Evaluation of pesticides against major pests of jute (Corchorus olitorius L.) in West Bengal,India

Among the pesticides evaluated against the jute pests under field conditions, endosulfan 35 EC at 350 g a.i./ha was found to be the most effective insecticide for controlling semilooper, Bihar hairy caterpillar and myllocerus weevil. Endosulfan and fenpropathrin provided good control of yellow mite as well. Even, endosulfan-treated plots gave maximum fibre and stick yield with greater benefit–cost ratio (BCR) over others. Next to endosulfan and chlorpyriphos, neemazal (azadirachtin 50,000 ppm) are useful and safer options against semilooper, Bihar having caterpillar, myllocerus and yellow mite. Methoxyfenocide 10 EC at 200g a.i./ha provided good control (70.60%) of S. obliqua even after 14 days of spraying, but it was not effective against other pests of jute. Further, almost similar efficacy of neemazal and chlorpyriphos was found against the pest complex of jute and based on BCR, neemazal could be an alternative choice over chlorpyriphos.     

Cytokinin-like active principle associated with rice necrosis mosaic virus induced growth promotion in jute (Corchorus olitorius L.)

Rice necrosis mosaic virus-inoculated jute plants looked more juvenile with enhanced leaf size than control ones. Such enlarged leaves and those from control ones were collected separately and extracted in chilled methanol. The crude tissue extract in case of inoculated ones showed three times higher activity in bioassay for cytokinin over control. Biological assay with fractions of crude extract separated by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) was ascertained, and one fraction from inoculated sample showing higher activity in terms of growth over respective control was selected. Ultraviolet/visible absorbance spectra of TLC-separated fractions revealed the presence of different quantities of similar kind of compounds in both control and inoculated samples. A major compound with same m/z value of 217.1 was found in both cases as revealed through electrospray ionisation mass spectrophotometry analysis along with some other minor compounds. Different proton–proton coupling and a molecular structure of the highly substituted aliphatic groups were found in the material from inoculated sample having higher cytokinin-like activity than the control one, which was noticed through ¹H one-dimensional nuclear magnetic resonance analysis.     

Estimation of aeromycoflora in jute fields

An air survey of jute fields for two seasons in West Bengal, India, revealed that the total colony forming units (CFUs) varied with time, showing peaks (231 and 483 CFUs, respectively) during harvesting of the crop. The effect of temperature as well as relative humidity is probably not so significant. However, the total rainfall does count. The CFUs are inversely proportional to the total rainfall. In the survey conducted, it was found that the rainfall of 1346.3 mm and 947.1 mm, during the two seasons corresponded to 574 and 1002 CFUs respectively, irrespective of growth phases of the crop. Penicillium and Aspergillus were the most dominant saprophytes followed by Curvularia and Cladosporium in the first season, while in 1991 Aspergillus and Curvularia were the most dominant, followed by Cephlalosporium, Penicillium and Cladosporium, along with Pullularia in the mid season. Pathogenic Macrophomina phaseolina causing stem rot disease, although appeared irregularly in the first season, became more frequent in later stages in the second season. Amongst other pathogens Helminthosporium occurred twice and three times in the earlier part of the two crop season, while Alternaria, Nigrospora and Fusarium occurred very occasionally.     

Quantitative studies on the mating system of jute (Corchorus olitorius L.)

Summary More than 100,000 individuals of C. olitorius were scored for selfing versus outcrossing in various populations, at several locations, over a number of years and seasons. Different marker loci, such as A ^d /a ⁰, Sh/sh, Cr/cr and Pl/pl, were used to determine the male gametes which had effected fertilization. The results showed that the frequency of outcrossing was extremely variable among loci, crosses and samples within a single locus. The outcrossing parameter, , was found to differ with years, locations and seasons within years. It was also found that outcrossing, in general, was nonrandom. Nonrandomness was also independent of flowering dates. The amount of outcrossing was directly associated with the frequency of F ₂ plants flowering at different dates. A recalculated outcrossing parameter from different authors' reported data, representing different years and locations, has been found to be nonrandom. It was observed that the propensity to outcross was not a simple function of changing gene frequency but was associated with the genotype of individual selected.     

Comparative molecular cytogenetic analyses of a major tandemly repeated DNA family and retrotransposon sequences in cultivated jute Corchorus species (Malvaceae)

Background and Aims

The cultivated jute species Corchorus olitorius and Corchorus capsularis are important fibre crops. The analysis of repetitive DNA sequences, comprising a major part of plant genomes, has not been carried out in jute but is useful to investigate the long-range organization of chromosomes. The aim of this study was the identification of repetitive DNA sequences to facilitate comparative molecular and cytogenetic studies of two jute cultivars and to develop a fluorescent in situ hybridization (FISH) karyotype for chromosome identification.

Methods

A plasmid library was generated from C. olitorius and C. capsularis with genomic restriction fragments of 100–500 bp, which was complemented by targeted cloning of satellite DNA by PCR. The diversity of the repetitive DNA families was analysed comparatively. The genomic abundance and chromosomal localization of different repeat classes were investigated by Southern analysis and FISH, respectively. The cytosine methylation of satellite arrays was studied by immunolabelling.

Key Results

Major satellite repeats and retrotransposons have been identified from C. olitorius and C. capsularis. The satellite family CoSat I forms two undermethylated species-specific subfamilies, while the long terminal repeat (LTR) retrotransposons CoRetro I and CoRetro II show similarity to the Metaviridea of plant retroelements. FISH karyotypes were developed by multicolour FISH using these repetitive DNA sequences in combination with 5S and 18S–5·8S–25S rRNA genes which enable the unequivocal chromosome discrimination in both jute species.

Conclusions

The analysis of the structure and diversity of the repeated DNA is crucial for genome sequence annotation. The reference karyotypes will be useful for breeding of jute and provide the basis for karyotyping homeologous chromosomes of wild jute species to reveal the genetic and evolutionary relationship between cultivated and wild Corchorus species.     

Tissue culture independent transformation for Corchorus olitorius

An efficient microprogation protocol has been developed for Dendrobium densiflorum Lindl. ex Wall., a traditional medicinal plant, through protocorm-like bodies (PLBs) from nodal stem segments using 6-benzylamino-purine (BAP) and the lanthanoid neodymium. The highest percentage of explants producing PLBs (72%), with an average of 15 PLBs per explant, was induced by culturing stem segments on Murashige and Skoog (MS) medium supplemented with 5.0 mg l⁻¹ BAP. The newly formed PLBs proliferated well on the basal MS medium and completely converted into shoots on MS medium containing 2.0 mg l⁻¹ BAP. Shoots produced an average of 22 roots per plantlet when cultured on MS medium supplemented with 2.0 mg l⁻¹ neodymium nitrate. Healthy plantlets with well-developed roots were successfully acclimatized. The obtained result suggests that the lanthanoids can be used to effectively initiate rooting in the micropropagation and conservation of D. densiflorum.     

Plant regeneration from cotyledonary explants of jute, Corchorus capsularis L.

A liquid culture protocol was developed to regenerate shoots from cotyledons of germinating seeds of jute (Corchorus capsularis L.). Reproducibility of the protocol was tested in three genotypes of jute. Highest bud differentiation rates into normal shoots (via shoot-forming explants) were obtained on modified Murashige and Skoog's liquid medium containing 2.7 μM α-naphthaleneacetic acid and 4.4 μM benzylaminopurine. Regenerated shoots were excised, and the best root formation could be induced in medium with 2.5 μM indole-3-butyric acid and 1.5% sucrose. Bud primordia were formed directly on the cut surface of the cotyledons. Scanning electron micrographs and histological studies confirmed the organogenic nature of the regenerated shoots. The physical condition of the culture medium and the age of the explants played crucial roles in the induction of shoot development using shoots; 2-day-old explants being optimal. Approximately 70% of the shoots were successfully established in soil after hardening. Received: 20 October 1997 / Revision received: 4 October 1998 / Accepted: 27 October 1998     

Chromosome‐specific physical localisation of expressed sequence tag loci in Corchorus olitorius L.

Jute (Corchorus spp.), as a natural fibre‐producing species, ranks next only to cotton. Inadequate understanding of its genetic architecture is a major lacuna for genetic improvement of this crop in terms of yield and quality. Establishment of a physical map provides a genomic tool that helps in positional cloning of valuable genes. In this report, an attempt was initiated to study association and localisation of single copy expressed sequence tag (EST) loci in the genome of Corchorus olitorius. The chromosome‐specific association of EST was determined based on the appearance of an extra signal for a single copy cDNA probe in mitotic interphase nuclei of specific trisomic(s) for fluorescence in situ hybridisation, and validated using a cDNA fragment of the 26S rRNA gene (600 bp) as molecular probe. The probe exhibited three signals in meiotic interphase nuclei of trisomic 5, instead of two as observed in diploids and other trisomics, indicating its association with chromosome 5. Subsequent hybridisation of the same probe on the pachytene chromosomes of diploids confirmed that 26S rRNA occupies the terminal end of the short arm of chromosome 5 in C. olitorius. Subsequently, chromosome‐specific association of 63 single copy EST and their physical localisation were determined on chromosomes 2, 4, 5 and 7. The study describes chromosome‐specific physical localisation of genes in jute. The approach used here could be a step towards construction of genome‐wide physical maps for any recalcitrant plant species like jute.     

Clonal propagation byin vitro culture of Corchorus (jute)

Callus was produced on cotyledon, shoot tip, hypocotyl and root explants of twoCorchorus species on several media. Cytokinin was necessary for callus production on cotyledon explants. BothC.olitorius genotypes produced most callus on media with zeatin and either NAA or IAA, and theC.capsularis genotype produced most callus on media with IAA and either zeatin or BA. High frequencies of regenerated shoots were obtained from shoot tip explants of both species, from the apical meristem and from callus. Media with 2.0 mg 1⁻¹ BA were superior for both species, and media with zeatin were equally good forC.capsularis only. More regeneration was obtained for all genotypes after subculture of callus on media with 2.0 mg 1⁻¹ zeatin. Cotyledon callus produced less regeneration, also with differences between genotypes; explants of both genotypes ofC.olitorius produced regeneration on a medium with NAA and zeatin, and theC.capsularis genotype produced regeneration on a medium with IAA and BA. Limited regeneration from root explant callus was obtained forC.capsularis only on medium with BA and IAA. Regeneration was not obtained from hypocotyl callus. Further regeneration of shoots of both species was obtained from secondary callus after subculture, and from nodal segments of regenerated shoots and of seedling shoots cultured on basic MS medium without growth hormones. Roots were produced on about 80% of all shoots after transference to medium with 0.2 mg 1⁻¹ IBA, and rooted plantlets survived and flowered normally after transference to compost.     

Effects of toxic concentrations of natrium fluoride on growth and enzyme activities of rice (Oryza sativa L.) and jute (Corchorus olitorius L.) seedlings

Germination was increasingly inhibited at concentrations above 5 and 20 mM and stopped altogether at 80 and 50 mM NaF in rice and jute respectively, whereas the inhibition of seedling growth began at much lower concentrations. Of the enzymes, RNase activity was increased by fluoride, while α-amylase, protease, phytase and ATPase activities exhibited distinct inhibition from the control.     

黄麻种质资源遗传多样性的SRAP分析

为明确黄麻(Corchorus L.)种质资源的遗传多样性,采用SRAP分子标记方法,对来自13个国家的两个黄麻栽培种及野生种共96份黄麻种质资源进行了分析。研究结果如下:(1)供试黄麻种质资源之间的遗传距离在0.0169至0.9667之间,变幅较大,其中近缘野生种与其他种质的遗传距离最大,基本在0.8以上;圆果栽培黄麻与其他种质的遗传距离最小,平均<0.5。(2)当在聚类图上遗传距离为0.53处划切割线L₁时,96份黄麻种质资源被分为两个大类群(Ⅰ、Ⅱ)、一个小类群(Ⅲ)和5个独立个类。(3)当在遗传距离为0.33处作切割线L₂时,各大类群被分为不同的亚类群,并表现出按地域聚类的趋势。(4)供试黄麻种质资源基于SRAP分子标记的聚类与形态学上的表现并不完全一致。     

Genetic control of secondary phloic fibres in jute (Corchorus capsularis L.)

The anatomical characteristics were studied of one X-ray induced macromutant, Undulating stem. This true-breeding mutant produces only primary phloic fibres. The secondary phloic fibres, which are the derivatives of vascular cambium, are found lacking, though there is formation of secondary phloem pyramids from the cambial tissue. Inheritance of fibre (bast) in jute (C. capsularis) is monogenic and recessive.     

A complete genetic linkage map and QTL analyses for bast fibre quality traits, yield and yield components in jute (Corchorus olitorius L.)

We report the first complete microsatellite genetic map of jute (Corchorus olitorius L.; 2n = 2 × = 14) using an F₆ recombinant inbred population. Of the 403 microsatellite markers screened, 82 were mapped on the seven linkage groups (LGs) that covered a total genetic distance of 799.9 cM, with an average marker interval of 10.7 cM. LG5 had the longest and LG7 the shortest genetic lengths, whereas LG1 had the maximum and LG7 the minimum number of markers. Segregation distortion of microsatellite loci was high (61%), with the majority of them (76%) skewed towards the female parent. Genomewide non-parametric single-marker analysis in combination with multiple quantitative trait loci (QTL)-models (MQM) mapping detected 26 definitive QTLs for bast fibre quality, yield and yield-related traits. These were unevenly distributed on six LGs, as co-localized clusters, at genomic sectors marked by 15 microsatellite loci. LG1 was the QTL-richest map sector, with the densest co-localized clusters of QTLs governing fibre yield, yield-related traits and tensile strength. Expectedly, favorable QTLs were derived from the desirable parents, except for nearly all of those for fibre fineness, which might be due to the creation of new gene combinations. Our results will be a good starting point for further genome analyses in jute.     

Characterization of a lignified secondary phloem fibre-deficient mutant of jute (Corchorus capsularis)

BACKGROUND AND AIMS: High lignin content of lignocellulose jute fibre does not favour its utilization in making finer fabrics and other value-added products. To aid the development of low-lignin jute fibre, this study aimed to identify a phloem fibre mutant with reduced lignin. METHODS: An x-ray-induced mutant line (CMU) of jute (Corchorus capsularis) was morphologically evaluated and the accession (CMU 013) with the most undulated phenotype was compared with its normal parent (JRC 212) for its growth, secondary fibre development and lignification of the fibre cell wall. KEY RESULTS: The normal and mutant plants showed similar leaf photosynthetic rates. The mutant grew more slowly, had shorter internodes and yielded much less fibre after retting. The fibre of the mutant contained 50 % less lignin but comparatively more cellulose than that of the normal type. Differentiation of primary and secondary vascular tissues throughout the CMU 013 stem was regular but it did not have secondary phloem fibre bundles as in JRC 212. Instead, a few thin-walled, less lignified fibre cells formed uni- or biseriate radial rows within the phloem wedges of the middle stem. The lower and earliest developed part of the mutant stem had no lignified fibre cells. This developmental deficiency in lignification of fibre cells was correlated to a similar deficiency in phenylalanine ammonia lyase activity, but not peroxidase activity, in the bark tissue along the stem axis. In spite of severe reduction in lignin synthesis in the phloem cells this mutant functioned normally and bred true. CONCLUSIONS: In view of the observations made, the mutant is designated as deficient lignified phloem fibre (dlpf). This mutant may be utilized to engineer low-lignin jute fibre strains and may also serve as a model to study the positional information that coordinates secondary wall thickening of fibre cells.     

Production of n + 1 plants and tetrasomics by means of anther culture of trisomic plants in rice (Oryza sativa L.)

Summary Eleven primary trisomics of rice, variety Nipponbare, were subjected to anther culture. The 12th trisomic did not produce normal anthers. A total of 3,734 plants were obtained, which were examined morphologically at the seedling stage in the greenhouse. A number of plants appeared in the progenies of ten trisomics which had unique morphological features. The frequency of these variant types differed among different progenies. Cytological observations revealed that 43 variant plants in the progenies of nine trisomics had 13 chromosomes (n + 1), and 56 were tetrasomics (2n = 26). The tetrasomic plants in the progeny of a trisomic were morphologically identical. Similarly, n + 1 plants in the progeny of a trisomic were also identical. Plants with 23, 25, 36, 39, and 73 chromosomes were also obtained. Results show that valuable aneuploids such as n + 1 and 2n + 2 can be obtained in the anther-culture-derived progenies of trisomics.     

Characterization of the Type of Photosynthetic Carbon Dioxide Fixation in Jute (Corchorus olitorius L.)

Activities of photosynthetic and photorespiratory enzymes viz.,ribulose bisphosphate carboxylase, phosphoenol pyruvate carboxylaseand glycolate oxidase from jute (Corchorus olitorius L.; cv.JRO 632) leaves were compared with those from maize (C₄) andsunflower (C₃) leaves. The photosynthetic CO₂ fixation products,the release of ¹⁴CO₂ in light and dark following photosynthesisin ¹⁴CO₂, chlorophyll a: b ratio, gross leaf photosyntheticrate and dry matter production rate were also studied. The resultsshow that jute is a C₃ plant. Key words: Jute, Corchorus olitorius, C₃ photosynthesis     

Inheritance of a male sterile complex mutant in white jute (Corchorus capsularis L.)

A perfectly monofactorially segregating male sterility mutant in jute, associated with a morphological marker (ribbon leaf, rl) was found to form a pleiotropic complex with several undesirable characters, which make it unsuitable for hybrid breeding, in spite of unimpaired viability. It is improbable that the unfavorable characters can be made harmless by selection for compensating genes.