Somaclonal variation of regenerated plants in chili pepper (Capsicum annuum L.)

The morphological and genetic variations in somaclones of chili pepper (Capsicumannuum L.) derived from tissue culture were evaluated. Cotyledonary node explants of cultivars, Shishitou and Takanotsume, were cultured on Murashige and Skoog (MS) medium supplemented with benzyladenine (BA)5 mg/l for shoots regeneration and regenerated shoots were rooted on MS medium supplemented with naphthalene acetic acid(NAA) 0.1 mg/l and indol-3-butyric acid(IBA) 0.05 mg/l. The regenerated plants(R₀) were selfed to obtain seeds for next generation (R₁ lines). Qualitative characters were studied in R₀generation and both qualitative and quantitative characters were studied in R₁ generation. In R₀ generation, variations were noticed in plant growth habit, stem color, flower color and color of unripe fruits, and expression of anthocyanin in unripe fruits. Comparison among the R₁ lines and their parents were made for morphological and agronomic characters. Significant variation among R₁ lines and differences between R₁ lines and their parents were observed. Genetic variations among three somaclones were revealed by random amplified polymorphic DNA (RAPD) analysis. Variation, such as early flowering and increase of yield components, is an indication of the response to selection for any specific character. Occurrence of productive variants among somaclones of established cultivars, like Shishitou and Takanotsume, indicates the possibility of their improvement through somaclonal variation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lead and Zinc Extraction Potential of Two Common Crop Plants, Helianthus Annuus and Brassica Napus

Phytoextraction is a remediation technology that uses plants to remove heavy metals from soil. The success of a phytoextraction process depends on adequate plant yield (aerial parts) and high metal concentrations in plant shoots. A pot experiment was conducted to investigate the combination effects of plants [sunflower (Helianthus annuus) and canola (Brassica napus)] with soil treatments (manure, sulfuric acid and DTPA). Treatments, including two plants and seven soil treatments, which applied according to completely randomized factorial design with three replications. The largest shoot dry weight biomass production occurred in manure treatments for both plants. The maximum shoot concentrations of Pb and Zn were 234.6 and 1364.4 mg kg^?1 respectively in three mmoles DTPA kg^?1 treatment of sunflower. Furthermore the results showed that sunflower had a higher extracting potential for removal of Pb and Zn from polluted soil.     

A major variation in the virulence of the Asian soybean rust pathogen (Phakopsora pachyrhizi) in Bangladesh

Asian soybean rust (ASR) caused by Phakopsora pachyrhizi is a major threat to soybean production in Bangladesh. Understanding the yearly changes and the current status of pathogenic structures is essential for developing appropriate breeding strategies for obtaining ASR-resistant soybean lines. Thirty-four P. pachyrhizi samples were collected from ASR hotspot areas (Chandpur, Lakshmipur, Noakhali, Barisal and Bhola districts) of Bangladesh in 2018 and 2019 and evaluated for pathogenicity on 12 soybean differential lines. The tested samples showed similar and dissimilar pathogenicity patterns on the differentials, yielding 21 distinct pathotypes. The cluster analysis, principal coordinate analysis and principal component analysis of the disease phenotypes of 47 samples collected in 2016, 2018 and 2019 indicated a higher pathogenic diversity and virulence variation in the P. pachyrhizi samples of 2018 and 2019 compared to that of 2016. The pathogenicity profiles of the Bangladeshi P. pachyrhizi samples appeared distinct from those of Argentinian and Brazilian samples, but showed slight similarities with Japanese, Mexican and Paraguayan samples. Furthermore, none of the resistance genes for P. pachyrhizi (Rpp genes) was solely effective against all the tested samples from 2018 and 2019, while samples (BdRP-48, BdRP-56 and BdRP-58) virulent to all Rpp1–Rpp6 genes were detected. The Rpp-pyramided line No6–12–1, carrying Rpp2, Rpp4 and Rpp5, was capable of conferring robust resistance to these virulent samples. Altogether, these results indicate an increase in the virulence of the current ASR pathogen in Bangladesh, which can be resolved by pyramiding different resistance genes in soybean cultivars.     

A collision tumor consisting of granular cell tumor and adenocarcinoma in the uterus of an aged djungarian hamster

A neoplastic nodular lesion consisting of an admixture of granular cell tumor and adenocarcinoma was found in the uterus of a 26-month-old Djungarian hamster. Neoplastic cells of the uterine adenocarcinoma showed an epithelial nature in their growth patterns and by cytokeratin-immunopositive reaction, exhibiting nuclear pleomorphism. The granular cells had an abundant amount of fine granular eosinophilic cytoplasm and eccentric or central nuclei with no nuclear atypia; the granular structures were positive for periodic acid-Schiff with diastase resistance and were confirmed as lysosomes/autophagosomes by electron microscopy; immunohistochemically, the cells reacted to desmin, vimentin and α-smooth muscle actin and negatively for neurogenic, histiocyte/macrophage or epithelial markers, indicating smooth muscle origin. Because these tumors were generated from different cell origins, a diagnosis of collision tumor was made.     

Nursery practice on seed germination and seedling growth of <Emphasis Type="Italic">Dalbergia sissoo</Emphasis> using beneficial microbial inoculants

Nursery practice using microbial inoculants was performed to find out the efficacy of the inoculants on seed germination and seedling growth of sissoo (Dalbergia sissoo Roxb.). Microbial inoculants or effective microorganisms (EM) are a mixture of many different beneficial microorganisms in a solution. The seedlings were grown in a mixture of sandy soil and cowdung (3:1) kept in polybags with pouring EM solution at different concentrations (0.1%, 0.5%, 1%, 2%, 5% and 10%) before and after a week of sowing the seeds. Seed germination rate and growth parameters of seedlings were measured, such as, shoot and root length, vigor index, fresh and dry weight of shoot and root and total biomass increment. The nodulation status influenced by EM was also observed along with the measurement of pigment contents in leaves. The highest germination rate (69%) was observed in 2% EM treatment, followed by 67% and 65% in 1% and 5% EM. The highest shoot length (33.2 cm) was in 2% EM, whereas highest root length (26.3 cm) was in 1% EM. Both fresh and dry weights from shoot and root, were maximum (4.16 g and 1.57 g; 2.12 g and 0.83 g respectively) in 2% EM and were significantly (p ≤ 0.05) different from control. Vigor index was highest (4071) in 2% EM, which was significantly (p ≤ 0.05) different from control. Total dry weight increment was highest in 2% EM treatment, followed by 1% and 5% concentrations of EM. Nodulation number was higher at very low (0.1%) concentration of EM solution but it normally decreased with the increase of EM concentrations. The contents of chlorophyll a, chlorophyll b and carotenoid were highest (60.11, 17.05 and 42.48 mg·L⁻¹ respectively) in 2% EM treatment and lowest (39.35, 13.55 and 27.29 mg·L⁻¹ respectively) in control treatment. Therefore, low concentration of EM (up to 2%) can be used for getting maximum seed germination rate and seedling development of Dalbergia sissoo Roxb.     

Comparison of Sampling Techniques for the European Red Mite,Panonychus ulmi (Koch) (Acari: Tetranychidae) and the Apple Rust Mite,Aculus schlechtendali (Nalepa) (Acari: Eriophyidae)

Abstract

Several methods were tested for estimating population size of two phytophagous mites on the apple cultivars Aroma, Summerred and Gravenstein. The washing technique was rated as most efficient for estimating the Panonychus ulmi population. Counting one quarter of the total number of mites in the sample gave a sufficiently precise estimate of the P. ulmi population. The mites are easily washed off and are well preserved for further study. The brushing technique was more efficient than direct counting of Aculus schlechtendali, and is the better way to handle an extensive sampling programme.     

Zinc nutrition and levels of endogenous lndole‐3‐acetic acid in radish shoots

Radish (Raphanus sativus cv. Akamaru‐Hatsukadaikon) was grown for several experiments in a glasshouse with zinc (Zn) supply in the nutrient solution. Lack of Zn resulted in stunted growth and reduced leaf of radish shoots were observed. Two‐dimensional thin layer chromatography (TLC) and gas chromatography‐mass spectrometry (GC‐MS) analysis revealed the presence of endogenous indole‐3‐acetic acid (IAA) in Zn‐deficient radish shoots. An estimate has been made of alkali‐labile (1 and 7N NaOH) IAA in Zn‐deficient radish shoots with the use of gas chromatography (GC). The level of 7N NaOH‐labile IAA (peptidic + ester + free) and IN NaOH‐labile IAA (ester + free) in Zn‐deficient radish shoots was almost the same as that of control radish shoots. These results suggest that Zn nutrition did not affect the level of endogenous IAA in radish shoots.     

Effect of Rhizobium inoculation on growth,modulation, and nitrogenase activity of some legume tree species

An experiment was conducted to study the effect of inoculation of Rhizobium suspension in Albizia procera (Roxb.) Benth, Albizia lebbeck (L.) Benth, and Leucaena leucocephala (Lam.) De Wit. seedlings grown in sterilized and non‐sterilized soil media. Control treatments were maintained by non‐inoculation. Inoculation response was observed strong in sterilized and modest in non‐sterilized soil when compared to respective control treatments. Increase in height was found 105.07%, 63.42%, and 109% higher in sterilized soil and 52.1%, 68.6%, and 95.8% in non‐sterilized soil for Albizia procera, Albizia lebbeck, and Leucaena leucocephala, respectively, after a period of 4 months. Nodule number increased up to 10.27 and 3.51 times in Albizia procera, 11.47 and 4.3 times in Albizia lebbeck, and 7.22 and 2.9 times in Leucaena leucocephala due to inoculation in sterilized and non‐sterilized soil media respectively. Significant increase in nodule dry weight and nitrogenase activity was also recorded in both sterilized and non‐sterilized soil for all the species tested. Nitrogenase activity per plant per hour was recorded 68.75,11.58, and 13 times higher in sterilized and 6.7,5.53, and 3.38 times higher in non‐sterilized soil over control for the species respectively after 4 months. In the tree species tested the inoculation of Rhizobium showed higher productivity, modulation and nitrogenase activity than control suggesting the idea that application of Rhizobium suspension greatly enhances plant growth, modulation, and nitrogenase activity.     

Optimization of stocking density of freshwater prawn Macrobrachium rosenbergii (de Man) in carp polyculture in Bangladesh

A study was conducted to optimize stocking density of freshwater prawn, Macrobrachium rosenbergii, in carp polyculture for 3 months in 10 experimental ponds of 80 m². Five stocking densities of prawn, 2500, 5000, 7500, 10 000 and 12 500 ha^?1, were assigned to treatments T₁, T₂, T₃, T₄ and T₅ respectively. The densities of catla, Catla catla, rohu, Labeo rohita and silver carp, Hypophthalmicthys molitrix, were 2500, 5000, and 2500 ha^?1, respectively, in each treatment. Each treatment had two replicate ponds. The mean initial weights of prawn, catla, rohu and silver carp were 1.1±0.02, 8.28±0.1, 25.2±1.1 and 36.32±1.2 g respectively. A pelleted diet containing 30% protein was prepared using fish meal, meat and bone meal, mustard oilcake, rice bran, wheat bran and molasses, and was fed twice daily at a rate of 5% of fish biomass. Water quality parameters were measured fortnightly and the ranges of temperature, pH and dissolved oxygen were 27.5–1.3°C, 6.9–8.6 and 4.5–8.6 mg L^?1 respectively. Feed conversion ratios ranged from 2.05 to 2.20 among the treatments. Per cent survival (%) of prawns ranged from 72% to 78%, while it varied from 80% to 93%, 90% to 95% and 90% to 92% for catla, rohu and silver carp respectively. The results showed that there were no significant differences among the weight gains of prawn and carp in different treatments. However, the overall total production of prawn and fish together was significantly (P<0.05) higher in T₃ and T₄ compared with other treatments. The total production for 3 months ranged between 2618 and 2916 kg ha^?1. The production of prawn was significantly higher (361.3 kg ha^?1) in T₅ with a highest stocking density of 12 500 prawn ha^?1. Although there was no significant difference (P>0.05) between the total production of prawn and fish together in T₃ and T₄, the highest net profit (Tk. 69 006 ha^?1) was obtained in T₄. Therefore, from the result of the study it may be concluded that a stocking ratio of 4:1:2:1 of prawn:catla:rohu:silver carp at a total density of 20 000 ha^?1 may be recommended for prawn–carp polyculture in ponds.     

Effect of mixed feeding schedules with varying dietary protein levels on the growth of sutchi catfish, Pangasius hypophthalmus (Sauvage) with silver carp, Hypophthalmichthys molitrix (Valenciennes) in ponds

A 6‐month feeding trial was conducted in field condition using 10 farm ponds (400–600 m²) to investigate the effect of mixed feeding schedules on the growth of sutchi catfish, Pangasius hypophthalmus with silver carp, Hypophthalmichthys molitrix. Fish were stocked at a ratio of 80:20 (sutchi catfish, 4.9±0.5 g: silver carp, 12.0±0.8 g) at the total rate of 25 000 ha^?1. Two diets of high protein (30%, HP) and low protein (16%, LP) were prepared using locally available feed ingredients. Five different feeding schedules of high‐protein diet continuously (HP), low‐protein diet continuously (LP), 1‐day low–protein/1‐day high‐protein diet (1LP/1HP), 7 days low–protein/7 days high‐protein diet (7LP/7HP) and 14 days low–protein/14 days high‐protein diet (14LP/14HP) were tested. The fish were fed twice daily at the rate of 15%, 10%, 8% and 5% of their body weight for first, second, third month and rest of experimental period respectively. Feeding rate was calculated only on the basis of sutchi catfish weight only and was adjusted every 2 weeks according to weight gain. Fish fed LP and HP on alternate day (1LP/1HP) resulted in significantly (P<0.05) higher growth rate, feed utilization and production among the treatments. However, there were no significant differences (P>0.05) between the growth rates and production of fish fed HP regularly and fish fed 7 days LP followed by 7 days HP (7LP/7HP). Fish maintained on LP grew the least. The feed conversion ratio (FCR) values for sutchi catfish ranged between 2.04 and 2.79 with feeding schedule 1LP/1HP showing the best FCR. The total production of fish (including silver carp) ranged between 8310 and 12 422 kg ha^?1 6 months^?1 with 1LP/1HP feeding schedule resulting in the highest production and net profit. The study demonstrated that feeding fish continuously with HP is less economical. Thus, for profitable sutchi catfish culture with silver carp, farmers can use the mixed feeding schedule of alternate day feeding of LP and HP as a means of reducing feed costs.