Wheat Sequences Research Articles

Stable expression of 1Dx5 and 1Dy10 high-molecular-weight glutenin subunit genes in transgenic rye drastically increases the polymeric glutelin fraction in rye flour

We generated and characterized transgenic rye synthesizing substantial amounts of high-molecular-weight glutenin subunits (HMW-GS) from wheat. The unique bread-making characteristic of wheat flour is closely related to the elasticity and extensibility of the gluten proteins stored in the starchy endosperm, particularly the HMW-GS. Rye flour has poor bread-making quality, despite the extensive sequence and structure similarities of wheat and rye HMW-GS. The HMW-GS 1Dx5 and 1Dy10 genes from wheat, known to be associated with good bread-making quality were introduced into a homozygous rye inbred line by the biolistic gene transfer. The transgenic plants, regenerated from immature embryo derived callus cultures were normal, fertile, and transmitted the transgenes stably to the sexual progeny, as shown by Southern blot and SDS-PAGE analysis. Flour proteins were extracted by means of a modified Osborne fractionation from wildtype (L22) as well as transgenic rye expressing 1Dy10 (L26) or 1Dx5 and 1Dy10 (L8) and were quantified by RP-HPLC and GP-HPLC. The amount of transgenic HMW-GS in homozygous rye seeds represented 5.1% (L26) or 16.3% (L8) of the total extracted protein and 17% (L26) or 29% (L8) of the extracted glutelin fraction. The amount of polymerized glutelins was significantly increased in transgenic rye (L26) and more than tripled in transgenic rye (L8) compared to wildtype (L22). Gel permeation HPLC of the un-polymerized fractions revealed that the transgenic rye flours contained a significantly lower proportion of alcohol-soluble oligomeric proteins compared with the non-transgenic flour. The quantitative data indicate that the expression of wheat HMW-GS in rye leads to a high degree of polymerization of transgenic and native storage proteins, probably by formation of intermolecular disulfide bonds. Even gamma-40k secalins, which occur in non-transgenic rye as monomers, are incorporated into these polymeric structures. The combination 1Dx5 + 1Dy10 showed stronger effects than 1Dy10 alone. Our results are the first example of genetic engineering to significantly alter the polymerization and composition of storage proteins in rye. This may be an important step towards improving bread-making properties of rye whilst conserving its superior stress resistance.

PCR Amplification of Wheat Sequences from DNA Extracted During Milling and Baking

ABSTRACTDNA‐based analyses are highly sensitive and specific. Because processing steps can have profound effects on the proteins and DNA present in foods, this project examined the effects of breadmaking on wheat DNA size and polymerase chain reaction (PCR)‐based detection of sequences. DNA was extracted from wheat kernels, milling fractions, and flour, and from samples taken at various steps during and after the baking process. Kernels contained primarily high molecular weight DNA (>12,000 base pairs [bp]), whereas flour DNA exhibited a broad range of molecular weights from >12,000 bp to <300 bp. A marked reduction in DNA yield and size occurred after the first 5 min of baking. PCR successfully amplified products of both high and low copy number genes, even from DNA extracted from bread loaves five days after baking. However, successful amplification required that the maximum product size be no more than the average molecular weight of the DNA recovered from the source. The data also demonstrate that PCR can be used to detect the presence of yeast (Saccharomyces cerevisiae), a minor ingredient.

Change in carbon and nitrogen stocks in soil under 13 years of conventional or zero tillage in southern Brazil

The objective of this study was to determine in a long-term experiment (13 years) the effect of three different crop rotations (R1: wheat ( Triticum aestivum)–soybean ( Glycine max), R2: wheat–soybean–vetch ( Vicia villosa)–maize ( Zea mays), and R3: wheat–soybean–oat ( Avena sativa)–soybean–vetch–maize) under zero tillage (ZT) and conventional tillage (CT) on the stocks of soil organic matter (SOM) in a clayey Oxisol soil of Passo Fundo, Rio Grande do Sul. At the end of 13 years, soil samples were taken to a depth of 100 cm, and analysed for bulk density, chemical composition and 13 C natural abundance. Under a continuous sequence of wheat (winter) and soybean (summer) the stock of soil organic C to 100 cm depth under ZT (168 Mg ha −1) was not significantly different (LSD at P=0.05 of 11 Mg ha −1) to that under CT (168 Mg ha −1). However, in the rotations with vetch planted as a winter green-manure crop (R2 and R3), soil C stocks were approximately 17 Mg ha −1 higher under ZT than under CT. Between 46 and 68% of this difference occurred at 30–85 cm depth. The 13 C abundance data indicated that under ZT the decomposition of the original native SOM was not affected by the different composition of crops in the different rotations, but under CT the rotations R2 and R3, which included vetch and maize, stimulated the decay of the original native SOM compared to the continuous wheat/soybean sequence (R1). It appears that the contribution of N 2 fixation by the leguminous green manure (vetch) in the cropping system was the principal factor responsible for the observed C accumulation in the soil under ZT, and that most accumulated C was derived from crop roots.

Change in carbon and nitrogen stocks in soil under 13 years of conventional or zero tillage in southern Brazil

The objective of this study was to determine in a long-term experiment (13 years) the effect of three different crop rotations (R1: wheat (Triticum aestivum)–soybean (Glycine max), R2: wheat–soybean–vetch (Vicia villosa)–maize (Zea mays), and R3: wheat–soybean–oat (Avena sativa)–soybean–vetch–maize) under zero tillage (ZT) and conventional tillage (CT) on the stocks of soil organic matter (SOM) in a clayey Oxisol soil of Passo Fundo, Rio Grande do Sul. At the end of 13 years, soil samples were taken to a depth of 100 cm, and analysed for bulk density, chemical composition and 13C natural abundance. Under a continuous sequence of wheat (winter) and soybean (summer) the stock of soil organic C to 100 cm depth under ZT (168 Mg ha−1) was not significantly different (LSD at P=0.05 of 11 Mg ha−1) to that under CT (168 Mg ha−1). However, in the rotations with vetch planted as a winter green-manure crop (R2 and R3), soil C stocks were approximately 17 Mg ha−1 higher under ZT than under CT. Between 46 and 68% of this difference occurred at 30–85 cm depth. The 13C abundance data indicated that under ZT the decomposition of the original native SOM was not affected by the different composition of crops in the different rotations, but under CT the rotations R2 and R3, which included vetch and maize, stimulated the decay of the original native SOM compared to the continuous wheat/soybean sequence (R1). It appears that the contribution of N2 fixation by the leguminous green manure (vetch) in the cropping system was the principal factor responsible for the observed C accumulation in the soil under ZT, and that most accumulated C was derived from crop roots.

Crop residue and fertiliser N effects on nitrogen fixation and yields of legume–cereal rotations and soil organic fertility

Improved management of nitrogen (N) in low N soils is critical for increased land productivity and economic sustainability. We report results of a rainfed rotation experiment, conducted in the Northwest Frontier Province (NWFP), Pakistan, during 1995–1999 to evaluate effects of residue retention and fertiliser N on N 2 fixation inputs and yields of a mungbean ( Vigna radiata)–wheat ( Triticum aestivum) sequence, and a lentil ( Lens culinaris)–summer cereal sequence. Mungbean and sorghum ( Sorghum bicolor) or maize ( Zea mays) were grown in the summers and lentil and wheat in the winters. Immediately after grain harvest, above-ground residues of all crops were either completely removed (−residue), or chopped into 5–20 cm pieces, spread across the plots and incorporated by chisel plough (+residue). Fertiliser N rates were nil or 120 kg N/ha for wheat and nil or 150 kg N/ha for sorghum/maize. The percentage of mungbean N derived from N 2 fixation (%Ndfa) ranged from 47% to almost 100% (mean of 75%). On average, mungbean fixed 112 kg N/ha (+residues) and 74 kg N/ha (−residues), with N balances of +64 kg N/ha (+residues) and +9 kg N/ha (−residues). Lentil %Ndfa ranged from 50 to 87% (mean of 73%). Values for crop N fixed were 42–85 kg N/ha, with a mean of 68 kg N/ha. Average N balances for lentil were +27 kg N/ha (+residues) and +16 kg N/ha (−residues). Grain yields of the 0N wheat responded to the previous mungbean (36% increase over the 0N sorghum), but showed an even greater response to fertiliser N applied to the previous sorghum (150% increase). Highest yields were recorded for the N-fertilised wheat (average of 2.27 t/ha). Shoot biomass yields of the 0N sorghum and maize responded strongly to the previous lentil crop (49% average increase over the 0N wheat) and fertiliser N, applied either to the crop itself (140%) or to the previous wheat crop (32%). Residue retention increased shoot biomass yields of both the summer (average of 20%) and winter crops (average of 9%). Grain yield benefits of residues were 13% for mungbean, and 8% for wheat and lentil. Soil organic N and total organic C, labile C and C management index (CMI), were all increased by N inputs, from both fertiliser and N 2 fixation, and by retention of residues We concluded that retention of residues improves the N economy of the cropping system and enhances crop productivity through the additional N and other soil effects. The question of whether farmers who traditionally remove residues for fodder and fuel would change practices and return the residues to the soil will depend to a large extent on the relative profitability of both options.

Isolation and identification of Triticeae chromosome 1 receptor-like kinase genes (Lrk10) from diploid, tetraploid, and hexaploid species of the genus Avena.

The DNA sequence of an extracellular (EXC) domain of an oat (Avena sativa L.) receptor-like kinase (ALrk10) gene was amplified from 23 accessions of 15 Avena species (6 diploid, 6 tetraploid, and 3 hexaploid). Primers were designed from one partial oat ALrk10 clone that had been used to map the gene in hexaploid oat to linkage groups syntenic to Triticeae chromosome 1 and 3. Cluster (phylogenetic) analyses showed that all of the oat DNA sequences amplified with these primers are orthologous to the wheat and barley sequences that are located on chromosome 1 of the Triticeae species. Triticeae chromosome 3 Lrk10 sequences were not amplified using these primers. Cluster analyses provided evidence for multiple copies at a locus. The analysis divided the ALrk EXC sequences into two groups, one of which included AA and AABB genome species and the other CC, AACC, and CCCC genome species. Both groups of sequences were found in hexaploid AACCDD genome species, but not in all accessions. The C genome group was divided into 3 subgroups: (i) the CC diploids and the perennial autotetraploid, Avena macrostachya (this supports other evidence for the presence of the C in this autotetraploid species); (ii) a sequence from Avena maroccana and Avena murphyi and several sequences from different accessions of A. sativa; and (iii) A. murphyi and sequences from A. sativa and Avena sterilis. This suggests a possible polyphyletic origin for A. sativa from the AACC progenitor tetraploids or an origin from a progenitor of the AACC tetraploids. The sequences of the A genome group were not as clearly divided into subgroups. Although a group of sequences from the accession 'SunII' and a sequence from line Pg3, are clearly different from the others, the A genome diploid sequences were interspersed with tetraploid and hexaploid sequences.

Variation in the effects of take-all disease on grain yield and quality of winter cereals in field experiments.

Relationships between take-all intensity and grain yield and quality were determined in field experiments on cereal crops using regression analyses, usually based on single-point disease assessments made during anthesis or grain-filling. Different amounts of take-all were achieved by different methods of applying inoculum artificially (to wheat only) or by using different cropping sequences (in wheat, triticale or barley) or sowing dates (wheat only) in crops with natural inoculum. Regressions of yield or thousand-grain weight on take-all intensity during grain filling were similar to those on accumulated disease (area under the disease progress curve) when these were compared in one of the wheat experiments. Regressions of yield on take-all intensity were more often significant in wheat than in the less susceptible crops, triticale and barley, even when a wide range of disease intensities was present in the latter crops. The regressions usually had most significance when there were plots in the severe disease category. Thousand-grain weight and hectolitre weight usually responded similarly to total grain yield. Decreased yield was often accompanied by a significant increase in the percentage of small grains. When severe take-all was present in wheat, regressions showed that nitrogen uptake was usually impaired. This was sometimes accompanied, however, by increased percentage nitrogen in the grain as a consequence of smaller grain size with decreased endosperm. Significant effects of take-all, both positive and negative, on Hagberg falling number in wheat sometimes occurred. Significant regressions of yield on take-all assessed earlier than usual, ie during booting rather than grain-filling in wheat and triticale and during anthesis/grain-filling rather than ripening in barley, had steeper slopes. This is consistent with observations that severe disease that develops early can be particularly damaging, whilst the crops, especially barley, can later express tolerance by producing additional, healthy roots. The regression parameters, including maximum potential yield (y-axis intercept) and the extrapolated maximum yield loss, also varied according to the different growing conditions, including experimental treatments and other husbandry operations. These differences must be considered when assessing the economic potential of a control measure such as fungicidal seed treatment.

Genus-specific localization of the TaiI family of tandem-repetitive sequences in either the centromeric or subtelomeric regions in Triticeae species (Poaceae) and its evolution in wheat.

The TaiI family sequences are classified as tandem repetitive DNA sequences present in the genome of tribe Triticeae, and are localized in the centromeric regions of common wheat, but in the subtelomeric heterochromatic regions of Leymus racemosus and related species. In this study, we investigated the chromosomal distribution of TaiI family sequences in other Triticeae species. The results demonstrated a centromeric localization in genera Triticum and Aegilops and subtelomeric localization in other genera, thus showing a genus-dependent localization of TaiI family sequences in one or the other region. The copy numbers of TaiI family sequences in species in the same genus varied greatly, whether in the centromeric or subtelomeric regions (depending on genus). We also examined the evolution of TaiI family sequences during polyploidization of hexaploid common wheat. A comparison of chromosomal locations of the major TaiI family signals in common wheat and in its ancestral species suggested that the centromeric TaiI family sequences in common wheat were inherited from its ancestors with little modification, whereas a mixed origin for the B genome of common wheat was indicated.

Logit models for identifying the factors that influence the uptake of new ‘no-tillage’ technologies by farmers in the rice–wheat and the cotton–wheat farming systems of Pakistan's Punjab

In the ‘rice–wheat’ and the ‘cotton–wheat’ farming systems of Pakistan's Punjab, late planting of wheat is a perennial problem due to often delayed harvesting of the previously planted and late maturing rice and cotton crops. This leaves very limited time for land preparation for ‘on-time’ planting of wheat. ‘No-tillage’ technologies that reduce the turn-round time for wheat cultivation after rice and cotton have been developed, but their uptake has not been as expected. This paper attempts to determine the farm and farmer characteristics and other socio-economic factors that influence the adoption of ‘no-tillage’ technologies’. Logit models were developed for the analysis undertaken. In the ‘cotton–wheat’ system personal characteristics like education, tenancy status, attitude towards risk implied in the use of new technologies and contact with extension agents are the main factors that affect adoption. As regards the ‘rice–wheat’ system, resource endowments such as farm size, access to a ‘no-tillage’ drill, clayey soils and the area sown to the rice–wheat sequence along with tenancy and contact with extension agents were dominant in explaining adoption.

Frequencies of Ty1- copia and Ty3- gypsy retroelements within the Triticeae EST databases.

The frequency of Ty1- copia-type and Ty3- gypsy-type retrotransposons in the International Triticeae EST Consortium (ITEC) database (61,942 sequences: 82% wheat, 10% barley, 8% rye) and the DuPont EST database (86,628 wheat sequences) was estimated using BLASTN searches. These ESTs were obtained from 94 cDNA libraries from different tissues (leaves, roots, spikes, flowers and seeds) and different growing conditions, excluding subtracted and normalized cDNA libraries. Triticeae EST databases were screened using four different Ty1- -copia-type, 12 reverse transcriptase sequences, and three Ty3- gypsy-type Triticeae retrotransposon sequences. Using a selection threshold of BLASTN scores higher than 100 or E values smaller than e(-20), 0.145% of the ESTs were found to be significantly similar to at least one of the retrotransposons used in the search (0.064% Ty1- copia, 0.081% Ty3- gypsy). This percentage increased to 0.176% when the BLASTN threshold was changed to E<e(-10). The percentage of ESTs similar to retrotransposons was significantly higher ( P < 0.05) in cDNA libraries from leaf tissues than in cDNA libraries from roots, anthers, or spikes. In addition, the percentage of ESTs similar to retrotransposons in cDNA libraries from plants under stress conditions (0.25% at E<e(-20), and 0.30% at E<e(-10)) was three to four folds higher ( P < 0.0001) than in cDNA libraries from plants grown under normal conditions (0.07% at E<e(-20), and 0.09% at E<e(-10)). Identification of retrotransposons within the Triticeae EST databases provides an indirect estimation of the patterns of transcriptional activity of these repetitive elements and is important to improve the annotation of genomic sequences used to search these EST databases.

Starch synthesis in potato tubers transformed with the wheat genes for ADPglucose pyrophosphorylase.

The aim of this work was to study the role of ADPglucose pyrophosphorylase (AGPase) in starch biosynthesis of non-photosynthetic organs. Agrobacterium tumefaciens was used to transform potato plants (Solanum tuberosum L. cv. Desireé) with the wheat AGPase genes (AGP-S and AGP-L, coding for the small and large subunits, respectively). Neither of these genes contains a recognisable plastid targeting sequence. Southern analysis and analysis of starch content identified four lines that contained both wheat sequences. Immunoblotting indicated that, in the tubers, three lines expressed the wheat small subunit (AGP-S), but AGP-L cross-reacting protein was not apparent. The fourth transgenic line had reduced AGPase activity. AGPase activity in the AGP-transgenic tubers ranged from 15 to 165% of that found in β-glucuronidase (GUS) control lines.

Identification and mapping of polymorphic SSR markers from expressed gene sequences of barley and wheat

The growing availability of EST sequences from a range of crop plantsprovides a potentially valuable source of new DNA markers. We have examined theInternational Triticeae EST Cooperative database for the presence ofdinucleotide and trinucleotide simple sequence repeats. Analysis of 24,344 ESTsidentified 388 dinucleotide repeats and 978 trinucleotide repeats in ESTs,representing 1.6% and 4.0% of the total number of ESTs, respectively. To testthe utility and cross-species transferability of EST-derived SSR markers,primers were designed to the flanking regions of 41 barley SSRs and used toscreen 11 barley and 15 wheat varieties. Sixteen of the barley SSR markers werepolymorphic in barley and five were polymorphic in wheat. This represents arelatively high level of transferability of SSR markers between barley andwheat, which has important implications for the development of new markers andcomparative mapping of barley, wheat and other cereals. An additional 56 SSRsfrom wheat ESTs were tested in the same barley and wheat varieties. Four wheatEST SSR markers were polymorphic in wheat and one in barley. Chromosomallocations in barley and wheat were determined for the majority of polymorphicmarkers.

High selectivity of human tissue transglutaminase for immunoactive gliadin peptides: implications for celiac sprue.

Celiac Sprue is an HLA DQ2 (or DQ8)-associated autoimmune disorder of the human small intestine that is induced by dietary exposure to wheat gliadin and related proteins from barley, rye, and possibly other food grains. Recently, tissue transglutaminase (tTGase)-catalyzed deamidation of gliadin peptides has been shown to increase their potency for activating patient-derived, gliadin-specific T cells, suggesting that tTGase plays a causative role in the onset of an inflammatory response to toxic food grains. To dissect the molecular recognition features of tTGase for gluten derived peptides, the regioselectivity and steady-state kinetics of tTGase-catalyzed deamidation of known immunogenic peptides were investigated. The specificity of recombinant human tTGase for all immunogenic peptides tested was comparable to and, in some cases, appreciably higher than the specificity for its natural substrate. Although each peptide was glutamine-rich, tTGase exhibited a high degree of regioselectivity for a particular glutamine residue in each peptide. This selectivity correlated well with Q --> E substitutions that have earlier been shown to enhance the immunogenicity of the corresponding gliadin peptides. The specificity of tTGase toward homologues of PQPQLPY, a sequence motif found in immunodominant gliadin peptides, was analyzed in detail. Remarkably, the primary amino acid sequences of wheat-, rye-, and barley-derived proteins included many single-residue variants of this sequence that were high-affinity substrates of tTGase, whereas the closest homologues of this sequence found in rice, corn, or oat proteins were much poorer substrates of tTGase. (Rice, corn, and oats are nontoxic ingredients of the Celiac diet.) No consensus sequence for a high-affinity substrate of tTGase could be derived from our data, suggesting that the secondary structures of these food-grain peptides were important in their recognition by tTGase. Finally, under steady-state turnover conditions, a significant fraction of the tTGase active site was covalently bound to a representative high-affinity immunogenic gliadin peptide, suggesting a common mechanism by which cells responsible for immune surveillance of the intestinal tract recognize and generate an antibody response against both gliadin and tTGase. In addition to providing a quantitative framework for understanding the role of tTGase in Celiac Sprue, our results lay the groundwork for the design of small molecule mimetics of gliadin peptides as selective inhibitors of tTGase.

WEED ABOVEGROUND AND SEEDBANK COMMUNITY RESPONSES TO AGRICULTURAL MANAGEMENT SYSTEMS

The development of integrated weed management programs requires a clear understanding of the factors and mechanisms conditioning weed community dynamics in agroecosystems. This study evaluated the effect of different agricultural management systems on the aboveground and seedbank weed communities in annual row crops at the Long Term Ecological Research project in agricultural ecology at the W. K. Kellogg Biological Station, Michigan, USA. Weed biomass and species composition were sampled for six years over two corn–soybean–wheat sequence cycles in four agricultural management systems: (1) conventional (high external chemical input, moldboard plowed); (2) no-till (high external chemical input, no tillage); (3) low-input (low external chemical input, moldboard plowed); and (4) organic (no external chemical input, moldboard plowed). A greenhouse germination study assessed variation in the abundance and composition of the weed seedbank across the studied systems in the first and sixth year of this study. Abov...

Evaluation of allelic diversity at chloroplast microsatellite loci among common wheat and its ancestral species

Twenty four chloroplast microsatellite loci having more than ten mononucleotide repeats were identified from the entire chloroplast DNA sequence of common wheat, Triticum aestivum cv Chinese Spring. For each microsatellite, a pair of primers were designed to produce specific PCR products in the range of 100– 200 bp. The allelic diversity at the microsatellite loci was evaluated using 43 accessions from 11 Triticum and Aegilops species involved in wheat polyploid evolution. Polymorphic banding patterns were obtained at 21 out of 24 chloroplast microsatellite loci. The three monomorphic microsatellites were found to be located in coding regions. For the polymorphic microsatellites, the number of alleles per microsatellite ranged from 2 to 7 with an average of 4.33, and the diversity values (H) ranged from 0.05 to 0.72 with an average of 0.47. Significant correlations (P<0.01) were observed between the number of repeats and the number of alleles, and between the number of repeats and diversity value, respectively. The genetic diversity explained by chloroplast microsatellites and nuclear RFLP markers were compared using 22 tetraploid accessions. Although the number of alleles for nuclear RFLP markers was found to be higher than that for chloroplast microsatellites, similar diversity values were observed for both types of markers. Among common wheat and its ancestral species, the percentages of common chloroplast microsatellite alleles were calculated to examine their phylogenetic relationships. As a result, Timopheevi wheat species were clearly distinguished from other species, and Emmer and common wheat species were divided into two main groups, each consisting of a series of wild and cultivated species from tetraploid to hexaploid. This indicates that the two types of chloroplast genomes of common wheat might have independently originated from the corresponding types of wild and cultivated Emmer wheat species.

Total productivity, nitrogen, phosphorus and potassium removal and economics of rice (Oryza sativa)-wheat (Triticum aestivum) cropping system with integrated nitrogen management in rice

A field experiment was conducted during 2000-2001 and 2001-2002 to evaluate the effect of 5 organic sources of nutrients along with 4 levels of N to rice (Oryza sativa L.) and 3 levels of N to wheat (Triticum aestivum L. emend. Fiori &amp; Paol.) on the total productivity, nutrient removal and economics of rice-wheat system. Inte- grated use of Sesbania g;een-manure along with 180 kg Ntha gave 7.1 tonnestha of rice grain and subsequent application of 150 kg Ntha to succeeding wheat crop yielded 6.0 tonnestha of wheat'grain, t h u s giving a total production of 13.1 tonnestha from rice - wheat sequence. At this production level and fertilizer use, rice removed 136.7, 24.2 and 165.1 kg N, P and Wha and respective values for wheat were 107.8, 20.0 and 124.7 kgtha, mak- ing a total removal of 578.5 kg nutrients (NPWhalannum) from rice-wheat system. The same treatment also gave higher, net return and benefit : cost ratio in the system.

Alternate cropping system for central plateau zone of Maharashtra

A field experiment was conducted during 200810 at Parbhani, to evaluate the production potential of 12 crop- ping systems in central plateau zone of Maharashtra. Of the 12 cropping systems, turmeric (Curcuma longa L.) + castor (Ricinus communis L.) (4:1) intercropping system gave significantly highest net profit ( 171.10 103/ha), economic efficiency of 616.9/day/ha on net monetary return (NMR) basis and soybean-equivalent yield (SEY) (10.5 t/ha), followed by soybean [Glycine max (L.) Merr.]onion (Allium cepa L.), which recorded the net profit of 125.2 103, economic efficiency of 536.4/day/ha, soybean-equivalent yield of 8.2 t/ha, and Bt. cotton (Gossypium hirsutum L.)wheat [Triticum aestivum (L.) emend. Fiori &amp; Paol]coriander (Coriandrum sativum L.) (SEY 8.5 t/ha). Among the cropping sequences, maize (Zea mays L.)chickpea (Cicer arientinum L.)okra (Abelomoschus esculentus L) recorded the highest land-use efficiency (83.6%) followed by maizewheat greengram (83.4%), Bt cottonwheatcoriander (81.7%) and turmeric + castor intercropping system (75.9%). The lowest land-use efficiency was recorded in sorghum [Sorghum bicolor (L.) Moench]wheat sequence (62.1%). The highest benefit: cost ratio was recorded in turmeric + castor (4:1 ratio) intercropping system (3.8), followed by pigeonpea [Cajanus cajan (L.) Millsp.]groundnut (Arachis hypogaea L.) (3.7). The employment generation was the highest (317 man-days/ha/year) in maizechickpeaokra system, followed by Bt cottonwheatcoriander (289 man-days/ha/year). The turmeric + castor intercropping system (4:1) recorded the lowest employment generation (136 man-days/ha/year). The highest consumptive use of water (140.2 cm) and water-use efficiency (56 kg/ha-cm) were recorded in maizewheatgreengram cropping sequence, followed by Bt cottonwheatcoriander cropping sequence. The highest soil-nutrient status was maintained in pigeonpeagroundnut cropping system, followed by cottonsummer groundnut.

Grain production of wheat (Triticum aestivum), and nitrogen and phosphorus balance sheet in soil under sorghum (Sorghum bicolor) cowpea (Vigna unguicu1ata) wheat crop sequence

A 2 year (1995 96 and 1996 97) field experiment showed that grain and straw yields of wheat (Triticum aestivum L. emend. Fiori Paol.) were maximum when grown after sorghum [Sorghum bicolor (L.) Moench] cowpea [Vigna unguiculata (C) Walp.] (F), followed by cowpea grain (SI) and these were found to be significantly higher than after sole crop of sorghum (F.) Phosphorus applied to previous rainy season crops up to 30 kglha and direct applied N to wheat up to 75 kglha helped in inireasing the grain and straw yields of wheat in both the years. The nitrogen, phosphorus and organic carbori (%) of soil improved owing to legume introduction in the cropping systems. The net returns and benefit :cost ratio from sorghum cowpea (F) wheat sequence were maximum, while sorghum (F) wheat sequence gave least net returns.

Effect of zinc levels and incubation with cow dung on yield and zinc uptake by soybean (Glycine max)wheat (Triticum aestivum) sequence in Vertisols

A field experiment was conducted in Vertisols of Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur during 2007-2008 to study the direct effect of Zn levels (0, 1.25, 2.5 and 5 kg/ha) alone and the Zn levels incubated with 200 kg cow dung/ha on yield of soybean {Glycine max (L.) Merrill} JS93 05 and the residual effect on wheat {Triti- cum aestivum (L.) emend. Fiori and Paol} GW 273. Application of 5 kg Zn alone and 5 kg Zn + 200 kg cow dung in soybean significantly increased the Zn uptake (181.9 g/ha), grain (1.71 t/ha) and stover (2.36 t/ha) yields over control. Zn uptake and wheat grain yield significantly increased with the residual effect of 2.5 and 5 kg Zn over control. The findings further, revealed that the 5 kg Zn alone and incubated with cowdung was found beneficial for yield, uptake and Zn availability under soybeanwheat cropping system in Vertisols.

Effect of-Udsripur rock phosphate aloneand in -combination with maize organics-on (Zea.3nu.s)-wheat (Triticunt nestivum) production under acid soil .

Craps vary greatly in their ability to uti- - is of immense importance. The present in- . lize phosphorus from rock phosphates under vestigation. was therefore, undertaken to acid soil conditions. This differential behav- - study the effect of Udaipur rock phosphate iour may be related to their demand for cal- and organic manures on maize (Zeu mays . cium in addition to P. Among the important L.) wheat (Triticum aesiivlrllr L.) sequence means evolved to increase P utilization from under acid soil conditions. rock phosphate, the use of organics, viz. To meet out the ob.jeclives n field experi- farmyard manure (FYM) and biogas slurry ment was conducted at (lie HPKV,