Different Agro-climatic Zones Of India Research Articles

Agroforestry Site Suitability for Wasteland Greening - A case study of selected districts of various agroclimatic zones

Agroforestry Site Suitability for Wasteland Greening - A case study of selected districts of various agroclimatic zones

Application of ESACCI SM product-assimilated to a statistical model to assess the drought propagation for different Agro-Climatic zones of India using copula

Meteorological drought precedes the agricultural drought and studying the propagation time from meteorological to agricultural drought can substantially reduce agricultural losses. To find this propagation time between the meteorological and agricultural drought, this study analyzed the copula-based conditional probability between the Standardized Precipitation Index at 12 timescales (SPI-1 to12, meteorological drought) and Standardized Soil Moisture Index at 1 month timescale (SSI-1, agricultural drought), over the fifteen Agro-Climatic Zones (ACZs) of India. SSI is computed using a total column Soil Moisture (SM) derived from ESACCI SM using the Statistical Soil Moisture Profile (SSMP) model. The SSMP-based ESACCI SM is positively correlated (Correlation Coefficient of 0.871) with ERA5 Land SM. To compute the conditional probability, three copulas namely Frank, Clayton, and Gumbel copulas are fitted between SPI-1 to 12 and SSI-1. The Goodness of Fit analysis showed the dominance of the Gumbel copula among the Clayton, Frank, and Gumbel copulas. Gumbel copula completely dominated the SPI timescales of 1–3 and 11–12 whereas Clayton copula was relatively favored for SPI timescales of 4–10. The propagation time results revealed that the monsoon season (JAS) consistently exhibits the highest propagation time, averaging around 10 months followed by summer (AMJ, 7 months), spring (JFM, 4 months), and winter (OND, 2–3 months) seasons. The Mann-Kendall trend test revealed that the same season can have different trends in different ACZs and vice versa, underlining the localized and season-specific strategies for drought management, considering each ACZ's unique environmental, agricultural, and socio-economic conditions in each zone. Overall, this study showcases the capability of remote sensing and copula-based statistical models, in understanding meteorological to agricultural drought propagation. It also highlights the efficiency of statistical models in deriving total column SM from surface SM.

Identification of bacterial endosymbionts in rice weevil, Sitophilus oryzae Linnaeus (Coleoptera: Curculionidae) populations of North India

Aim: The present study was undertaken to screen the most commonly occurring endosymbionts in S. oryzae populations from varied geographical regions of North India. Methodology: The six most common endosymbionts (Wolbachia, Arsenophonus, Spiroplasma, Rickettsia, Cardinium and Hamiltonella) were screened in 15 different populations of S. oryzae, representing five different agro-climatic zones of India. For this, the samples of S. oryzae were collected and identified using taxonomic keys and through PCR amplification of the COI gene followed by Sanger sequencing and comparison of obtained sequences with the NCBI database. Thereafter, the screening of endosymbionts was performed using 16S rRNA gene-specific primers for the respective endosymbionts. Results: The results showed the presence of Wolbachia and Spiroplasma in all 15 populations with infection rates of 100 and 85 per cent, respectively. Arsenophonus was detected in only 12 populations with 60 per cent infection rate. Concurrent infections of Wolbachia, Arsenophonus and Spiroplasma within the same individuals of S. oryzae were also detected. However, no infections of Cardinium, Rickettsia and Hamiltonella were found. Interpretation: Thus, it can be inferred that Wolbachia, Spiroplasma and Arsenophonus are the most common endosymbionts which can be exploited for the development of better management strategies against S. oryzae. Key words: 16S rRNA, Co-infection, Endosymbionts, Rice weevil, Sitophilus oryzae

Weed management strategies in elephant foot yam (<i>Amorphophallus paeoniifolius</i>) under different agro environments in India

In elephant foot yam [Amorphophallus paeoniifolius (Dennst.) Nicolson], weeds are the major constraints cause yield reduction up to 100% due to its very slow initial sprouting, establishment and plant growth. Information on proper weed management in elephant foot yam in India is limited as its commercial cultivation started very recently. For arriving at suitable and better weed control, field experiments were conducted for 3 growing seasons (2019 to 2021) at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, Kerala with 8 treatments in 6 different agro-climatic zones of India. The treatments included a combination of pre emergence (PE) and post emergence (POE) herbicides, PE followed by hand weeding (HW), intercropping followed by POE, HW with POE, POE alone, and weed control ground cover cloth mulch (WCGCC), three HW, and a weedy check were included for comparison. Weed flora was dominated by broad-leaf weeds, Digera arvensis (L.), Commelina benghalensis (L.); grasses, Pennisetum pedicellatum Trin., Cynodon dactylon (L.) pers.; and the sedge, Cyperus rotundus (L.), in most of the locations. Pooled analysis of data collected over different locations indicated that the lower mean weed biomass (21.24 g/m) and higher mean corm yield (35.13 t/ha), higher mean net income (`0.326 million/ha) were recorded with weed control ground cover mulch and higher mean B:C ratio (2.39) by application of post emergence herbicide at 30, 60 and 90 days after planting (DAP).

Intra-specific pharmacognostic biochemical screening of various populations of Clitoria ternatea L. using liquid chromatography/tandem mass spectrometry product ion scanning (LC-MS2 PIS)

Purpose of the researchWhile many inferences have been made about the low degree of genetic variation among intra specific populations of Clitoria ternatea L. (CT), pharmacognostic biochemical investigations using tandem mass spectrometry have never been conducted. Methanol leaf extract of Clitoria ternatea L., populations collected from 13 different agro-climatic zones of India was assessed for identification and characterization of targeted nootropic metabolites, using liquid chromatography tandem mass spectrometry product ion scanning (LC-MS2 PIS). Based on the RI values derived from LC-MS2 (PIS) superior population(s), in terms of the presence of the presence of nootropic metabolites, were identified. The intra-specific correlation among different populations, was analyzed through PCA (principal component analysis), scree plot, correlation matrix and hierarchical cluster analysis. Principal resultsThe targeted mass spectrum obtained by tandem mass spectrometric analysis revealed the presence of acetylcholine, choline, caffeic acid, gallic acid, ferulic acid, kaempferol and D-L valine mass fragments in the leaf of CT. These mass groups are belonging to four classes viz., phenols, flavonoids, neurotransmitters and amino acids. Based on the high degree of relative intensities of targeted nootropic metabolites, the Odisha population, collected from Cuttack, outperformed the rest of twelve populations. Correlation matrix data also revealed that populations habituated in similar climatic conditions show significant correlation with each other. Hierarchical cluster analysis classified the 13 populations in two groups. The first group contained 11 populations and the second group is restrained into two populations; one from Cuttack, Odisha and second one from Udaipur, Rajasthan. Major conclusionThis is the first report to identify the superior population of Clitoria ternatea L. across India, through multivariate statistical analysis of LC-MS2(PIS) for gallic acid, ferulic acid, caffeic acid, kaempferol, D-L-valine, acetylcholine, and choline. Even though earlier studies reported an enhancement of acetylcholine content in the central nervous system. The present work may explain that the plant is a producer of acetylcholine and choline itself so it can directly affect the memory and cognition of the brain. Simultaneously, the study confirms the presence of abovementioned seven nootropic metabolites in the leaf of CT. The Odisha population (collected from Cuttack) transcends over all other 12 populations, with highest RI values of seven nootropic metabolites. According to hierarchical cluster analysis, two populations, viz., the one collected from Cuttack, Odisha and the other collected from Udaipur, Rajasthan were distantly clustered from other eleven populations. Hence, both these populations should be given priority for pharmaceutical supply and value chain management systems.

Protein profiling and physico-chemical properties of Acacia nilotica Linn. gum exudates collected from different agro-climatic zones in India

Protein profiling and physico-chemical properties of Acacia nilotica Linn. gum exudates collected from different agro-climatic zones in India

Field-evolved resistance and mechanisms in Bemisia tabaci Asia I to a novel pyropene insecticide, afidopyropen, in India

The cotton whitefly, Bemisia tabaci (Gennadius) is a devastating polyphagous insect pest worldwide and has been shown to be resistant to insecticides in most chemical classes. The newly commercialized pyropene insecticide afidopyropen provided a new tool to control B. tabaci because of high selectivity and its novel mode of action. This study aimed to evaluate the susceptibility of B. tabaci Asia I from ten provinces of India to afidopyropen and other commonly used insecticides. Most field-collected populations were susceptible to afidopyropen, with LC50 values varying from 4.37 to 16.62 mg L−1. However, four field populations (W-MH, K-UP, M-WB and L-PN) exhibited moderate levels of resistance (28.53, 19.09, 35.27 and 30.81-fold, respectively), but no cross-resistance to cyantraniliprole and pymetrozine. Diethyl maleate (DEM) significantly restored the susceptibility of W-MH, M-WB and L-PN strains of B. tabaci to afidopyropen, whereas piperonyl butoxide (PBO) significantly inhibited afidopyropen resistance in K-UP, M-WB and L-PN populations. The activities of glutathione S-transferase (GST) and P450 monooxygenase increased in the afidopyropen-resistant field strains, while esterase activity did not change significantly. The present study showed a regional variation in afidopyropen toxicities among B. tabaci Asia I populations from different agro-climatic zones of India, which suggests a potential risk of afidopyropen resistance development. Metabolic detoxification mediated by GST and P450 monooxygenase was associated with afidopyropen resistance in B. tabaci Asia I.

Biomass Production and Carbon Sequestration Potential of Different Agroforestry Systems in India: A Critical Review

Agroforestry systems (AFS) and practices followed in India are highly diverse due to varied climatic conditions ranging from temperate to humid tropics. The estimated area under AFS in India is 13.75 million ha with the highest concentration being in the states of Uttar Pradesh (1.86 million ha), followed by Maharashtra (1.61 million ha), Rajasthan (1.55 million ha) and Andhra Pradesh (1.17 million ha). There are many forms of agroforestry practice in India ranging from intensified simple systems of monoculture, such as block plantations and boundary planting, to far more diverse and complex systems, such as home gardens. As a result, the biomass production and carbon sequestration potential of AFS are highly variable across different agro-climatic zones of India. Studies pertaining to the assessment of biomass and carbon storage in different agroforestry systems in the Indian sub-continent are scanty and most of these studies have reported region and system specific carbon stocks. However, while biomass and carbon stock data from different AFS at national scale has been scanty hitherto, such information is essential for national accounting, reporting of C sinks and sources, as well as for realizing the benefits of carbon credit to farmers engaged in tree-based production activities. Therefore, the objective of this study was to collate and synthesize the existing information on biomass carbon and SOC stocks associated with agroforestry practices across agro-climatic zones of India. The results revealed considerable variation in biomass and carbon stocks among AFS, as well as between different agro-climatic zones. Higher total biomass (>200 Mg ha−1) was observed in the humid tropics of India which are prevalent in southern and northeastern regions, while lower total biomass (<50 Mg ha−1) was reported from Indo-Gangetic, western and central India. Total biomass carbon varied in the range of 1.84 to 131 Mg ha−1 in the agrihorticulture systems of western and central India and the coffee agroforests of southern peninsular India. Similarly, soil organic carbon (SOC) ranged between 12.26–170.43 Mg ha−1, with the highest SOC in the coffee agroforests of southern India and the lowest in the agrisilviculture systems of western India. The AFS which recorded relatively higher SOC included plantation crop-based practices of southern, eastern and northeastern India, followed by the agrihorticulture and agrisilviculture systems of the northern Himalayas. The meta-analysis indicated that the growth and nature of different agroforestry tree species is the key factor affecting the carbon storage capacity of an agroforestry system. The baseline data obtained across various regions could be useful for devising policies on carbon trading or financing for agroforestry.

Suitability of invasive species for briquette production: Lantana camara and Prosopis juliflora

Study on production of briquettes from two invasive forest weeds, i.e., Lantana camara and Prosopis juliflora was carried out. The experiments were carried out using a 70 mm industrial briquetting unit. The optimum moisture content for briquetting was found around 10–12%. Lantana camara and Prosopis juliflora biomass briquettes were found to have high density (1.1 g cm-3). In this study, fuel properties (proximate and ultimate analysis), combustion characteristics and ash elemental composition of Lantana camara and Prosopis juliflora biomass were investigated. Both the species are found to have less ash content. The emphasis was given to these species because of the huge biomass they produce. These species are widely present in different agro-climatic zones of India and can play a major role in future bioenergy schemes.

Assessment of genetic diversity of ninety-one bottle gourd [Lagenaria siceraria (Mol.) Standl.] genotypes from fourteen different agro-climatic zones of India using agro-morphological traits and SSR markers.

The evaluation of the magnitude of genetic diversity present in the germplasm collection is prerequisite for bottle gourd improvement programme. The characterization of the diversity pattern of Indian bottle gourd accessions will facilitate the optimal use of genetic resources for breeding improved cultivars. In the present study, the magnitude of genetic diversity was evaluated in ninety-one genotypes of bottle gourd collected across fourteen different agro-climatic zones of India. Significant variations were observed for all the studied ten quantitative and nine qualitative traits. The ninety-one genotypes were grouped into nine clusters based on cluster analysis of morphological characteristics. Eigen value from principal component analysis depicted first seven quantitative traits accounted for more than 97.5 cumulative percent of the total variations. The first two components accounted for 50 cumulative percent of the total variation, which signifies a high degree of correlation between the analyzed traits. Molecular diversity with the 40 SSR markers screened revealed 11 polymorphic markers in the genotypes studied. Population structure analysis divulged five populations, conforming to the Principal Coordinate Analysis. Molecular analysis revealed genetically diverse genotypes along with the morphologically divergent genotypes from the quantitative traits and highest inter-cluster distance would be the most appropriate parents for exploiting heterosis. The results of this study will facilitate the optimal use of genetic resources for breeding improved cultivars of bottle gourd and the adoption of the identified superior genotypes directly by the breeders.

Pyramiding of genes for grain protein content, grain quality, and rust resistance in eleven Indian bread wheat cultivars: a multi-institutional effort.

The online version contains supplementary material available at 10.1007/s11032-022-01277-w.

Impact of climate change on Helicoverpa armigera voltinism in different Agro-Climatic Zones of India

The Gram pod borer, Helicoverpa armigera (Noctuidae: Lepidoptera) is a cosmopolitan agricultural insect pest that prefers to feed on plant’s protein biomolecules. Out of different density-independent factors, surface air temperature majorly affects the incidence and damage of the H. armigera on the crops. Early prediction of H. armigera generations (voltinism) in future climate years perhaps prevent additional damage in various crops and improve the farmers preparedness. In this study, future climate data that is temperature obtained for eleven Agro-Climatic Zones (ACZs) of India under four Representative Concentration Pathways (RCPs) scenarios in different climate years (2010, 2030, 2050, 2070, 2090) using weather file generator MarkSim web application. The accumulation of Growing Degree-days (GDD) by H. armigera at eleven ACZs in each climate year under different RCP scenarios was estimated using temperature data. The mean surface air temperature is predicted to 0.51 °C, 1.03 °C, 1.57 °C and 2.1 °C in climate years 2030, 2050, 2070 and 2090, which escalated annual H. armigera Gen. to 12.88, 13.33, 13.79 and 14.23, respectively over the baseline climate year 2010. Likewise, under RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5 scenarios H. armigera Gen. is predicted to 12.86, 13.29, 13.23 and 13.97 per annum with mean surface air temperatures 27.4 °C, 27.92 °C, 27.86 °C and 28.72 °C, respectively. The Eastern Coastal Plains and Hills Zone (ACZ 11) across climate years and RCPs has experienced a considerable increase in mean surface air temperature minimum (25.22 °C) and maximum (34.61 °C), which likely favor the GDD accumulation (6319.91) and the Genrations (14.97) in H. armigera. Therefore, the Eastern Coastal Plains and Hills Zone of India could be identified as H. armigera risk zone in near future. The present predictions in various ACZs of India may be significant in planning H. armigera management.

Phenotypic screening of cultivated and wild okra germplasm against yellow vein mosaic and enation leaf curl diseases of okra in India

Okra yellow vein mosaic (OYVMD) and enation leaf curl diseases (OELCuD) caused by whitefly (Bemisia tabaci) transmitted begomoviruses are important constraint for improvement and production okra in India. Okra germplasms consists of 178 cultivated/advanced lines (147 Advances okra lines + 31 popular varieties) and 146 accessions from 14 wild species originally collected from different national institutes located at different agro-climatic zones of India were evaluated for their response against OYVMD and OELCuD. The resistance levels both cultivated and wild species were assessed by visual scoring of symptoms in the field under natural conditions for two consecutive years in 2015 and 2016. None of the cultivated genotypes and wild species tested was found to be disease free except Abelmoschus enbeepeegeearnse, however, considerable variation in responses against OYVMD and OELCuD was observed among the genotypes. Of the 178 cultivated/advanced lines screened against OYVMD and OELCuD, seven genotypes showed highly resistant, one resistant, 2 moderately resistant and 146 accessions from 14 wild species, 17 accessions were showed highly resistant reaction, one accession resistant, 5 accessions moderately resistant for OYVMD. Similarly, for OELCuD, fifty-two okra genotypes showed highly resistant, three moderately resistant in cultivated/advanced lines and 125 accessions were found to be highly resistant, two resistant and three moderately resistant in wild accessions. The resistance cultivated/advanced lines could be used directly as varieties to manage OYVMD and OELCuD after adaption to various agro-climatic regions. The resistance in wild accessions could be used in future breeding programmes to develop okra cultivars resistant against both OYVMD and OELCuD.

Large-scale Characterization for Management and Utilization of Indian National Genebank Collections

Globally, plant genetic resources (PGR) are the key biological resources having great potential to meet the challenges of food and nutritional security. ICAR-National Bureau of Plant Genetic Resources (NBPGR) has been working with a network of 10 regional stations located in different agro-climatic zones of India for the management of genetic resources. The linkages established with CGIAR centres, national crop-based institutes and state agricultural universities are the backbones of PGR utilization. NBPGR characterizes and evaluates germplasm conserved in the Indian national genebank for different traits and provides material to breeders. The effective utilization of PGR in crop improvement programmes depends mainly on their systematic characterization and evaluation, and identification of potentially useful germplasm. To date, we have characterized more than 2.35 lakh accessions of different agri-horticultural crops and developed core collections for the effective management of a large number of accessions. Presently, our focus is on the large-scale characterization of entire germplasm conserved in the Indian National Genebank and detailed evaluation of prioritized crops; identification of reference sets and core sets for enhanced utilization.

Studying the effect of morphotype and harvest season on yield and quality of Indian genotypes of Centella asiatica: A potential medicinal herb cum underutilized green leafy vegetable

Centella asiatica (L.) Urban commonly known as Gotukola is an important medicinal herb cum nutrient rich green leafy vegetable. The present investigation was undertaken at ICAR-Indian Institute of Horticultural Research, Bengaluru to evaluate thirteen accessions of Centella asiatica collected from different agroclimatic zones of India viz., Northern, North eastern and Southern India for studying the effect of morphotype and harvest season on biomass yield and secondary metabolite content. The study was conducted for two consecutive years (2019 and 2020) for two seasons (March and July). Observations for mature leaf size (4 and 8 month after planting) in the studied genotypes depicted the presence of small leaved (1–20 cm2) and broad-leaved accessions (>20 cm2) which differed significantly with respect to fresh biomass yield and secondary metabolite content. Accessions, IIHR-CA-17 and IIHR-CA-18 recorded highest mean fresh biomass yield of 13.95 t and 13.11 t ha−1year−1 and were on par with each other. Both these accessions can be recommended for the leafy vegetable type, whereas accessions, IIHR-CA-13 and IIHR-CA-23 recorded the highest mean total triterpenoid content of 5.07% and 5.03% during 2019 and 6.88% and 6.69% during 2020, respectively showing their promising potential as medicinal types. Pearson's correlation studies showed that the leaf size and asiaticoside content is significantly negatively correlated inferring that the small leaved accessions reported higher secondary metabolite content as compared to the broad-leaved accessions. The study also showed that coinciding harvest with the summer season (March) under Bengaluru conditions (temperature and relative humidity ranges from 33 to 35 °C and 35–38%, respectively) recorded higher biomass yield and high retention of bioactive content. Thus, the study concluded that under Indian conditions, the selection of small leaved genotypes and harvesting during summer months will be beneficial for the farmers as well as herbal industries for obtaining higher yield.

Genetic variability, character association and path analysis of oil yield and its component characters in Cymbopogon sp.

Seeking an opportunity for genetic improvement in aromatic grasses lead to an explorative study on the aspects of genetic variability, character association and path analysis between essential oil yield/plot and its contributing traits in twenty five genotypes of Cymbopogon sp. collected from different agro-climatic zones of India, grown in RBD with three replicates. Highly significant differences between genotypes were recorded for the traits that were brought under study. High genotypic and phenotypic coefficients of variation coupled with high heritability and moderate to high genetic advance over mean were recorded in geraniol content, citral content and geranyl acetate content indicating predominance of additive gene effects controlling these traits. Correlation and path analysis revealed that oil content, herb yield/plot and geranyl acetate content are overriding traits among all other growth and yield parameters, therefore more emphasis should be laid upon them while designing selection indices for improvement of essential oil yield.

Trichovariability in rhizosphere soil samples and their biocontrol potential against downy mildew pathogen in pearl millet

The present work is aimed to examine the genetic variability and the distribution pattern of beneficial Trichoderma spp. isolated from rhizosphere samples and their mode of action in improving the plant health. A total of 131 suspected fungi were isolated from the rhizospheric soil and 91 isolates were confirmed as Trichoderma spp. T. asperellum and T. harzianum were found high in the frequency of occurrence. Genetic diversity analysis using RAPD and ISSR revealed the diverse distribution pattern of Trichoderma spp. indicating their capability to adapt to broad agroclimatic conditions. Analysis of genetic diversity using molecular markers revealed intra-species diversity of isolated Trichoderma spp. The frequency of pearl millet (PM) root colonization by Trichoderma spp. was found to be 100%. However, they showed varied results for indole acetic acid, siderophore, phosphate solubilization, β-1,3-glucanase, chitinase, cellulase, lipase, and protease activity. Downy mildew disease protection studies revealed a strong involvement of Trichoderma spp. in direct suppression of the pathogen (mean 37.41) in the rhizosphere followed by inducing systemic resistance. Our findings highlights the probable distribution and diversity profile of Trichoderma spp. as well as narrate the possible utilization of Trichoderma spp. as microbial fungicides in PM cultivation across different agroclimatic zones of India.

Estimation of evapotranspiration from a suite of geostationary satellites

ABSTRACT Multi-spectral and diurnal meteorological data from optical-thermal observations of Indian Geostationary satellites were used to estimate country-scale evapotranspiration (ET). In this study radiation and vegetation products from a suite of Indian geostationary satellites, Kalpana-1 (K-1) and Indian National SATellite (INSAT) 3A Charged Couple Detector (CCD), were used. ET was derived as a function of net available energy and evaporative fraction within a single-source energy balance framework. The scaling function for albedo, net radiation and soil heat flux were developed with ground measured data from twenty-three Agro-Met Station (AMS) installed in different agro-climatic zones of India. These scaling functions were applied on the satellite data to derive intermediate inputs for surface energy balance. Further, evaporative fraction was derived from Priestley-Taylor parameter (φ) and day-time net available energy. On regional scale, pixel-by-pixel dynamic φi was computed from upper (φ max) and lower (φ min) limits of warm and wet edges of thermal inertia-Normalized Difference Vegetation Index (NDVI) triangle. Here, thermal inertia was represented by morning rise in surface brightness temperature (ΔT) between 02:30 and 06:30 Greenwich Mean Time (GMT). The dynamic φi with upper and lower limits were computed using ΔT – NDVI triangle. The derived net radiation was validated with AMS measured net radiation at seven agro-climatic zone of India showed Root mean Square Error (RMSE) between 37 and 87 W m−2. The estimated ET was validated at six agricultural and five natural grassland and wetland vegetation sites with AMS measured ET for a year. The RMSE of 10 days ET sum were varying from 7.50 to 17.70 mm for agricultural and for natural vegetation sites it varies from 8.60 to 13.10 mm. The errors variation among all site is depending on the sub-pixel heterogeneity and difference in K-1 and AMS footprints. The ET sum over agricultural kharif (June to October) and rabi (November to April) season also able distinguish normal and drought year. This study provides a robust methodology for generating near real time ET at country scale from Indian Space Research Organisation (ISRO’s) present and future high-resolution geostationary satellites over India.

Agro-climatic zone-based identification of elite Terminalia arjuna accessions concerning to arjunolic acid production

Man has been dependent on vegetation in different forms since antiquity. Plants and trees have been used in the form of medications since the old times. Although the use of plant parts in the form of medicine has been less than that of the plants, therefore today it is necessary to explore some such medicinal trees. Among these, one of these trees is Arjun, whose bark is described also in Ayurveda due to its divine medicinal properties in heart diseases. The present study based on the isolation and analysis of the Phyto-constituents of the stem bark extract of Terminalia arjuna member to the family Combretaceae collected from different agro-climatic zones of India. The samples were subjected to quantitative phytochemical analysis i.e., arjunolic acid, screening by implementing the standard procedure. Observation has shown the presence of arjunolic acid in the stem bark extracts in different fractions obtained by the use of various organic solvents. Therefore, the bark extracts of the chosen plants may function as a good source of components of useful drugs for cardiovascular disorders and may also be used for the preparation of other pharmaceutical products.

Identification of new resistant sources against downy mildew disease from a selected set of cucumber germplasm and its wild relatives

This study was undertaken to identify new sources of resistance against downy mildew of cucumber caused by Pseudoperonospora cubensis [(Berk. and Cart.) Rostow]. Pot experiments were conducted with 16 accessions each of Cucumis sativus and C. hardwickii during the years 2017 and 2018 using 12 isolates of P. cubensis representing different agroclimatic zones of India. The accession, IC331627 from Dehradun, Uttarakhand showed plant disease index (PDI) ranging from 5.55-20.35 per cent with an average PDI of 11.56 and 11.87 per cent during the years, 2017 and 2018, respectively. Hence, IC331627 was identified to be resistant against the five isolates of P. cubesis (Pc12, Pc17, Pc19, Pc21 and Pc24) and moderately resistant against one isolate (Pc22). This resistant accession C. hardwickii (IC331627) could be utilized to develop mapping population to map genomic regions conferring the resistance to downy mildew in cucumber.