Evaluation of millets for physio-chemical and root morphological traits suitable for resilient farming and nutritional security in Eastern Himalayas.

Introduction: Millets are nutritionally superior and climate-resilient short-duration crops and hold a prominent place in cropping sequences around the world. They have immense potential to grow in a marginal environment due to diverse adaptive mechanisms. Methods: An experiment was conducted in an organic production system in the North Eastern Himalayan foothills of India for 3 consecutive years by evaluating high-yielding varieties (HYVs) of different millets, viz., finger millet, foxtail millet, little millet, barnyard millet, proso millet, and browntop millet, along with local landraces of finger millets (Sikkim-1 and Sikkim-2; Nagaland-1 and Nagaland-2) to identify stable, high-yielding, and nutritionally superior genotypes suited for the region. Results: Among the various millets, finger millet, followed by little millet and foxtail millet, proved their superiority in terms of productivity (ranging between 1.16 and 1.43 Mg ha-1) compared to other millets. Among different varieties of finger millets, cv. VL Mandua 352 recorded the highest average grain yield (1.43 Mg ha-1) followed by local landraces, Nagaland-2 (1.31 Mg ha-1) and Sikkim-1 (1.25 Mg ha-1). Root traits such as total root length, root volume, average diameter of roots, and root surface area were significantly higher in finger millet landraces Nagaland-1, Nagaland-2, and Sikkim-1 compared to the rest of the millet genotypes. The different millets were found to be rich sources of protein as recorded in foxtail millet cv. SiA 3088 (12.3%), proso millet cv. TNAU 145 (11.5%), and finger millet landraces, Sikkim-1 and Nagaland-2 (8.7% each). Finger millet landrace Sikkim-2 recorded the highest omega-6 content (1.16%), followed by barnyard millet cv. VL 207 (1.09%). Barnyard millet cv. VL 207 recorded the highest polyunsaturated fatty acid (PUFA) content (1.23%), followed by foxtail millet cv. SiA 3088 (1.09%). The local finger millet landraces Sikkim-1 and Sikkim-2 recorded the highest levels of histidine (0.41%) and tryptophan (0.12%), respectively. Sikkim-1 and Nagaland-2 recorded the highest level of thiamine (0.32%) compared to the HYVs. Conclusion: These findings indicate that finger millet has great potential in the organic production system of the North Eastern Himalayan Region (NEHR) of India, and apart from HYVs like VL Mandua 352, local landraces, viz., Nagaland-2 and Sikkim-1, should also be promoted for ensuring food and nutritional security in this fragile ecosystem.

Converting primary forests to cultivated lands: Long-term effects on the vertical distribution of soil carbon and biological activity in the foothills of Eastern Himalaya.

The conversion of primary forests to cultivation brings a significant change in soil carbon (C) forms. In the foothills of the Eastern Himalayan Region of India (Manipur), such conversions are prevalent. However, little is known about the response of C forms, particularly in deep soil, to land use conversion in the region. We evaluated changes in soil C forms (total organic, inorganic, and pools) and microbiological properties (up to 1.0 m depth) mediated by C when the 45-year-old forest had been cultivated for 18-25 years. The cultivated land uses were tree-based agroforestry (LAF: legumes, NAF: non-legumes), horticultural fruits (WHF: woody, NHF: non-wood, mainly vegetables), and paddy agriculture system (AUS: upland, ALS: lowlands). Forest conversion significantly (p < 0.05) decreased the total carbon (TC) in the surface soil (0.0-0.15 m) from 4.88 % to 3.04-3.93 % in the tree-based land uses (LAF, NAF, and WHF). TC further declined to 2.05-2.81 % under seasonal crops (NHF, AUS, and ALS). Seasonal crop cultivation also caused a higher decline in microbial biomass carbon, soil enzymes, and carbon pools (active and passive) than the tree-based land use with the soil depth. The vertical distribution of C in the soil profile was inconsistent: organic C (including C pools) decreased, while inorganic C increased. The profile TC stock to a depth of 1.0 m in the forest was 358.8 Mg ha-1, of which 81 % were organic C, and 19 % were inorganic C. In comparison with forest soil, total soil C stocks (organic and inorganic) decreased more (-44.1 to -55.1 %) in seasonal crops than in tree-based (-15.4 to -36.3 %) land uses. The degradation index (DI) also confirmed that seasonal crop cultivation caused a larger decline in surface soil quality (DI: -423 % to -623 %) than tree-based land use (DI: -243 % to -317 %). The topsoil (up to 0.45 m) of seasonal crops was more degraded than that of the subsoil (>0.45 m-1.0 m). Forests converted to seasonal cultivation (upland rice and vegetables) caused higher degradation of soil C forms and overall soil health in the Himalayan foothills of northeastern India. We suggest the promotion of Agroforestry based on legumes (Parkia spp.) and woody fruits (mango/citrus/guava) in the uplands to minimize soil C degradation while ensuring nutritional security in the hill agro-ecosystems of the Indian Himalayas.

Effect of land-use change along altitudinal gradients on soil micronutrients in the mountain ecosystem of Indian (Eastern) Himalaya.

Management of soil micronutrients for better crop production needs a sound understanding of their status and causes of variability. This is more relevant for acid soils of the mountain ecosystem of Eastern Himalaya (Northeast India). We assessed the status, and the effect of land uses along altitudinal gradients (14 to 4090 masl) on soil properties and micronutrient concentrations (DTPA extractable Fe, Mn, Cu, and Zn) across the region. Soils varied widely in micronutrient concentrations: Fe from 0.665 to 257.1 mg kg-1 while Mn, Cu, and Zn from traces to 93.4, 17.1, and 34.2 mg kg-1, respectively. On conversion of evergreen forests (EF) to upland agriculture (Shifting-SC and Settled-SA) and plantation (PH), Mn, Cu, and Zn concentrations decreased significantly from 30.5, 1.74, and 2.13 mg kg-1 to 6.44-17.8, 0.68-0.81, and 1.06-1.42 mg kg-1, respectively. Grassland (GL) and lowland paddy (LP) had comparable Fe, Mn, and Cu concentrations (except Zn). Degradation of EF to scrubland (SL) recorded the lowest Mn (5.91 mg kg-1), Cu (0.59 mg kg-1), and Zn (0.68 mg kg-1) concentrations. Fe concentration was however increased in degraded SL (+ 73%) over EF (48.7 mg kg-1). The distribution of micronutrients among the land uses was inconsistent and followed the order: (i) Fe: SL > PH > LP > EF > GL > SC > SA, (ii) Mn: EF > GL > LP > PH > SC > SA > SL; (iii) Cu: EF > GL > LP > SC > SA = PH > SL; and (iv) Zn: GL > EF > LP > SC > SA > PH > SL. Four micronutrients responded differently and followed a non-linear, 6th-order polynomial trend along the altitudinal gradients (< 500 to 4100 masl). Peak concentrations of Fe, Mn, and Cu were recorded at 1001-2000 m while Zn was recorded at > 4000 masl. The variability (54-64%) in soil micronutrients was mainly controlled by three key soil properties: acidity, clay, and organic carbon contents. Thus, altitude-specific land-use management holds significance in the distribution of available soil micronutrients in hilly ecosystems.

Genetic Variability Based on Tandem Repeat Numbers in a Genomic Locus of 'Candidatus Liberibacter asiaticus' Prevalent in North East India.

The genetic variability of 'Candidatus Liberibacter asiaticus' (CLas) population associated with huanglongbing (HLB) disease of citrus in North Eastern (NE) region of India, a geographically locked region, and home for the diversity of many citrus species was analyzed on the basis of tandem repeat numbers (TRN) in variable CLIBASIA_01645 genomic loci. Fifty-five CLas strains sampled from different groves of NE Hill (NEH) region of India were in single amplicon group, but there was remarkable genetic variability in TRNs. The TRN in HLB-associated CLas strains varied from 0-21 and two novel repeat motifs were also identified. Among the NE population of CLas, TRN5 and TRN9 were most frequent (total frequency of 36.36%) followed by TRN4 (14.55%) and TRN6, TNR7 with a frequency of 12.73% each. Class II type CLas genotypes (5 < TRN ≤ 10) had highest prevalence (frequency of 60.00%) in the samples characterized in present study. Class I (TRN ≤ 5) genotypes were second highest prevalent (29.09%) in the NEH region. Further analysis of genetic diversity parameters using Nei's measure (H value) indicated wide genetic diversity in the CLas strains of NE India (H value of 0.58-0.86). Manipur CLas strains had highest genetic variability (0.86) as compared to Eastern, Southern and Central India. The R10 values (TRN ≤ 10/TRN > 10) of NE CLas population was 10.43 (73/7), higher from other regions of India. Present study conclusively reported the occurrence of high genetic variability in TRN of CLas population in North East Indian citrus groves which have evolved to adapt to the specific ecological niche.

Feather degrading, phytostimulating, and biocontrol potential of native actinobacteria from North Eastern Indian Himalayan Region.

Twelve actinobacterial strains were isolated from tomato rhizospheric soil from Manipur, a state in North East Indian Himalayan Region and screened for keratinolytic and plant growth promoting traits. Nine promising isolates were identified as Streptomyces species using partial 16S rRNA gene sequencing. Among the seven isolates showing chicken feather degradation activity, three keratinolytic strains RCM-SSR-2, -6, and -12 were found to be the most efficient feather degrading strains achieving 90% feather weight loss within 48 h of incubation. They also showed maximum keratinase and soluble peptide production. Strain RCM-SSR-2, -5, -6, -8, and -11 showed positive results for all plant growth promoting traits tested. Maximum indole-3-acetic acid production was exhibited by RCM-SSR-6. Strain RCM-SSR-1, -2, -5, -6, -9, and -11 showed antagonistic activity against three important plant pathogens. Feather hydrolysate of RCM-SSR-6 was also evaluated for in vitro seed germination test using garden pea seeds. Higher concentration of feather protein hydrolysate (3 mg ml-1 ) inhibited shoot and root length of the germinating embryo. However, lower concentration (0.01 mg ml-1 ) of feather protein hydrolysate promoted seed germination. Among the 12 strains, four isolates namely RCM-SSR-1, -2, -5, and -6 were found to be promising as multi-traits plant growth promoting rhizobacteria for development of organic fertilizer, phytostimulator, and biocontrol agents.