Multifarious plant growth promotion by an entomopathogenic fungus Lecanicillium psalliotae.

An entomopathogenic fungus, Lecanicillium psalliotae strain IISR-EPF-02 previously found infectious to cardamom thrips, Sciothrips cardamomi promoted plant growth in cardamom, Elettaria cardamomum. The isolate exhibited direct plant growth promoting traits by production of indole-3-acetic acid and ammonia and by solubilizing inorganic phosphate and zinc. It also showed indirect plant growth promoting traits by producing siderophores and cell wall-degrading enzymes like, α-amylases, cellulases and proteases. In pot culture experiments, application of the fungus at the root zone of cardamom seedlings significantly increased shoot and root length, shoot and root biomass, number of secondary roots and leaves and leaf chlorophyll content compared to untreated plants. This is the first report on the plant growth promoting traits of this fungus. The entomopathogenic and multifarious growth promoting traits of L. psalliotae strain IISR-EPF-02 suggest that it has great potential for exploitation in sustainable agriculture.

Integrated plant nutrient system - with special emphasis on mineral nutriton and biofertilizers for Black pepper and cardamom - A review.

Integrated Plant Nutrition System (IPNS) as a concept and farm management strategy embraces and transcends from single season crop fertilization efforts to planning and management of plant nutrients in crop rotations and farming systems on a long-term basis for enhanced productivity, profitability and sustainability. It is estimated that about two-thirds of the required increase in crop production in developing countries will have to come from yield increases from lands already under cultivation. IPNS enhances soil productivity through a balanced use of soil nutrients, chemical fertilizers, combined with organic sources of plant nutrients, including bio-inoculants and nutrient transfer through agro-forestry systems and has adaptation to farming systems in both irrigated and rainfed agriculture. Horticultural crops, mainly plantation crops, management practices include application of fertilizers and pesticides which become inevitable due to the depletion of soil organic matter and incidence of pests and diseases. The extensive use of chemical fertilizers in these crops deteriorated soil health that in turn affected the productivity. To revitalize soil health and to enhance productivity, it is inexorable to enrich the soil using microorganisms. The lacunae observed here is the lack of exploitation of indigenous microbes having the potential to fix atmospheric nitrogen (N) and to solubilize Phosphorus (P) and Potassium (K). The concept of biofertilizer application appears to be technically simple and financially feasible, but the task of developing biofertilizers with efficient strains in appropriate combinations in a consortia mode is not easier. More than developing consortia, a suitable delivery system to discharge the microbial inoculants warranted much effort. This review focuses on the integrated plant nutrition system incorporating biofertilizer with special emphasis on developing and formulating biofertilizer consortium.

Analysis of the essential oil of large cardamom (Amomum subulatum Roxb.) growing in different agro-climatic zones of Himachal Pradesh, India.

BACKGROUND: The aim of the present study was to investigate variations in the chemical composition of the essential oil from seeds of large cardamom grown at different altitudes in Himachal Pradesh, India. The composition of the essential oil was determined by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). RESULTS: The oil components showed qualitative and quantitative variations in the composition. GC and GC-MS analysis led to the identification of 55 compounds representing 98% of total oil. Major components in the oil were 1,8-cineole, α-terpineol, DL-limonene, nerolidol, 4-terpineol, δ-terpineol, δ-3-carene, ß-myrcene, germacrene D, α-terpinene and longifolenaldehyde. The oil yields obtained were 9.8-19.5 g kg(-1). Cardamom oil from Himachal Pradesh was found to contain new compounds, viz. 4-terpineol, δ-3-carene, trans-sabinene hydrate, 1-phellandrene, α-terpinene, bicyclo-germacrene, isopinocarveol and ledenoxid-II. α-Terpenyl acetate, the major constituent of small cardamom, was also detected in the oil of large cardamom grown in Himachal Pradesh. Application of aroma extract dilution analysis revealed 35 compounds having aroma impact with the flavour dilution factor ranging from 2 to 1024, and 34 of these compounds were identified. The five most intense aromatic components are dl-limonene, 1,8-cineole, ß-myrcene, α-pinene, α-basabolol. This is the first time that the characterisation of odour-active compounds has been carried out on large cardamom. CONCLUSION: The presence of 4-terpineol, δ-3-carene, trans-sabinene hydrate, 1-phellandrene, α-terpinene, 1-terpineol, bicyclogermacrene, isopinocarveol, ledenoxid-II, longifolenaldehyde and α-terpenyl acetate make the aroma of the oil different from large cardamom oil of Sikkim and could offer potential as a new food flavour.

Domestication of cardamom (Elettaria cardamomum) in Western Ghats, India: divergence in productive traits and a shift in major pollinators.

BACKGROUND AND AIMS: Elettaria cardamomum, a highly priced spice, is native to the Western Ghats of South India. Wild populations still occur in isolated patches in their natural habitats; however, much of today's commercial product comes from cultivated sources. There is no information on domestication-related traits of this species; the main objective of this study was to compare wild and cultivated populations of cardamom in terms of vegetative and reproductive features in order to identify domestication syndromes and to examine whether the two populations have developed reproductive barriers. METHODS: Two wild populations and five cultivated plantations were used for the present study. Vegetative and floral traits, flowering phenology, pollination biology and breeding systems of wild and cultivated populations were compared. Effective pollinators amongst floral visitors were identified by confirming pollen transfer as well as by fruit set following their visit to virgin flowers. Manual pollinations were carried out in order to study the breeding systems of the two populations and reproductive barriers, if any, between them. KEY RESULTS: Several productive traits including the number of branches, number of inflorescences, and total number of flowers per clump, number of flowers that open each day, the duration of flowering, the length of the flower and the amount of nectar per flower are significantly greater in cultivated cardamom. The principal pollinators in wild cardamom are solitary bees, Megachile sp. and two species of Amegilla, whereas those in cultivated cardamom are the social bees Apis dorsata, A. cerana and Trigona iridipennis. Both the wild and cultivated populations are self-compatible and there are no reproductive barriers between the two populations. CONCLUSIONS: Domestication in cardamom has brought about significant changes in vegetative and reproductive traits and a shift in effective pollinators from native solitary bees to social bees. The shift in pollinators seems to be due to the availability of a large number of flowers for prolonged periods in cultivated cardamom that can attract and sustain social bees, rather than due to co-evolution of the flower and the pollinator.

Performance of an age series of alnus-cardamom plantations in the Sikkim Himalaya: productivity, energetics and efficiencies.

Biomass, net primary productivity, energetics and energy efficiencies were estimated in an age series of Alnus-cardamom plantations in the eastern Himalaya. The impact of stand age (5, 10, 15, 20, 30 and 40 years) on the performance of mixtures of N2-fixing (Alnus nepalensis) and non-N2-fixing (large cardamom) plants was studied. Large cardamom (Amomum subulatum) is the most important perennial cash crop in the region and is cultivated predominantly under Alnus trees. Net primary productivity was lowest (7 t ha(-1) per year) in the 40-year-old stand and was more than three times higher (22 t ha(-1) per year) in the 15-year-old stand. Agronomic yield of large cardamom peaked between 15 and 20 years of age. Cardamom productivity doubled from the 5- to the 15-year-old stand, and then decreased with plantation age to reach a minimum in the 40-year-old stand. Performance of cardamom in association of N2-fixing Alnus remained beneficial until 20 years of age. Annual net energy fixation was highest (444 x 10(6) kJ ha(-1) per year) in the 15-year-old stand, being 1.4 times that of the 5-year-old stand and 2.9-times that of the 40-year-old stand. Inverse relationships of production efficiency, energy conversion efficiency and energy utilized in N2-fixation against stand age, and a positive relationship between production efficiency and energy conversion efficiency suggest that the younger plantations are more productive. The Alnus-cardamom plantation system will be sustainable by adopting a rotational cycle of 15 to 20 years.

Performance of an age series of Alnus-cardamom plantations in the Sikkim Himalaya: nutrient dynamics.

Nutrient cycling, nutrient use efficiency and nitrogen fixation in an age series of Alnus-cardamom plantations were studied in the eastern Himalaya. The impact of stand age (5, 10, 15, 20, 30 and 40 years) on the nutrient dynamics of mixtures of N2-fixing (Alnus nepalensis) and non-N2-fixing (large cardamom) plants was assessed. Foliar nutrient concentrations of Alnus decreased with advancing age groups of plantations and showed an inverse relationship with stand age. Annual N fixation increased from the 5-year-old stand (52 kg ha(-1)), peaking in the 15-year-old stand (155 kg ha(-1)) and then decreased with increasing plantation age. Nitrogen and phosphorus uptake was lowest in the 40-year-old stand, and highest in the 15- and 5-year-old stand, respectively. Nutrient storage in understorey cardamom was very high: up to 31 % N and 59 % P of the stand total in the 15-year-old stand. Nutrient use efficiency was higher (with faster turnover times) in younger stands and decreased (with slower turnover times) in older plantations. Nitrogen retranslocation showed a strong positive relationship with stand age, while that of P was inversely related to stand age. Nutrient standing stock, uptake and return were also highest in the 15-year-old stand. Nitrogen and P cycling in Alnus-cardamom plantations was functionally balanced. Nutrient cycling and dynamics indicated that Alnus-cardamom plantations performed sustainably up to 15-20 years. The management practice should be altered to incorporate replantation after this age.