE, SGECdt/SGECdt, SGE/SGECdt, and SGECdt/SGE. They were grown in hydroponics in the presence of 1 μM CdCl2 for 30 d. The SGE and SGECdt scions on the SGECdt rootstock had a higher root and shoot biomass and an elevated root and shoot Cd content compared with the grafts having SGE rootstock. Only the grafts with the SGE rootstock showed chlorosis and roots demonstrating symptoms of Cd toxicity. The content of nutrient elements in roots (Fe, K, Mg, Mn, Na, P, and Zn) was higher in the grafts having the SGECdt rootstock, and three elements, namely Ca, Fe, and Mn, were efficiently transported by the SGECdt root to the shoot of these grafts. The content of other measured elements (K, Mg, Na, P, and Zn) was similar in the root and shoot in all the grafts. Then, the non-grafted plants were grown in the presence of Cd and subjected to deficit or excess concentrations of Ca, Fe, or Mn. Exclusion of these elements from the nutrient solution retained or increased differences between SGE and SGECdt in growth response to Cd toxicity, whereas excess of Ca, Fe, or Mn decreased or eliminated such differences. The obtained results assign a principal role of roots to realizing the increased Cd-tolerance and Cdaccumulation in the SGECdt mutant. Efficient translocation of Ca, Fe, and Mn from roots to shoots appeared to counteract Cd toxicity, although Cd was actively taken up by roots and accumulated in shoots. [ABSTRACT FROM AUTHOR]

Elucidation of mechanisms underlying plant tolerance to cadmium, a widespread toxic soil pollutant, and accumulation of Cd in plants are urgent tasks. For this purposes, the pea (Pisum sativum L.) mutant SGECdt (obtained by treatment of the laboratory pea line SGE with ethylmethane sulfonate) was reciprocally grafted with the parental line SGE, and four scion/rootstock combinations were obtained: SGE/SGE, SGECdt/SGECdt, SGE/SGECdt, and SGECdt/SGE. They were grown in hydroponics in the presence of 1 μM CdCl2 for 30 d. The SGE and SGECdt scions on the SGECdt rootstock had a higher root and shoot biomass and an elevated root and shoot Cd content compared with the grafts having SGE rootstock. Only the grafts with the SGE rootstock showed chlorosis and roots demonstrating symptoms of Cd toxicity. The content of nutrient elements in roots (Fe, K, Mg, Mn, Na, P, and Zn) was higher in the grafts having the SGECdt rootstock, and three elements, namely Ca, Fe, and Mn, were efficiently transported by the SGECdt root to the shoot of these grafts. The content of other measured elements (K, Mg, Na, P, and Zn) was similar in the root and shoot in all the grafts. Then, the non-grafted plants were grown in the presence of Cd and subjected to deficit or excess concentrations of Ca, Fe, or Mn. Exclusion of these elements from the nutrient solution retained or increased differences between SGE and SGECdt in growth response to Cd toxicity, whereas excess of Ca, Fe, or Mn decreased or eliminated such differences. The obtained results assign a principal role of roots to realizing the increased Cd-tolerance and Cdaccumulation in the SGECdt mutant. Efficient translocation of Ca, Fe, and Mn from roots to shoots appeared to counteract Cd toxicity, although Cd was actively taken up by roots and accumulated in shoots. [ABSTRACT FROM AUTHOR]

This study reports the development of a garden pea genotype ‘VRPM–901–5’ producing five flowers per peduncle at multiple flowering nodes, by using single plant selection approach from a cross ‘VL-8 × PC-531’. In addition, five other stable genetic stocks, namely VRPM-501, VRPM–502, VRPM–503, VRPM–901–3 and VRPSeL–1 producing three flowers per peduncle at multiple flowering nodes were also developed. All these unique genotypes were of either mid- or late- maturity groups. Furthermore, these multi-flowering genotypes were identified during later generations (F4 onward), which might be because of fixation of certain QTLs or recessive gene combinations. Surprisingly, a common parent PC–531, imparting multi-flowering trait in ten cross combinations was identified. Thus, the genotype PC–531 seems to harbor some recessive gene(s) or QTLs that in certain combination(s) express the multi-flowering trait. The interaction between genotype and environment showed that temperature (11–20°C) plays a key role in expression of the multi-flowering trait besides genetic background. Furthermore, the possible relationship between various multi-flowering regulatory genes such as FN, FNA, NEPTUNE, SN, DNE, HR and environmental factors was also explored, and a comprehensive model explaining the multi-flowering trait in garden pea is proposed. [ABSTRACT FROM AUTHOR]

Winter pea (Pisum sativum L.) is desirable for grain production in the southeastern United States to increase feed protein availability; however, there has not been any previous effort devoted to maximizing pea genetics for grain production in this region. Studies were conducted at six environments in North Carolina to assess pea grain potential. Nineteen pea cultivars/breeding lines were planted in monoculture and in mixture with three wheat (Triticum aestivum L.) cultivars of differing maturities. Pea cold tolerance, biomass production, disease incidence, maturity, lodging, and pea and wheat grain yield were assessed. The growth of only one pea cultivar/breeding line was severely inhibited by cold injury. Disease incidence was influenced by pea cultivars/breeding lines but not growth in monoculture or mixture with wheat. At the environments with heavy Sclerotinia pressure, grain yield of all pea cultivars/breeding lines was severely inhibited. All wheat cultivars reached physiological maturity prior to any pea cultivar/breeding line, and both species were harvested simultaneously using a combine with minimal difficulties. Pea yield was influenced by pea cultivar/breeding line but not growth in monoculture or mixture. Pea yield was greater with early maturing varieties. Pea grain yield potential across all pea cultivars/breeding lines was likely restricted by excessive heat during flowering. Many pea cultivars/breeding lines screened in this study out-yielded the current pea available in North Carolina. Results indicated that pea and wheat can be grown simultaneously and that regional pea cultivar recommendations will enhance pea grain yield in the southeastern United States. [ABSTRACT FROM AUTHOR]

The diversity and population structure of twenty-two genotypes of peas (Pisum sativum L.) grown in Iraq were estimated using microsatellite [simple sequence repeats (SSRs)]. Nineteen SSR primers generated sixty-eight polymorphic bands with an average of 3.789 polymorphic bands per primer. The highest number of polymorphic bands stated for the locus AA5 (eight alleles). Means of gene diversity, PIC, marker index, resolving power and Shannon index were 0.562, 0.513, 2.090, 2.703 and 0.833, respectively. Principal component analysis and hierarchical cluster analysis clustered the pea genotypes into three major clades. Genotypes G1 (ORP-2), G5 (ORP-11) and G6 (ORP-12) and G7 (ORP-13) were genetically the most distant from the other genotypes. Analysis of molecular variance (AMOVA) revealed that differences among the populations accounted for 14 % of the total variation, whereas difference within the population was 86 %. The population structure assay conceded that the genotypes were grouped into two evident subpopulations. Only three genotypes: G4 (ORP-10), G11 (Ns minima) and G17 (Karina) were considered to be admixture. The multi-locus FST analysis revealed strong differentiation within the populations and significant isolation by distance.0T The results of this study revealed that 0Tdifferent origins of genotypes had played a remarkable role in shaping the current patterns of genetic variation among these populations, many of which serve as good candidates for conservation and breeding programs. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, transgenic approaches have played a significant role in improving traits that help plants overcome abiotic stresses. Combined gene discovery and functional genomics have helped identify diversified mechanisms and gene families, which improved productivity under various abiotic stresses. We report on the genetic stability and persistent morphological features of transgenic pea (Pisum sativum L.) plants harboring the dicistronic vector construct pG0229MASnhx1/luc over five generations. In addition to salt stress tolerance, the transgenic plants showed frost tolerance compared to wild-type (WT) plants. Frost tolerance of AtNHX1 transgenic pea plants was unexpected and needs further investigation. We report morphological and molecular characteristics of transformed plants after long-term storage at 30-50 °C. The transgenic plants were morphologically stable and genetic stability of integrated genes was confirmed prior to and after transfer of plants to a glasshouse. Leaf size, shape, and color, plant height, number of tendrils, flower shape, pod shape, and grains were morphologically similar to the WT counterpart in all transgenic generations. This is the first report showing the genetic stability of transgenic pea plants harboring the salt stress tolerance gene (AtNHX1) from Arabidopsis thaliana in subsequent generations over a period of 6 years. [ABSTRACT FROM AUTHOR]

This study describes the impact of crop genetics and processing in two pea lines ( Pisum sativum L.) on starch digestion kinetics. Mutation at the rugosus ( r ) locus leads to wrinkled pea seeds, a reduction in starch content and a lower extent of in vitro starch digestibility. The Logarithm of Slope (LOS) kinetic model was used to analyse digestion curves obtained using porcine pancreatic α-amylase for a range of particle size fractions. Changes in starch structure induced by the r mutation led to clear differences in starch digestion kinetics for purified starches and pea flours. Larger particle size fractions showed slower starch digestion relative to the purified starch, but significant differences still existed between r and wild type pea lines. It is expected that this work will help inform the design of future studies where both starch structure and food structure are important determinants of digestion behaviour. [ABSTRACT FROM AUTHOR]

Leguminous plant roots can form a symbiosis with soil-dwelling nitrogen-fixing rhizobia, leading to the formation of a new root organ, the nodule. Successful nodulation requires co-ordination of spatially separated events in the root, including infection in the root epidermis and nodule organogenesis deep in the root cortex. We show that the hormone gibberellin plays distinct roles in these epidermal and cortical programmes. We employed a unique set of genetic material in pea that includes severely gibberellin-deficient lines and della-deficient lines that enabled us to characterize all stages of infection and nodule development. We confirmed that gibberellin suppresses infection thread formation and show that it also promotes nodule organogenesis into nitrogen-fixing organs. In both cases, this is achieved through the action of DELLA proteins. This study therefore provides a mechanism to explain how both low and high gibberellin signalling can result in reduced nodule number and reveals a clear role for gibberellin in the maturation of nodules into nitrogen-fixing organs. We also demonstrate that gibberellin acts independently of ethylene in promoting nodule development. [ABSTRACT FROM AUTHOR]

Knowledge of current genetic diversity and mating systems of crop wild relatives (CWR) in the Fertile Crescent is important in crop genetic improvement, because western agriculture began in the area after the cold-dry period known as Younger Dryas about 12,000 years ago and these species are also wild genepools of the world’s most important food crops. Wild pea (Pisum sativum subsp. elatius) is an important source of genetic diversity for further pea crop improvement harbouring traits useful in climate change context. The genetic structure was assessed on 187 individuals of Pisum sativum subsp. elatius from fourteen populations collected in the northern part of the Fertile Crescent using 18,397 genome wide single nucleotide polymorphism DARTseq markers. AMOVA showed that 63% of the allelic variation was distributed between populations and 19% between individuals within populations. Four populations were found to contain admixed individuals. The observed heterozygosity ranged between 0.99 to 6.26% with estimated self-pollination rate between 47 to 90%. Genetic distances of wild pea populations were correlated with geographic but not environmental (climatic) distances and support a mixed mating system with predominant self-pollination. Niche modelling with future climatic projections showed a local decline in habitats suitable for wild pea, making a strong case for further collection and ex situ conservation. [ABSTRACT FROM AUTHOR]

Forty nine pigeon pea genotypes were evaluated at Agricultural Research Station Tandur during kharif 2015-16. Genotypes were grouped into six clusters based on Mahalonobis D2 statistics. Days to maturity contributed to maximum genetic divergence followed by days to 50% flowering. Maximum inter cluster distance was observed between clusters II and VI and intra cluster distance in cluster I and II. Genotypes in cluster V recorded highest mean values for number of secondary branches/plant and number of pods/plant and seed yield. Broad sense heritability estimates were highest for days to maturity and days to 50% flowering. Significant and positive genotypic and phenotypic correlation was observed between seed yield and number of pods/plant and number of secondary branches/plant. The range of GCV observed was 4.55 to 22.07% for the traits under study indicating the extent of variability present among the pigeon pea genotypes. Path coefficient analysis revealed that days to maturity exhibited maximum direct effect followed by number of pods/plant. [ABSTRACT FROM AUTHOR]

The pea seeds are photosynthetically active until the end of the maturation phase, when the embryonic chlorophylls degrade. However, in some cultivars, the underlying mechanisms are compromised, and the mature seeds preserve green colour. The residual chlorophylls can enhance oxidative degradation of reserve biomolecules, and affect thereby the quality, shelf life and nutritive value of seeds. Despite this, the formation, degradation, and physical properties of the seed chlorophylls are still not completely characterised. So here we address the dynamics of seed photochemical activity in the yellow- and green-seeded pea cultivars by the pulse amplitude modulation (PAM) fluorometric analysis. The experiments revealed the maximal photochemical activity at the early- and mid-cotyledon stages. Thereby, the active centres of PSII were saturated at the light intensity of 15-20 μmol photonsm-2 s-1. Despite of their shielding from the light by the pod wall and seed coat, photochemical reactions can be registered in the seeds with green embryo. Importantly, even at the low light intensities, the photochemical activity in the coats and cotyledons could be detected. The fast transients of the chlorophyll a fluorescence revealed a higher photochemical activity in the coat of yellow-seeded cultivars in comparison to those with the green-seeded ones. However, it declined rapidly in all seeds at the late cotyledon stage, and was accompanied with the decrease of the seed water content. Thus, the termination of photosynthetic activity in seeds is triggered by their dehydration. [ABSTRACT FROM AUTHOR]

Local damage induces generation and propagation of variation potentials (VPs) that affect physiological processes in plants. The aims of the work presented here were to investigate parameters of VP induced by burning, heating and mechanical injury in pea seedlings, and to undertake a theoretical analysis of the mechanisms underlying the differences inVPparameters and a study of the photosynthetic responses caused byVPsinduced by the damaging factors. The velocity of propagation of burn-induced VP decreased with distance from the damaged area whereas the velocities of heating- and injury-induced VPs were constant. The amplitudes of burn- and heating-induced VPs did not depend on distance whereas the amplitude of VP induced by mechanical injury decreased. VP propagation has been simulated on the basis of wound substance spread. The simulation revealed two possible ways of wound substance propagation: turbulent diffusion from the damaged area and secondary active production in intact cells. The photosynthetic response (decrease in the quantum yield of PSII and raising the level of non-photochemical fluorescence quenching (NPQ)) developed in case of VP entering the intact leaf under heating and burn but was not registered after mechanical injury. An increase inNPQlevel was biphasic under burn in comparison with a single-phase one under heating, and theNPQamplitude was slightly higher under burn.Wesuggest that differences in photosynthetic responses may be determined by the parameters of VPs induced by stimuli of different nature. [ABSTRACT FROM AUTHOR]

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Trehalose 6-phosphate (Tre6P) is a signal of sucrose availability in plants, and has been implicated in the regulation of shoot branching by the abnormal branching phenotypes of Arabidopsis ( Arabidopsis thaliana) and maize ( Zea mays) mutants with altered Tre6P metabolism. Decapitation of garden pea ( Pisum sativum) plants has been proposed to release the dormancy of axillary buds lower down the stem due to changes in sucrose supply, and we hypothesized that this response is mediated by Tre6P. Decapitation led to a rapid and sustained rise in Tre6P levels in axillary buds, coinciding with the onset of bud outgrowth. This response was suppressed by simultaneous defoliation that restricts the supply of sucrose to axillary buds in decapitated plants. Decapitation also led to a rise in amino acid levels in buds, but a fall in phospho enolpyruvate and 2-oxoglutarate. Supplying sucrose to stem node explants in vitro triggered a concentration-dependent increase in the Tre6P content of the buds that was highly correlated with their rate of outgrowth. These data show that changes in bud Tre6P levels are correlated with initiation of bud outgrowth following decapitation, suggesting that Tre6P is involved in the release of bud dormancy by sucrose. Tre6P might also be linked to a reconfiguration of carbon and nitrogen metabolism to support the subsequent growth of the bud into a new shoot. [ABSTRACT FROM AUTHOR]

Pea (Pisum sativum L.) is the oldest model object of plant genetics and one of the most agriculturally important legumes in the world. Since the pea genome has not been sequenced yet, identification of genes responsible for mutant phenotypes or desirable agricultural traits is usually performed via genetic mapping followed by candidate gene search. Such mapping is best carried out using gene-based molecular markers, as it opens the possibility for exploiting genome synteny between pea and its close relative Medicago truncatula Gaertn., possessing sequenced and annotated genome. In the last 5 years, a large number of pea gene-based molecular markers have been designed and mapped owing to the rapid evolution of “next-generation sequencing” technologies. However, the access to the complete set of markers designed worldwide is limited because the data are not uniformed and therefore hard to use. The Pea Marker Database was designed to combine the information about pea markers in a form of user-friendly and practical online tool. Version 1 (PMD1) comprises information about 2484 genic markers, including their locations in linkage groups, the sequences of corresponding pea transcripts and the names of related genes in M. truncatula. Version 2 (PMD2) is an updated version comprising 15944 pea markers in the same format with several advanced features. To test the performance of the PMD, fine mapping of pea symbiotic genes Sym13 and Sym27 in linkage groups VII and V, respectively, was carried out. The results of mapping allowed us to propose the Sen1 gene (a homologue of SEN1 gene of Lotus japonicus (Regel) K. Larsen) as the best candidate gene for Sym13, and to narrow the list of possible candidate genes for Sym27 to ten, thus proving PMD to be useful for pea gene mapping and cloning. All information contained in PMD1 and PMD2 is available at . [ABSTRACT FROM AUTHOR]

Pea (Pisum sativum, L.) is a major pulse crop used both for animal and human alimentation. Owing to its association with nitrogen-fixing bacteria, it is also a valuable component for low-input cropping systems. To evaluate the genetic diversity and the scale of linkage disequilibrium (LD) decay in pea, we genotyped a collection of 917 accessions, gathering elite cultivars, landraces, and wild relatives using an array of ~13,000 single nucleotide polymorphisms (SNP). Genetic diversity is broadly distributed across three groups corresponding to wild/landraces peas, winter types, and spring types. At a finer subdivision level, genetic groups relate to local breeding programs and type usage. LD decreases steeply as genetic distance increases. When considering subsets of the data, LD values can be higher, even if the steep decay remains. We looked for genomic regions exhibiting high level of differentiation between wild/landraces, winter, and spring pea, respectively. Two regions on linkage groups 5 and 6 containing 33 SNPs exhibit stronger differentiation between winter and spring peas than would be expected under neutrality. Interestingly, QTL for resistance to cold acclimation and frost resistance have been identified previously in the same regions. [ABSTRACT FROM AUTHOR]

In pea, the auxins 4-chloroindole-3-acetic acid (4-Cl-IAA) and indole-3-acetic acid (IAA) occur naturally; however, only 4-Cl-IAA stimulates pericarp growth and gibberellin (GA) biosynthesis, and inhibits the ethylene response in deseeded ovaries (pericarps), mimicking the presence of seeds. Expression of ovary ethylene biosynthesis genes was regulated similarly in most cases by the presence of 4-Cl-IAA or seeds. PsACS1 [which encodes an enzyme that synthesizes 1-aminocyclopropane-1-carboxylic acid (ACC)] transcript abundance was high in pericarp tissue adjacent to developing seeds following pollination. ACC accumulation in 4-Cl-IAA-treated deseeded pericarps was driven by high PsASC1 expression (1800-fold). 4-Cl-IAA, but not IAA, also suppressed the pericarp transcript levels of PsACS4. 4-Cl-IAA increased PsACO1 and decreased PsACO2 and PsACO3 expression (enzymes that convert ACC to ethylene) but did not change ACO enzyme activity. Increased ethylene was countered by a 4-Cl-IAA-specific decrease in ethylene responsiveness potentially via modulation of pericarp ethylene receptor and signaling gene expression. This pattern did not occur in IAA-treated pericarps. Overall, the effect of 4-Cl-IAA and IAA on ethylene biosynthesis gene expression generally explains the ethylene evolution patterns, and their effects on GA biosynthesis and ethylene signaling gene expression explain the tissue response patterns in young pea ovaries. [ABSTRACT FROM AUTHOR]

The article focuses on the effect of gamma radiation on macro mutations and their effectivenes and efficiency in pea. The practical utility of induced mutations for the improvement of inherited characters in pea is recognized. These have been used to find out sensitivity of crop plants to mutagens and to elucidate effectiveness and efficiency of mutagen.

Pea (Pisum sativum L.) is an important food and feed legume grown across many temperate regions of the world, especially from Asia to Europe and North America. The goal of this study was to use 30 informative pea microsatellite markers to compare genetic diversity in a global core from the USDA and a core collection from the National Genebank of China (NGC). The Chinese and global collections had 295 and 305 accessions, respectively. A total of 259 alleles were detected in the full 600 accessions, with a mean of 8.7 alleles per locus. Given the range of countries represented, the global collection was found to be more diverse than the Chinese core. However, the Chinese accessions still formed two distinct groups. The first group had 90.6% spring-planted peas from northern China. The second group had 65.9% winter-planted peas from southern China. An outlier group included wild peas from the P. sativum elatius and asiaticum subspecies. In conclusion, the USDA collection had slightly more overall diversity than the NGC collection given its global nature, but the Chinese accessions represented a considerable fraction of overall diversity, with accessions representing spring and winter pea types from northern and southern China, respectively, that are only weakly represented in the USDA core. The origin of Chinese peas is likely to be from the region of domestication in the Middle East through an ancient route of dissemination through southern Asia, where some genetically similar peas are grown. [ABSTRACT FROM AUTHOR]

The defense gene activations that provide non-host disease resistance in plants are signaled by various elicitors. A number of the fungal-derived signal such as chitosan and DNase are uniquely able to promote transcription through direct effects on the DNA of pea chromatin at sites of defense gene transcription. Other biological signals are contained within the reactive oxygen species (ROS) and make substantial changes in DNA in other tissues. The current research probes the ROS elicitor concentrations and the conditions within pea endocarp nuclear material temporally associated with the activation of pathogenesis-related (PR) genes. Within 10 min, ROS accumulate in response to a bean pathogen Fusarium solani f.sp. phaseoli (Fsph) to levels 4-fold those elicited by the pea pathogen Fusarium solani f.sp. pisi (Fspi). Application of Hydrogen peroxide (H 2 O 2 ) (HP) increases DNA fragmentation and activates the PR genes ( DRR206, defensin, PR10, and PR1b ) within 50 min and changes the nuclear diameters of the pea host cells in 3 h. Increased levels of the phytoalexin, pisatin and the growth suppression of the pea pathogen, Fspi, were observed within 24 h after H 2 O 2 treatment to the endocarp. Our results suggest that H 2 O 2 contributes to the induction of the defense response in pea endocarp tissue, which is likely mediated by activation of DNA damage responses. [ABSTRACT FROM AUTHOR]

An investigation was carried out to evaluate 51 diverse field pea genotypes at Langol Research farm, ICAR, RC, NEH Region, Manipur Centre for nine yield related quantitative traits and four morphological qualitative traits for practical field pea improvement in Manipur. The combined analysis of variance of genotypes for all the nine traits was found to be significant. The amount of variability in one variable as a linear function of another variable was also measured through phenotypic and genotypic correlation among nine quantitative traits. The pod number per plant, seed number per pod and 100 seed weight showed significant positive correlation with seed yield per plant both at phenotypic and genotypic levels. Multivariate analysis using principal component analysis (PCA) indicated that three principal components (PCs) accounted for > 75% of the total variation. The genotypes were grouped into seven clusters using distance based Agglomerative "Average linkage" method. Three genotypes IPF-5-19, EC-8495, HUDP-15 belonging to cluster II and DDR-30, early maturing variety belonging to Cluster VI were found promising in terms of seed yield for the region. [ABSTRACT FROM AUTHOR]

This study elucidates mechanisms conferring differential tolerance to cadmium (Cd) stress in contrasting pea genotypes. Cd stress caused a significant decline in morphophysiological traits in Hurst Green Shaft but not in Kelvedon Wonder, suggesting that Cd-stress tolerance does exist in Kelvedon Wonder. Results showed a significant increase of Cd in roots of both genotypes but not in leaves of Kelvedon Wonder due to Cd stress. Consistently,RIT1(Fe transporter) transcript showed downregulation and upregulation in Kelvedon Wonder and Hurst Green Shaft, respectively, in leaves upon Cd exposure. This consistent atomic absorption spectroscopy and expression data suggest that limiting Cd translocation by decreasedRIT1expression is related to the ability of Kelvedon Wonder plants to cope with Cd stress. Furthermore, an enhanced antioxidant activity was only observed in leaves of Kelvedon Wonder under Cd stress. Finally, high-performance liquid chromatography analysis showed elevated cysteine, methionine and glutathione in leaves of Kelvedon Wonder, suggesting better protection of pea plants from Cd-induced oxidative stress. Our findings reveal that differential tolerance to Cd stress is mainly attributed to Cd translocation and antioxidant defense in pea plants, which can be further implemented for Cd-free transgenic peas to limit environmental toxicity and health hazards. [ABSTRACT FROM AUTHOR]

This paper presents the inter-laboratory studies for the successful validation of qualitative real-time Polymerase Chain Reaction methods for the detection of Genetically Modified Organisms in food and feed. Two singleplex TaqMan methods were developed for the detection of the tE9 terminator present in several genetically modified events and the detection of the endogenous lectin gene from pea; the tE9 terminator donor organism. In addition, a TaqMan duplex method was validated, which allows the simultaneous detection of the pat and bar elements. The paper explains the different acceptance parameters used during the in-house validation, the method transferability study and finally the inter-laboratory validation, how this validation was conducted and the problems encountered. Statistical methods for the validation of the qualitative methods are also presented. This information can be used by laboratories for the verification of these methods during their implementation and for the validation of new methods. [ABSTRACT FROM AUTHOR]

Pea seed-borne mosaic virus (PSbMV) significantly reduces yields in a broad spectra of legumes. The eukaryotic translation initiation factor has been shown to confer resistance to this pathogen, thus implying that translation and proteome dynamics play a role in resistance. This study presents the results of a proteome-wide analysis of Pisum sativum L. response to PSbMV infection. LC–MS profiling of two contrasting pea cultivars, resistant (B99) and susceptible (Raman) to PSbMV infection, detected > 2300 proteins, 116 of which responded to PSbMV ten and/or twenty days post-inoculation. These differentially abundant proteins are involved in number of processes that have previously been reported in the plant-pathogen response, including protein and amino acid metabolism, stress signaling, redox homeostasis, carbohydrate metabolism, and lipid metabolism. We complemented our proteome-wide analysis work with targeted analyses of free amino acids and selected small molecules, fatty acid profiling, and enzyme activity assays. Data from these additional experiments support our findings and validate the biological relevance of the observed proteome changes. We found surprising similarities in the resistant and susceptible cultivars, which implies that a seemingly unaffected plant, with no detectable levels of PSbMV, actively suppresses viral replication. Biological significance Plant resistance to PSbMV is connected to translation initiation factors, yet the processes involved are still poorly understood at the proteome level. To the best of our knowledge, this is the first survey of the global proteomic response to PSbMV in plants. The combination of label-free LC–MS profiling and two contrasting cultivars (resistant and susceptible) provided highly sensitive snapshots of protein abundance in response to PSbMV infection. PSbMV is a member of the largest family of plant viruses and our results are in accordance with previously characterized potyvirus-responsive proteomes. Hence, the results of this study can further extend our knowledge about these pathogens. We also show that even though no viral replication is detected in the PSbMV-resistant cultivar B99, it is still significantly affected by PSbMV inoculation. [ABSTRACT FROM AUTHOR]

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 (H) varied from 0.10 to 0.99 in primers AB-64 and AD-160, respectively, with a mean value of 0.46. Expected heterozygosity (H) 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. [ABSTRACT FROM AUTHOR]

Pea enation mosaic virus 1 (PEMV1) and Pea enation mosaic virus 2 (PEMV2) are two viruses in an obligate symbiosis that cause pea enation mosaic disease mainly in plants in the Fabaceae family. This virus system is a valuable model to investigate plant virus replication, movement and vector transmission. Thus, here we describe growth conditions, virus detection methods, and virus accumulation behavior. To measure the accumulation and movement of PEMV1 and PEMV2 in plants during the course of infection, we developed a quantitative real-time one-step reverse transcription PCR procedure using the SYBR-green ® technology. Viral primers were designed that anneal to conserved but distinct regions in the RNA-dependent RNA polymerase gene of each virus. Moreover, the normalization of viral accumulation was performed to correct for sample-to-sample variation by designing primers to two different Pisum sativum housekeeping genes: actin and β-tubulin. Transcript levels for these housekeeping genes did not change significantly in response to PEMV infection. Conditions were established for maximum PCR efficiency for each gene, and quantification using QuBit ® technology. Both viruses reached maximum accumulation around 21 days post-inoculation of pea plants. These results provide valuable tools and knowledge to allow reproducible studies of this emerging model virus system virus complex. [ABSTRACT FROM AUTHOR]

This study was conducted by using Jinks-Hayman type analyses on four pea genotypes (PS4009, PS3053, PS3073 and Reyna) and their population of the complete diallel reciprocal crosses in order to examine the genetic structure. According to the results of all diallel crosses, environmental variance (E) and additive gene variance (D) was not significant. All the features of the dominant gene variances were higher than the additive gene variances (H1) and D-H1 value was found to be negative. In the population, dominant genes were found significant for all the characteristics except number of seed per pod. Result of Wr, Vr graphics indicated partial dominancy for the number of seed per pod, and over dominancy for the rest of the characters studied. [ABSTRACT FROM AUTHOR]

Key message : This work discusses several selected topics of plant genetics and breeding in relation to the 150th anniversary of the seminal work of Gregor Johann Mendel. Abstract: In 2015, we celebrated the 150th anniversary of the presentation of the seminal work of Gregor Johann Mendel. While Darwin's theory of evolution was based on differential survival and differential reproductive success, Mendel's theory of heredity relies on equality and stability throughout all stages of the life cycle. Darwin's concepts were continuous variation and 'soft' heredity; Mendel espoused discontinuous variation and 'hard' heredity. Thus, the combination of Mendelian genetics with Darwin's theory of natural selection was the process that resulted in the modern synthesis of evolutionary biology. Although biology, genetics, and genomics have been revolutionized in recent years, modern genetics will forever rely on simple principles founded on pea breeding using seven single gene characters. Purposeful use of mutants to study gene function is one of the essential tools of modern genetics. Today, over 100 plant species genomes have been sequenced. Mapping populations and their use in segregation of molecular markers and marker-trait association to map and isolate genes, were developed on the basis of Mendel's work. Genome-wide or genomic selection is a recent approach for the development of improved breeding lines. The analysis of complex traits has been enhanced by high-throughput phenotyping and developments in statistical and modeling methods for the analysis of phenotypic data. Introgression of novel alleles from landraces and wild relatives widens genetic diversity and improves traits; transgenic methodologies allow for the introduction of novel genes from diverse sources, and gene editing approaches offer possibilities to manipulate gene in a precise manner. [ABSTRACT FROM AUTHOR]

Grain yield is a complex character representing a multiplicative end product of many yield attributes. However, understanding the genetics and inheritance that underlies yield and its component characters pose a prerequisite to attain the actual yield potential of any crop species. The knowledge pertaining to gene actions and interactions is likely to direct and strengthen the crop breeding programmes. With this objective, the present investigation was undertaken by using six generations derived from three different crosses in grass pea. The study underscores the significance of additive-dominance model, gene action involved in inheritance of quantitative characters and heritability. Of note, nonallelic interactions influencing the traits were detected by both scaling test and joint scaling test, indicating the inadequacy of the additive-dominance model alone in explaining the manifestation of complex traits such as yield. Besides, additive ( d) and dominance ( h) gene effects, different types of interallelic interactions ( i, j, l) contributed towards the inheritance of traits in the given crosses. Nevertheless, predominance of additive variance suggests a difference between homozygotes at a locus with positive and negative alleles being distributed between the parents. Duplicate epistasis was prevalent in most of the cases for traits like plant height, seeds/pod, 100-seed weight and pod width. In view of the diverse gene actions, i.e. additive, dominant and epistasis, playing important roles in the manifestation of complex traits like yield, we advocate implementation of population improvement techniques in particular reciprocal recurrent selection to improve productivity gains in grass pea. [ABSTRACT FROM AUTHOR]

Mendel's data exhibit remarkable agreement to the ratios he predicted. In this article, alternative explanations for this close agreement (that inheritance in pea does not conform to the standard statistical model, that data were omitted, that ambiguous data were categorized to better match predicted ratios, and that some data were deliberately falsified) are tested using approaches that are designed to distinguish between these alternatives. The possibility that garden pea (Pisum sativum L.) naturally produces segregation ratios more closely matching Mendelian expectations than predicted by statistical models is rejected. Instead the opposite is found to be the case, making Mendel's results even more remarkable. Considerable evidence is introduced that Mendel omitted some of his experimental results, but this alternative cannot adequately explain the low average deviation from expectations that is characteristic of the segregation data he presented. An underlying bias in Mendel's data favoring the predicted ratio is present, but my analysis could not clearly determine whether the bias was caused by misclassifying ambiguous phenotypes or deliberate falsification of the results. A number of Mendel's statements are argued to be unrealistic in terms of practical pea genetics, suggesting that his text does not represent a strictly accurate description of his experimental methods. Mendel's article is probably best regarded as his attempt to present his model in a simple and convincing format with a minimum of additional details that might obscure his message. [ABSTRACT FROM AUTHOR]

The present research work was designed to find out the amount of genetic variability that may exist in different pea cultivars. For this purpose six advance lines/commercial pea varieties were collected from Ayub Agricultural Research Institute (AARI) Faisalabad and one local variety was included in the experiment as a control. The experiment was conducted during 2014-15 at National Tea & High Value Crops Research Institute (NTHRI) Shinkiari, Mansehra. Altogether seven pea genotypes were laid out in Randomized Complete Block Design (RCBD) with three replications. Normal agronomic practices were carried out during the growth period and data was recorded on different growth parameters. Significant differences were observed for all the agronomic traits studied. Root rot attack was observed during the growth period. Pea variety 'Meteor' was found susceptible against this disease followed by 'Sarsabz 9800-1' as moderately susceptible and 9375 as resistant. The other varieties/lines Pea-09, Climax, Local and PF-400 were found tolerant against this disease. Green pod yield per hectare data revealed that pea variety 'Climax' produced the highest yield (11.6 t ha-1) followed by advance lines PF-400 (11.5 t ha-1) and 9375 (9.9 t ha-1), respectively. The lowest yield (2.1 t ha-1) was recorded for 'Meteor' which was also found susceptible against root rot disease. Based on our findings, it is recommended that pea variety 'Climax' cultivation should be promoted in the area at large scale in order to increase the production and give more financial benefits to the farmers of the area. Advance lines PF-400 & 9375 which performed well in the experiment and bear bright future prospects should be considered in designing future hybridization programs. [ABSTRACT FROM AUTHOR]

Genetic divergence in the 54 genotypes of pea was worked-out using Mahalanobis's D2 statistics to identify the potential parents to be involved in the hybridization programme so that superior segregants can be selected in the segregating generations. On the basis of performance of various traits, 54 genotypes of pea were grouped into four clusters and maximum number of genotypes was accommodated in cluster II. The average intra-cluster distance was found maximum in cluster II and minimum in cluster III. Inter-cluster distance was maximum between cluster II and III indicating that hybridization between genotypes from cluster II and III can be utilized for getting the superior recombinants in segregating generations. Furthermore, on the basis of cluster means for various traits studied, cluster II was found superior for number of pods per plant, pod length, number of seeds per pod, shelling percentage, pod yield, total sugars and total soluble solids, whereas cluster III was found superior for plant height and total phenols. Hence, hybridization between parents from cluster II and cluster III for these characters may produce new recombinants with desired traits in the segregating generations which can be further purified by various plant breeding schemes. [ABSTRACT FROM AUTHOR]

Background: Cultivated crops have repeatedly faced new climatic conditions while spreading from their site of origin. In Sweden, at the northernmost fringe of Europe, extreme conditions with temperature-limited growth seasons and long days require specific adaptation. Pea (Pisum sativum L.) has been cultivated in Sweden for millennia, allowing for adaptation to the local environmental conditions to develop. To study such adaptation, 15 Swedish pea landraces were chosen alongside nine European landraces, seven cultivars and three wild accessions. Number of days to flowering (DTF) and other traits were measured and the diversity of the flowering time genes HIGH RESPONSE TO PHOTOPERIOD (HR), LATE FLOWERING (LF) and STERILE NODES (SN) was assessed. Furthermore, the expression profiles of LF and SN were obtained. Results: DTF was positively correlated with the length of growing season at the site of origin (GSO) of the Swedish landraces. Alleles at the HR locus were significantly associated with DTF with an average difference of 15.43 days between the two detected haplotypes. LF expression was found to have a significant effect on DTF when analysed on its own, but not when HR haplotype was added to the model. HR haplotype and GSO together explained the most of the detected variation in DTF (49.6%). Conclusions: We show local adaptation of DTF, primarily in the northernmost accessions, and links between genetic diversity and diversity in DTF. The links between GSO and genetic diversity of the genes are less clear-cut and flowering time adaptation seems to have a complex genetic background. [ABSTRACT FROM AUTHOR]

Pea (Pisum sativum L.) is an important legume worldwide. The importance of pea in arable rotations and nutritional value for both human and animal consumption have fostered sustained production and different studies to improve agronomic traits of interest. Moreover, complete sequencing of the pea genome is currently underway and will lead to the identification of a large number of genes potentially associated with important agronomic traits. Because stable genetic transformation is laborious for pea, virus-induced gene silencing (VIGS) appears as a powerful alternative technology for determining the function of unknown genes. In this work, we present a rapid and efficient viral inoculation method using DNA infectious plasmids of Bean pod mottle virus (BPMV)-derived VIGS vector. Six pea genotypes with important genes controlling biotic and/or abiotic stresses were found susceptible to BPMV carrying a GFP reporter gene and showed fluorescence in both shoots and roots. In a second step, we investigated 37 additional pea genotypes and found that 30 were susceptible to BPMV and only 7 were resistant. The capacity of BPMV to induce silencing of endogenes was investigated in the most susceptible genotype using two visual reporter genes: PsPDS and PsKORRIGAN1 (PsKOR1) encoding PHYTOENE DESATURASE and a 1,4-b-D-glucanase, respectively. The features of the 'one-step' BPMV-derived VIGS vector include (i) the ease of rub-inoculation, without any need for biolistic or agro-inoculation procedures, (ii) simple costeffective procedure and (iii) noninterference of viral symptoms with silencing. These features make BPMV the most adapted VIGS vector in pea to make low- to high-throughput VIGS studies. [ABSTRACT FROM AUTHOR]

Bacterial blight caused by Pseudomonas syringae pv. pisi is an important disease of pea ( Pisum sativum L.). Knowledge about the genes or mechanisms acting against this pathogen is scarce. A genetic mapping study of the resistance was performed using a recombinant inbred line mapping population generated by crossing the susceptible cultivar Cheyenne to the resistant line ZP0104. Resistance to race 2 was a dominant monogenic trait mapped at 109.4 cM on LGVII between AB114 and AB122 simple sequence repeat markers. It is assumed to be the previously Ppi2 based on its location. Resistance to races 4 and 8 behaved also as dominant monogenic traits and presumably due to a single gene conferring resistance to both races. It was mapped on LGIII at 11.2 cM of the AD57 microsatellite marker. This gene has been named Ppi8 and it is proposed as a new resistance gene. Ppi8 and Ppi2 are associated to the pea consensus map for the first time. To identify genes related to resistance and susceptibility, a DeepSuperSAGE genome-wide transcription profiling approach was conducted producing 45,261 different pea unitags. A set of 651 unitags were differently represented in the susceptible versus the resistant response with a significance of P < 0.001 and a fold change >4. These putative differentially expressed set includes genes previously related to responses to biotic stresses (pathogenesis-related or related to disease resistance responses), abiotic stresses or of unknown function, among other. [ABSTRACT FROM AUTHOR]