AMMI and GGE biplot analysis of genotype by environment interaction for yield and yield contributing traits in confectionery groundnut.

The global market has a high demand for premium edible grade groundnut, particularly for table use. India, in particular, exhibits significant potential for exporting confectionary grade large seeded groundnut. The environment plays a significant impact in influencing the expression of seed traits, which subsequently affects the confectionary quality of groundnut genotypes. The states of Gujarat and Rajasthan in India are prominent producers of high-quality groundnuts specifically used for confectionary purposes. The current study was conducted with 43 confectionery groundnut genotypes at Junagadh, Gujarat, and Bikaner, Rajasthan, with the goals of understanding genotype-by-environment interaction (GEI) effects and identifying stable, high yielding confectionery quality groundnut genotypes using AMMI and GGE biplot models. Pod yield per plant (PYP), number of pods per plant (NPP), hundred kernel weight (HKW), and shelling percent (SP) were estimated. The interplay between the environment and genotype has had a notable impact on the manifestation of confectionary grade characteristics in peanuts. The results from the Interaction Principal Component Analysis (IPCA) indicate that HKW contributed 76.68% and 18.95% towards the Global Environmental Index (GEI) through IPCA1 and IPCA2, respectively. Similarly, NPP contributed 87.52% and 8.65%, PYP contributed 95.87% and 2.1%, and SP contributed 77.4% and 16.22% towards GEI through IPCA1 and IPCA2, respectively. Based on the ranking of genotypes, the ideal genotypes were PBS 29079B for HKW, PBS 29230 for NPP. The genotypes PBS 29233 and PBS 29230 exhibited superior performance and stability in terms of pod yield, hundred kernel weight, number of pods per plant, and shelling percentage across various sites. These breeding lines have the potential to be developed for the purpose of producing confectionary grade groundnut with larger seeds, in order to fulfil the growing demand for export.

Accumulation of resveratrol, ferulic acid and iron in seeds confer iron deficiency chlorosis tolerance to a novel genetic stock of peanut (Arachis hypogaea L.) grown in calcareous soils.

Peanut is mostly grown in calcareous soils with high pH which are deficient in available iron (Fe2+) for plant uptake causing iron deficiency chlorosis (IDC). The most pertinent solution is to identify efficient genotypes showing tolerance to limited Fe availability in the soil. A field screening of 40 advanced breeding lines of peanut using NRCG 7472 and ICGV 86031 as IDC susceptible and tolerant checks, respectively, was envisaged for four years. PBS 22040 and 29,192 exhibited maximum tolerance while PBS 12215 and 12,185 were most susceptible. PBS 22040 accumulated maximum seed resveratrol (5.8 ± 0.08 ppm), ferulic acid (378.6 ± 0.31 ppm) and Fe (45.59 ± 0.41 ppm) content. Enhanced chlorophyll retention (8.72-9.50 µg ml-1), carotenoid accumulation (1.96-2.08 µg ml-1), and antioxidant enzyme activity (APX: 35.9-103.9%; POX: 51- 145%) reduced the MDA accumulation (5.61-9.11 µM cm-1) in tolerant lines. The overexpression of Fe transporters IRT1, ZIP5, YSL3 was recorded to the tune of 2.3-9.54; 1.45-3.7; 2.20-2.32- folds respectively in PBS 22040 and 29,192, over NRCG 7472. PBS 22040 recorded the maximum pod yield (282 ± 4.6 g/row), hundred kernel weight (55 ± 0.7 g) and number of pods per three plants (54 ± 1.7). The study thus reports new insights into the roles of resveratrol, ferulic acid and differential antioxidant enzyme activities in imparting IDC tolerance. PBS 22040, being the best performing line, can be the potent source of IDC tolerance for introgression in high yielding but susceptible genotypes under similar edaphic conditions. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01321-9.

Metabolic profiling for dissection of late leaf spot disease resistance mechanism in groundnut.

Late leaf spot (LLS) caused by fungi Passalora personata is generally more destructive and difficult to control than early leaf spot. The aim of this study was to decipher biochemical defense mechanism in groundnut genotypes against P. personata by identifying resistance specific biomarkers and metabolic pathways induced during host-pathogen interaction. Metabolomics of non-infected and infected leaves of moderately resistant (GPBD4 and ICGV86590), resistant (KDG128 and RHRG06083) and susceptible (GG20, JL24 and TMV2) genotypes was carried out at 5 days after infection (65 days after sowing). Non-targeted metabolite analysis using GC-MS revealed total 77 metabolites including carbohydrates, sugar alcohols, amino acids, fatty acids, polyamines, phenolics, terpenes and sterols. Variable importance in projection (VIP) measure of partial least squares-discriminant analysis (PLS-DA) showed that resistant and moderately resistant genotypes possessed higher intensities of ribonic acid, cinnamic acid, malic acid, squalene, xylulose, galactose, fructose, glucose, ß-amyrin and hydroquinone while susceptible genotypes had higher amount of gluconic acid 2-methoxime, ribo-hexose-3-ulose and gluconic acid. Heat map analysis showed that resistant genotypes had higher intensities of ß-amyrin, hydroquinone in non-infected and malic acid, squalene, putrescine and 2,3,4-trihydroxybutyric acid in infected leaves. Dendrogram analysis further separated resistant genotypes in the same cluster along with infected moderately resistant genotypes. The most significant pathways identified are: linoleic acid metabolism, flavone and flavonol biosynthesis, cutin, suberin and wax biosynthesis, pentose and glucuronate interconversions, starch and sucrose metabolism, stilbenoid biosynthesis and ascorbate and aldarate metabolism. Targeted metabolite analysis further confirmed that resistant genotypes possessed higher content of primary metabolites sucrose, glucose, fructose, malic acid and citric acid. Moreover, resistant genotypes possessed higher content of salicylic, coumaric, ferulic, cinnamic, gallic acid (phenolic acids) and kaempferol, quercetin and catechin (flavonols). Thus metabolites having higher accumulation in resistant genotypes can be used as biomarkers for screening of LSS resistant germplasm. These results unravel that higher amount of primary metabolites leads to stimulate the accumulation of more amounts of secondary metabolites such as phenolic acid, flavanols, stilbenes and terpenoids (squalene and ß-amyrin) biosynthesis which are ultimately involved in defense mechanism against LLS pathogen. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-021-00985-5.

Distinguish metabolic profiles and defense enzymes in Alternaria leaf blight resistant and susceptible genotypes of groundnut.

Alternaria leaf blight is major fungal disease of summer groundnut, causes significant loss of haulm and pod yield. Aims of this study were to understand the role of metabolites and phenylpropanoid related enzymes in Alternaria leaf blight resistance and to find out metabolic marker for disease resistance. Alternaria leaf blight resistant (GPBD4 and CS186) and susceptible genotypes (GG2 and TPG41) of groundnut were grown in pots during rabi-summer 2015. Groundnut plants were infected with Alternaria alternata (Fr.) Keissler at 40 days after sowing. 5 days after infection, upper second leaves were collected from both control and infected plants for analysis. A total of 67 metabolites comprising sugars, sugar alcohols, amino acids, organic acids, fatty acids, sterols and phenolic were identified using gas chromatography-mass spectrometry (non-targeted metabolomics). Constitutive levels of alpha-d-galactoside, d-mannitol, d-erythropentitol, glycine, and hexadecanoic acid were observed higher in resistant genotypes compared to susceptible genotypes. Moreover, arabinofuranose, cinnamic acid, 2-butendioic acid, and linoleic acid were observed only in resistant genotypes at both control and infected stage. In susceptible genotypes myo-inositol, glucose and fructose content was increased after infection with pathogen while decreased in resistant genotypes. Resistant genotypes had higher constitutive level of cinnamic and salicylic acid compared to susceptible genotypes. Non-infected leaves of resistant genotypes also had higher activities of phenylalanine ammonia lyase and tyrosine ammonia lyase activities. Our results suggest that metabolites specifically present in resistant genotypes impart defense mechanism against Alternaria pathogen and can be used as bio-marker for screening of germplasm.

Nutritional composition and antioxidant activity of Spanish and Virginia groundnuts (Arachis hypogaea L.): a comparative study.

Kernels of sixty groundnut genotypes comprising thirty each of Spanish and Virginia groups were characterized and compared for the content of oil, protein, phenols and antioxidant activity along with their fatty acid and sugars profiles. The antioxidant activity for Virginia genotypes was ranged from 12.5 to 16.5 µM Trolox equivalent activity for Spanish genotypes ranged from 6.8-15.2 µM. Amongst Virginia types, the highest oleic acid/linoleic acid (O/L) ratio of 2.38 was observed for NRCG 12312 while from Spanish group the highest O/L ratio of 1.24 was observed for NRCG 12731. The sucrose content for Virginia genotypes ranged from 38.5 to 69.0 mg/g while it was 27.9 to 53.3 mg/g for Spanish genotypes. Average myo-inositol content was higher for Spanish genotypes (0.8-2.1 mg/g) compared to Virginia (0.4-1.8 mg/g) while the reverse was true for stachayose content (Spanish: 3.5-7.9 mg/g; Virginia: 4.6-10.3 mg/g). Thus, Virginia genotypes could be preferred to Spanish genotypes for better oil stability and antioxidant activity.

Quality traits of Indian peanut cultivars and their utility as nutritional and functional food.

Peanut (Arachis hypogaea L.) is considered as a highly nutritious foodstuff. Of late, the importance of peanut as a functional food has been growing. Kernels of forty-one Indian peanut cultivars were analyzed for their oil, fatty acid profiles, sucrose, raffinose family oligosaccharides (RFOs); phenolics, and free amino acids contents along with antioxidant capacity. The range and the mean value (given in parenthesis) for each of the traits analysed were, oil: 44.1-53.8% (50.1%), O/L ratio: 0.9-2.8 (1.4), sucrose: 2.61-6.5% (4.63%), RFOs: 0.12-0.76% (0.47%), phenolics: 0.14-0.39% (0.23%), free amino acids: 0.052-0.19% (0.12%) and antioxidant capacity: 1.05-6.97 (3.40) µmol TEg(-1). The significant correlation between phenol content and antioxidant capacity suggests phenol content as an easy marker for rapid screening of genotypes for their antioxidant capacity. A few cultivars with desirable traits and their prospective utility were identified which would be useful for future breeding programme to develop nutritional superior peanuts.

Variation in metabolites constituent in leaves of downy mildew resistant and susceptible genotypes of pearl millet.

In the present investigation biochemical characterization of pearl millet genotypes was carried at pre (45 DAS) and post-infection (57 DAS i.e. 7 days after infection) stage. Total soluble sugar was greater at pre infection than post infection in downy mildew resistant and susceptible genotypes of pearl millet. Total soluble sugar decreased in all genotypes at 7 days after infection (d.a.i.) except in 7042 S in which it increased 4.6 %. However, total soluble sugar was 2-3 folds more in highly susceptible genotypes (J-2296 and 7042 S) compared to resistant genotypes at 7 d.a.i. but it was decreased as compared to pre infection. The total amino acid content of all genotypes whether resistant or susceptible, finally increased as a result of infection. Moreover, susceptible genotypes registered 2-2.5 % higher amino acid, whereas resistant genotypes possessed 6.2-76 % higher amino acid than their constitutive level. Total chlorophyll and carotenoids content did not show any clear cut difference in resistant and susceptible genotypes at pre-infection stage. However, at post-infection stage a significant decrease in chlorophyll and carotenoids content occurred in susceptible genotypes from pre-infection. Amino acid profiling through HPTLC showed sulphur containing amino acids were higher in resistant genotypes.