Single seed-based high-throughput genotyping and rapid generation advancement for accelerated groundnut genetics and breeding research

The groundnut breeding program at International Crops Research Institute for the Semi-Arid Tropics routinely performs marker-based early generation selection (MEGS) in thousands of segregating populations. The existing MEGS includes planting of segregating populations in fields or glasshouses, label tagging, and sample collection using leaf-punch from 20–25 day old plants followed by genotyping with 10 single nucleotide polymorphisms based early generation selection marker panels in a high throughput genotyping (HTPG) platform. The entire process is laborious, time consuming, and costly. Therefore, in order to save the time of the breeder and to reduce the cost during MEGS, we optimized a single seed chipping (SSC) process based MEGS protocol and deployed on large scale by genotyping >3000 samples from ongoing groundnut breeding program. In SSC-based MEGS, we used a small portion of cotyledon by slicing-off the posterior end of the single seed and transferred to the 96-deep well plate for DNA isolation and genotyping at HTPG platform. The chipped seeds were placed in 96-well seed-box in the same order of 96-well DNA sampling plate to enable tracking back to the selected individual seed. A high germination rate of 95–99% from the chipped seeds indicated that slicing of seeds from posterior end does not significantly affect germination percentage. In addition, we could successfully advance 3.5 generations in a year using a low-cost rapid generation turnover glass-house facility as compared to routine practice of two generations in field conditions. The integration of SSC based genotyping and rapid generation advancement (RGA) could significantly reduce the operational requirement of person-hours and expenses, and save a period of 6–8 months in groundnut genetics and breeding research

High-density genetic map using whole-genome resequencing for fine mapping and candidate gene discovery for disease resistance in peanut

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

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Not AvailableFruit maturity and associated changes in terms of physicochemical and sensorial qualities of Khasi mandarin (Citrus reticulat Blanco) grown at different altitudes, viz. 500-600 m, 700-800 m, 900-1 000 m and 1 300-1 400 m were studied under humid tropical climate of Meghalaya. Rapid increase in fruit growth was recorded from fruit development to colour break stage, however it was slow thereafter at all the altitudes. At 500-600m and 700-800m, juice yield was recorded highest at fruit maturity stage (46.64% and 49.11%) while, it was highest in advanced fruit maturity stage (50.90% and 51.15%) at 900-1 000 m and 1 300-1 400 m. Diurnal variation in climate stimulated drop in chlorophyll (‘a’, ‘b’ and total) and promoted development of yellowish orange colouration on fruit peel at altitude of 500-600 m and 700-800 m while deep orange colouration at 900-1 000 m and 1 300-1 400 m. Significant rise in TSS and TSS: acid ratio with drop in titratable acidity were recorded during maturation. Ascorbic acid content was recorded maximum at 1 300-1 400 m (44.13 mg/100 g) and 900-1 000 m (41.05 mg/100 g) compared with 700-800 m (37.56 mg/100 g) and 500-600 m (35.66 mg/100 g) at advanced maturity stage. Duration of 1 and 1 ½ month (fruit development to colour break stage) represents maturation at 500-600 m and 700-800 m considering TSS (10.23 °B and 10.13 °B), TSS: acid ratio (13.22 and 12.60), sweetness (3.93 and 3.67), flavour (8.00 and 7.93) and appearance (8.07 and 7.87) score. While duration of 2 and 2 ½ months (fruit development to fruit maturity stage) required at 900-1 000 m and 1 300-1 400 m considering TSS (10.07 °B and 10.16 °B), TSS: acid ratio (12.40 and 12.02), sweetness (4.07 and 3.93), flavour (7.87 and 7.93) and appearance (7.93 and 8.00) score.Not Availabl

Legislations for Seed Quality Regulation in India

Not AvailableAgriculture production is purely based on the basic input, seed. Until unless the purity, quality and seed standards are maintained, production programme cannot be successful. To maintain these quality standards, legislations are equally important. Therefore Government of India had taken steps in framing Seed Act, Seed Rules, Seed (control) order, National Seed Policy, Plant quarantine order, PPV & FR Act to not only to protect breeders, researchers but also a common farmer. These legislations have taken care of the quality of the seeds at production, processing, marketing and labeling and marketing levels to ensure the farmer gets the best quality seed. Therefore it is necessary that the information regarding seed legislations must reach farmers also to make them aware of their rights

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Not AvailableThe physico-mechanical properties of Prunus nepalensis fruit and seed were determined at moisture content of 88.50 and 15.62%, respectively. Image processing technique was also used to measure major dimensions and data was compared and correlated with experimental data. Significant correlation was observed between length and width of fruit and seed measured by experimental and image processing technique. The true density, bulk density and porosity of fruit were measured as 1077.41; 598.08 kg m-3; and 43.42%, respectively whereas, for seed these values were observed to be 1178.84; 508.80 kg m-3; and 57.94%. The angle of repose of fruit and seed was found to be 26.43 and 22.13°, respectively. Frictional coefficient was found lower in aluminium sheet than other surfaces. The obtained properties can be helpful for designing of processing equipment for this fruit.Not Availabl

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Not AvailableBiomass production in arid and semi-arid regions requires a special attention owing to spatiotemporal scarcity of irrigation water wherein improved water use efficiency (WUE) of the crop is targeted. Under field conditions, the crop undergoes dynamic changes in near ground or within-canopy microenvironments. This changed microclimatic condition may have an impact on phenological response of the oilseed crop which in turn would affect biomass productivity, economic seed yield and water use efficiency of the crop. Henceforth, quantification of biomass production and its WUE of oilseed Brassica crop is essentially required owing to have better understanding of the crop water requirement under the era of climate change. Following a 2 years field experiment, it was revealed that the changes in leaf area index were explained by about 68e74%. The best fit polynomial third order regression analysis indicated >93% prediction in biomass production as a function of time factor. Improved biomass partitioning into economic sinks was also observed. Small scale change in near ground microenvironment may reduce the prediction of biomass variability to the extent of 3%. The mean ET variations were observed as 2.4, 1.5 and 3.2 mm day_1 during the critical phenological stages. Mean seed yield, biomass WUE and seed yield WUE ranged between 2.71 and 2.87 Mg ha_1, 11.4 and 13.1 g m_2 mm_1 and 19.3 and 22.9 kg ha_1 mm_1 respectively. Variations in both biomass and seed yield water use efficiencies due to small scale change in near ground microclimates were revealed.Not Availabl

Hybrid Seed Production in Cotton

Not AvailableIndia is the pioneer country for commercial cultivation of cotton hybrids which covers more than 50% of the cotton area. Cotton hybrids have 50% higher productivity than varieties. Moreover, hybrids have wider adaptability, high degree of resistance to biotic and abiotic stresses and better fibre quality. Hybrids can be developed with comparatively lesser time frame than straight varieties. The hybrids are highly productive and have uniform fibre quality. Among the major cotton producing countries, India and China are the only two in which hybrid cottons are being cultivated on a large scale. India is the pioneer country in the world for development of cotton hybrid for commercial cultivation