Exogenous Calcium Supplementation Improves Salinity Tolerance in BRRI Dhan28; a Salt-Susceptible High-Yielding Oryza Sativa Cultivar

Journal of Crop Science and Biotechnology - Salinity is one of the most brutal abiotic stressors, commencing a great stumbling block in the way of attaining food security in Bangladesh. Cultivation...     

Evaluation of chitosan and alginate immobilized Methylobacterium oryzae CBMB20 on tomato plant growth

Methylobacterium oryzae CBMB20, a promising plant growth promoting bacteria (PGPB) and a biocontrol agent, was immobilized in different formulations such as wet chitosan, dry chitosan, wet alginate and dry alginate and were tested for tomato plant growth promotion. Chitosan solution (1.5%) with pH 5.5–6.0 and 90 min contact time was found optimal for immobilization. The chitosan formulations showed better entrapment efficiency and good degradability resistance apart from slow release of cells under prolonged incubation. Survivability of bacteria (80%) was observed in wet chitosan formulation even after 90 days of storage at 4°C. The spermosphere survival of bacteria was high in both dry and wet chitosan formulations applied soils even after 21 days under greenhouse conditions. While the alginate formulation degraded fully, partial degradation of chitosan formulation was observed even after 30 days, indicating its ability to support the survival of M. oryzae CBMB20 in soil. Plants inoculated with wet chitosan formulation registered 1.3 fold increase in the shoot and root length and dry weight compared to other treatments. Hence, chitosan formulation supporting better plant growth compared to alginate will be a better carrier for taking bacteria to the plant rhizosphere and thereby promote plant growth.     

Occurrence of postharvest gray mold rot of sweet cherry due to Botrytis cinerea in Korea

Journal of Plant Diseases and Protection - In May 2016, we observed gray mold rot symptoms on harvested and refrigerated cherry fruit in Gangneung, Gangwon Province, Korea. The symptoms included...     

Species Composition,Diversity and Productivity of Homesteads in Southeastern Bangladesh

A homestead is an integrated production system where trees, crops, livestock and poultry are found in and around the household residence in Bangladesh. It is a potential production unit that provides various product, service and ecological functions. Almost all people in Bangladesh including landless households have homesteads in which they grow trees and crops even in a small piece of land. This study characterizes the species composition, diversity and productivity of the homestead production system in the Teknaf peninsula, southeastern Bangladesh. Survey data collection was from a total of 180 homesteads covering five household categories: large, medium, small, marginal and landless. Vegetable, fruit, timber, and livestock and poultry were common components in the homestead production system. Various types of plants were mainly concentrated in back yards, front yards, boundaries and corners of homesteads. The mean number of tree species per homestead was about 15. In total, 189 tree and shrub species were recorded, and were distinctly high and low in the large (363.7) and landless (55.7) household categories. Species composition, diversity and productivity of homesteads were found to be related to household categories. Richness and diversity of tree and shrub species increased with household size. Betel nut was the dominant tree species followed by mango, jackfruit and coconut. Annual income from homesteads also varied among the household categories, with a mean contribution of the homestead to annual income of about 25 %. A large portion of homestead income came from betel nut trees. There is scope to increase species diversity and income by designing homesteads with the engagement of women and other family members.     

Variation of mineral nutrient contents of modern and heirloom cultivars of cabbage in different regimes of soil fertility

An improvement in the mineral nutrient contents of fruits and vegetables is needed to offset reported declines in concentrations of these elements in fruits and vegetables. The declines have been associated with the high productivity of modern cultivars and to depleted soil fertility. This research addressed differences in mineral nutrient concentrations between modern F1 hybrids and heirloom cultivars of cabbage (Brassica oleraceae var. capitata L.)and among fertilization practices with conventional chemical or organic fertilizers and compost. Crop production was greater with the chemical or organic fertilizers than with the compost. Mineral nutrient composition did not vary between modern or heirloom cultivars or among fertilization regimes but varied among cultivars, suggesting that cultivar selection could lead to production of nutrient-rich cabbage. Neither mass of heads nor days to maturation of crops affected nutrient composition.     

Allelopathic potential and an allelopathic substance in mango leaves

The present study was aimed to determine the allelopathic potential of mango (Mangifera indica L.) leaves and to identify allelopathic substances in the leaves. The aqueous methanol extracts of mango leaves inhibited seedling growth of garden cress, radish, rapeseed, foxtail fescue and crabgrass, and the inhibitory effects increased with the increasing extract concentration, suggesting that mango leaves may contain allelopathic substances. The extract was then purified by several chromatographic runs through a bioassay-directed fractionation, and an growth inhibitory substance was isolated and identified by spectral data as methyl-3,4,5-trihydroxybenzoate (methyl gallate). Methyl gallate at the concentration of 10 mM inhibited 98.6% and 99.8% of root and shoot growth of garden cress relative to the control, respectively, and 94.4% and 49.3% of those of foxtail fescue, respectively. The concentrations of methyl gallate required for 50% growth inhibition (I₅₀) on garden cress roots and shoots were 3.9 and 3.3 mM, and those on foxtail fescue roots and shoots were 1.5 and 9.5 mM, respectively. It is the first report of an allelopathic substance in mango leaves and allelopathic activity of methyl gallate. Therefore, the mango leaves may have potential as a soil additive material for the weed management options.     

Dietary taurine enhances growth and feed utilization in larval Nile tilapia (Oreochromis niloticus) fed soybean meal‐based diets

This study was conducted to evaluate the effects of dietary taurine on growth performance and feed utilization of Nile tilapia (Oreochromis niloticus) larvae. Four plant protein‐based, isonitrogenous (400 g kg^?1 protein), isoenergetic (19 MJ kg^?1) diets supplemented with four taurine concentrations (0.0, 5.0, 10.0 and 15.0 g kg^?1; designated as T₀, T_0.5, T₁ and T_1.5, respectively) were prepared. The diets were fed to triplicate groups of fish larvae (0.024 g average body weight), to apparent satiation, three times per day for 60 days. Larval growth rates and feed utilization efficiency were significantly improved with increasing supplemental taurine up to 10 g kg^?1 and decreased with further taurine supplementation. The quadratic regression analyses indicated that the maximum larval performance occurred at about 9.7 g kg^?1 of total dietary taurine. Fish survival was significantly lower at 15 g kg^?1 dietary taurine than at other taurine levels. Body protein significantly increased, while body moisture and ash decreased, with increasing dietary taurine up to 10 g kg^?1 and decreased with further taurine supplementation to 15 g kg^?1. Body lipid was not significantly affected by dietary taurine concentration. A number of body amino acids (tryptophan, arginine, histidine, leucine, isoleucine, valine, alanine, glycine, threonine and taurine) significantly increased with increasing supplemental taurine up to 10 g kg^?1 and then decreased with further increase in dietary taurine levels. The rest of body amino acids were not significantly affected by dietary taurine. The present results suggest that about 9.7 g kg^?1 dietary taurine is required for optimum performance of Nile tilapia larvae fed soybean meal‐based diets.     

Anaesthetic efficacy of MS‐222 and AQUI‐S® in advanced size fry of rohu,Labeo rohita, (Hamilton‐Buchanan)

Anaesthetic agents are very useful for reducing the stress caused by handling, sorting, transportation, artificial reproduction, tagging, administration of vaccines and surgical procedures in fish. The efficacy of two anaesthetics: MS‐222 and AQUI‐S^® were tested on rohu, Labeo rohita advanced size fry. The lowest effective doses that produced induction in 3 min or less and recovery times 5 min or less and meet the most criteria of good anaesthetic characteristics were 125 mg L^?1 of MS‐222, and 30 mg L^?1 of AQUI‐S^® in rohu, Labeo rohita advanced size fry. Induction times were significantly decreased with increased in the concentrations of any of the two tested anaesthetic agents. The lowest doses suitable for transportation of rohu advanced size fry observed were: 10–15 mg L^?1 of MS‐222 and 2.5 mg L^?1 AQUI‐S^®. Both anaesthetics showed promising to be used as anaesthetics for handling and transportation in rohu (Labeo rohita) advanced fry.     

Valuation of gamma irradiation for proficient production of parasitoids (Hymenoptera: Chalcididae & Eucoilidae) in the management of the peach fruit-fly,Bactrocera zonata (Saunders)

Recognizing the potential significance of using nuclear techniques in biological control, investigations were conducted on the rearing of parasitoids of the peach fruit-fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) to lead to a greater flexibility in the use of irradiated hosts. For improving mass production of the biological control agents, the use of irradiated fruit-fly larvae at the dose of 15 Gy proved useful for enhancing the parasitism and adult emergence of the larval parasitoid, Trybliographa daci (Weld) (Hymenoptera: Eucoilidae) due to no negative repercussions on parasitoid development. Overall, parasitism by the parasitoid increased with age of the host larvae; however, significantly higher parasitism occurred on 4 d-old irradiated larvae of B. zonata compared to those aged 5 d. The female parasitoids preferred the irradiated larvae, and significantly higher numbers of larvae were parasitized compared with non-irradiated larvae. There was no significant difference in adult parasitoid emergence with respect to the sex of the host. A radiation level of 80 Gy was the best dose for rearing of the pupal parasitoid, Dirhinus giffardii (Silvestri) (Hymenoptera: Chalcididae) owing to broad tolerances in the use of irradiation for the rearing of fruit-fly's parasitoids. Percentage parasitism by D. giffardii varied with host pupal age, and the preference of the female parasitoid was lower on 48 h old host pharate pupae due to optimum size and mass of host. Present findings further revealed that the 24 h old host pupae of B. zonata were relatively more suitable for the maximum parasitism and progeny production of D. giffardii. Parasitisms by D. giffardii and T. daci were significantly higher on B. zonata host when parasitoids were released at a density of 3000 individuals per acre (7500 per hectares) than the other release rates of parasitoids for the management of fruit-flies in mango orchards. The implementation of these findings ought to help improve the mass production of parasitoids and the effectiveness of releases of biocontrol agents for control of B. zonata in mango plantations.