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Peanut is an important oil and economic crop in China. The rainy season (April–June) in the downstream Yangtze River in China always leads to waterlogging, which seriously affects plant growth and development. Therefore, understanding the metabolic mechanisms under waterlogging stress is important for future waterlogging tolerance breeding in peanut. In this study, waterlogging treatment was carried out in two different peanut cultivars [Zhonghua 4 (ZH4) and Xianghua08 (XH08)] with different waterlogging tolerance. The data-independent acquisition (DIA) technique was used to quantitatively identify the differentially accumulated proteins (DAPs) between two different cultivars. Meanwhile, the functions of DAPs were predicted, and the interactions between the hub DAPs were analyzed. As a result, a total of 6,441 DAPs were identified in ZH4 and its control, of which 49 and 88 DAPs were upregulated and downregulated under waterlogging stress, respectively, while in XH08, a total of 6,285 DAPs were identified, including 123 upregulated and 114 downregulated proteins, respectively. The hub DAPs unique to the waterlogging-tolerant cultivar XH08 were related to malate metabolism and synthesis, and the utilization of the glyoxylic acid cycle, such as L-lactate dehydrogenase, NAD+-dependent malic enzyme, aspartate aminotransferase, and glutamate dehydrogenase. In agreement with the DIA results, the alcohol dehydrogenase and malate dehydrogenase activities in XH08 were more active than ZH4 under waterlogging stress, and lactate dehydrogenase activity in XH08 was prolonged, suggesting that XH08 could better tolerate waterlogging stress by using various carbon sources to obtain energy, such as enhancing the activity of anaerobic respiration enzymes, catalyzing malate metabolism and the glyoxylic acid cycle, and thus alleviating the accumulation of toxic substances. This study provides insight into the mechanisms in response to waterlogging stress in peanuts and lays a foundation for future molecular breeding targeting in the improvement of peanut waterlogging tolerance, especially in rainy area, and will enhance the sustainable development in the entire peanut industry. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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 Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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 Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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 Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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 Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

One of the main reasons for the losses in mechanized harvesting of peanuts is the insufficient strength of the gynophores that bind each fruit to the stem of the plant. A method for determining the energy consumption for dynamic tearing off single peanut fruits from gynophore is justified and based on the pendulum principle. The derived dependencies show that the mentioned energy is influenced by the generalized inertia moment of the rotating parts and the angular velocity of the pendulum before and after the tearing off the fruit. An experimental device for determining the mentioned energy consumption has been developed. It provides opportunities to study the influence of factors that determine the dynamic strength of gynophore, which is crucial for fruit loss at mechanized peanut harvesting. The device can be used for breeding and selection of peanut varieties that are suitable for mechanized harvesting. [ABSTRACT FROM AUTHOR]

The yield loss in peanut due to peanut bud necrosis disease ranges from 30 to 80%. Quantitative trait loci (QTL) were mapped using 108 RILs from a cross between JL-24 × NRCGCS-85. Phenotyping of these RILs was performed at natural hotspot under field conditions in 2017 post-rainy and 2018 rainy seasons. Significant variations were observed among the RILs confirming polygenic control and additive type of gene action for the disease. After screening of 1980 SSR markers, 227 were found polymorphic between the parents. Out of them 49 polymorphic markers effectively amplified codominant amplicons between homozygotes (parent) and heterozygotes (F1s). Linkage maps with 49 markers showed eight linkages having 47 markers. Using inclusive composite interval mapping, two major QTLs, namely QTLPBND-01 and QTLPBND-02 for PBND resistance, were detected, explaining 12.38–16.88% of phenotypic variance. Besides, superior RILs, (JL 24 × NRCGCS 85)-26-13 and (JL 24 × NRCGCS 85)-10-12 were identified with 26% and 17% higher pod yield over JL 24 and resistant to PBND with less than 5% disease scoring. These two RILs also contains two freshly identified QTLs. Among three tightly linked markers, AHS0006 associated with QTLPBND-01 was found stable and to code for sialyl transferase-like protein 1 responsible for protein glycosylation and sialyl transferase activity. This is also the first report of stlp 1 gene associated with PBND resistance, which will help in accelerating the genomic breeding approaches for PBND resistance in peanut in the future. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

Seed size/weight, a key domestication trait, is also an important selection target during peanut breeding. However, the mechanisms that regulate peanut seed development are unknown. We re-sequenced 12 RNA samples from developing seeds of two cultivated peanut accessions (Lines 8106 and 8107) and wild Arachis monticola at 15, 30, 45, and 60 days past flowering (DPF). Transcriptome analyses showed that ∼36,000 gene loci were expressed in each of the 12 RNA samples, with nearly half exhibiting moderate (2 ≤ FPKM < 10) expression levels. Of these genes, 12.2% (4,523) were specifically expressed during seed development, mainly at 15 DPF. Also, ∼12,000 genes showed significant differential expression at 30, 45, and/or 60 DPF within each of the three peanut accessions, accounting for 31.8–34.1% of the total expressed genes. Using a method that combined comprehensive transcriptome analysis and previously mapped QTLs, we identified several candidate genes that encode transcription factor TGA7, topless-related protein 2, IAA-amino acid hydrolase ILR1-like 5, and putative pentatricopeptide repeat-containing (PPR) protein. Based on sequence variations identified in these genes, SNP markers were developed and used to genotype both 30 peanut landraces and a genetic segregated population, implying that EVM0025654 encoding a PPR protein may be associated with the increased seed size/weight of the cultivated accessions in comparison with the allotetraploid wild peanut. Our results provide additional knowledge for the identification and functional research into candidate genes responsible for the seed size/weight phenotype in peanut. [ABSTRACT FROM AUTHOR]

Late leaf spot (LLS) disease caused by Nothopassalora personata (Berk. & M.A. Curtis) U. Braun, C. Nakash, Videira & Crous is prevalent among pathogens encountered in peanut (Arachis hypogaea L.) growing regions. Chemical control is expensive, sometimes inaccessible, and can be difficult to apply. One effective solution to control this disease is the deployment of resistant cultivars. IAC 322 is a breeding line resistant to foliar fungal disease and harbors alien introgressions from A. cardenasii Krapov. & W.C. Gregory, a wild diploid relative of peanut. The objective of this study was to determine the level of LLS resistance conferred by introgressed segments in families derived from TifNV‐High O/L × IAC 322. Phenotyping for LLS resistance was performed under both in vitro and field conditions, which provided sufficient disease pressure to separate the means of susceptible and resistant checks, although there was no statistically significant separation of LLS resistance among the families with introgressions. However, consistent levels of LLS resistance observed in the family with A02‐top/A03‐bottom segments makes it a valuable resource for peanut breeding. In addition, late‐season field disease ratings were found to correlate with the entire LLS infection progression under both field and in vitro conditions. Among the parameters collected for in vitro experiments, numbers of LLS lesions and sporulating LLS lesions at late stages of LLS infection and incubation period can be used to predict LLS resistance under field conditions. [ABSTRACT FROM AUTHOR]

Peanut (Arachis hypogaea L.) is one of the most important oil and industrial crops. However, heavy-metal pollution and frequent soil diseases, poses a significant threat to the production of green and healthy peanuts. Herein, we investigated the effects of heavy metal Cd2+ toxicity to the peanuts, and screened out two peanut cultivars H108 and YZ 9102 with higher Cd2+-tolerance. RNA-seq revealed that N atural resistance-associated macrophage proteins (NRAMP) -like genes were involved in the Cd2+ stress tolerance in H108. Genome-wide identification revealed that 28, 13 and 9 Nramp-like genes existing in the A. hypogaea , A. duranensis and A. ipaensis , respectively. The 50 peanut NRAMP genes share conserved architectural characters, and they were classified into two groups. Expressions of AhNramps , particularly AhNramp4 , AhNramp12 , AhNramp19 , and AhNramp25 could be greatly induced by not only cadmium toxicity, but also copper and zinc stresses. The expression profiles of AhNramp14 , AhNramp16 and AhNramp25 showed significant differences in the H108 (resistance) and H107 (susceptible) under the infection of bacterial wilt. In addition, we found that the expression profiles of AhNramp14 , AhNramp16 , and AhNramp25 were greatly up- or down-regulated by the application of exogenous salicylic acid, methyl jasmonate, and abscisic acid. The AhNramp25 , of which expression was affected by both heavy metal toxicity and bacterial wilt infection, were selected as strong candidate genes for peanut stress breeding. Our findings will provide an additional information required for further analysis of AhNramps involved in tolerance to heavy metal toxicity and resistance to bacterial wilt of peanut. [Display omitted] • The peanut cultivar H108 was screened to be tolerant to Cd2+ stress..• Nramp-like genes were identified to be involved in the Cd2+ tolerance of H108. • Expression profiling were employed for identification of Nramp-like genes in peanut. • AhNramp25 responses to both of Cd2+ toxicity and bacterial wilt infection. [ABSTRACT FROM AUTHOR]

Drought is one of the major abiotic stress factors limiting peanut production. It causes the loss of pod yield during the pod formation stage. Here, one previously identified drought-tolerant cultivar, "L422" of peanut, was stressed by drought (35 ± 5%) at pod formation stage for 5, 7, and 9 days. To analyze the drought effects on peanut, we conducted physiological and transcriptome analysis in leaves under well-watered (CK1, CK2, and CK3) and drought-stress conditions (T1, T2, and T3). By transcriptome analysis, 3,586, 6,730, and 8,054 differentially expressed genes (DEGs) were identified in "L422" at 5 days (CK1 vs T1), 7 days (CK2 vs T2), and 9 days (CK3 vs T3) of drought stress, respectively, and 2,846 genes were common DEGs among the three-time points. Furthermore, the result of weighted gene co-expression network analysis (WGCNA) revealed one significant module that was closely correlated between drought stress and physiological data. A total of 1,313 significantly up-/down-regulated genes, including 61 transcription factors, were identified in the module at three-time points throughout the drought stress stage. Additionally, six vital metabolic pathways, namely, "MAPK signaling pathway-plant," "flavonoid biosynthesis," "starch and sucrose metabolism," "phenylpropanoid biosynthesis," "glutathione metabolism," and "plant hormone signal transduction" were enriched in "L422" under severe drought stress. Nine genes responding to drought tolerance were selected for quantitative real-time PCR (qRT-PCR) verification and the results agreed with transcriptional profile data, which reveals the reliability and accuracy of transcriptome data. Taken together, these findings could lead to a better understanding of drought tolerance and facilitate the breeding of drought-resistant peanut cultivars. [ABSTRACT FROM AUTHOR]

Cultivated peanut (Arachis hypogaea) is one of the most widely grown food legumes in the world, being valued for its high protein and unsaturated oil contents. Drought stress is one of the major constraints that limit peanut production. This study's objective was to identify the drought-responsive genes preferentially expressed under drought stress in different peanut genotypes. To accomplish this, four genotypes (drought tolerant: C76-16 and 587; drought susceptible: Tifrunner and 506) subjected to drought stress in a rainout shelter experiment were examined. Transcriptome sequencing analysis identified that all four genotypes shared a total of 2,457 differentially expressed genes (DEGs). A total of 139 enriched gene ontology terms consisting of 86 biological processes and 53 molecular functions, with defense response, reproductive process, and signaling pathways, were significantly enriched in the common DEGs. In addition, 3,576 DEGs were identified only in drought-tolerant lines in which a total of 74 gene ontology terms were identified, including 55 biological processes and 19 molecular functions, mainly related to protein modification process, pollination, and metabolic process. These terms were also found in shared genes in four genotypes, indicating that tolerant lines adjusted more related genes to respond to drought. Forty-three significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways were also identified, and the most enriched pathways were those processes involved in metabolic pathways, biosynthesis of secondary metabolites, plant circadian rhythm, phenylpropanoid biosynthesis, and starch and sucrose metabolism. This research expands our current understanding of the mechanisms that facilitate peanut drought tolerance and shed light on breeding advanced peanut lines to combat drought stress. [ABSTRACT FROM AUTHOR]

Genome instability in newly synthesized allotetraploids of peanut has breeding implications that have not been fully appreciated. Synthesis of wild species-derived neo-tetraploids offers the opportunity to broaden the gene pool of peanut; however, the dynamics among the newly merged genomes creates predictable and unpredictable variation. Selfed progenies from the neo-tetraploid Arachis ipaënsis Arachis correntina (A. ipaënsis A. correntina) 4x and F1 hybrids and F2 progenies from crosses between A. hypogaea [A. ipaënsis A. correntina] 4x were genotyped by the Axiom Arachis 48 K SNP array. Homoeologous recombination between the A. ipaënsis and A. correntina derived subgenomes was observed in the S0 generation. Among the S1 progenies, these recombined segments segregated and new events of homoeologous recombination emerged. The genomic regions undergoing homoeologous recombination segregated mostly disomically in the F2 progenies from A. hypogaea [A. ipaënsis A. correntina] 4x crosses. New homoeologous recombination events also occurred in the F2 population, mostly found on chromosomes 03, 04, 05, and 06. From the breeding perspective, these phenomena offer both possibilities and perils; recombination between genomes increases genetic diversity, but genome instability could lead to instability of traits or even loss of viability within lineages. [ABSTRACT FROM AUTHOR]

Peanut is one of major sources for vegetable oil. Improving oil content is an important goal for peanut breeding programs. Major loci with linked markers for oil content could facilitate rapid development of high-oil varieties through marker-assisted breeding. To identify major loci underlying the oil content, we conducted the QTL analysis based on the high-dense genetic map, using RIL population derived from Zhonghua10 and ICG12625. A total of 18 additive QTLs, including two major and stable QTLs (qOCB06 and qOCB10.1), were identified in three environments. Besides, 26 pairs of QTLs with epistatic (additive × additive) interaction were mapped on 17 linkage groups. qOCB06 with up to 22.59% of the phenotypic variations was located in a 0.6-Mb interval of B06. qOCB10.1 on B10 explained 9.18–12.55% of the phenotypic variations. The additive effect of two QTLs ranged from 0.70 to 1.13% oil content in different environments. Favorable alleles of the two loci were from male and female parent, respectively. Pyramiding the two favorable alleles in the RIL population could increase "2.66 ± 0.48%" oil content across multiple environments. The marker Ai06B29452 and AGGS2133-1 linked to qOCB06 and qOCB10.1, respectively, were validated to be associated with oil content in peanut germplasms with diverse phenotypes. These markers were valuable in marker-assisted selection and pyramiding breeding for improving oil content in peanut. Major and stable QTLs with linked markers in the present study provided resources to discovery candidate genes in the future and to guide marker-assisted selection for improving oil content in peanut. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) 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.)

Nonspecific lipid transfer proteins (nsLTPs) play vital roles in lipid metabolism, cell apoptosis and biotic and abiotic stresses in plants. However, the distribution of nsLTPs in Arachis duranensis has not been fully characterized. In this study, we identified 64 nsLTP genes in A. duranensis (designated AdLTPs), which were classified into six subfamilies and randomly distributed along nine chromosomes. Tandem and segmental duplication events were detected in the evolution of AdLTPs. The K s and ω values differed significantly between Types 1 and D subfamilies, and eight AdLTPs were under positive selection. The expression levels of AdLTPs were changed after salinity, PEG, low-temperature and ABA treatments. Three AdLTPs were associated with resistance to nematode infection, and DOF and WRI1 transcription factors may regulate the AdLTP response to nematode infection. Our results may provide valuable genomic information for the breeding of peanut cultivars that are resistant to biotic and abiotic stresses. • AdLTPs were classified into 6 subfamilies and were randomly distributed along 9 chromosomes. • The tandem and segmental duplication events were detected in the evolution of AdLTPs. • The K s and ω values were significantly different between Type 1 and D subfamilies. • The expression level of AdLTPs was changed after salinity, PEG, low temperature and ABA treatments. • DOF and WRI1 transcription factors may regulate the AdLTP response to nematode infection. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

'Georgia‐19HP' (Reg. no. CV‐141, PI 693908) is a new high‐yielding, high‐protein (HP), high‐oleic, Tomato spotted wilt virus (TSWV) resistant, root‐knot nematode (RKN) and leafspot resistant, virginia‐type peanut (Arachis hypogaea L. ssp. hypogaea var. hypogaea) cultivar released by the Georgia Agricultural Experiment Station in 2019. It was developed at the University of Georgia Coastal Plain Experiment Station, Tifton, GA. Georgia‐19HP originated from a cross made between an advanced Georgia breeding line, GA 072515 × 'Tifguard'. Pedigree selection was practiced within the early segregating generations. Performance testing began in the F4:6 generation with the advanced pure‐line selection GA 132724, the experimental designation of Georgia‐19HP. During 3 yr (2016–2018) averaged across 30 tests at three locations in Georgia, Georgia‐19HP had significantly less TSWV and total disease incidence and higher pod yield, total sound mature kernels grade, and dollar value return per hectare than the widely popular virginia‐type cultivar 'Bailey'. Georgia‐19HP was also found to have a similar percentage of extra large kernels but a smaller percentage of fancy pods compared with 'Georgia‐11J'. Georgia‐19HP combines high yield, grade, and dollar value with TSWV resistance, leafspot resistance, RKN resistance, and the high‐protein and high‐oleic trait for longer shelf life and improved protein and oil quality of peanut and peanut products. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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 Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

To screening and identify peanut tolerance to low temperature, and to establish a comprehensive mathematical evaluation model of peanut, low temperature stress on 11 peanut cultivars were carried out at 5°C for 72 hours. 15 physiological and biochemical indexes were tested, including chlorophyll SPAD value, chlorophyll fluorescence parameters, photosynthetic gas exchange parameters, relative conductivity, SOD activity, POD activity, CAT activity, MDA content and soluble protein content in peanut seedlings at 0 h and 72 h. The chilling tolerant coefficient of each index was used as basis for evaluation. Comprehensive mathematical evaluation model was evaluated by principal components analysis, hierarchical cluster analysis and regression analysis. Results showed that the 15 single indexes could be classified into 5 independent comprehensive components. Cluster analysis results showed that 11 cultivars were divide into 3 tolerant types (Shanhua 8, Jihua 1954Z, Jihua 1955Z), intermediate type (Jihua 1953Z, Shitouqi, Jiyou 6, Yueyou 92, Zhonghua 8) and sensitive type (Fuhuasheng, Kainong 53, Jihua 11). The mathematical evaluation model for low temperature tolerance was established by stepwise regression equation, and evaluation accuracy of the equation was higher than 99.00%. The screened 7 indexes (Pn, ФPSII, Fv/Fm, 1-qP, SP, POD and CAT) were found closely relate to the tolerance. Results indicated that the reaction center was more open and photosystem was more injured after low-temperature stress in tolerant type that could maintain higher net photosynthetic rate, better removal of reactive oxygen species and free radicals from cells, with low peroxide damage on membrane lipids. The rapid identification and prediction of low-temperature tolerance of peanut cultivar could be carried out by measuring 7 indicators at the same low-temperature treatment. The tolerance cultivars were expected to provide a basis for peanut breeding tolerant to low temperature in Northeast China. [ABSTRACT FROM AUTHOR]

Key message: Two QTLs on ChrB09 significantly associated with both early and late leaf spots were identified by genome-wide association study in the US peanut mini-core collection. Early leaf spot (ELS) and late leaf spot (LLS) are two serious peanut diseases in the USA, causing tens of millions of dollars of annual economic losses. However, the genetic factors underlying resistance to those diseases in peanuts have not been well-studied. We conducted a genome-wide association study for the two peanut diseases using Affymetrix version 2.0 SNP array with 120 genotypes mainly coming from the US peanut mini-core collection. A total of 46 quantitative trait loci (QTLs) were identified with phenotypic variation explained (PVE) from 10.19 to 24.11%, in which eighteen QTLs are for resistance to ELS and 28 QTLs for LLS. Among the 46 QTLs, there were four and two major QTLs with PVE higher than 16.99% for resistance ELS and LLS, respectively. Of the six major QTLs, five were located on the B sub-genome and only one was on the A sub-genome, which suggested that the B sub-genome has more potential resistance genomic regions than the A sub-genome. In addition, two genomic regions on chromosome B09 were found to provide significant resistance to both ELS and LLS. A total of 74 non-redundant genes were identified as resistance genes, among which, twelve candidate genes were in significant genomic regions including two candidate genes for both ELS and LLS, and other ten candidate genes for ELS. The QTLs and candidate genes obtained from this study will be useful to breed peanuts for resistances to the diseases. [ABSTRACT FROM AUTHOR]

Although seed and pod traits are important for peanut breeding, little is known about the inheritance of these traits. A recombinant inbred line (RIL) population of 156 lines from a cross of Tifrunner xNC3033 was genotyped with the Axiom_Arachis1 SNP array and SSRs to generate a genetic map composed of 1524 markers in 29 linkage groups (LG). The genetic positions of markers were compared with their physical positions on the peanut genome to confirm the validity of the linkage map and explore the distribution of recombination and potential chromosomal rearrangements. This linkage map was then used to identify Quantitative Trait Loci (QTL) for seed and pod traits that were phenotyped over three consecutive years for the purpose of developing trait-associated markers for breeding. Forty-nine QTL were identified in 14 LG for seed size index, kernel percentage, seed weight, pod weight, singlekernel, double-kernel, pod area and pod density. Twenty QTL demonstrated phenotypic variance explained (PVE) greater than 10% and eight more than 20%.Of note, seven of the eightmajorQTL for pod area, podweight and seed weight (PVE.20% variance) were attributed toNC 3033 and located in a single linkage group, LGB06_1. In contrast, the most consistent QTL for kernel percentage were located on A07/B07 and derived from Tifrunner. [ABSTRACT FROM AUTHOR]

Background: Peanut is one of the primary sources for vegetable oil worldwide, and enhancing oil content is the main objective in several peanut breeding programs of the world. Tightly linked markers are required for faster development of high oil content peanut varieties through genomics-assisted breeding (GAB), and association mapping is one of the promising approaches for discovery of such associated markers. Results: An association mapping panel consisting of 292 peanut varieties extensively distributed in China was phenotyped for oil content and genotyped with 583 polymorphic SSR markers. These markers amplified 3663 alleles with an average of 6.28 alleles per locus. The structure, phylogenetic relationship, and principal component analysis (PCA) indicated two subgroups majorly differentiating based on geographic regions. Genome-wide association analysis identified 12 associated markers including one (AGGS1014_2) highly stable association controlling up to 9.94% phenotypic variance explained (PVE) across multiple environments. Interestingly, the frequency of the favorable alleles for 12 associated markers showed a geographic difference. Two associated markers (AGGS1014_2 and AHGS0798) with 6.90–9.94% PVE were verified to enhance oil content in an independent RIL population and also indicated selection during the breeding program. Conclusion: This study provided insights into the genetic basis of oil content in peanut and verified highly associated two SSR markers to facilitate marker-assisted selection for developing high-oil content breeding peanut varieties. [ABSTRACT FROM AUTHOR]

Background: Web blotch is one of the most important foliar diseases worldwide in peanut (Arachis hypogaea L.). The identification of quantitative trait loci (QTLs) for peanut web blotch resistance represents the basis for gene mining and the application of molecular breeding technologies. Results: In this study, a peanut recombinant inbred line (RIL) population was used to map QTLs for web blotch resistance based on high-throughput genome-wide sequencing. Frequency distributions of disease grade and disease index in five environments indicated wide phenotypic variations in response to web blotch among RILs. A high-density genetic map was constructed, containing 3634 bin markers distributed on 20 peanut linkage groups (LGs) with an average genetic distance of 0.5 cM. In total, eight QTLs were detected for peanut web blotch resistance in at least two environments, explaining from 2.8 to 15.1% of phenotypic variance. Two major QTLs qWBRA04 and qWBRA14 were detected in all five environments and were linked to 40 candidate genes encoding nucleotide-binding site leucine-rich repeat (NBS-LRR) or other proteins related to disease resistances. Conclusions: The results of this study provide a basis for breeding peanut cultivars with web blotch resistance. [ABSTRACT FROM AUTHOR]

GP‐VT NC 01 (Reg. no. GP‐238, PI 691613) is a virginia‐type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) with good agronomic characteristics and improved drought tolerance. GP‐VT NC 01 was tested under the experimental designation N05006. Replicated yield tests started in the F6 generation in North Carolina in 2005. From 2008 through 2010, GP‐VT NC 01 was tested in replicated trials in the Peanut Variety and Quality Evaluation, multistate project S1038, in Virginia, North Carolina, and South Carolina. In 2013 and 2014, GP‐VT NC 01 was tested in the field at the Tidewater Agricultural Research and Experiment Station in Suffolk, VA, under rain exclusion shelters with controlled water regimes ranging from optimum soil moisture to severe drought. In these tests, GP‐VT NC 01 was compared with the current cultivars grown in Virginia and the Carolinas—'Bailey', 'Sugg', 'Sullivan', and 'Wynne'—and a drought‐tolerant species derived germplasm line (GP‐NC WS17). Under "normal" weather, in rainfed production, GP‐VT NC 01 had similar yield to Bailey and Sugg and significantly better yield than Sullivan or Wynne. Extra‐large kernels content was least, although not significantly smaller than Sullivan and Wynne. No significant differences in sound mature kernels were noted among the cultivars tested. However, during dry and hot years, and under drought‐controlled conditions, the yield of GP‐VT NC 01 was significantly higher than that of the other cultivars tested. Thus, the release of GP‐VT NC 01 provides producers with a profitable option that will perform well under drought stress. [ABSTRACT FROM AUTHOR]

Key message: A total of 33 additive stem rot QTLs were identified in peanut genome with nine of them consistently detected in multiple years or locations. And 12 pairs of epistatic QTLs were firstly reported for peanut stem rot disease. Stem rot in peanut (Arachis hypogaea) is caused by the Sclerotium rolfsii and can result in great economic loss during production. In this study, a recombinant inbred line population from the cross between NC 3033 (stem rot resistant) and Tifrunner (stem rot susceptible) that consists of 156 lines was genotyped by using 58 K peanut single nucleotide polymorphism (SNP) array and phenotyped for stem rot resistance at multiple locations and in multiple years. A linkage map consisting of 1451 SNPs and 73 simple sequence repeat (SSR) markers was constructed. A total of 33 additive quantitative trait loci (QTLs) for stem rot resistance were detected, and six of them with phenotypic variance explained of over 10% (qSR.A01-2, qSR.A01-5, qSR.A05/B05-1, qSR.A05/B05-2, qSR.A07/B07-1 and qSR.B05-1) can be consistently detected in multiple years or locations. Besides, 12 pairs of QTLs with epistatic (additive × additive) interaction were identified. An additive QTL qSR.A01-2 also with an epistatic effect interacted with a novel locus qSR.B07_1-1 to affect the percentage of asymptomatic plants in a row. A total of 193 candidate genes within 38 stem rot QTLs intervals were annotated with functions of biotic stress resistance such as chitinase, ethylene-responsive transcription factors and pathogenesis-related proteins. The identified stem rot resistance QTLs, candidate genes, along with the associated SNP markers in this study, will benefit peanut molecular breeding programs for improving stem rot resistance. [ABSTRACT FROM AUTHOR]

Key message: Two novel and adjacent genomics and candidate genes for bacterial wilt resistance were identified on chromosome B02 in peanut variety Zhonghua 6 using both traditional QTL mapping and QTL-seq methods. Peanut (Arachis hypogaea) is an important oilseed crop worldwide. Utilization of genetic resistance is the most economic and effective approach to control bacterial wilt, one of the most devastating plant diseases, in peanut production. To accelerate the genetic improvement of bacterial wilt resistance (BWR) in peanut breeding programs, quantitative trait locus (QTL) mapping has been conducted for two resistant varieties. In this context, we deployed linkage mapping as well as sequencing-based mapping approach, QTL-seq, to identify genomic regions and candidate genes for BWR in another highly resistant variety Zhonghua 6. The recombination inbred line population (268 progenies) from the cross Xuhua 13 × Zhonghua 6 was used in BWR evaluation across five environments. QTL mapping using both SSR- and SNP-based genetic maps identified a stable QTL (qBWRB02-1) on chromosome B02 with 37.79–78.86% phenotypic variation explained (PVE) across five environments. The QTL-seq facilitated further dissection of qBWRB02-1 into two adjacent genomic regions, qBWRB02-1-1 (2.81–4.24 Mb) and qBWRB02-1-2 (6.54–8.75 Mb). Mapping of newly developed Kompetitive allele-specific PCR (KASP) markers on the genetic map confirmed their stable expressions across five environments. The effects of qBWRB02-1-1 (49.43–68.86% PVE) were much higher than qBWRB02-1-2 (3.96–6.48% PVE) and other previously reported QTLs. Nineteen putative candidate genes affected by 49 non-synonymous SNPs were identified for qBWRB02-1-1, and ten of them were predicted to code for disease resistance proteins. The major and stable QTL qBWRB02-1-1 and validated KASP markers could be deployed in genomics-assisted breeding (GAB) to develop improved peanut varieties with enhanced BWR. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

Background: Cultivated peanut (Arachis hypogaea. L) represents one of themost important oil crops in the world. Although much effort has been expended to characterize microsatellites or Simple Sequence Repeats (SSRs) in peanut, the quantity and quality of the markers in breeding applications remain limited. Here, genome-wide SSR characterization and marker development were performed using the recently assembled genome of the cultivar Tifrunner. Results: In total, 512,900 microsatellites were identified from 2556.9-Mb genomic sequences. Based on the flanking sequences of the identified microsatellites, 7757 primer pairs (markers) were designed, and further evaluated in the assembled genomic sequences of the tetraploid Arachis cultivars, Tifrunner and Shitouqi, and the diploid ancestral species, A. duranensis and A. ipaensis. In silico PCR analysis showed that the SSR markers had high amplification efficiency and polymorphism in four Arachis genotypes. Notably, nearly 60% of these markers were single-locus SSRs in tetraploid Arachis species, indicating they are more specific in distinguishing the alleles of the A and B sub-genomes of peanut. In addition, two markers closely related with purple testa color and 27 markers near to FAD2 genes were identified, which could be used for breeding varieties with purple testa and high-oleic acid content, respectively. Moreover, the potential application of these SSR markers in tracking introgressions from Arachis wild relatives was discussed. Conclusions: This study reported the development of genomic SSRs from assembled genomic sequences of the tetraploid Arachis Tifrunner, which will be useful for diversity analysis, genetic mapping and functional genomics studies in peanut. [ABSTRACT FROM AUTHOR]

THE CURRENT work was carried out at the Agriculture Research Station of East Al- Eweinat, New Valley Governorate to evaluate the yield potential of 16 peanut genotypes during 2016 and 2017 growing seasons. The used experimental design was a randomized complete block design with three replicates. Correlation coefficients were computed between pod yields and its related attributes as well as normal and sequential path analysis models were automated to obtain information on the direct and indirect effects of important traits affecting pod yields for using them as selection criteria in future peanut breeding programs. Results showed that genotypes 7, 11 and 16 produced the heaviest pod yields while genotypes 13 and 15 recorded the lowest pod yields. Concerning the normal path analysis model, several undesirable symptoms were obtained indicating the presence of multicollinearity problem. Subsequently, the poor estimators of normal path analysis model, as a result of multicollinearity, enough to reject the normal form of path analysis. Statistically, more precise results were obtained using the sequential path analysis model. Results revealed that the pod yields depended primarily upon pod weight per plant and number of pods per plant as first-order variables accounted for nearly 98% of the variation in pod yields. The maximum positive direct effects were obtained by pods weight per plant (0.91) followed by number of pods per plant (0.14) indicting that the indirect selection for pod yields through these traits would be effective for peanut improvement. The second-order path analysis showed that seeds weight per plant had the considerable positive direct and indirect effects toward each of number of pods per plant and pods weight per plant. In fact, the sequential path analysis gave a somewhat different picture from what the normal model path analysis did. [ABSTRACT FROM AUTHOR]

Key message: ddRAD-seq-based high-density genetic map comprising 2595 loci identified a major and consensus QTL with a linked marker in a 0.8-Mb physical interval for oil content in peanut. Enhancing oil content is an important breeding objective in peanut. High-resolution mapping of quantitative trait loci (QTLs) with linked markers could facilitate marker-assisted selection in breeding for target traits. In the present study, a recombined inbred line population (Xuhua 13 × Zhonghua 6) was used to construct a genetic map based on double-digest restriction-site-associated DNA sequencing (ddRAD-seq). The resulting high-density genetic map contained 2595 loci, and spanned a length of 2465.62 cM, with an average distance of 0.95 cM/locus. Seven QTLs for oil content were identified on five linkage groups, including the major and stable QTL qOCA08.1 on chromosome A08 with 10.14–27.19% phenotypic variation explained. The physical interval of qOCA08.1 was further delimited to a ~ 0.8-Mb genomic region where two genes affecting oil synthesis had been annotated. The marker SNPOCA08 was developed targeting the SNP loci associated with oil content and validated in peanut cultivars with diverse oil contents. The major and stable QTL identified in the present study could be further dissected for gene discovery. Furthermore, the tightly linked marker for oil content would be useful in marker-assisted breeding in peanut. [ABSTRACT FROM AUTHOR]

Peanut (Arachis hypogaea L.) is an important nutrient-rich food legume and valued for its good quality cooking oil. The fatty acid content is the major determinant of the quality of the edible oil. The oils containing higher monounsaturated fatty acid are preferred for improved shelf life and potential health benefits. Therefore, a high oleic/linoleic fatty acid ratio is the target trait in an advanced breeding program. The two mutant alleles, ahFAD2A (on linkage group a09) and ahFAD2B (on linkage group b09) control fatty acid composition for higher oleic/linoleic ratio in peanut. In the present study, marker-assisted backcrossing was employed for the introgression of two FAD2 mutant alleles from SunOleic95R into the chromosome of ICGV06100, a high oil content peanut breeding line. In the marker-assisted backcrossing-introgression lines, a 97% increase in oleic acid, and a 92% reduction in linoleic acid content was observed in comparison to the recurrent parent. Besides, the oleic/linoleic ratio was increased to 25 with respect to the recurrent parent, which was only 1.2. The most significant outcome was the stable expression of oil-content, oleic acid, linoleic acid, and palmitic acid in the marker-assisted backcrossing-introgression lines over the locations. No significant difference was observed between high oleic and normal oleic in peanuts for seedling traits except germination percentage. In addition, marker-assisted backcrossing-introgression lines exhibited higher yield and resistance to foliar fungal diseases, i.e., late leaf spot and rust. [ABSTRACT FROM AUTHOR]

Background: The cultivated peanut (Arachis hypogaea) is one of the most important oilseed crops worldwide, however, its improvement is restricted by its narrow genetic base. The highly variable wild peanut species, especially within Sect. Arachis, may serve as a rich genetic source of favorable alleles to peanut improvement; Sect. Arachis is the biggest taxonomic section within genus Arachis and its members also include the cultivated peanut. In order to make good use of these wild resources, the genetic bases and the relationships of the Arachis species need first to be better understood. Results: Here, in this study, we have sequenced and/or assembled twelve Arachis complete chloroplast (cp) genomes (eleven from Sect. Arachis). These cp genome sequences enriched the published Arachis cp genome data. From the twelve acquired cp genomes, substantial genetic variation (1368 SNDs, 311 indels) has been identified, which, together with 69 SSR loci that have been identified from the same data set, will provide powerful tools for future explorations. Phylogenetic analyses in our study have grouped the Sect. Arachis species into two major lineages (I & II), this result together with reports from many earlier studies show that lineage II is dominated by AA genome species that are mostly perennial, while lineage I includes species that have more diverse genome types and are mostly annual/biennial. Moreover, the cultivated peanuts and A. monticola that are the only tetraploid (AABB) species within Arachis are nested within the AA genome species-dominated lineage, this result together with the maternal inheritance of chloroplast indicate a maternal origin of the two tetraploid species from an AA genome species. Conclusion: In summary, we have acquired sequences of twelve complete Arachis cp genomes, which have not only helped us better understand how the cultivated peanut and its close wild relatives are related, but also provided us with rich genetic resources that may hold great potentials for future peanut breeding. [ABSTRACT FROM AUTHOR]

Soil Ca deficiency hinders the development of the peanut industry, and inappropriate Ca fertilizer application increases the risk of soil environmental degradation and reduces the fertilizer utilization rate and yield in peanuts. N fertilizer doses are frequently split and applied over different time periods. However, whether this widespread method is applicable to Ca fertilizer and improves peanut growth and yield in southern China requires further investigation. Thus, this study evaluated the effects of timing and splitting Ca applications on the dry matter accumulation and partition, fertilizer use efficiency, and yield of different low-Ca-tolerant peanut varieties (low-Ca-sensitive Jihua 16 and low-Ca-tolerant Yueyou 45) in the early and late seasons. The results showed that the early timing and splitting of Ca application significantly increased the pod yield of Jihua 16 by increasing nitrogen and calcium use efficiencies, dry matter accumulation, and assimilate transfer from vegetative parts to the pods in both years. The highest pod yield of Jihua 16 was obtained with 300 kg CaO ha−1 basal application before sowing and 300 kg CaO ha−1 top-dressing application at the flowering stage (B300:T300) in the early season and 600 kg CaO ha−1 basal application before sowing and 600 kg CaO ha−1 top-dressing application at the flowering stage (B600:T600) in the late season; the yields were significantly increased by 91.87 % in 2020, 92.15 % in 2021, and by 255.36 % in 2020, 248.22 % in 2021, respectively, compared with those obtained with no Ca fertilizer use. However, the Ca treatments did not significantly affect pod yield or the related parameters of Yueyou 45 in either season. The pod yield of both cultivars was higher in the early season than that in the late season because of the higher effective accumulated temperature and precipitation during the reproductive stage in the early season of both years. The results of this study indicate that the early season is most suitable for peanut production, and the B300:T300 and no Ca application strategies are appropriate for the Ca-sensitive and -tolerant cultivars, respectively, in the early season in southern China. Notably, additional Ca-tolerant cultivars should be selected for cultivation in southern China to reduce future fertilizer application. These results provide useful information for improving double-cropping systems, Ca fertilization strategies, and peanut cultivar breeding in southern China. • Higher effective accumulated temperature and precipitation achieved higher yield. • Timing and splitting of calcium application increased the pod yield. • Peanut variety specificity response to the calcium application existed. [ABSTRACT FROM AUTHOR]

Early and late leaf spots (LLSs) are the major foliar diseases of peanut responsible for severely decreased yield in the absence of intensive fungicide spray programs. Pyramiding host resistance to leaf spots in elite cultivars is a sustainable solution to mitigate the diseases. In order to determine the genetic control of leaf spot disease resistance in peanut, a recombinant inbred line population (Florida-07 × GP-NC WS16) segregating for resistance to both diseases was used to construct a SNP-based linkage map consisting of 855 loci. QTL mapping revealed three resistance QTLs for LLS qLLSA05 (phenotypic variation explained, PVE = 7–10%), qLLSB03 (PVE = 5–7%), and qLLSB05 (PVE = 15–41%) that were consistently expressed over multi-year analysis. Two QTL, qLLSA05 and qLLSB05 , confirmed our previously published QTL-seq results. For early leaf spot, three resistance QTLs were identified in multiple years, two on chromosome A03 (PVE = 8–12%) and one on chromosome B03 (PVE = 13–20%), with the locus qELSA03_1.1 coinciding with the previously published genomic region for LLS resistance in GPBD4. Comparative analysis of the genomic regions spanning the QTLs suggests that resistance to early and LLSs are largely genetically independent. In addition, QTL analysis on yield showed that the presence of resistance allele in qLLSB03 and qLLSB05 loci might result in protection from yield loss caused by LLS disease damage. Finally, post hoc analysis of the RIL subpopulation that was not utilized in the QTL mapping revealed that the flanking markers for these QTLs can successfully select for resistant and susceptible lines, confirming the effectiveness of pyramiding these resistance loci to improve host-plant resistance in peanut breeding programs using marker-assisted selection. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences 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.)

Cultivated peanut (Arachis hypogaea L.) is an economically important crop grown around the world. Compared with the entire Arachis genus, cultivated peanut germplasm has low levels of genetic diversity for several economically important traits, resulting in the need for alternative sources of favorable alleles. Wild diploid species of Arachis are a source of such alleles to improve cultivated peanut for many economically important traits. An A. hypogaea × A. diogoi Hoehne introgression population was produced via the triploid–hexaploid method; the fourth generation after tetraploidy was used to initiate this study. The introgression lines were genotyped using a single nucleotide polymorphism (SNP) marker array to estimate the percentage of A. diogoi chromatin introgression. Morphologically, the introgression lines varied for an array of measured traits, with the majority being intermediate to the two parents. The average amount of A. diogoi genome introgressed was 8.12% across the tetraploid genome and ranged from 3.00 to 18.14% on individual chromosomes. The average A. diogoi introgression across all lines was 7.70% and ranged from 0.17 to 51.12%. Principal component analysis of morphological data and SNP markers revealed similarities and groupings of introgression lines. This introgression population demonstrates the potential of using wild diploid Arachis species for peanut improvement and has great potential for use in cultivated peanut breeding programs. [ABSTRACT FROM AUTHOR]

Genetic diversity among 32 genotypes of groundnut was estimated for six characters using Mahalanobis D2 statistic. The analysis of variance revealed significant differences among the genotypes for all characters. The characters, pod yield per plant, 100 seed weight and SLA at 60 DAS recorded moderate to high GCV, high heritability coupled with high genetic advance as percent of mean indicating that these traits were mainly under the influence of additive gene action and simple selection may be effective for improvement of these traits. Based on Tocher's method of clustering, 32 genotypes were grouped into eight clusters, of which cluster II was the largest containing 10 genotypes followed by cluster I with seven genotypes. The inter-cluster distance was maximum between cluster II and cluster VIII (2031.75) followed by cluster V and cluster VIII (1768.25) and cluster VII and VIII (1702.17). Considering the cluster distances and cluster means, crossing between the genotypes of cluster II and cluster VIII, and cluster VIII and cluster V is suggested in order to get transgressive segregants for yield and yield parameters. [ABSTRACT FROM AUTHOR]

Breeding for improved blanchability--the propensity of the testa (skin) to be removed from the kernel following rapid heat treatment--is a priority for improvement in the Australian Peanut Breeding Program (APBP). Easy removal of the testa by blanching is required for processing of peanuts into peanut butter and various other confectionary products. Thus, blanchability is an economically important trait in any newly released cultivar in Australia. A better understanding of the range of genetic variation, nature of inheritance and genotype x environment (G x E) interactions, and the development of a low-cost method to phenotype in early generations, could speed up breeding for this trait. Studies were conducted to develop a low-cost, rapid method utilising minimal amounts of seed to phenotype in early generations, along with an assessment of G x E interactions over a range of years and environments to derive optimal selection protocols. Use of a smaller kernel sample size than standard (50 vs 200 g) was effective for accurately assessing blanchability in breeding lines and could allow selection in early generations (e.g. in seed produced from a single F2 plant where seed supply is adequate). G x E interaction for blanchability was shown to be very low. Genotypic variance explained 62-100% of the total variance for blanchability, assessed in two diverse germplasm pools including 107 accessions in the USA mini-core over three environments and multiple APBP breeding lines grown over nine different years--environments. Genotypic correlations between all environments were very high (~0.60-0.96), with heritability for the blanchability trait estimated to be very high (0.74-0.97) across the 13 trials. The results clearly demonstrate that effective selection for improved blanchability can be conducted in early generations and in a limited number of contrasting environments to ensure consistency of results. [ABSTRACT FROM AUTHOR]

Summary: Whole‐genome resequencing (WGRS) of mapping populations has facilitated development of high‐density genetic maps essential for fine mapping and candidate gene discovery for traits of interest in crop species. Leaf spots, including early leaf spot (ELS) and late leaf spot (LLS), and Tomato spotted wilt virus (TSWV) are devastating diseases in peanut causing significant yield loss. We generated WGRS data on a recombinant inbred line population, developed a SNP‐based high‐density genetic map, and conducted fine mapping, candidate gene discovery and marker validation for ELS, LLS and TSWV. The first sequence‐based high‐density map was constructed with 8869 SNPs assigned to 20 linkage groups, representing 20 chromosomes, for the 'T' population (Tifrunner × GT‐C20) with a map length of 3120 cM and an average distance of 1.45 cM. The quantitative trait locus (QTL) analysis using high‐density genetic map and multiple season phenotyping data identified 35 main‐effect QTLs with phenotypic variation explained (PVE) from 6.32% to 47.63%. Among major‐effect QTLs mapped, there were two QTLs for ELS on B05 with 47.42% PVE and B03 with 47.38% PVE, two QTLs for LLS on A05 with 47.63% and B03 with 34.03% PVE and one QTL for TSWV on B09 with 40.71% PVE. The epistasis and environment interaction analyses identified significant environmental effects on these traits. The identified QTL regions had disease resistance genes including R‐genes and transcription factors. KASP markers were developed for major QTLs and validated in the population and are ready for further deployment in genomics‐assisted breeding in peanut. [ABSTRACT FROM AUTHOR]

In 2012, a single Spear‐shaped Leaf mutant peanut (Reg. no. GS‐11, PI 693219) (Arachis hypogaea L.) plant was identified in a breeding trial plot of 'Georgia‐06G' at the University of Georgia, Coastal Plain Experiment Station's Gibbs Research Farm in Tifton, GA. It was believed to be a spontaneous mutation; an inheritance study examining segregation in an F2 population concluded single gene inheritance with incomplete dominance, and the gene was designated SpL. The unique phenotype and inheritance of this mutation makes the Spear‐shaped Leaf an interesting mutant to be preserved as a genetic stock and released to the public for researchers interested in the genetic, biochemical, and physiological aspects of leaf shape and leaf development. The Spear‐shaped Leaf mutant could also serve as a tool to measure outcrossing in the field or as a border or plot marker. [ABSTRACT FROM AUTHOR]

The present investigation was carried out to study the impact of climate change on summer groundnut in middle Gujarat using calibrated CROPGRO-peanut model by changing maximum and minimum temperatures by -2 to +3°C and increasing concentration of CO2 upto 550 ppm. Results revealed that with increase in maximum temperature by 3 °C, the pod yield was decreased by 39 to 48 per cent in different cultivars. The effect of minimum temperature on pod yield was less as compared to maximum temperature. The simulated pod yield increased upto 41 per cent with elevated CO2 concentration of 550 ppm. However, if the maximum temperature was increased alongwith increase in CO2 concentration the pod yield could be compensated upto 2 °C with CO2 of 500 ppm, but further increasing of the maximum temperature and carbon dioxide caused decrease in the pod yield. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: Relationships between process and peanut texture have only been studied in Hypogaea species, and focused on very limited processing conditions. In this study, 94 samples were prepared from a combination of 12 raw materials (Arachis hypogaea and fastigiata cultivars) and 11 roasting conditions (maceration in water, aqueous glucose and at different pH values followed by frying or baking). Texture was analyzed by a trained sensory panel (spectrum method) and large deformation compression tests (TA/XT2), and the microstructure probed with confocal microscopy and X‐ray tomography. RESULTS: The impact of maceration on ‘crispy’, ‘crunchy’ and ‘hardness’ sensory attributes was significantly larger when adding glucose in this step, whereas the effect of pH was minor. The relationship held for both fried and baked peanuts as well as for both A. hypogaea and fastigiata subspecies. The degree of alveolation was similar in differently processed peanuts, even though sensory attributes were significantly different. CONCLUSIONS: Maceration in different media can yield large textural changes in both peanut species, for both baking and frying. Maceration in glucose solutions can induce much larger textural changes than maceration in water. Quantitative data on alveolation show that microstructure disruption through steam generation cannot explain all the texture differences among processed peanuts. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background The nutritional quality, flavor, and shelf-life of both peanut products and its seeds are dependent on relative quantity of various fatty acids (FAs) like saturated, mono unsaturated fatty acid (MUFA) and poly unsaturated fatty acid (PUFA) present in its oil. High oleic (HO) peanut oils are extremely valued due to its superior nutritional composition for human health and augmented thermo-oxidative stability for industrial purposes. Scope and approach From the research perspective, noteworthy progress has been made during last three decades for the development of peanut lines having HO trait in its oil. In this review, the research achievements, perspectives, and prospects of peanut genetic improvement for HO trait is thoroughly discussed. Key findings and conclusions The research has helped not only understanding the genetics of HO traits and its genotype (G) by environment (E) interaction but also produced an enormous number of HO line throughout the world. Although, as of now, most of the high O/L cultivars developed are the outcome of traditional breeding efforts. But, with the advent of novel molecular techniques like CAPS and AS-PCR assay for HO peanut breeding program, it is extremely easy to achieve the traits through marker assisted selection (MAS) rather than through either conventional or genetic engineering approaches. The availability of peanut genome sequence and identification of different ahFAD2 gene families is also expediting the research for the breeding of HO peanut genotypes. [ABSTRACT FROM AUTHOR]

Allopolyploidy is a significant evolutionary process involved in the origin of many crops, including peanut (Arachis hypogaea L.). The process usually results in a series of chromosome, genomic and epigenetic rearrangements in the derived polyploids. Here, we examined the chromosomal consequences undergone by AABB tetraploids of Arachis after the genome merger. For that objective, different chromosome markers and DNA contents were compared among peanut, its wild tetraploid ancestor, and the diploid genome donors A. duranensis Krapov. & W.C. Gregory (AA, female) and A. ipaënsis Krapov. & W.C. Gregory (BB, male). The analysis also included an artificially synthesized allotetraploid using A. ipaënsis as a female [(A. ipaënsis x A. duranensis) 4x]. The karyotypes in the natural (originated ~10,000 yr ago) and newly synthesized allopolyploids have largely maintained the patterns of heterochromatin and ribosomal RNA loci detected in the diploid progenitors. Intergenomic translocations were not evident using genome in situ hybridization, and the DNA contents of the allotetraploids corresponded to the expected sum of those observed in their parental species. The analysis of ribosomal DNA loci and their association with nucleolar organizing regions revealed a rapid establishment of nucleolar dominance in favor of the A genome. The large macrostructural stability of karyotype observed here after polyploidization has not been frequently cited for polyploid crop plants. This stability is significant for peanut breeding, since it suggests that effective introgression of wild useful alleles into cultivated peanut may potentially occur in most of the extension of the A and B chromosome complements. [ABSTRACT FROM AUTHOR]

Salinity is one of the main and common challenges in the world. This study was conducted to determine the effect of salinity and water requirements of peanuts, with main factors including water requirement 40% (WR4), 60% (WR3), 80% (WR2), and 100% (WR1); sub-treatment including salinity with values of 1 (S1), 3 (S2), 5 (S3), and 7 (S4) dS/m; and sub-sub-treatment including four cultivars Guil (V1), Gorgani (V2), Jonobi (V3), and Mesri (V4). The experimental design was conducted in the form of split factorial in a completely randomized block with 3 replications in 2015 and 2016. The results showed that the maximum seed yields in salinity levels of 1 dS m-1 in 2015 and 2016 were 1,142 and 987 kg ha-1, respectively. On the interaction effect of irrigation and salinity, maximum seed yields in 80% water requirement and salinity of 1 dS m-1 in 2015 and 2016 were 1,393 and 1,265 kg ha-1, respectively. The maximum seed yields in Jonobi cultivar with salinity of 1 dS m-1 and in Guil cultivar in salinity of 5 dS m-1 were 1,254 and 1,127 kg ha-1, respectively. The Guil cultivar in 100% water requirement and with salinity of 1 dS m-1 in 2015 and 2016 had the highest seed yield, with 1,883 and 1,710 kg ha-1, respectively. [ABSTRACT FROM AUTHOR]