Cotton leaf curl is a devastating disease of cotton that has resulted in severe losses (estimated at more than US$87 million per annum) in Pakistan. The epidemic is centered in Punjab, the province that contributes approximately 80% of Pakistan's cotton. Previously, the disease had been observed sporadically on single plants in the northern Sindh Province but did not cause economically significant damage. During the years 2004 and 2005, a high incidence (approximately 20%) of the disease was observed in Shahdadpur and parts of District Sanghar, located in central Sindh Province. The disease was also observed at low incidence (<1%) in southern Sindh. To confirm the identity of the causal agent of the disease, 18 samples from three districts in central southern Sindh (Sanghar, Hala, and Hyderabad) were collected, and total DNA was extracted using cetyltrimethylammoniumbromide (2). Universal primers for begomoviruses based on conserved sequences as follows were used in polymerase chain reaction (PCR): BegomoF (5'-CCGTGCTGCTGCCCCCATTGTCCGCGTCAC-3') and BegomoR (5'-CTGCCACAACCATGGATTCACGCACAGGG-3'). Universal primers for amplification of DNA β with PCR were also used (1). A full-length clone of Cotton leaf curl Multan virus (CLCuMV) was labeled with alpha-32PdCTP by the oligo-labeling method and used as a probe in Southern hybridization for the detection of geminivirus DNA forms (2). Similarly, cotton leaf curl disease associated DNA β was also labeled and used as a probe in Southern hybridization. The use of universal primers for begomoviruses resulted in amplification of viral DNA of the expected size from all samples while no PCR product was obtained from healthy plants. PCR results confirmed that all plants were infected with begomoviruses. Southern hybridization with CLCuMV and DNA β probes detected begomovirus DNA forms associated with virus replication when washed at medium stringency, further confirming that the plants were infected with the cotton leaf curl geminivirus complex (2). Our results indicate that cotton leaf curl complex has become established in central and southern districts of Sindh Province and it poses a major threat to cotton grown in the region. References: (1) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (2). S. Mansoor et al. Arch. Virol. 148:1969, 2003.

Transgenes in plastids are contained by stringent maternal inheritance in most cultivated plant species and their expression yields high levels of protein with bona fide structure. Nevertheless, transfer of plastid genes to the nucleus has been reported, with implications for transgene containment. The significance of these transfers will depend on the likelihood that they will become functional nuclear genes. Recently a novel approach, intein-mediated protein trans-splicing, has been demonstrated promising to yield transgenic plants with greatly reduced risk of genetic outcrossing.

Thirty rhizobacteria isolated from maize grown in Pakistani and Indonesian soils were evaluated for their morphological characteristics, nitrogen fixation, P-solubilization, indole acetic acid (IAA) and siderophores production. Nitrogenase activity was detected in nineteen isolates ranging from 21.8-3624 n moles C2H4 produced/h/mg protein. Most of the isolates produced IAA, ten were capable of siderophore production while four were P-solubilizers. Ultrastructural studies of Pseudomonas sp. F14 indicated characteristic rhizospheric colonization within 48 h that was observed to change considerably with the passage of time from few bacteria to micro colonies. Random amplified polymorphic DNA (RAPD) analysis of 30 bacterial strains using 30 oligonucleotide primers resulted in considerable level of genetic diversity, with genetic distance ranging from 2-16%. Indonesian isolates were found to be more diverse as compared to Pakistani isolates. The characterization and screening of rhizobacteria of maize rhizosphere has helped in selection of isolates F7, LS-1, 3.1.1.C, F2, F3 and F13 as superior strains for use as bioinoculant. Moreover isolate F14 identified, as Pseudomonas fulgida by partial 16S rRNA sequence analysis is a novel strain regarding its tremendous potentials for inoculum production to enhance the yield of maize.

Antagonism amongst mixtures of inoculant strains of Rhizobiaceae on the basis of bacteriocin production was assessed. A total number of 10 strains of Rhizobium, Bradyrhizobium and Agrobacterium were screened for their bacteriocin production ability. It was observed that Rhizobium leguminosarum bv. viciae strain LC-31 produced a medium typed bacteriocin that was found to be highly effective in growth inhibition of some strains of R. leguminosarum bv. viciae and Agrobacterium sp.It was isolated and partially purified to homogeneity by chloroform extraction followed by ammonium sulfate fractionation. The bacteriocin fraction consistently migrated as a 50 kDa polypeptide on SDS-PAGE. Ex vivo assays were carried out using the partially purified bacteriocin protein fraction of R. leguminosarum bv. viciae strain LC-31 against related strains of the same species. It showed an activity pattern similar to that exhibited by strain LC-31. (C) 2004 Elsevier B.V. All rights reserved.

Experiments were conducted to determine the growth promoting activities of various rhizobia in cotton (Gossypium hirsutum L.) under growth room conditions. Seeds of 4 cotton cultivars were inoculated with 4-indole-3-acetic acid producing selected (Brady) rhizobium strains and Azotobacter plant growth promoting rhizobacteria strains, included as a positive control. Growth responses to inoculation exhibited bacterial strain-cotton cultivar specificity and also included increase in rate of seedling emergence by 3–9%. Shoot dry weight, biomass and N uptake were increased by 48, 75 and 57%, respectively, due to inoculation with both the Rhizobium leguminosarum bv. trifolii E11 and Azotobacter sp. S8, whereas, strain E11 also increased root dry weight, root length and area by 248, 332 and 283%, respectively. K+ and Ca2+ uptake was also increased by 2–21% and 9–14%, respectively, due to rhizobial inoculation. The results also showed that (Brady) rhizobium strains promoted cotton growth through efficient nutrient uptake, which was mainly related to increased root growth due to the effect of IAA produced by these strains. However, growth promotion by Azotobacter sp. S8, in addition to 4-indole-3-acetic acid production, might also involve biological N2 fixation by this rhizobacterial strain at some stage during its growth.

Rhizobial strains were isolated from the root nodules of Medicago saliva (alfalfa) and Trifolium subterraneum (clover) plants. These strains were tested for their growth rate, morphological characteristics and utilization of different carbon sources. Four out of six strains isolated from the alfalfa plants re-nodulated the host plant confirming them as the strains of Rhizobium meliloti. Similarly five out of eight strains isolated from clover plants caused infection on clover corroborated as Rhizobium leguminosarum bv. trifolii strains. The nitrogen fixing ability of these strains ranged from 266 - 673 n moles of C2H4 produced h(-1)g(-1) nodule dry weight. The competitive ability of inoculated strains with indigenous population was studied with two local soils selected on the basis of their cropping history in a pot experiment. The isolated strains MS4 and TS1 were found to be most effective and competitive for alfalfa and clover respectively. Overall recovery of the inoculated strains was 30% for alfalfa and 100% for clover as determined by fluorescent antibody technique. MS4 and TS1 are potent strains for the production of biofertilizer for fodder legumes.

The hydrogel amendments may improve seedling growth and establishment by increasing water retention capacity of soils and regulating the plants available water supplies, particularly under arid environments. The effects of different levels of a locally prepared hydrogel were studied on the moisture properties of sandy loam and loam soils (fine-loamy, mixed, hyperthermic Typic Haplargids, USDA, Luvic Yermosol, FAO) and on growth response of three plant species, viz. barley (Hordeum vulgare L.), wheat (Triticum aestivum L.) and chickpea (Cicer arietinum L.). Water absorption by gel was rapid and highest in distilled water and was inhibited by an increase in water salinity. The addition of 0.1, 0.2 and 0.3% hydrogel increased the moisture retention (θr) at field capacity linearly (r = 0.988) and thus the amount of plant available water significantly in both sandy loam and loam soils compared to the untreated soils. Seed germination of wheat and barley was not affected but seedling growth of both species was improved by the gel amendment. In loam soil, seed germination of chickpea was higher with 0.2% gel and seedling growth increased with increase in gel level compared with control conditions. The hydrogel amendment caused a delay by 4-5 days in wilting of seedlings grown in both soils compared with control conditions. The hydrogel amendment was effective in improving soil moisture availability and thus increased plant establishment. However, the varied responses of plant species in sandy loam and loam soils warrant further studies on the behaviour of different soil types with gel amendments.

Isolation of phosphate solubilising bacterial strains was carried out from rhizosphere, roots and nodules of chickpea, to study the viability for solubilisation of tri-calcium phosphate and the effect on growth of chickpea plants. The potential of isolated bacterial strains to solubilise phosphate was qualitatively evaluated by the measurement of a clear zone around the colonies. The diameter of this zone ranged from 21 to 83 mm. Phosphate solubilisation, by phosphate solubilising bacterial isolates, was quantified by spectrophotometry and was found to range from 65 to 130.5 μg/mL. The drop in pH ranged from 5.6 to 3.6. The plant growth, shoot phosphorus and nitrogen concentrations, nodulation efficiency and nitrogenase activity were significantly enhanced, showing the positive effect of phosphate solubilising bacteria inoculation. Phosphate solubilising bacterial strains CPS-2, CPS-3 and Ca-18 had the maximum positive effect on shoot length, shoot dry weight and nodulation of chickpea plants. Treatments inoculated with non-phosphate solubilising bacterial strains IFA1 and IFA2 showed the minimum values in all the parameters.

This study was undertaken to isolate and characterize plant growth promoting bacteria (PGPB) occurring in four soils of Zanzibar, Tanzania as well as to evaluate their potential use as biofertilizers for rice. A total of 12 PGPB strains were isolated from rice and studied for growth characteristics, carbon/nitrogen source utilization patterns using QTS-24 kits, phosphate solubilization, indole acetic acid (IAA) production, antibiotic resistance patterns and growth at different pH, temperature and salt concentrations. All the isolates were motile and gram negative except Z3-4. Acetylene reduction activity was detected in all isolates ranging from 5.9-76.4 nmole C2H2 reduced/h x mg protein while 9 isolates produced IAA ranged from 20-90.8 mg/l. Most of the isolates showed resistance against different environmental stresses like 10-40 degrees C temperature, 0.2-1 M salt concentration and 4-8.5 pH range. Only one isolate Z2-7 formed clear zones on Pikovskaia's medium showing its ability to solubilize phosphates. Z3-2 was used to develop fluorescent antibodies to check the cross reactivity of the isolates. Inoculation of these bacterial isolates resulted in higher plant biomass, root area, and total N and P contents on Tanzanian rice variety BKN PRAT3036B under controlled conditions. Bacillus sp. Z3-4 and Azospirillum sp. Z3-1 are effective strains and, after further testing under field conditions, can be used for inoculum production of rice in Tanzania. The plant growth promoting effects of these PGPRs suggest that these can be exploited to improve crop productivity of rice in Tanzania.

Plant PathologyVolume 52, Issue 6 p. 809-809 Free Access First report of cotton leaf curl disease affecting chili peppers M. Hussain, M. Hussain National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorS. Mansoor, S. Mansoor National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; and E-mail: smansoor@nibge.orgSearch for more papers by this authorI. Amin, I. Amin National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorS. Iram, S. Iram National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorY. Zafar, Y. Zafar National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorK. A. Malik, K. A. Malik National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorR. W. Briddon, R. W. Briddon Department of Disease and Stress Biology, The John Innes Centre, Colony Lane, Norwich, NR4 7UH, UKSearch for more papers by this author M. Hussain, M. Hussain National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorS. Mansoor, S. Mansoor National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; and E-mail: smansoor@nibge.orgSearch for more papers by this authorI. Amin, I. Amin National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorS. Iram, S. Iram National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorY. Zafar, Y. Zafar National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorK. A. Malik, K. A. Malik National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; andSearch for more papers by this authorR. W. Briddon, R. W. Briddon Department of Disease and Stress Biology, The John Innes Centre, Colony Lane, Norwich, NR4 7UH, UKSearch for more papers by this author First published: 12 December 2003 https://doi.org/10.1111/j.1365-3059.2003.00931.xCitations: 11 AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Cotton leaf curl disease (CLCuD) is an important disorder of cotton in Pakistan and northern India and is associated with begomovirus species. A symptom-modulating DNA satellite (CLCuD DNA β) is also required to induce CLCuD (Briddon et al., 2001; Mansoor et al., 2003b). Recently a CLCuD begomovirus/DNA β complex that overcomes disease resistance in cotton has been found in Pakistan (Mansoor et al., 2003a). This prompted efforts to identify alternative host plants that may affect the epidemiology. A survey of cotton-growing areas in 2002/2003 found typical CLCuD symptoms, leaf curling (LC) and vein thickening (VT) on chili pepper (Capsicum annuum). Chili pepper production often overlaps with cotton in Pakistan and might serve as an important inoculum source. Chili peppers with LC have been shown to contain begomoviruses and a distinct DNA β has been isolated (Briddon et al., 2003). However, there are no reports of CLCuD affecting chili pepper. To assess CLCuD in chili pepper, plants with LC and VT were collected from the Vehari and Khanewal districts of Punjab province. To identify the begomoviruses present, total DNA was isolated from leaf samples, resolved in agarose gels and blotted onto nylon membranes. A sample from the Jhang district previously shown to contain chili leaf curl disease (ChLCD) DNA β was included. Blots were probed with a nonradioactive probe derived from Cotton leaf curl Multan virus (Briddon et al., 2001) and washed at low stringency. A positive signal was detected in all chili pepper samples showing symptoms. PCR using primers CLCV1 [5′-CCGTGCTGCTGCCCCCATTGTCCGCGTCAC-3′] and CLCV2 [5′-CTGCCACAACCATGGATTCACGCACAGGG-3′], designed to conserved sequences of begomoviruses isolated from cotton and okra, produced products of the expected size from all samples with symptoms. DNA β was determined by PCR using a set of universal primers (Briddon et al., 2003). An amplicon of the expected size (approx. 1350 nucleotides) was produced in assays of all these samples. Southern blots of extracts from affected chili peppers, probed with CLCuD DNA β and washed at high stringency, yielded a strong signal in samples from Vehari and Khanewal districts but not from the Jhang district. The results confirm the presence of CLCuD DNA β in chili pepper. This is the first report of CLCuD in this crop. References Briddon RW, Bull SE, Amin I, Idris AM, Mansoor S, Bedford ID, Dhawan P, Rishi N, Siwatch SS, Abdel-Salam AM, Brown JK, Zafar Y, Markham PG, 2003. Diversity of DNA beta; a satellite molecule associated with some monopartite begomoviruses. Virology 312, 106– 21. Google Scholar Briddon RW, Mansoor S, Bedford ID, Pinner MS, Saunders K, Stanley J, Zafar Y, Malik KA, Markham PG, 2001. Identification of DNA components required for induction of cotton leaf curl disease. Virology 285, 234– 43. CrossrefCASPubMedWeb of Science®Google Scholar Mansoor S, Amin I, Iram S, Hussain M, Zafar Y, Malik KA, Briddon RW, 2003a. The breakdown of resistance in cotton to cotton leaf curl disease in Pakistan. Plant Pathology 52, 784. Wiley Online LibraryWeb of Science®Google Scholar Mansoor S, Briddon RW, Bull SE, Bedford ID, Bashir A, Hussain M, Saeed M, Zafar Y, Malik KA, Fauquet C, Markham PG, 2003b. Cotton leaf curl disease is associated with multiple monopartite begomoviruses supported by single DNA β. Archives of Virology 148, 1969– 86. Google Scholar Citing Literature Volume52, Issue6December 2003Pages 809-809 ReferencesRelatedInformation

Cotton leaf curl disease (CLCuD), a devastating disorder of cotton in Pakistan, is caused by a whitefly-transmitted begomovirus (Cotton leaf curl virus; CLCuV) that requires a satellite DNA β to cause disease symptoms (Mansoor et al., 1993; Briddon et al., 2001). CLCuD-resistant cotton varieties, in which no virus can be detected, have been developed through conventional breeding (Rahman et al., 2002). During the 2001 growing season, symptoms of CLCuD were observed on all hitherto resistant varieties at Burewala, District Vehari, Pakistan, and by 2002 disease symptoms were seen throughout the district. To determine if a resistance-breaking strain of CLCuV had arisen, resistant and susceptible varieties were grown in the field at NIBGE (Faisalabad) and at the Cotton Research Station (Vehari). Plants of six commercial virus-resistant varieties (CIM 448, CIM 443, CIM 446, CIM 473, CIM 435 and FH 900) showed no disease symptoms at Faisalabad, while susceptible varieties S-12 and CIM70 had symptoms typical of CLCuD. At Vehari, plants of the same six resistant varieties showed between 15 and 50% infection, while the two susceptible varieties were all infected. Scions of CLCuD-affected resistant varieties, collected from Vehari, were grafted onto 10 plants of each resistant genotype at NIBGE. This resulted in disease symptoms on 20–40% of plants, confirming a breakdown of resistance. To identity the resistance-breaking virus, nucleic acid was extracted from plants with and without symptoms collected at both sites. Samples were Southern-blotted and probed with a biotinylated DNA A clone of CLCuV. The probe detected both the ss and ds DNA forms characteristic of begomoviruses, confirming the association of a begomovirus with the disease. Universal primers for DNA β of CLCuV were used to amplify DNA β from leaves with symptoms collected from resistant varieties in the Vehari area and the PCR product from one location was cloned in a T/A cloning vector (Fermentas). Since CLCuV DNA β is specific to CLCuV (Briddon et al., 2003), a DNA β cloned from cotton plants of resistant varieties showing symptoms of CLCuD in the Burewala area was used as a disease-specific probe in Southern blot hybridizations. The probe hybridized only with DNA extracted from CLCuV affected cotton plants while no signal was detected from a tomato plant (Lycopersicon esculentum) that was previously shown to be associated with a DNA β distinct from that associated with CLCuV (Briddon et al., 2003). Samples collected from both locations hybridized with this probe. A duplicate blot was probed with a previously reported CLCuV DNA β (Briddon et al., 2001) and this resulted in a similar pattern of hybridization. Based on the data presented here, it was concluded that the plants of resistant varieties were infected with CLCuV (Briddon et al., 2001). These results strongly suggest the emergence of a resistance-breaking strain of CLCuV in Pakistan.

The present study deals with the isolation of plant growth promoting rhizobacteria (PGPR) from rice (variety NIAB IRRI-9) and the beneficial effects of these inoculants on two Basmati rice varieties. Nitrogen-fixing activity (acetylene-reduction activity) was detected in the roots and submerged shoots of field-grown rice variety NIAB IRRI-9. Estimation of the population size of diazotrophic bacteria by ARA-based MPN (acetylene reduction assay-based most probable number) in roots and shoots indicated about 10(5)-10(6) counts/g dry weight at panicle initiation and grain filling stages. Four bacterial isolates from rice roots and shoots were obtained in pure culture which produced phytohormone indoleacetic acid (IAA) in the growth medium. Among these, three isolates S1, S4, and R3 reduced acetylene to ethylene in nitrogen-free semi-solid medium. Morphological and physiological characteristics of the isolates indicated that three nitrogen-fixing isolates S1, S4, and R3 belonged to the genus Enterobacter, while the non-fixing isolate R8 belonged to the genus Aeromonas. 16S rRNA sequence of one isolate from root (R8) and one isolate from shoot (S1) was obtained which confirmed identification of the isolates as Aeromonas veronii and Enterobacter cloacae, respectively. The 1517-nucleotide-long sequence of the isolate R8 showed 99% similarity with Aeromonas veronii (accession No. AF099023) while partial 16S rRNA sequence (two stretches of total 1271 nucleotide length) of S1 showed 97% similarity with the sequence of Enterobacter cloacae (accession No. AJ251469). The seedlings of two rice varieties Basmati 385 and Super Basmati were inoculated with the four bacterial isolates from rice and one Azospirillum brasilense strain Wb3, which was isolated from wheat. In the rice variety Basmati 385, maximum increase in root area and plant biomass was obtained in plants inoculated with Enterobacter S1 and Azospirillum Wb3, whereas in the rice variety Super Basmati, inoculation with Enterobacter R3 resulted in maximum increase of root area and plant biomass. Nitrogen fixation was quantified by using 15N isotopic dilution method. Maximum fixation was observed in Basmati 385 with the inoculants Azospirillum Wb3 and Enterobacter S1 where nearly 46% and 41% of the nitrogen was derived from atmosphere (%Ndfa), respectively. In general, higher nitrogen fixation was observed in variety Basmati 385 than in Super Basmati, and different bacterial strains were found more effective as inoculants for the rice varieties Basmati 385 and Super Basmati.

Cotton leaf curl disease (CLCuD) is a major constraint to cotton production in Pakistan. Infectious clones of the monopartite begomovirus cotton leaf curl virus (CLCuV), associated with diseased cotton, are unable to induce typical symptoms in host plants. We have identified and isolated a single-stranded DNA molecule approximately 1350 nucleotides in length which, when coinoculated with the begomovirus to cotton, induces symptoms typical of CLCuD, including vein swelling, vein darkening, leaf curling, and enations. This molecule (termed DNA beta) requires the begomovirus for replication and encapsidation. The CLCuV/DNA 1/DNA beta complex, together with a similar complex previously identified in Ageratum conyzoides, represent members of an entirely new type of infectious, disease-causing agents. The implications of this finding to our understanding of the evolution of new disease-causing agents are discussed.

Annual crop legumes, grown in rotation with cereal crops, contribute to the total pool of nitrogen in the soil and improve the yield of cereals. The present study aimed at the quantification of nitrogen fixation by mungbean and blackgram using N-15 isotopic dilution methodology; and the quantification of grain and nitrogen yield differences of succeeding rice and wheat crops compared with a cereal-cereal rotation. There were 2 experiments in separate fields but with the same layout: in experiment 1, rice followed the mungbean and blackgram varieties and in experiment 2, wheat followed the mungbean and blackgram varieties. Nitrogen fixed ranged from 26 to 36 kg/ha in experiment 1 and from 30 to 36 kg/ha in experiment 2. Soil nitrogen spared by legume crops ranged from 2 to 26 kg/ha in experiment 1 and from 4 to 23 kg/ha in experiment 2. Rice paddy yields were 0.6-1.1 t/ha higher in the legume-cereal rotation than in the cereal-cereal sequence. Similarly, wheat grain yields were 0.5-1.1 t/ha higher in the legume-cereal rotation.

Alcaligenes faecalis A 1501 could grow well in solid of liquid medium containing 4%NaCl. A 1501 could produce IAA under the salt stress and maintain efficient N-fixing activity when NaCl concentration is lower than 4%. Bacteria lost chemotactic capability when concentration of ammonia is higher than 3.0%. A1501 colonized on root surface and root hairs, especially on zones of emergence of lateral roots and efficiently fix nitrogen there under the salt stress. 0.5% of NaCl enhanced colonization of A 1501 on root surface. A1501 could enter the roots at points of emergence of lateral roots.

Cynodon dactylon (L.) Pers., Desmostachya bipinnata (L.) Stapf, Kochia indica Wight, Polypogon nonspeliensis (L.) Desf., Sporobolus arabicus Boiss., and Suaeda fruticosa (L.) Forssk. established in well-defined patches in saline fields planted with Kallar grass (Leptochloa fusca (L.) Kunth). Water extracts, shoot material of different species decomposing in soil and leachates from soils amended with shoot materials inhibited seed germination and/or growth of Kallar grass to varying degrees. Each species showed allelopathic potential against Kallar grass in one or more tests. Six allelochemicals viz., benzoic, ferulic, caffeic, p-OH-benzoic, vanillic and syringic acids were identified in water and/or hydrolysis extracts of different species. Four of these compounds (present in all species) inhibited seed germination and seedling growth of Kallar grass. Allelopathic influence of invading species and autotoxicity are important factors causing elimination of Kallar grass from weed patches and its decreased productivity in older stands.