A simple method for indexing Phytophthora and nematode infections in black pepper (Piper nigrum L.)

A simple method for indexing Phytophthora foot rot disease of black pepper (Piper nigrum) caused by the fungns P. capsici and the nematodes Radopholus similis and Meloidogyne incognita was derived. The index is based on foliar yellowing and defoliation which are the predominant aerial symptoms of the disease. &nbsp

Diversity in floral characters of monoecious nutmeg (Myristica fragrans Houtt.)

Floral diversity in monoecious type nutmeg reveals three types of flowers namely; pistillate, staminate and hermaphrodite flowers. The structure of hermaphrodite flowers in nutmeg is reported for the first time. The flowers are borne on the leaf axil, flowering habit of the three types of flowers are seen in cymes as well solitary in the same tree. The gynoecium consists of single ovary with bifid stigma in the pistillate flowers and the androecium of staminate flowers has adnate 7-13 anthers. Intra flower variability is evident in case of hermaphrodite flowers. In hermaphrodite flower the androecium ranges with 1-4 anthers, in the form of fused filament or free filament or both; some anthers are fused with the gynoecium. Besides remnants of the stamen in the developed fruits of hermaphrodite flowers, staminodes are also observed in the flowers. Colour of all the three types of flowers are light creamy yellow, with thick gamosepalous perianth which bursts as bilobed, trilobed, tetralobed and pentalobed lobes during anthesis. Analysis of variance of trees for flower types and floral attributes like flower type, number of anthers, length of anthers, length of filaments and length of ovary are found to be highly significant. High coefficient of variation is recorded for hermaphrodite (183.84) and pistillate (171.71%) flowers. The pollen viability of the hermaphrodite flowers are found less as compared to the staminate flowers. The percentage of pollen viability is 79.74% and 90.77% in hermaphrodite and male flower respectively. In the population studied, the occurrence of hermaphrodite flower in monoecious tree ranged from 0 - 10%

Standardization of soil-less nursery mixture for black pepper (Piper nigrum L.) multiplication using plug-trays

Availability of quality planting material of high yielding varieties is a major production constraint in all black pepper (Piper nigrum L.) growing countries, and hence there is a need for technology that boosts production of quality planting material. An investigation was carried out to study the effect of different combinations of soil-less coir pith based nursery mixtures on rooting and growth of black pepper cuttings in the nursery. Among the different nursery media combinations, coir pith with Trichoderma and vermicompost recorded significantly higher growth parameters. The study confirmed that composted coir pith with vermicompost and Trichoderma is an ideal potting medium for black pepper nursery. In the second experiment, among the single node cuttings with three different maturities (collected from the serpentine method runners), maximum nursery grwoth, was recorded in the terminal portion of the runners (11-15th nodes). Similarly, higher growth parameters were recorded in the cuttings planted with full leaf compared to halfleaf cuttings. The study indicated that the rooted cuttings with full leaf from middle and top portions recorded higher growth parameters. Use of Trichoderma and vermicompost enriched coir pith in black pepper nurseries minimizes chemical fungicides besides Trichoderma that colonizes the root system of seedlings will help in preventing the infection by pathogens in the main field. Since there is no high additional cost involved, the use of Trichoderma enriched coir pith can also be adopted by commercial nurseries. &nbsp

A method for isolation and reverse transcription of high quality RNA from Piper species

A rapid and efficient protocol for isolation of RNA from Piper leaves is described. RNA was extracted from two Piper species namel y, P. nigrum and P. colubrinulI1, using strong denaturing buffer containing guanidinum thiocyanate and polyvinylpyrollidone followed by p recipitation with pre-cooled sodium acetate and extraction with phenol:chloroform : isoamyl alcohol (25:24:1). RNA was precipitated with isopropanol. The extraction procedure reliably yielded high quality RNA suitable for reverse transcription experiments. &nbsp

Screening of rhizobacterial isolates against soft rot disease of ginger (Zingiber officinale Rosc.)

Twenty rhizobacterial cultures including Pseudomonas fluorescens, Enterobacter agglomerans and Bacillus sp. were tested under in vitro and in vivo conditions to evaluate their efficacy in inhibiting Pythium myriotylum and reducing the incidence of soft rot disease in ginger (Zingiber officinale). Under in vitro conditions, 19 of the tested rhizobacterial cultures significantly inhibited P. myriotylum. Evaluation of these cultures under in vivo conditions indicated that seven of the isolates were effective in suppressing the pathogen. Five of the isolates when inoculated along with Glomus sp. (vesicular arbuscular mycorrhizae) also enhanced root development without disease incidence. &nbsp

Screening of black pepper (Piper nigrum L.) germplasm for resistance to foot rot disease caused by Phytophthora capsici Leonian

Studies were conducted at Calicut (Kerala) to locate sources of resistance among 491accessions of cultivars, 691 hybrids, 124 wild accessions and 182 Karimunda and 60Kottanadan selections of black pepper (Piper nigrum) using stem inoculation technique againstfoot rot disease caused by Phytophthora capsici. One hybrid (Acc. 1375), two wild accessions(Accs. 3160 and 3260) and four Kottanadan selections (2466, 2471, 2515 and 2433) werepromising with disease index 1 and no external lesion after inoculation of the pathogenunder greenhouse conditions. &nbsp

Economic viability of large-scale production of the biocontrol agent Trichoderma harzianum Rifai

The economic viability of large scale production of the biocontrol agent Trichoderma harzianumeffective against the soil-borne disease Phytophthora foot rot (caused by  P. capsici)  of blackpepper (Piper nigrum) was studied.  The enterprise was highly profitable for the entrepreneurwith a benefit:cost ratio of 1.84. The investment returned a net present worth of Rs. 2,42,618@ 11% interest rate for 10 years period with an internal rate of return of 121%. &nbsp

High nitrous oxide fluxes from rice indicate the need to manage water for both long- and short-term climate impacts

Global rice cultivation is estimated to account for 2.5% of current anthropogenic warming because of emissions of methane (CH4), a short-lived greenhouse gas. This estimate assumes a widespread prevalence of continuous flooding of most rice fields and hence does not include emissions of nitrous oxide (N2O), a long-lived greenhouse gas. Based on the belief that minimizing CH4 from rice cultivation is always climate beneficial, current mitigation policies promote increased use of intermittent flooding. However, results from five intermittently flooded rice farms across three agroecological regions in India indicate that N2O emissions per hectare can be three times higher (33 kg-N2O⋅ha−1⋅season−1) than the maximum previously reported. Correlations between N2O emissions and management parameters suggest that N2O emissions from rice across the Indian subcontinent might be 30–45 times higher under intensified use of intermittent flooding than under continuous flooding. Our data further indicate that comanagement of water with inorganic nitrogen and/or organic matter inputs can decrease climate impacts caused by greenhouse gas emissions up to 90% and nitrogen management might not be central to N2O reduction. An understanding of climate benefits/drawbacks over time of different flooding regimes because of differences in N2O and CH4 emissions can help select the most climate-friendly water management regimes for a given area. Region-specific studies of rice farming practices that map flooding regimes and measure effects of multiple comanaged variables on N2O and CH4 emissions are necessary to determine and minimize the climate impacts of rice cultivation over both the short term and long term