Studies on Management of Chromium(VI) – Contaminated Industrial Waste Effluent using Hydrous Titanium Oxide (HTO)

The anion exchange behaviour of hydrous titanium oxide(HTO) has been exploited for the management of industrialwaste effluents contaminated with chromium(VI). Theadsorption of chromium(VI) by HTO (74.0–140.0 micron) in thepH range 0.5–8.0 has been studied. It is found that theadsorption of chromium(VI) by HTO is at a maximum in the pHrange 1.5–2.0. The interference of diverse foreign ionssuch as nitrate, chloride, sulfate, phosphate, calcium,magnesium, nickel, iron(III), barium etc. on the adsorptionof chromium(VI) by HTO at optimum pH has been investigatedby a batch-operation technique. Break-through capacity,adsorption and elution of chromium(VI) using HTO have beenstudied. It is found that HTO could be reused as anadsorbent for chromium(VI). Finally, chromium(VI) wasrecovered as insoluble chromate compound from waste effluentof Hindustan Motor Limited (HML) of Hooghly, West Bengal, India.     

Identification and Characterization of Slow Rusting Components in Pea (Pisum sativum L.)

Three hundred and forty five accessions of pea of diverse origin, height, leaf types and disease reaction were screened for rust disease severity and area under disease progress curve (AUDPC). The frequency of slow rusting types in the tall, dwarf, early and late groups appeared comparable. Of the 345 accessions, forty-four genotypes were evaluated for disease intensity, which was converted into AUDPC, number of pustules/leaf and pustule size. Wide range of variation was found for these traits. The slow rusting attribute of 16 genotypes was further confirmed by testing these under unprotected (inoculated) and protected (fungicidal spray) conditions for two successive years for disease intensity by assessing the AUDPC, seed yield/plot, and 100-seed weight. The fast rusting genotypes exhibited lower AUDPC, accompanied with increased seed yield and seed weight when grown under the protected condition, as compared to those raised under the unprotected condition. The genotypes Pant P 11, FC 1, HUDP 16, JPBB 3 and HUP 14 appeared as slow rusting genotypes.     

Seasonal changes in microbial biomass in soils cropped with palmarosa (Cymbopogon martinii L.) and Japanese mint (Mentha arvensis L.) in subtropical India

Changes in microbial C, N, and P were investigated for 1 year in two soils with similar physicochemical properties but supporting different crops under subtropical conditions. One was cropped with palmarosa (Cymbopogon martinii L.) and the other with Japanese mint (Mentha arvensis L.). Both the season and the type of cropping had a significant influence on changes in the soil microbial biomass. In general, soil microbial biomass C, N, and P were highest in summer months and lowest in midwinter. Soil microbial biomass levels and microbial C:N and C:P ratios were higher and N:P ratios lower under palmarosa soil than under mint.     

Helminthosporium leaf blight resistance and agronomic performance of wheat genotypes across warm regions of South Asia

Helminthosporium leaf blight (HLB) is the most important disease constraint to wheat (Triticum aestivum L.) cultivation in the eastern Gangetic Plains of South Asia. A Helminthosporium Monitoring Nursery (HMN) including potential adapted and exotic sources of HLB resistance was developed in Bangladesh, India and Nepal to assess the stability of genetic resistance across locations. The 8th, 9th and 10th HMN assessed the HLB resistance and agronomic traits of 17 wheat genotypes across 20 environments of Bangladesh, India and Nepal in the 1999‐2000, 2000‐2001 and 2001‐2002 cropping seasons, respectively. The area under the disease progress curve (AUDPC) for HLB, grain yield, thousand‐kernel weight (TKW), days to heading, days to maturity, and plant height were examined. The 17 genotypes showed a range of variability for disease and agronomic characters. Disease severity (AUDPC) differed in the 3 years and showed the highest values in 2002. The increase in AUDPC in 2002 caused the lowest grain yield, with an average 18% reduction due to HLB. A few genotypes (SW 89‐5422, Yangmai‐6 and Ning 8201) appeared to have stable HLB resistance across environments. However, most of the higher‐yielding genotypes, except BL 1883, were unstable. The results suggest that careful selection of HLB resistance with acceptable grain yield, TKW and plant height may be possible using the wheat genotypes included in the HMN.     

Characterization of different cytoplasmic male sterility systems in Indian mustard (Brassica juncea L. Czern & Coss)

Six cytoplasmic male sterility (CMS) systems, viz. moricandia, ogura, oxyrrhina, siifolia, tournefortii and trachystoma of Indian mustard (Brassica juncea L.) were characterized for agronomic and floral characteristics. Introgression of alien cytoplasm caused alterations in different floral traits in ogura, siifolia, tournefortii and trachystoma CMS systems. Varied response to different genetic backgrounds of CMS lines indicated the presence of cytoplasmic–nuclear interaction in alteration of floral traits. On the basis of floral characteristics, CMS systems could be grouped into distinct classes. Siifolia, tournefortii and trachystoma CMS lines had narrow petals, while moricandia, ogura and oxyrrhina had wider petals, which were distinguishable on the basis of visual observations. The ratio between length and width of petals were >2.0 in wide petal group but <2.0 in narrow petal group. Further, the relative position of anther and stigma, which was estimated as the ratio between stamen and style length could differentiate the CMS systems. Stamens were longer than styles in oxyrrhina, equal in moricandia and shorter in ogura, siifolia, tournefortii and trachystoma male sterile lines. Non‐viable pollen grains were present in moricandia and oxyrrhina systems, but absent in other systems. In tournefortii and trachystoma, few flowers showed petaloid corolla. All male sterile lines, except trachystoma, which showed crooked siliqua formation were at par with their respective maintainers for flower initiation, plant height, primary branches, seeds per siliqua, seed yield, harvest index, oil and protein content. In general, flower senescence and maturity occurred earlier in male sterile lines than in their respective maintainer lines.     

Inheritance of resistance to spot blotch caused by Bipolaris sorokiniana in spring wheat

Three F₁ progenies and their families in the segregating generations (F₃, F₄, F₅ and F₆), obtained after crossing resistant × susceptible wheat genotypes were studied in the field to determine the genetics of resistance to spot blotch caused by Bipolaris sorokiniana. Spot blotch scores in the F₁ generation showed absence of dominance. Individually threshed F₂ plants were used to advance the generations. Progenies (200‐250) of resistant genotypes Acc. No. 8226, Mon/Ald, Suzhoe#8 crossed with susceptible ‘Sonalika’ were evaluated in the F₃, F₄, F₅ and F₆ generations under induced epiphytotic conditions. Based on disease score distribution in individual progeny rows, F₃ progenies were grouped into four classes: homozygous resistant, homozygous susceptible, segregating resistant and segregating susceptible. Resistance appeared to be under the control of three additive genes. The presence of three genes was also noted in the distribution of F₄ and F₅ lines. In the case of F₆ progeny rows, both quantitative and qualitative models were used to estimate the number of segregating genes based on a 2‐year trial. It appeared that resistance to spot blotch was controlled by the additive interaction of more than two genes, possibly only three.     

Forage production and nitrogen nutrition in three grasses under coconut tree shades in the humid-tropics

Reduction in forage production (FP) under trees in the humid tropics is well known, but information on how different levels of nitrogen (N) fertilizer influence FP under trees is meager. The present study reports effects of four N fertilizer levels (0, 60, 80 and 120 kg ha⁻¹ N) on net soil N mineralization rate (NMR) and soil moisture (SM), FP, shoot biomass/root biomass ratio (SB/RB), N concentration in SB, N uptake and nitrogen use efficiency (NUE) of three grasses [guinea (Panicum maximum Jacq.), para (Brachiaria mutica (Forssk) Stapf) and hybrid-napier (Pennisetum purpureum Schumach.)] under three canopy positions [under canopy (UC, representing high shade), between canopy (BC, representing low shade) and open] of coconut trees (Cocos nucifera L.) in a coconut based silvopastoral system in the humid tropical climate of South Andaman Island of India. The study was performed for two annual cycles (2005–2006 and 2006–2007). The hypotheses tested were: (1) FP would decline under tree shades, both in N fertilized as well as no N fertilized conditions, when SM was not growth limiting in the open. However, amount of decline in the FP would depend on grass species and intensity of shades i.e., higher was the shade greater would be the decline; (2) N fertilizer would increase FP under tree shades, but the increase depended on grass species, intensity of shades and amount of N applied. Amount of N applied, however, would not annul the shades effects when SM was not growth limiting in the open. The study revealed that the tree reduced light 59% under UC and 32% under BC positions, but the N fertilizer levels increased NMR by 11–51% under UC and 3–44% under BC positions compared to the open. SM did not differ across the canopy positions. Under all situations, FP of all grasses declined under UC (47–78%) and BC (18–32%) positions compared to the open; the decline was greater in Hybrid-napier than Guinea and Para grasses. Forage production of all grasses increased with N fertilizer increments under all canopy positions reaching 32 t ha⁻¹ dry matters for hybrid-napier at 120 kg ha⁻¹ N in the open. Both guinea and para grasses outyielded hybrid-napier grass under UC but not under BC or in the open. N concentration in the forage (SB) also increased as N fertilizer level increased. These observations support our hypotheses and suggest that forage production under coconut palms can be increased by the application of N fertilizer with both guinea and para grasses being more productive than hybrid-napier grass under the high shade. Where light conditions are better, hybrid-napier would produce more forage than the other species.     

Influence of earthworm culture on fertilization potential and biological activities of vermicomposts prepared from different plant wastes

The present investigation was aimed to analyze influence of earthworm culture on nutritive status, microbial population, and enzymatic activities of composts prepared by utilizing different plant wastes. Vermicomposts were prepared from different types of leaves litter of horticulture and forest plant species by modified vermicomposting process at a farm unit. Initial thermophilic decomposition of waste load using cow‐dung slurry was done in the separate beds. The culture of Eisenia fetida was used for vermicomposting in specially designed vermibeds at the farm unit. The physico‐chemical characteristics, enzyme activities (oxido‐reductases and hydrolases), and microbial population (bacteria, fungi, free‐living nitrogen‐fixing bacteria, actinomycetes, Bacillus, Pseudomonas, phosphate‐solubilizing bacteria and fungi) of vermicomposts were found significantly higher (p < 0.05) than those of control (without earthworm inoculum). The study quantified significant contributions of earthworm culture to physico‐chemical, enzymatic, and microbiological properties of vermicompost and confirmed superior fertilization potential of vermicompost for organic farming. The agronomic utility of vermicompost was assessed on yellow mustard plant in a pot experiment. Pot soil was amended with different ratios (5%, 10%, 20%) of vermicompost and normal compost (without earthworm inoculum). Effects of these amendments on the growth of Brassica comprestis L. were studied. The significant differences (p < 0.05) in the growth of plant were observed among vermicompost‐, compost‐amended soil, and control. Vermicompost increased the root and shoot lengths, numbers of branches and leaves per plant, fresh and dry weights per plant, numbers of pods and flowers, and biochemical properties of plant leaf significantly, especially in 20% amendment. These results proved better fertilization potential of vermicompost over non‐earthworm‐inoculated compost.