S. V. Ngachan

Long-term effect of pastures on soil quality in acid soil of North-East India

North-East India is known for its complex, diverse, risk-prone, and fragile hilly ecosystem. Natural resources in terms of soil, water, vegetation, and soil organic carbon (SOC) are much degraded. Effects of long-term perennial grasses maintained at a permanent fodder block of the ICAR Research Complex, Meghalaya, on soil quality were examined after 15 cropping cycles. The aims were (i) to ascertain whether perennial grass primarily maintained as fodder source for ruminants could conserve resources and improve soil quality in the hilly ecosystem of North-East India, and (ii) to select a suitable perennial grass to minimise land degradation, restore SOC, and improve the soil quality. Soil samples were collected in 2007–08 (dry season) from plots of 8 perennial grasses [Setaria sphacelata (setaria), Brachieria rosenesis (congosignal), Thysanolaena maxima (broom), Penicum maximum var. Makunia and var. Hamil (guinea), Pennisetum purpureum (napier), Paspalum conjugalum (paspalam), Arachis pintoi (wild groundnut)] and analysed for physical, chemical, and biological properties. A control plot had no grass cover. Hamil and Makunia produced a large amount of green fodder, while Makunia, paspalam, setaria, and congosignal had greatest root biomass. Relative to the control, soil under perennial grasses showed increases of ~30% SOC, 70% mean weight diameter, 20% available soil water, 40% hydraulic conductivity, 63% infiltration rate, and 10% soil microbial biomass carbon. Among grasses, soil under setaria, congosignal, and Makunia had higher values of these attributes than under other species because of better soil binding through an extensive root system. Improvement of soil physical properties and processes under these grasses, coupled with complete ground cover, reduced soil erosion by ~33% and also signified ecological benefits through C-sequestration. Soil quality management in the fragile ecosystem of North-East India should include permanent pastural grasses, particularly, setaria, congosignal, and Makunia.

Genetic Diversity and Population Structure in Aromatic and Quality Rice (Oryza sativa L.) Landraces from North-Eastern India.

The North-eastern (NE) India, comprising of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, possess diverse array of locally adapted non-Basmati aromatic germplasm. The germplasm collections from this region could serve as valuable resources in breeding for abiotic stress tolerance, grain yield and cooking/eating quality. To utilize such collections, however, breeders need information about the extent and distribution of genetic diversity present within collections. In this study, we report the result of population genetic analysis of 107 aromatic and quality rice accessions collected from different parts of NE India, as well as classified these accessions in the context of a set of structured global rice cultivars. A total of 322 alleles were amplified by 40 simple sequence repeat (SSR) markers with an average of 8.03 alleles per locus. Average gene diversity was 0.67. Population structure analysis revealed that NE Indian aromatic rice can be subdivided into three genetically distinct population clusters: P1, joha rice accessions from Assam, tai rices from Mizoram and those from Sikkim; P2, chakhao rice germplasm from Manipur; and P3, aromatic rice accessions from Nagaland. Pair-wise FST between three groups varied from 0.223 (P1 vs P2) to 0.453 (P2 vs P3). With reference to the global classification of rice cultivars, two major groups (Indica and Japonica) were identified in NE Indian germplasm. The aromatic accessions from Assam, Manipur and Sikkim were assigned to the Indica group, while the accessions from Nagaland exhibited close association with Japonica. The tai accessions of Mizoram along with few chakhao accessions collected from the hill districts of Manipur were identified as admixed. The results highlight the importance of regional genetic studies for understanding diversification of aromatic rice in India. The data also suggest that there is scope for exploiting the genetic diversity of aromatic and quality rice germplasm of NE India for rice improvement.

Crop diversification, crop and energy productivity under raised and sunken beds: results from a seven-year study in a high rainfall organic production system

Low productivity, crop diversification, employment and income are the major constraints of existing production systems of the high-rainfall north-eastern hill region (NEHR) of India. Field experiments were conducted for seven consecutive years to evaluate crop performance, production and energy balance of cropping sequences under raised and sunken bed (RSB) systems in mid-hills (950 m above mean sea level) of subtropical Meghalaya, India. Five vegetable-based cropping sequences on raised beds and six rice-based sequences on sunken beds were tested and compared with rice monocropping (control) under an organic production system. On raised beds, tomato–okra–French bean gave highest rice equivalent yield (REY; 44.7 t ha− 1) followed by carrot–okra–French bean (42.5 t ha− 1). Rice (cv. Shahsarang 1)-pea (cv. Prakash) gave highest REY (17.3 t ha− 1) on sunken beds. Among raised bed sequences, tomato–okra–French bean recorded greatest production efficiency (162 kg ha− 1 day− 1) and carrot–okra–French bean recorded highest land use efficiency (77%). Employment was enhanced by 187% with potato–okra–French bean and 181% with tomato–okra–French bean on raised beds, whereas rice–pea sequence on sunken beds enhanced employment by 62% over monocropping of rice. The energy productivity (energy output/input) was also higher with these cropping sequences. The adoption of RSB land configuration facilitated 244% cropping intensity (gross cultivated area/net cultivated area × 100) compared with 100% in rice monocropping. There was a significant improvement in soil chemical and biological parameters due to continuous organic production under RSB land configuration, indicating potential for organic farming in the subtropical hill ecosystem of India.

IMPROVING PRODUCTIVITY, WATER AND ENERGY USE EFFICIENCY IN LOWLAND RICE ( ORYZA SATIVA ) THROUGH APPROPRIATE ESTABLISHMENT METHODS AND NUTRIENT MANAGEMENT PRACTICES IN THE MID-ALTITUDE OF NORTH-EAST INDIA

Rice is the major staple food crop in the North Eastern Region of India (26.2 million hectare geographical area) and the region has a deficit of 1.40 million tones of rice, mainly due to low productivity (1.72 t ha −1 ). Field experiments were conducted for the first time to evaluate the new techniques of rice cultivation, viz. the system of rice intensification (SRI) and integrated crop management (ICM) along with conventional rice culture (CRC) for improving productivity, water and energy use efficiency during the rainy seasons of 2004–07 at the ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya (950 m msl), India. Three stand establishment methods, viz. SRI, ICM and CRC in main plots, and five nutrient management practices, viz. recommended dose of fertilizers (RDF = 80:26:33 kg NPK ha −1 ), farmyard manure (FYM) 10 t ha −1 , RDF + FYM 5 t ha −1 , 50% RDF + FYM 10 t ha −1 , and a control (no fertilizer and manure) in sub-plots, were tested in a split-plot design; only few meaningful interactions were found. Results showed a higher number of panicles per square metre under CRC and ICM compared with SRI. However, the number of panicles per hill, grains per panicle and the test weight remained higher in the SRI method. In terms of mean grain yield, ICM (4.86 t ha −1 ) and SRI (4.72 t ha) produced 12.8 and 9.6%, respectively, higher grain yield over CRC (4.3 t ha −1 ). Among the nutrient management practices, the application of RDF + FYM 5 t ha −1 (5.0 t ha −1 ) and 50% RDF + FYM 10 t ha −1 (4.87 t ha −1 ) not only produced higher grain yield of rice (23.8 and 20.5%, respectively, higher yield over control) but also maintained higher soil available N, P and organic carbon at harvest compared with other nutrient management practices. Photosynthesis rate and water use efficiency were found to be significantly ( p

Compost Quality Prepared from Locally Available Plant Biomass and their Effect on Rice Productivity under Organic Production System

Low concentrations of native nutrients in soil, especially nitrogen and phosphorus, are a major constraint limiting crop productivity in highly leached acid soils of the subtropical Indian Himalayas. This is coupled with the negligible use of fertilizers and pesticides, which restricts the productivity of field crops. Further, this area has acute shortage of farmyard manure (FYM) and other organic manures. In a 2-year field study (2004-06) the performance of eight different types of composts prepared from rice straw (Oryza sativa), Eupatorium adhenophorum, Lantana camara, and grass/weed mixtures was evaluated and compared with the recommended combinations of NPK (80:60:40 kg/ha) and FYM on productivity of lowland rice (Oryza sativa L) under organic production. Two composting procedures were evaluated. One was the Microbial Enriched Compost (MEC), procedure consisting of mixing plant biomass and cow dung in equal proportion (weight basis) followed by addition of microbial inoculants in a slurry of fresh cow dung, virgin soil and well rotten compost mixed in a ratio of 1:1: 0.5 along with appropriate amount of water. The second was Microbial and Nutrient Fortified Compost (MNFC) consisting of MEC, 2.5% rock phosphate (w/w) and 1% neem cake. Bioinoculums such as cellulose decomposers (Aspergillus terrus, Trichoderma harzianum, T. viride, T. virens), P-solubilizing microbes (Bacillus polymyxa and Pseudomonas striata) and free-living N-fixers (Azotobacter spp) were used as microbial inoculants to hasten the composting and improve the nutritional quality of the composts. The matured composts had higher NPK contents and lower C/N ratio compared to the fresh dry biomass of the substrates (plant materials used for composting) and FYM. The bacterial population in matured rice straw MNFC compost was about five times higher and fungal and actininomycetes population was about 3 times higher than that recorded with decomposed FYM. The study indicated that the significantly (p = 0.05) higher grain yield was recorded with rice straw MNFC compost in both years (4.50 t/ha in 2005 and 4.68 t/ha in 2006) followed by the Eupatorium MNFC compost (4.33 t/ha and 4.56 t/ha). In general MNFC composts recorded significantly higher grain yields compared to MEC composts indicating superiority of nutritional quality of MNFC composts. The nutrient uptake and post harvest soil fertility status were found to be significantly improved due to application of various composts. Composting with locally available biomass results in higher rice crop productivity and in maintenance of soil health of acid soils of Northeastern region of India.

First report of Chilli veinal mottle virus in Naga chilli (Capsicum chinense) in Meghalaya, India

The present study confirms the occurrence of Chilli veinal mottle virus (ChiVMV) under the genus Potyvirus in Naga chilli (Capsicum chinense) in Meghalaya based on mechanical transmission assay, transmission electron microscopy, RT-PCR and sequence analysis. This is the first record of Chivmv in Naga chilli in North-East India.

TILLAGE AND RESIDUE MULCHING EFFECT ON PRODUCTIVITY OF MAIZE ( ZEA MAYS )–TORIA ( BRASSICA CAMPESTRIS ) CROPPING SYSTEM IN FRAGILE ECOSYSTEM OF NORTHEAST INDIAN HIMALAYAS

The north eastern region (NER) of India receives a high amount of rainfall (2450 mm) both in terms of intensity and frequency. Most of the precipitation goes waste because of improper conservation measures and inadequate rainwater harvesting. Growing a second crop during winter ( rabi ) season on hill slopes and uplands without moisture conservation measure is almost impossible. A simple and very low-cost technique of in situ soil moisture conservation in maize ( Zea mays L.)–toria ( Brassica campestris L.) system has been developed using residue of preceding rainy season maize crop and mulching with locally available weed biomass Ambrosia artemisiifolia . Six residue mulching combinations tested were viz. control, Maize stalk cover (MSC), MSC + Ambrosia sp. 5 t/ha, MSC + Ambrosia sp. 10 t/ha, MSC + farmyard manure (FYM) 10 t/ha and MSC + Ambrosia sp. 5 t/ha + poultry manure 5 t/ha under zero tillage (ZT) and conventional tillage (CT) systems. Results showed that in situ residue retention of preceding maize crop along with green biomass of Ambrosia sp., applied before sowing of toria, maintained optimum soil moisture for good growth and higher yield of toria. The soil moisture content was consistently higher under residue mulched plots than that under control. All the residue mulching measures recorded higher crop yield for maize and toria than those observed under residue removal (control). The productivity of toria was enhanced by about 99%, only due to retention of MSC as mulch. Mulching with MSC + Ambrosia sp. 5 t/ha + poultry manure 5 t/ha recorded the highest seed yield of toria (four-year average: 641 kg/ha), which was 228% and 64% higher than no mulching (control) and MSC alone. MSC + FYM 10 t/ha (568.3 t/ha) and MSC + Ambrosia sp. 10 t/ha (517.4 t/ha) were found equally effective and produced significantly higher toria yield than that of control. MSC + Ambrosia mulch 10 t/ha gave the highest net returns and B:C ratio of the maize–toria system. The overall B:C ratios were better under ZT than CT. Thus, the study indicated that the integrated management of crop residues and weed biomass ( Ambrosia sp.) under ZT created favourable soil moisture to support double cropping with high yield in hill eco-system of northeastern Indian Himalayas.

CONTINUOUS APPLICATION OF ORGANIC AMENDMENTS ENHANCES SOIL HEALTH, PRODUCE QUALITY AND SYSTEM PRODUCTIVITY OF VEGETABLE-BASED CROPPING SYSTEMS IN SUBTROPICAL EASTERN HIMALAYAS

SUMMARY The hill ecosystem of Northeastern Himalayas is suitable for organic farming due to negligible use of fertilizer (<12 kg ha −1 ) and agrochemicals, abundance of organic manure, especially plant biomass, and favourable climatic conditions for diverse crops. For successful organic farming, efficient cropping systems and organic amendments are to be identified to sustain soil health on one hand and productivity and enhanced income on the other. The efficacy of three organic amendments, namely, farmyard manure (FYM), vermicompost (VC) and integrated nutrient source (INS; 50% recommended dose of nitrogen (N) through FYM + 50% N through VC) on performance of three-vegetable-based cropping systems, namely, maize + soybean (2:2 intercropping)–tomato, maize + soybean–potato and maize + soybean– French bean was evaluated for five consecutive years (2005–06 to 2009–10) under subtropical climate at Umiam, Meghalaya, India (950 m above sea level). All the organic amendments were applied on N equivalent basis and phosphorus (P) requirement was compensated through rock phosphate. The results revealed that the yield of vegetables, except root vegetables, was maximum with FYM as soil amendment. Total system productivity in terms of maize equivalent yield (MEY) was significantly higher under FYM followed by INS. Pooled analysis revealed that MEY was enhanced by 200 and 191% with continuous application of FYM and INS, respectively, over control (no manure). Maize + soybean–tomato system recorded the highest MEY (28.78 Mg ha −1 ; Mg – megagram) followed by maize + soybean–French bean (24.37 Mg ha−1). INS as organic amendment resulted in maximum improvement in soil organic carbon (SOC), available P and potassium (K), soil microbial biomass carbon and water holding capacity and was similar to those under FYM. The SOC concentration under INS (23.6 g kg−1), FYM (23.3 g kg−1 )a nd VC (22.3 g kg −1 ) after five years of organic farming were 31.0, 29.4 and 23.8% higher than the initial and 26.2, 24.6 and 19.3% higher than those under control, respectively. The quality traits of tomato such as total soluble solids (5%), ascorbic acid (28.6 mg 100 g −1 ) and lycopene content (19.35 mg 100 g −1 ) were higher under FYM application than other amendments. The study indicated that FYM and INS are equally good as organic amendment and their continuous application not only improves soil health but also crop productivity. FYM application was also found to be cost effective as it resulted in a higher benefit: cost ratio (4.4:1) compared to other amendments irrespective of cropping sequences during transition to organic farming.

Complete mitochondrial genome sequence of a phytophagous ladybird beetle, Henosepilachna pusillanima (Mulsant) (Coleoptera: Coccinellidae).

Abstract Ladybird beetles are generally considered as agriculturally beneficial insects, but the ladybird beetles in the coleopteran subfamily Epilachninae are phytophagous and major plant feeding pest species which causes severe economic losses to cucurbitaceous and solanaceous crops. Henosepilachna pusillanima (Mulsant) is one of the important pest species of ladybird beetle. In this report, we sequenced and characterized the complete mitochondrial genome of H. pusillanima. For sequencing of the complete mitochondrial genome, we used the Ion Torrent sequencing platform. The complete circular mitochondrial genome of the H. pusillanima was determined to be 16,216 bp long. There were totally 13 protein coding genes, 22 transfer RNA, 2 ribosomal RNA and a control (A + T-rich) region estimated to be 1690 bp. The gene arrangement and orientations of assembled mitogenome were identical to the reported predatory ladybird beetle Coccinella septempunctata L. This is the first completely sequenced coleopteran mitochondrial genome from the beetle subfamily Epilachninae from India. Data generated in this study will benefit future comparative genomics studies for understanding the evolutionary relationships between predatory and phytophagous coccinellid beetles.

Utility of ITS1 as a molecular tool for reliable identification of Henosepilachna pusillanima and H. septima (Coleoptera: Coccinellidae)

A majority species of the ladybird beetles are generally considered as beneficial insects, but the Coleopteran subfamily Epilachninae has major plant-feeding ladybird beetles. Therefore, these beetles are considered economically most important pests within the beetle groups (Li and Cook 1961). Both grubs and adults of Epilachninae cause serious economic loss to the crops and in some cases posing threat to successful cultivation of crops like potato in India (Ratul and Misra 1979). Within the subfamily Epilachninae, many species of the genus Henosepilachna Li feed on either cucurbitaceous or solanaceous plants (Katakura et al. 1992). Besides causing economic loss to the crops they are also responsible for pollen transfer in cucurbit ecosystem (Das et al. 2009). The taxonomy of the species belonging to the genusHenosepilachna remains confusing because of its wide variation in the external appearance/morphological characters which resulted in the misidentification of species in this genus (Naz et al. 2012). For example in literature,Henosepilachna pusillanima (Mulsant) has been known as H. dodecastigma or even by other names (Katakura 1988). However, H. pusillanima has now been accepted as a synonym of H. dodecastigma (Wiedemann) (Dharmaretnam 2002). The existences of intraspecific variations in these species also complicated the reliable identification process (Dharmaretnam 2002). Both H. septima (Dieke) and H. pusillanima feed on cucurbitaceous plants concurrently and cause severe economic losses in Japan (Nakano and Katakura 1999), India (Mahalya and Jesudasan 1996) and other parts of the world. Interestingly, H. septima superficially resembles H. pusillanima in size and colouration (Kapur 1967). Moreover, H. pusillanima is also morphologically similar to another cucurbit feeder, H. boisduvali (Mulsant) which has similar body