Contributions of algalization to rice growth,yield, N attributes and incidence of infestation with the blast fungusPyricularia oryzae under different fungicidal treatments

Inoculation of the Japonica rice, Giza 171, with blue-green algae along with 36 kg N/ha or complete N fertilization by 108 kg N/ha were tested along with blast-controlling fungicides: Kitazin-17, Fuji-one and Beam. The algal inoculum, which containedAnabaena cylindrica, Anabaena oryzae, Nostoc muscorum and Tolypothrix tenuis, was applled as 100 kg soil-based inoculum (90% moisture)/ha 5 days after transplanting. Plant growth, yield, N content and fertilizer-N-use efficiency were increased and the incidence and severity of leaf and neck intection withPyricularia oryzae were decreased by treatment with the fungicides applied with the algae along with 36 kg N/ha inslead of 108 kg N/ha without algae.

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Résumé On a testé l'inoculation du riz Japonica, Giza 171 avec l'algue bleu-verte, simultanément avec la fertillisation azotée soit à 36 kg N/ha solt complète à 108 kg N/ha et simultanément avec les fongicides Kitazin-17, Fuji-1 et Beam. L'inoculum d'algues, qui contenaltAnabaena cylindrica, Anabaena oryzae, Nostoc muscorum etTolypothrix tenuis, étalt appliqué à raison de 100 kg humides à 90% d'inoculum à base de sol par ha, 5 jours aprés la transplantation. La croissance des plantes, leur rendement, leur contenu azoté ainsi que l'efficience de la fertillisation azotée ont augmenté tandis que l'incidence et la sévérité de l'infection des feullies et du col parPyricularia oryzae ont décru par le traitement aux fongicides appliqué simultanément avec les algues et 36 kg N/ha par rapport au traitement à 108 kg N/ha sans algues.

     

Efficiency of algalization of rice in the Nile Delta with different amounts of nitrogen and potassium fertilization

Indica rice var. IR 28 was inoculated with cyanobacteria (blue-green algae) together with elther 0,72 and 144 kg N/ha or 0,60 and 120 kg K₂O/ha. Plant performance, yield, nitrogen contents and chemical fertilizer-N-use efficiency positively responded to inoculation with the cyanobacteria and increased further with increasing amounts of both N and K. Effects arising from the cyanobacteria, N or K differed under the other two factors.     

Nodulation,vegetative growth,infestation with the spider miteTetranychus cucurbitacearum (Sayed) and seed yield of N-fertilized soybean plants in the Nile Delta

Summary A field experiment was conducted at Sakha Agricultural Research Station, Kafr El-Sheikh, A.R. Egypt, to study the effect of inoculation with the symbiotic N₂-fixerRhizobium japonicum on nodulation, vegetative growth and seed yield of soybeans cultivated in Nile Delta clay-loam alluvial soil, with N-fertilization rates of 48, 96, 144 or 192 kg N/ha. Special attention was given to infestation with the spider miteTetranychus cucurbitacearum (Sayed). Soybeans in noninoculated plots failed to nodulate. In the inoculated plots, nodule number and weight, plant dry weight and N-content, seed yield and N-content and weight/100 seeds responded to inoculation plus N-fertilization up to 96 kg N/ha added as one dose 30 days after planting. Inoculation at all levels of applied N gave higher yields than non-inoculation at corresponding N levels. Infestation with the spider miteTetranychus cucurbitacearum over a 10-week period was highest for inoculation with the symbiotic N₂-fixer and N-fertilization at 96 kg N/ha, the same treatment which gave the highest N-content in plant vegetative tissue.

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Resumen En la Estación de Investigación Agraria de Sakha, Kafr El-Sheik, A.R. Egipto, se estudió el efecto de la inoculación conRhizobium japonicum sobre la nodulación, el crecimiento vegetativo y el rendimiento en semillas, de plantas de soja, cultivadas en un suelo de aluvión, arcillo-limoso, del Delta del Nilo, con las siguientes dosis de abonado nitrogenado: 48, 96, 144 ó 192 kg N/ha. Se prestó especial atención a la infestación por el ácaroTetranychus cucurbitacearum (Sayed). Las plantas de soja de las parcelas no inoculadas no nodularon. En las parcelas inoculadas el número de nódulos y su peso, el peso seco y el contenido en nitrógeno de las plantas, la cosecha de semillas, el contenido en nitrógeno de estas y el peso de 100 semillas respondieron a la inoculación más la fertilización hasta la dosis de 96 kgN/ha añadidos de vez, 30 días después de la siembra. La inoculación incrementó la cosecha respecto al tratamiento no inoculado en todas las dosis de nitrógeno consideradas. La infestación por el ácaroTetranychus cucurbitacearum, observada durante un periodo de 10 semanas, fue máxima para el tratamiento inoculado con dosis de abonado de 96 KgN/ha, que fue así mismo el tratamiento que dió mayor contenido en N del tejido vegetativo de la planta.

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Résumé Une expérimentation sur le terrain a été conduite à la Station de Recherche en Agriculture de Sakha, Egypte, pour étudier l'effect de l'inoculation deRhizobium japonicum sur la nodulation, la croissance végétative et le rendement en graines du soja, cultivé dans un sol alluvial d'argile gras du Delta du Nil, avec un taux de fertilisation respectivement de 48, 96, 144 et 192 kg d'azote par hectare. Une attention particulière a été réservée à l'invasion par la mite araignéeTetranychus cucurbitacearum (Sayed). Les sojas de parcelles non-inoculées n'ont pas développés de nodules. Dans les parcelles inoculées, le nombre et le poids des nodules, le poids sec de la plante et sa teneur en azote, le rendement en graines ainsi que le poids et la teneur en azote par 100 graines ont répondu à l'inoculation plus la fertilisation azotée jusqu'à 96 kg d'azote par hectare et ajouté une dose unique 30 jours après la plantation. L'inoculation à tous les niveaux d'ajouts d'azote a produit des rendements plus élevés que la non-inoculation pour les mêmes taux d'ajout d'azote. L'invasion par la mite araignéeTetranychus cucurbitacearum pendant une période de 10 semaines a été la plus élevée dans le cas de l'inoculation avec le fixateur symbiotique d'azote et la fertilisation azotée à 96 kg par hectare, c'est-à-dire le même traitement que celui qui a résulté en la teneur la plus élevée en azote dans le tissus végétatif végétal.

     

Allelopathic effect of Nymphaea lotus L. on growth and yield of cultivated rice around Lake Manzala (Nile Delta)

Lotus infestation of ricefields is a major cause of crop failure and decrease of grain yield in the newly reclaimed cut-off areas around lake Manzala, Egypt. This study provides insights in the allelopathic effect of Nymphaea lotus L. on rice (Oryza sativa cavr. Giza-177). Lotus rhizome extracts were inhibitory to seed germination and seedling growth of rice. The degree of inhibition was dependent on extract type and concentration. Ethanol and water extracts were more inhibitory than chloroform extracts. The phenolic fraction of ethanol extracts showed the highest inhibitory effects. In a target (rice)-neighbour (lotus) pot experiment, rice dry mass and relative growth rate were dependent on its age and on lotus rhizome density, with decreased growth at increased lotus density. Field data on infested and non-infested ricefields demonstrated a decreased leaf area index and yield in infested fields. Identification of the potential allelochemical compounds by gas chromatography/mass spectrometry revealed the presence of allelopathic phenolics in lotus rhizomes.     

Proteomic analysis of rice leaf, stem and root tissues during growth course

Rice proteins were isolated from leaf, stem and root tissues, harvesting at 1, 2, 4, 8 and 10 weeks after budding. Each tissue of each age was separately pulverized in liquid nitrogen, and the resulted tissue powders were suspended in 10% TCA-acetone and followed by acetone suspension to precipitate at low temperature, which resulted in the tissue-specific and age-specific protein mixture. The protein mixtures were separated by 2-DE using polyacrylamide gels (26 x 20 cm). The protein spots were identified by N-terminal sequence analysis and by MALDI and LC-MS/MS analyses after in-gel tryptic digestion. From a total of 4532 spots, 676 unique proteins were identified, of which 80 proteins (12%) were observed in all three tissues: leaf, stem and root. In addition, 45 (7%) were common in leaf and stem, 57 (8%) in stem and root, and 10 (2%) proteins in root and leaf. Also 141 unique proteins (21%) were observed only for leaf, 96 (14%) for stem, and 247 (36%) for root tissue. Proteins playing a role for photosynthesis and energy production were most abundant in leaf and stem, and those for cell defense were rich in roots.     

Contribution of inoculation with azolla combined with nitrogen,phosphorus and zinc to rice in Nile Delta

Rice performance, in terms of plant height, productive tillering, yield and N-contents of grain and straw, harvest index (grain yield as a percentage of grain plus straw yields) and relative fertilizer N-use efficiency (kg grain yield/kg fertilizer-N) was enhanced by urea, ZnSO₄ and green manuring withAzolla caroliniana. Unlike urea fertilizer, calcium superphosphate increased the rate of azolla field colonization and promoted a thick, healthy dark-green mat of the fern. Response to ZnSO₄ was higher in the azolla-free sub-subplots. Application of ZnSO₄ corrected symptoms of Zn deficiency in rice but the addition of calcium superphosphate in the absence of Zn intensified the symptoms of Zn deficiency.     

不同生育期剪叶对水稻生长、产量及生理的影响

对两个水稻品种(超级杂交稻甬优8号和常规粳稻宁88)稻株进行了不同生育期(苗期、分蘖期和孕穗期)稻纵卷叶螟Cnaphalocrocis medinalis Guenée为害损失率剪叶模拟试验,测定了不同程度剪叶(苗期和分蘖期10%、30%、50%和70%,孕穗期10%、20%、30%和50%)对水稻生长和产量及剪叶后水稻叶片叶绿素含量和根系活力的影响。结果表明,苗期和分蘖期剪叶10%⁷0%均不会影响水稻生长和产量,适当地剪叶反而有增产趋势。在孕穗期剪叶率小于10%时,产量基本不受影响;剪叶率30%时,产量损失小于10%;剪叶率50%时,产量损失20%70%均不会影响水稻生长和产量,适当地剪叶反而有增产趋势。在孕穗期剪叶率小于10%时,产量基本不受影响;剪叶率30%时,产量损失小于10%;剪叶率50%时,产量损失20%²5%。苗期和分蘖期剪叶后,叶片中叶绿素含量不变,根系生长和根系活力增强。这说明,水稻生长前期对叶片受害有较强的耐受和补偿能力,对稻纵卷叶螟前期为害可减少化学防治。     

模拟酸雨对小麦叶片同化物、生长和产量的影响

以小麦为材料,通过大田试验研究了模拟酸雨对小麦生长和产量的胁迫效应.结果表明：酸雨胁迫对小麦产量有较大影响,当酸雨pH≤3.5时显著低于对照（P＜0.01）;当pH≤ 2.5时,小麦株高明显变矮,叶片外观出现明显的受害症状,当pH≤3.5时,叶面积和比叶 鲜质量显著降低.酸雨胁迫下,小麦叶片叶绿素a、b和类胡萝卜素含量都明显降低,但对叶绿素a的影响更显著.酸雨胁迫导致小麦叶片可溶性糖和还原糖的合成受抑,当pH≤3.5时, 受抑作用较强,且酸度越高,影响越大;酸雨胁迫下,小麦叶片的总游离氨基酸和可溶性蛋白质含量均随着酸雨酸度的增加而降低,并分别在pH≤3.5和pH≤4.5时显著低于对照（P＜0.05）.     

二化螟与稻纵卷叶螟幼虫取食诱导的水稻挥发物比较

前期研究结果表明,二化螟和稻纵卷叶螟幼虫为害所诱导的水稻挥发物能对二化螟绒茧蜂Apanteles chilonis Munakata、二化螟Chilo suppressalis(Walker)和稻纵卷叶螟Cnaphalocrocis medinalis(Guene)雌成虫的行为产生影响,并且两者的影响效应存在明显差异,但至今仍不清楚2种害虫危害后水稻挥发物的变化情况。利用动态吸附法对健康水稻苗、二化螟或稻纵卷叶螟幼虫为害苗的挥发物进行捕集与鉴定。在3种处理水稻苗中,共捕集到28种挥发物组分,包括萜类化合物、烷烃类化合物、酮类、醇类、水杨酸甲酯和一些未知化合物。二化螟和稻纵卷叶螟为害均能导致水稻挥发物总量和大多挥发物组分释放量的上升;同时,二化螟幼虫危害能诱导水稻新释放2-heptanonol,(E)-linalooloxide和2种未知挥发物组分,稻纵卷叶螟为害则可诱导水稻产生2-heptanonol,(E)-linalooloxide,MeSA和β-caryophyllene4种新化合物。2种虫害稻株间的比较表明,β-caryophyllene和MeSA是稻纵卷叶螟危害水稻后诱导产生的特有挥发物组分,并且linalool,α-copaene,(+)-cedrol,n-heptadecane和n-nonadecane在二化螟为害苗与稻纵卷叶螟为害苗之间差异显著。这一结果也许可以解释2种害虫诱导水稻挥发物对天敌和害虫行为影响不同的原因。     

Regulation of leaf senescence, grain-filling and yield of rice by kinetin and abscisic acid

Senescence of rice ( Oryza sativa L. cv. Jaya) leaves was regulated with kinetin and abscisic acid (ABA) sprays at the reproductive stage. The effect of such sprays on grain-filling and yield was analyzed. Spraying 100-day-old plants with kinetin solution (100 μg ml^-1) significantly delayed senescence as indicated by higher total chlorophyll and protein levels in the three uppermost leaves compared with the controls. In contrast, spraying with ABA (15 μg ml^-1) significantly promoted foliar senescence. The number of spikelets per panicle, number of panicles, percentage filled grains, panicle weight and grain yield per plant and the mobilization and harvest indices were significantly increased by kinetin treatment, while ABA decreased most of them. The possibility of increased grain-filling and thus, yield due to delayed foliar senescence by kinetin treatment and decreased grain-filling due to hastening of senescence by ABA is discussed.     

播栽期对水稻产量和产量构成因素及生育期的影响

研究了不同播栽期对水稻产量和产量构成因素及生育期的影响。结果表明 ,随播栽期推迟 ,水稻产量有所降低。每穗成粒数减少是推迟播栽期引起水稻减产的主要原因 ,其次是千粒重的下降和成穗数的降低。针对目前的生产实际 ,提出了一些应对播栽期推迟的技术措施。     

Influence of Azolla management on the growth,yield of rice and soil fertility

A field experiment conducted at Central Rice Research Institute, Cuttack, during three successive seasons showed that with the 120-day-duration variety Ratna two dual crops ofAzolla pinnata R. Brown (Bangkok isolate) could be achieved 25 and 50 days after transplanting (DAT) by inoculating 2.0 t ha⁻¹ of fresh Azolla 10 and 30 DAT respectively. One basal crop of Azolla could also be grown using the same inoculum 20 days before transplanting (DBT) in fallow rice fields. The three crops of Azolla grown—once before transplanting and twice after transplanting—gave an average total biomass of 38–63 and 43–64 t ha⁻¹ fresh Azolla containing 64–90 and 76–94 kg N ha⁻¹ respectively in the square and rectangular spacings. Two crops of Azolla grown only as a dual crop, on the other hand, gave 26–39 and 29–41 t ha⁻¹ fresh Azolla which contained 44–61 and 43–59 kg N ha⁻¹ respectively. Growth and yield of rice were significantly higher in Azolla basal plus Azolla dual twice incorporated treatments than in the Azolla dual twice incorporation, Azolla basal plus 30 kg N ha⁻¹ urea and 60 kg N ha⁻¹ urea treatments. Azolla basal plus 30 kg N ha⁻¹ urea and 60 kg N ha⁻¹ urea showed similar yields but Azolla dual twice incorporation was significantly lower than those. The different spacing with same plant populations did not affect growth and yield significantly, whereas Azolla growth during dual cropping was 8.3 and 64% more in the rectangular spacing than in the square spacing in Azolla basal plus Azolla dual twice incorporation and Azolla dual twice incorporation treatments.     

Effects of water regime on growth,yield, and nitrogen uptake of rice

Summary The effects of water regime on the performance of rice were investigated in a greenhouse experiment and two field experiments. The greenhouse experiment involved four water regimes (continuous flooding, and soil drying for 16 days — begun 2, 5, and 8 weeks after transplanting — followed by reflooding), four soils, and 0 and 100 mg N/kg. Soil drying raised the redox potentials of all soils beyond the aerobic threshold. Averaged for soils and N levels, yields from treatments in which soil drying was begun at 2 and 5 weeks after transplanting were lower than that from the continuously flooded treatment, but the simple effects of soil drying on yield and N uptake depended on the soil and the growth stage of the plant. None of the soil-drying treatments had adverse effects in the soil high in N but soil drying at 2 and 5 weeks after transplanting had adverse effects in the soil low in N. The field experiments tested the effects of three water regimes (continuous flooding, alternate drying and flooding every 2 weeks, and soil drying for 2 weeks at 6 weeks after transplanting following by reflooding), and 0, 50, 100, and 150 kg N/ha on a nearly neutral clay soil, during two seasons. None of the soil-drying treatments depressed growth, yield, or N uptake by rice at any level of N in either season. Nitrate was absent after drying, so denitrification was not possible on subsequent flooding. The adverse effects on yield of alternate flooding and drying, attributed to nitrification-denitrification, may be insignificant in wetland fields carrying an actively growing rice crop.     

Effects of soil fumigation on disease incidence, growth, and yield of spring wheat

Plots were fumigated with various amounts of D-D or 85% dazomet dust and sown with spring wheat given various amounts of nitrogenous fertilizer. Dazomet increased yield and decreased take-all disease in the first crop after application, but increased the disease in the second crop. Although D-D increased take-all slightly, it increased yield in 1966, but in 1967 it decreased yield and its use was associated with a severe ear deformity. Fumigation had little effect on eyespot, sharp eyespot, root browning (Fusarium spp.), or browning root rot (Pythium spp.), but decreased nematode damage where nematodes were numerous.     

Sexual differences in the incidence and severity of ectoparasitic infestation of the brown trout, Salmo trutta L.

Hatchery-reared and wild brown trout, Salmo trutta L., were examined for skin ectoparasites during their spawning period in 1977 and 1978. A total of eight genera of parasites, comprising five ciliates, one flagellate, one monogenean and one parasitic fungus, were identified with as many as five different genera occurring on a single fish. Sexually mature male fish were more frequently or more severely infested by species of Ichthyophthirius, Scyphidia, Gyrodactylus and Saprolegnia than were immature fish of either sex or mature female fish. The differences in ectoparasitic loading could not be correlated with known, seasonal changes in the mucus-producing potential of the epidermis. These findings are discussed in relation to the defence mechanisms of teleost fish and to some of the endocrinological changes that occur in salmonid fish during the spawning season.     

Climatic,ecological, and socioeconomic factors associated with West Nile virus incidence in Atlanta,Georgia, U.S.A.

The integrated effects of the many risk factors associated with West Nile virus (WNV) incidence are complex and not well understood. We studied an array of risk factors in and around Atlanta, GA, that have been shown to be linked with WNV in other locations. This array was comprehensive and included climate and meteorological metrics, vegetation characteristics, land use / land cover analyses, and socioeconomic factors. Data on mosquito abundance and WNV mosquito infection rates were obtained for 58 sites and covered 2009–2011, a period following the combined storm water – sewer overflow remediation in that city. Risk factors were compared to mosquito abundance and the WNV vector index (VI) using regression analyses individually and in combination. Lagged climate variables, including soil moisture and temperature, were significantly correlated (positively) with vector index as were forest patch size and percent pine composition of patches (both negatively). Socioeconomic factors that were most highly correlated (positively) with the VI included the proportion of low income households and homes built before 1960 and housing density. The model selected through stepwise regression that related risk factors to the VI included (in the order of decreasing influence) proportion of houses built before 1960, percent of pine in patches, and proportion of low income households.     

Seed priming with boron improves growth and yield of fine grain aromatic rice

Boron (B) is amongst the important micronutrients required for rice from start till physiological maturity. This study was conducted to explore the role of boron application in seedling emergence, leaf appearance and elongation, chlorophyll content, water relations and yield related traits of fine rice. Boron was applied as seed priming. For priming seeds of fine rice cultivars Super Basmati and Shaheen Basmati were soaked in 0.001 and 0.01?% aerated B solutions (w/v); while untreated dry seeds and water soaked (hydropriming) seeds were taken as control. Substantial improvement in seedling emergence was noted by seed priming in 0.001 and 0.01?% solutions. Rate of leaf emergence and elongation and tiller appearance were also improved in seedlings raised from seeds primed in 0.001?% B solution in the tested cultivars. Likewise, leaf chlorophyll contents were significantly improved by B especially with 0.001?% concentration; as was the case for water relations of rice cultivars. At final harvest, all yield contributing parameters were improved by B priming. Increase in yield was due to decrease in panicle sterility by B treatments. A linear increase in leaf and grain B contents was observed with increase in concentration of B priming solution. Overall, B application at very low rate substantially improved seedling emergence, leaf appearance and elongation, tillering, chlorophyll, water relations and yield related traits resulting in better yield and grain B contents. In this regard, seed priming offers an effective and pragmatic way of B application.     

The effect of insecticides on Bemisia tabaci, tomato leaf curl virus disease incidence and yield of tomatoes in the Sudan

The whitefly Bemisia tabaci infested winter-sown tomatoes immediately after germination. Soil-applied granular insecticides and foliar sprays of a synthetic pyrethroid reduced the number of nymphs and adults, but insecticides failed to reduce the incidence of tomato leaf curl virus disease which is transmitted by this insect. Results from pot experiments using aldicarb granules to tomato and to cotton plants indicated that the time and rate of application influence whitefly mortality and reproduction.