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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]

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]

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]

The study was undertaken to estimate genetic characterization, character association direct and indirect effects by path analysis for pod yield per plant and its components by using 15 groundnut genotypes. Dry pod yield per plant shown to have maximum genotypic coefficient of variation followed by kernel per plant suggesting substantial amount of genetic variability. Dry pod yield per plant, kernel yield per plant, 100- kernel weight, days to maturity was observed high heritability and high genetic advance these traits were controlled by additive genes and can easily be transferred to succeeding generations. Dry pods per plant registered positive and significant genotypic and phenotypic correlations with kernel yield per plant and 100- kernel weight. It indicated that the selection for increased dry pods per plant may give higher kernel yield per plant and 100- kernel weight and thus, may contribute in increasing the dry pods per plant. The path coefficient analysis revealed that the kernel yield per plant, oil content and shelling percentage exhibited high and positive direct effect on dry pod yield per plant. Thus, these characters turned out to be the major components of pod yield and direct selection for these traits may be rewarding for yield improvement. [ABSTRACT FROM AUTHOR]

Twenty F1s were developed by utilizing nine diverse parents 4 lines and 5 testers in Line x Testers mating design During Kharif 2015. The estimates of mean sum of squares due to male, female, male vs female, hybrids and parents vs hybrids showed significant variation. Large numbers of heterotic crosses were observed in most of the characters. The maximum positive standard heterosis for dry pod yield plant-1 (g) over best check TKG-Bold was observed in RHRG 6083 x TAG 24 (63.31%) followed by RHRG 6083 x JL 777(54.14%) and RHRG 1225 x TAG 24 (42.07%) and significant heterosis for other yield contributing traits viz., number of primary branches plant-1, number of pods plant-1, number of kernels pod-1, dry haulm yield plant-1, 100 kernel weight and shelling percentage. The maximum negative standard heterosis for days to maturity over best check TKG-Bold was observed in TG 37A x ICG 2630 (-18.61%) followed by RHRG 1225 x TAG 24 (- 12.50) and TG 37A x JL 777(-11.67). The combinations viz., RHRG 6083 x TAG 24, RHRG 6083 x JL 777 and RHRG 1225 x TAG 24 could be utilize for selection of desirable segregants in further segregating generations. [ABSTRACT FROM AUTHOR]

A set of 340 diverse groundnut genotypes included in Genomic Selection Panel (GSP) was used to evaluate genetic parameters and trait associations for resistance to rust and late leaf spot (LLS) along with yield and nutritional quality traits. The findings revealed high genetic variability coupled with high heritability and genetic advance as percent of mean (GAM) for resistance to both the diseases and yield traits, whereas low variability for nutritional quality traits with high heritability and low GAM. Disease severity scores for rust and LLS at 90 days after sowing (DAS) were negatively associated with yield, indicating pod yield penalty, thus deploying host-resistance for rust and LLS is a good strategy to plug the pod yield losses and reduce the input cost. It is possible to simultaneously improve the number of pods per plant and hundred kernel mass that contribute to pod yield as no trade-offs were detected between them. The association of oil and protein content with pod yield showed no tradeoffs, suggesting the possibility of simultaneous improvement of pod yield either with high oil or protein content. In breeding programs that target development of groundnut varieties to meet two distinct end-uses, oil milling, and food and confectionery, selection for either high oil (for oil purpose) or high protein and low oil (food/confections) will be efficient, as an inverse association between oil and protein content was observed. The use of disease score at 90 DAS for rust and LLS is effective and optimizes resources to make selection decisions in breeding as positive association among disease severity scores at different periods (75, 90 and 105 DAS) was observed. [ABSTRACT FROM AUTHOR]

Micronutrient malnutrition affects more than one-half of the world's population, especially women and pre-school children. Poor consumers in developing countries acquire roughly one-half of their total iron intakes and a higher percentage of zinc intakes from staple foods. Bio-fortification, an approach of breeding crop plants for higher micronutrient concentration, is a cost effective and sustainable solution for tackling the micronutrient deficiencies. Developing countries, where micronutrient deficiencies are widespread, contribute world's maximum peanut area and production. Thus, peanut can contribute significantly towards reduction of protein-energy and micronutrient malnutrition. With the advent of molecular markers, by using segregating populations for the trait of interest for breeders, it has now become effective to map genes or Quantitative Traits Loci (QTLs) and identify valuable alleles for the corresponding traits. In the present study, an F2:3 mapping population derived from the cross ICGV 06099 × ICGV 93468 was genotyped using 33 polymorphic SSR markers to identify the putative genomic regions associated with the kernel iron and zinc concentrations in groundnut using Single Marker Analysis (SMA). Results revealed that three markers viz., SEQ1B09 (0.23 %), IPAHM245 (2.19 %) and SEQ9G05 (6.34 %) showed significant association with the kernel iron and three markers viz., GM2638 (1.75 %), IPAHM245 (2.25 %) and SEQ9G05 (6.01 %) showed significant association with kernel zinc concentration. Significant positive association (0.549) was observed between kernel iron and zinc concentrations. Validation of these markers in an alternate F2:3 population derived from the cross ICGV 06040 × ICGV 87141 also showed strong association of these markers with the traits of interest. [ABSTRACT FROM AUTHOR]

The present study is aimed at evaluation of backcross derived high oleic advanced breeding lines for important nutritional quality traits and their association pattern for the improvement of low heritable traits through the indirect selection of the highly heritable traits. The estimates of the phenotypic coefficient of variation were higher than the genotypic coefficient of variation signifying the influence of environmental factors, while in certain cases the low magnitude of difference observed indicated that these characters were less influenced by the environments.PCV and GCV for different traits revealed that moderate to high variability among genotypes for, pod yield, and kernel yield indicating greater scope for improvement. Low to medium variability for 100 kernel weight whereas low variability for shelling per cent, protein content and oil content was recorded indicating the narrow range of variability for these characters and restricting the scope of selection. Pod yield was recorded as positively correlated with 100 seed weight and shelling percent whereas negatively correlated with foliar disease resistance. No significant correlation was reported between pod yield and oil quality traits like oleic acid, linoleic acid and O/L ratio indicating that pod yield can be increased without affecting the oleic acid content. In addition, high oleic lines along with higher yield and other quality traits and foliar disease resistance compared to check, GM4-3 were also selected. [ABSTRACT FROM AUTHOR]

Physiological traits are useful as representative characters for drought tolerance in peanut. The information on the responses of diverse peanut genotypes for physiological characters under mid-season drought is rather limited. The aim of this study was to examine the physiological traits for drought tolerance in diverse peanut genotypes responses under mid-season drought. The experiment was conducted from November 2011 to March 2012 and from November 2012 to March 2013. The experimental design was a split plot in randomized complete block. Two water regimes were assigned as the main plot (field capacity and mid-season drought). Five peanut genotypes were assigned in sub plot. Data were recorded for percent of root length density, relative water content (RWC) and stomatal conductance at 30, 45, 60, 75 and 90 days after planting. Shoot growth and pod growth rate were calculated. Drought significantly decreased RWC and stomatal conductance, but it increased root length density. High genotypic variation for root and physiological traits were observed at midseason drought and after recovery. Associated of physiological traits and biomass and pod yield were higher at mid-season drought and after recovery than at the initiation of drought. Genotypes KKU 60, ICGV 98305 and Tifton 8 increase high water uptake by root system except for Tainan 9 and KS 2. Selection for physiological traits using RWC and stomatal conductance might be effective improving peanut for drought tolerance. The knowledge of this study will be useful for breeding of peanut for mid-season drought condition. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in sandy loam soils to study the performance of groundnut cultivars (Abhaya, TAG-24, Dharani and Kadiri-6) under different plant populations (3.33, 4.44, 5.00 and 6.66 lakh ha-1) during early kharif, 2013, at Sri Venkateswara Agricultural College Farm, Tirupati campus of Acharya N.G. Ranga Agricultural University, Andhra Pradesh. The results revealed that the highest stature of yield attributes viz., number of filled pods plant-1, pod to peg percentage, hundred pod and kernel weight were significantly higher with groundnut variety Dharani compared to rest of the varieties due to better partitioning of photosynthates to sink. The groundnut cultivar Dharani recorded 42.0, 32.2 and 17.0 per cent higher pod yield compared to Abhaya, Kadiri-6 and TAG-24, respectively. All the yield components were significantly higher with plant population of 3.33 lakh ha-1. The pod yield of groundnut with plant population of 5.00 lakh ha-1 was increased by 2.8, 7.2 and 14.0 per cent compared to 3.33, 4.44 and 6.66 lakh ha-1, respectively. The higher pod yield of groundnut during early kharif in sandy loam soil was obtained with groundnut cultivar Dharani at plant population of 5.00 lakh ha-1. [ABSTRACT FROM AUTHOR]

Introgression lines ( ILs) of groundnut with enhanced resistance to rust and late leaf spot ( LLS) recorded increased pod and haulm yield in multilocation testing. Marker-assisted backcrossing ( MABC) approach was used to introgress a genomic region containing a major QTL that explains >80% of phenotypic variance ( PV) for rust resistance and 67.98% PV for LLS resistance. ILs in the genetic background of TAG 24, ICGV 91114 and JL 24 were evaluated for two seasons to select 20 best ILs based on resistance, productivity parameters and maturity duration. Multilocation evaluation of the selected ILs was conducted in three locations including disease hot spots. Background genotype, environment and genotype × environment interactions are important for expression of resistance governed by the QTL region. Six best ILs namely ICGV 13192, ICGV 13193, ICGV 13200, ICGV 13206, ICGV 13228 and ICGV 13229 were selected with 39-79% higher mean pod yield and 25-89% higher mean haulm yield over their respective recurrent parents. Pod yield increase was contributed by increase in seed mass and number of pods per plant. [ABSTRACT FROM AUTHOR]

Drought is a major constraint in peanut production. Drought not only reduces pod yield but also may affect phenolic compounds in peanut. This experiment was conducted for two years under field conditions. Soil moisture levels (field capacity and mid season drought stress) were assigned as main plots, and five peanut genotypes were assigned as sub plots. Peanut seeds were analyzed for phenolic compounds at harvest. Leaves and stems were also analyzed at 30 and 60 days after planting (DAP), and at harvest. Water regimes did not result in significant differences for phenolic compounds in seeds, whereas peanut genotypes were significantly different for this trait. Drought increased phenolic contents in leaves at 60 DAP and phenolic contents were reduced during the recovery period. The production of leaf phenolic compounds differed among genotypes. Mid season drought increased phenolic compounds in stems during the drought period and levels of phenolic production were different depending on peanut genotype. Breeding for high phenolic content and drought tolerance in peanut should be possible because mid season drought did not affect phenolic content in seeds. [ABSTRACT FROM AUTHOR]

Fifty diverse groundnut genotypes were assessed for associations among various agronomic characters and also path analysis for pod yield per plant. The magnitudes of genotypic correlation coefficients were generally higher compared to the corresponding phenotypic correlation coefficients for most of the traits. The pod yield per plant showed highly significant and positive correlations at both genotypic and phenotypic level with kernel yield per plant, number of mature pods per plant, harvest index, biological yield per plant, 100-kernel weight, days to 50% flowering, and shelling out-turn. Path analysis revealed high and positive direct effects of kernel yield per plant, while moderate and positive direct effects of number of mature pods per plant and harvest index on pod yield per plant. Days to 50% flowering and shelling out-turn contributed moderate and negative direct effects, but significant indirect effects along with 100-kernel weight for pod yield per plant. These results suggest kernel yield per plant, number of mature pods per plant, harvest index, 100-kernel weight, days to 50% flowering and shelling out-turn as useful traits for developing high yielding groundnut varieties. [ABSTRACT FROM AUTHOR]

The present investigation was carried out at Department of Genetics and Plant Breeding, Sam Higginbottom Institute of Agriculture, Technology & Sciences (SHIATS), Allahabad, Uttar Pradesh during kharif 2014. The experimental material consisted of 11 Groundnut genotypes along with one check (IND-156). The genotypes were sown at Field Experimentation Centre in three replications adopting randomized block design to evaluate seed yield and quality traits. Analysis of variance revealed that the presence of considerable variation among the genotypes for all the characters studied. On the basis of mean performance, genotype ICG 14127 revealed better performance in primary branches/ plant, pods per plant, pod yield/plant, seed yield/plant and ICG 14482 showed better performance in kernel yield q/ha, oil content, oil yield while ICG 188 showed higher protein content. [ABSTRACT FROM AUTHOR]

A rapid and cost-effective method is needed to evaluate parental lines and breeding populations for seed chemistry for use in peanut breeding and genetics. This study was initiated to compare oleic acid in segregating populations of peanut using gas liquid chromatography (GLC) and near--infrared reflectance spectroscopy (NIR). Twenty F2 crosses originating from 5 parent diallel crosses, and the generations of F2, F3, BC11S and BC12S originating from 3 parental lines were evaluated in 2 separate experiments during the 2008 rainy season. The bulk seeds were analyzed for oleic acid using GLC method, and a single seed was predicted for NIR method. The ranges for oleic acid were 47.5-79.6 for GLC and 59.6-85.2 for NIR estimates in both experiments. Oleic acid contents determined by NIR were relatively higher than those determined by GLC. However, estimated from both the methods showed high correlation coefficients 0.83 (P ≤ 0.01) in the 20 F2's of 5 parent diallel cross and 0.86 (P ≤ 0.01) in F2, F3, BC11S and BC12S of the 3 crosses. NIR method could be used to discard breeding lines with lower range in oleic acid and those retained should be further evaluated for accurate analysis of oleic content by GLC. [ABSTRACT FROM AUTHOR]

Breeding for enhanced nutritional quality is need of the hour. India not only needs increased quantity of food to feed the growing population but also quality food to mitigate hidden hunger. Oil is the major energy source of the Indian diet. Chemical composition of oil decides its edible nature. Even in edible oil fatty acid composition in general and ratio of oleic acid to linoleic acid of the oil plays major role in deciding its quality. In India, availability of breeding line to improve groundnut oil quality is limited. Screening of different botanical group may give some idea about choice of material for further crop improvement program. In present study botanical group hypogaea, found to have higher amount of oleic acid and fastigiata group recorded high protein and oil content. Growing season also matters in the expression of different fatty acid. Rainy season is found to have better for the better expression of all studied traits. [ABSTRACT FROM AUTHOR]

Reducing the release time of new peanut varieties is a key objective of peanut breeding programs. In the Australian Peanut Genetic Improvement Program release time has traditionally taken 10 to 15 years; however, the relatively recent use of winter breeding and seed increase nurseries has significantly reduced release times. Despite these improvements, full-season maturity cultivars are still limited to two generations in a calendar year, when grown under optimal environmental conditions. This paper describes a new speed breeding technique, which combines controlled environment conditions, continuous light in conjunction with optimal temperature, and a single seed descent breeding strategy in a greenhouse environment. Speed breeding was successful in reducing generation time of full-season maturity cultivars from 145 to 89 days. Speed breeding can rapidly progress the inbreeding of F2, F3 and F4 generations in less than 12 months, and potentially accelerate the development of first cross to commercial release in around six to seven years. [ABSTRACT FROM AUTHOR]

The success of any breeding programme depends upon the amount of variability present for different characters in a population and its efficient management. The genetic coefficient of variation is a useful measure of the magnitude of genetic variance present in the population. However, estimation of genetic variability alone cannot indicate the possible improvement that could be achieved through selection, but it should be used in conjunction with heritability and genetic advance. High heritability combined with high GAM was observed for most of the characters especially for shelling percentage, sound mature kernel weight and pod yield per plant. High heritability coupled with moderate genetic advance as percent of mean (GAM) was recorded for protein and sound mature kernel weight. Oil showed high heritability with low GAM. It was also observed that variability and heritability for chlorophyll and yield in 40 peanut genotypes and reported wide variability and moderate heritability values for chlorophyll and seed weight per plant. High GCV, PCV and heritability and genetic advance were noticed for harvest index and its component traits viz., pod yield per plant, number of branches per plant and sound mature kernel percentage. [ABSTRACT FROM AUTHOR]

With 3 figures and 7 tables Abstract With an objective of identification of highly informative set of SSR markers in cultivated groundnut ( Arachis hypogaea L.), a total of 4485 markers were used for screening using a set of 20 parental genotypes of 15 mapping populations. Although 3582 (79.9%) markers provided scorable amplification, only 1351 (37.3%) markers showed polymorphism. Polymorphism information content (PIC) value ranged from 0.10 (GM742) to 0.89 (S009) with an average of 0.31. Similarly, number of alleles ranged from 2 to 14 with an average of 3.2 alleles. In general, the SSR markers based on dinucleotide repeats displayed higher PIC value and number of alleles. Based on these polymorphism features, 199 markers with >0.50 PIC values have been identified. Polymorphism features of these markers along with the primer sequences, for the first time, for a total of 946 SSR markers have been provided. It is anticipated that the identified set of highly informative markers, instead of starting from the random set of SSR markers, should be very useful to initiate molecular genetics and breeding studies in cultivated groundnut. [ABSTRACT FROM AUTHOR]

Sixty four accessions of groundnut (Arachis hypogaea L.) evaluated under late kharif season have been classified using Principal component analysis (PCA) based on correlation matrix yielding eigen values and eigen vectors. Fourteen principal components (PC) have been extracted using the mean performance of the genotypes, first ten principal components contributed over 95% of variation. Relative positive weights by each of the component to each single character has shown pod yield per plant and kernel yield per plant being given high positive weight by first principal component. Biplot of first two principal components showed characters viz., plant height, harvest index, pod yield, kernel yield per plant and oil yield per plant distinguishing among the accessions along the first principal component vector. Cluster analysis was performed based on first ten PC scores accounting more than 95% of variation which classified the sixty four accessions in to three clusters. Accessions in clusters 1 and 2 showed a wide range for several agronomic characters. This provides convenience in selecting superior accessions from each of these clusters for various yield contributing in the future breeding programs. [ABSTRACT FROM AUTHOR]

Peanut is one of the most important oilseed crops in the world. Genomic research of cultivated peanut has lagged behind that of other crop species because of the paucity of polymorphic DNA markers found in this crop. Identification of molecular genetic diversity in cultivated peanut will help with effective genetic conservation along with establishing efficient breeding programmes in this crop. The present study was initiated to establish genetic diversity and relationships in the peanut collection in Iran using simple sequence repeat (SSR) markers. Thirteen SSR primer pairs generated 80 alleles among 68 peanut accessions, with an average of 6.15 alleles per locus. Polymorphic information content (PIC)-values were high and ranged from 0.47 (Locus pPGPseq-2C11) to 0.95 (Locus PM183), with a mean value of 0.80. Several accession- and group-specific markers were identified that could be effectively used for identification purposes. High genetic variability was found in the collection. Dice genetic similarity coefficients ranged from 0.08 (D15-A5) to 1 (A8-A10-A12 and E12-E14). A unweighted pair-group method using arithmetic average (UPGMA) dendrogram and principal-component analysis (PCA) revealed two distinct clusters with three sub-clusters in cluster one that is not group-based on morphological classification of accessions in groups A, B, C, D, and E. Some accessions in the same sub-cluster or group had the same pedigree, but the dendrogram was not fully in accordance with pedigree information. Analysis of molecular variance (AMOVA) for five groups as A, B, C, D and E showed a higher level of genetic variation within groups as compared with between groups (83% versus 17%). Results indicated that these previously classified groups do not truly categorize the accessions. Genetic variation detected within the Iranian peanut collection can be utilized for selection of diverse parents for breeding and development of mapping populations. [ABSTRACT FROM AUTHOR]

This paper describes a simple, low cost and reliable DNA template preparation protocol for polymerase chain reaction (PCR) using immature leaves from peanut seeds or leaves from field-grown plants. The technique may find wide utility in studies involving PCR-based molecular markers, rapid screening for transformants and gene cloning. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate reproductive growth, oil and protein accumulation in seeds, and some yield components of 8 groundnut genotypes in 2001 and 2002. The number of flowers, pegs, and pods per plant during the reproductive period were determined with periodic counts starting from flowering. The percentage of flowers turned to pegs and pods, and the percentage of pegs turned to pods were calculated at the end of the growing period. After pod setting, 6 plants per lot were harvested at 15-day intervals to determine oil and protein content of seeds. At final harvest pod yield and some yield components were determined, and correlations between reproductive growth parameters and pod yield were calculated. Genotypes had significantly different reproductive growth parameters. Total number of flowers per plant was negatively correlated with the percentage of flowers turned to pegs and pods, whereas the percentage of flowers turned to pegs and pods was positively correlated with pod yield. The highest pod yield was obtained from cv. Osmaniye 2005, which had the lowest number of flowers per plant and the highest percentage of flowers turned to pods. The results of the current study showed that percentage of flowers turned to pegs and the percentage of pegs turned to pods were the most promising generative plant characteristics that could contribute to seed yield increase in groundnut production in a typical eastern Mediterranean climate. Seed oil content of the groundnut genotypes increased rapidly until initiation of first maturity (R7) and then declined in the later growth stages, whereas protein content generally increased gradually until physiological maturity (R8) in all genotypes. [ABSTRACT FROM AUTHOR]

A sclerotia-forming fungus was isolated from a peanut field in eastern New Mexico, where Valencia peanut is grown. The isolated fungus was typified by its darkly pigmented mycelium when grown on culture media, with pigmentation influenced by media. The optimal temperature range for mycelial growth was 20 to 25°C. In pathogenicity test, the fungus caused water-soaked and light tan lesions on stems at points of inoculation, and lesions progressed up the stems into petioles followed by collapse of leaves. White fluffy mycelium and sclerotia were present on inoculated plants. Based on the examination of morphological and cultural characteristics of sclerotia, apothecia, asci, and ascospores, the isolated fungus with darkly pigmented mycelium on culture media was identified as Sclerotinia sclerotiorum. This study is the first report of S. sclerotiorum on peanut in New Mexico. [ABSTRACT FROM AUTHOR]

This study explores the efficacy of utilizing a novel ground penetrating radar (GPR) acquisition platform and data analysis methods to quantify peanut yield for breeding selection, agronomic research, and producer management and harvest applications. Sixty plots comprising different peanut market types were scanned with a multichannel, air-launched GPR antenna. Image thresholding analysis was performed on 3D GPR data from four of the channels to extract features that were correlated to peanut yield with the objective of developing a noninvasive high-throughput peanut phenotyping and yield-monitoring methodology. Plot-level GPR data were summarized using mean, standard deviation, sum, and the number of nonzero values (counts) below or above different percentile threshold values. Best results were obtained for data below the percentile threshold for mean, standard deviation and sum. Data both below and above the percentile threshold generated good correlations for count. Correlating individual GPR features to yield generated correlations of up to 39% explained variability, while combining GPR features in multiple linear regression models generated up to 51% explained variability. The correlations increased when regression models were developed separately for each peanut type. This research demonstrates that a systematic search of thresholding range, analysis window size, and data summary statistics is necessary for successful application of this type of analysis. The results also establish that thresholding analysis of GPR data is an appropriate methodology for noninvasive assessment of peanut yield, which could be further developed for high-throughput phenotyping and yield-monitoring, adding a new sensor and new capabilities to the growing set of digital agriculture technologies. [ABSTRACT FROM AUTHOR]

Two hundred and ten germplasm and breeding lines and landraces of groundnut were screened for resistance to the causal organism of bacterial wilt in preliminary field trials at infested locations in northern Vietnam during 1994-1995. Selected genotypes were further evaluated during the spring and autumn of 1995 and also during the 1996 spring season. Three genotypes (ICG 8666, ICG 5273, and Gie Nhoquan) were identified as resistant at several locations; these also showed a markedly lower incidence of bacterial wilt than the susceptive cultivars Sen Nghe An and ICG 3704 in greenhouse inoculation tests with several isolates of the bacterial wilt pathogen, Pseudomonas solanacearum. Of the four isolates (QO, HT1, HTR4, and HB) of the pathogen tested, HT1 induced much higher levels of wilt in ICG 5273 than the other isolates. Four breeding lines (ICGVs 87157, 87206, 87242, and 93188) showed moderate to high levels of field resistance, but gave erratic results in greenhouse inoculation tests. The characteristic features of identified sources of resistance are described, and the importance of their utilization in resistance breeding is discussed. [ABSTRACT FROM AUTHOR]

Twenty four genotypes of groundnut were evaluated for stability of dry pod yield in groundnut (Arachis hypogaea L.). All the genotypes differ significantly revealed enough genetic variability for dry pod yield. Linear component of genotype x environment interaction was higher than that of non-linear. All the twelve genotypes had above average mean, average responsive and genotype No.123 was stable for dry pod yield, hence their use in future breeding programme is aimed at stable dry pod yield in groundnut. [ABSTRACT FROM AUTHOR]

Eighty diverse genotypes of bunch groundnut were evaluated during summer 2006 for genetic parameters viz., variability, heritability and genetic advance. The estimates of PCV and GCV were high for number of secondary branches per plant and number of aerial pegs per plant. High heritability along with high genetic advance as per cent of mean was observed for number of secondary branches per plant and number of aerial pegs per plant indicating that these traits are mainly governed by additive gene action and responsive to selection for further improvement of these triats. [ABSTRACT FROM AUTHOR]

Co-occurrence of two devastating foliar-fungal diseases of peanut, viz., late leaf spot (LLS), and rust may cause heavy yield loss besides adversely affecting the quality of kernel and fodder. This study reports the mapping of seven novel stress-related candidate EST-SSRs in a region having major QTLs for LLS and rust diseases using an F2 mapping population (GJG17 × GPBD4) consisting of 328 individuals. The parental polymorphism using 1311 SSRs revealed 84 SSRs (6.4%) as polymorphic and of these 70 SSRs could be mapped on 14 linkage groups (LG). QTL analysis has identified a common QTL (LLSQTL1/RustQTL) for LLS and rust diseases in the map interval of 1.41 cM on A03 chromosome, explaining 47.45% and 70.52% phenotypic variations, respectively. Another major QTL for LLS (LLSQTL1), explaining a 29.06% phenotypic variation was also found on LG_A03. A major rust QTL has been validated which was found harboring R-gene and resistance-related genes having a role in inducing hypersensitive response (HR). Further, 23 linked SSRs including seven novel EST-SSRs were also validated in 177 diverse Indian groundnut genotypes. Twelve genotypes resistant to both LLS and rust were found carrying the common (rust and LLS) QTL region, LLS QTL region, and surrounding regions. These identified and validated candidate EST-SSR markers would be of great use for the peanut breeding groups working for the improvement of foliar-fungal disease resistance. [ABSTRACT FROM AUTHOR]