Economic and Academic Importance of Peanut

Peanut is an important oil, food and feed crop of the world. The kernels are rich in fats and protein, and 100 g of kernels provide 567 kcal of energy and 8.5 g of dietary fiber. Peanuts are source of minerals, vitamins and antioxidants and health improving bioactive compounds such as resveratrol, tocopherol, arginine etc. and hence are touted as functional food. Consumption of peanuts can reduce risk of inflammation, diabetes, cancer, alzheimer’s and gallstone disease. Peanut is cultivated in over 100 countries, with over 95% of cultivated area in Asia and Africa. Aflatoxin and allergens are major health deterrents in peanut and more research efforts are needed to develop aflatoxin and allergen free peanuts. There is a great demand for peanut and peanut-based products in the international market, especially for confectionary types. Breeding new cultivars that meet the needs of the producers, consumers and industry is an important research area with implications along the value chain. Conventional breeding approaches and phenotyping tools were widely used to breed several varieties and in the last decade, genomic tools are integrated for making selections. The advent of next-generation sequencing (NGS) tools and the availability of the draft genome sequence of the diploid progenitors of peanut A. duranensis and A. ipaensis is expected to play a key role in sequencing the genome of cultivated peanut. Transgenic peanuts with resistance to herbicide, fungus, virus, and insects; tolerance to drought and salinity and improved grain quality are under testing at different containment levels. The availability of sophisticated tools for both genotyping and phenotyping will lead to an increase in our understanding of key genes involved and their metabolic regulatory pathways

Combination of empirical and trait-based approaches for breeding drought tolerance in groundnut (Arachis hypogaea L.)

Breeding groundnut varieties that combine improved pod yield under water-deficit stress, and enhanced water use efficiency (WUE) is an important strategy to overcome the challenges in water-limited conditions. SPAD chlorophyll meter reading (SCMR) and specific leaf area (SLA) are the two important traits associated with WUE. SCMR is simple, non-destructive and robust method. Maintaining high chlorophyll density under water stress conditions is associated with high WUE in groundnut, and SCMR measures green colour intensity associated with chlorophyll density. A RIL population (280) was evaluated during 2015/16 under well-watered (WW) and water-deficit stress (WS) for yield parameters and SCMR. Pod yield is independent of SCMR (R2=0.003), suggesting the importance of simultaneous selection for both these traits in breeding programs. For breeding varieties suitable for water-stress conditions, measuring both pod yield under stress and WUE through its surrogate SCMR are useful. In Africa and Asia, groundnut is largely a rainfed crop. The frequency of drought is variable, and every year is not a drought year. Therefore, the commercial groundnut varieties should perform well under normal rainfall years, and have less yield penalty during drought years. The approach of measuring pod yield penalty under water-deficit stress compared to WW condition is a useful selection criterion in breeding programs, wherein the lines with minimum yield penalty are selected. Such a selection criteria enable selection of genotypes that perform well under normal seasons and have less yield penalty during drought seasons. In this paper, we discuss progress in groundnut breeding at ICRISAT using these two approaches

Multivariate analysis of colored and white grape grown under semi-arid tropical conditions of Peninsular India

Thirteen grape varieties (Eight colored and five white) were evaluated during 2007-2009 under semi-arid tropical conditions of Peninsular India for 17 agro-morphological traits. Red varieties were vigorous as they have recorded more summer and winter pruning weight. Based on bud burst, most of the red varieties were early and medium types except Ruby red. The mean number of canes per vine and shoot length was higher for red varieties than white varieties with more variation for cane diameter. Red varieties have also produced longer shoots than white varieties. Vigorous varieties such Chenin Blanc and Shiraz have produced comparatively shorter shoots than less vigorous varieties. White grape varieties have recorded more number of leaves (16.96) in comparison to red varieties (16.64)..

Efficient Partitioning of Assimilates in Stress-Tolerant Groundnut Genotypes under High-Temperature Stress

Groundnut (Arachis hypogaea L.) genotypes were assessed for pod yield and physiological parameters under heat-stress and non-stress environments. The air temperatures under heat-stress environments were 35 °C and above during flowering, and below 35 °C in non-stress environments. Variability was significant for pod yield and physiological parameters among the genotypes under heat stress. A pod yield reduction of 1.5% to 43.2% was observed under heat-stress environments. However, in heat-tolerant genotypes, either stable or increased pod yield was recorded under high-temperature stress. GJG 31, ICGV 87846, ICGV 03057, ICGV 07038 and GG 20 showed an increase in pod yield by 9.0% to 47.0% at high temperatures, with a 0.65% to 3.6% increase in pod growth rate, while ICGV 06420, ICGV 87128, ICGV 97182, TCGS 1043 and ICGV 03042 are stable for pod yield and recorded a 0.25% to 3.1% increase in pod growth rate. Pod yield, hundred-seed weight, and pod growth rate under heat stress can be used as criteria for selection of heat stress tolerant-genotypes. Based on stress tolerance indices and pod yield performance, ICGVs 07246, 07012, 06039, 06040, 03042, 07038 and 06424 were identified as heat-tolerant genotypes

Genotype × Environment Interactions for Oil Content in Peanut and Stable High-Oil-Yielding Sources

Peanut (Arachis hypogaea L.) genotypes with superior and stable agronomic performance and high oil content were identified from testing of 160 advanced breeding lines over six seasons. The study revealed significant genotype and genotype environment (G E) interaction determining oil and protein content; shelling outturn; and pod, kernel, and oil yield in peanut. The variability among genotypes was high across the environments for pod yield (546– 7382 kg ha−1), oil yield (301–2742 kg ha−1), oil content (37–60%), 100-seed weight (21–127 g), and protein content (19–31%). The GGE biplot technique revealed that ICGV 05155 is a stable genotype for oil yield with an average oil yield of 1886 kg ha−1. ICGV 05155 recorded highest average pod yield of 4928 kg ha−1, kernel yield of 3420 kg ha−1, and oil content of 55.1%. ICGV 06049, ICGV 06041, ICGV 06420, and ICGV 03043 were other genotypes with stable oil yield. Simple regression showed significant contributions of oil content (18–54%), and kernel yield (92–99%) to oil yield across the environments. Simultaneous improvement of kernel yield and oil content is feasible in breeding programs, as kernel yield had no negative association with oil content. The high oil content genotypes, ICGV 05155, ICGV 06049, ICGV 06041, ICGV 06420, and ICGV 03043, with stable oil yield were promoted to multilocation adaptive trials required for their release for cultivation and used as parents in breeding programs and development of mapping population to identify quantitative trait loci (QTL) governing oil content

Genetic analysis of foliar disease resistance, yield and nutritional quality traits in groundnut

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

Status of Adoption of Improved Groundnut Technologies in Odisha State

Paddy is the dominant staple crop in the state of Odisha in India. Groundnut, sesame, mustard and niger are the major oilseed crops cultivated in the state. Groundnut occupied about 34% of total oilseed area and contributed more than 68% of total oilseeds production during the triennium ending (TE) 2017-18. The area under groundnut declined from 318,000 ha to 210,000 ha between TE 1995-96 and 2017-18 (25 years) (Behura et al 2014, Odisha Agricultural Statistics - various issues. https://agriodisha.nic.in/Home/staticstics). It has registered a negative growth rate (cropped area) of 0.93% per annum. Production too declined from 466,000 tons to 374,000 tons during the same period. However, groundnut productivity saw an uptrend from 1465 kg/ha to 1783 kg/ha due to the introduction of modern high-yielding varieties. Figure 1 shows the trends in area, production and productivity of groundnut in the state

Standard Operating Procedures for Groundnut Breeding and Testing

The Standard Operating Procedures (SOP) is a reference or manual on breeding methodologies and testing procedures used at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) to breed new groundnut varieties. It describes the tools that are currently being used for phenotyping and genotyping specific traits in groundnut. The SOP will be useful to groundnut researchers, scientific and technical staff and scholars and the NARS (National Agriculture Research System) partners..

Improvement of three popular Indian groundnut varieties for foliar disease resistance and high oleic acid using SSR markers and SNP array in marker-assisted backcrossing

Foliar fungal diseases (rust and late leaf spot) incur large yield losses, in addition to the deterioration of fodder quality in groundnut worldwide. High oleic acid has emerged as a key market trait in groundnut, as it increases the shelf life of the produce/products in addition to providing health benefits to consumers. Marker-assisted backcrossing (MABC) is the most successful approach to introgressing or pyramiding one or more traits using traitlinked markers. We used MABC to improve three popular Indian cultivars (GJG 9, GG 20, and GJGHPS 1) for foliar disease resistance (FDR) and high oleic acid content. A total of 22 BC3F4 and 30 BC2F4 introgression lines (ILs) for FDR and 46 BC3F4 and 41 BC2F4 ILs for high oleic acid were developed. Recurrent parent genome analysis using the 58 K Axiom_Arachis array identified several lines showing upto 94% of genome recovery among second and third backcross progenies. Phenotyping of these ILs revealed FDR scores comparable to the resistant parent, GPBD 4, and ILs with high (~80%) oleic acid in addition to high genome recovery. These ILs provide further opportunities for pyramiding FDR and high oleic acid in all three genetic backgrounds as well as for conducting multi-location yield trials for further evaluation and release for cultivation in target regions of India

Combining High Oleic Acid Trait and Resistance to Late Leaf Spot and Rust Diseases in Groundnut (Arachis hypogaea L.)

High oleic trait, resistance to rust and late leaf spot (LLS) are important breeding objectives in groundnut. Rust and LLS cause significant economic loss, and high oleic trait is an industry preferred trait that enhances economic returns. This study reports marker-assisted selection to introgress high oleic content, resistance to LLS and rust into Kadiri 6 (K 6), a popular cultivar. The alleles for target traits were selected using linked allele-specific, simple sequence repeats and single nucleotide polymorphic markers. The F1s (384), intercrossed F1s (441), BC1F1s (380), BC1F2s (195), and BC1F3s (343) were genotyped to obtain desired allelic combination. Sixteen plants were identified with homozygous high oleic, LLS and rust resistance alleles in BC1F2, which were advanced to BC1F3 and evaluated for disease resistance, yield governing and nutritional quality traits. Phenotyping with Near-Infrared Reflectance Spectroscopy identified three lines (BC1F3-76, BC1F3-278, and BC1F3-296) with >80% oleic acid. The identified lines exhibit high levels of resistance to LLS and rust diseases (score of 3.0–4.0) with preferred pod and kernel features. The selected lines are under yield testing trials in multi-locations for release and commercialization. The lines reported here demonstrated combining high oleic trait with resistance to LLS and rust diseases