Influence of weeds on seed development, yield components and seed quality in Okra (Abelmoschus esculentus)

The presence of weeds during crop production is known to affect yield. However, changes to yield components, seed development and seed quality are not well documented. The study was conducted to determine the effect of weeds on accumulation of seed dry weight, yield components, and seed quality in okra (Abelmoschus esculentus). Treatments in the field consisted of manual weeding, no weeding or herbicide spraying. Flowers were tagged daily al flowering stage and fruits were harvested at 15, 20, 25, 30, 35 or 40 days after flowering (DAF). Changes in accumulation of seed dry weight, lOO0 seed weight, seed germination and field emergence were evaluated following all harvests. Yield components (fruits plant1 and seeds fruit1) were evaluated at 40 DAF. The presence of weeds did not affect the duration for seeds to reach maximum dry weight, but reduced lOO0 seed weight, fruits plant1 and seeds fruit1. Seeds harvested from manually weeded plats resulted in higher germination and field emergence compared with those from herbicide or no weeding plots. The presence of weeds >= 7.5% coverage) did not affect the time taken to achieve maximum germination and seed quality directly however, weeds directly affected rate of accumulation of seed d,y weight and seed size which subsequently affected germination and field emergence

Satu kajian kes pembangunan di mukim bandar Jugra Kuala Langat / Johana Juraimi

Projek kertas kerja ini adalah untuk memenuhi keperluan asas Kursus Diploma Pentadbiran Awam= Pelajar-pelajar dari semester Enam telah diminta untuk menyediakan satu kertas projek pengajian yang berkaitan dengan raata pelajaran yang dipelajari dalam kursus ini. Oleh yang demikian tajuk berikut telah dipilih oleh penyelidik; "Satu Kajian Pembangunan Di Mukim Bandar Jugra, Kuala Langat, Selangor Darul Ehsan

The Esterases of the Galleria Mellonella Larvae

Some properties of esterases of the greater wax moth larvae, Galleria mellonella (L.) were examined and the enzyme partially purified. Tris buffer was chosen as the buffer system over veronal buffer. The former causes less hydrolysis of the acetylsalicylic acid. Esterase activities were determined with acetylasalicylic acid in tris buffer (00.05 M, pH 7.85 with 0.1 M EDTA) and with acetyl-p-hydroxybenzoic acid in the same buffer. The enzyme was partially purified by combination of acetone powder preparation, ammonium sulfate precipitation, ion-exchange chromatography, and gel filtration. The starting enzyme preparation was obtained from aceton powder preparation. The ratio of esterase activity to protein content was increased 1.36-fold by 70% ammonium sulfate precipitation. The ammonium sulfate in the 60-70% saturation range is reproducible with the highest specific activity at 60% saturation. The ammonium sulfate fractionation increased the stability of the enzyme preparation. After 24 hours more than 55% of enzyme activity from the ammonium sulfate precipitate still remained, whereas only about 40% of the enzyme activity from the acetone powder preparation remained. The pH optimum was found to be 8.5 with acetyl-p-hydroxybenzoic acid as the substrate. The esterase had a linear increase in activity with increasing temperature. At 51°C, the specific activity was 27.60 micromoles/min mg protein in comparison to 12.94 micromoles/min mg protein at 20°C. The kinetic behavior of the enzyme with the different substrates was studied. The Vmax and Km values were 12.5 micromoles/min mg protein and 0.435 millimoles, respectively. The energy of activation with acetyl-p-hydroxybenzoic acid was 4.542 kcal K-1 mol-1. The esterase activity was inhibited by mercuric chloride and veratrine sulfate. It was activated by the chelating agent, EDTA. The esterase activity was not affected by p-chloromercuribenzoic acid and eserine salicylate

Contribution of morpho-physiological attributes in determining the yield of mungbean

Field experiments were conducted in 2006 and 2007 under subtropical conditions to investigate the variations in growth and reproductive characters, and yield attributes for selection of important source and sinks characters using correlation and path coefficient analyses in 45 mungbean genotypes. Large genetic variability existed in source characters viz., leaf area index (LAI) (1.22 to 3.80) and sink characters viz., number of racemes plant-1 (6.30 to 22.9), flowers plant-1 (18.1 to 51.9) and pods plant-1 (9.6 to 22.1). Genotypic correlation study revealed that among the traits investigated, LAI was the most important source that determined total dry mass (TDM) yield, and reproductive characters like number of racemes, flowers and pods plant-1 were the most important sinks that determined seed yield. Contrarily, reproductive efficiency (RE, % pod set to opened flowers) did not show significant relationship with pod number and seed yield, indicating that selection of high yield based on RE may be misleading. Path coefficient analysis further revealed that number of flowers, pods and 100-seed weight constituted central important sinks which exerted direct positive influence on seed yield. The results indicated that pod yield could be increased by increased raceme and flower production, while seed yield could be increased by increasing pod production. High yielding genotypes, in general, possessed higher earlier mentioned source (LAI) and sink (flower and pod number) characters which resulted in higher seed yield in mungbean. This information could be exploited in the future plant breeding programmes.Key words: Source-sink, correlation, path analysis, mungbean

Effects of sowing date and nutsedge removal time on plant growth and yield of tef [Eragrostis tef (Zucc.) Trotter]

Tef [Eragrostis tef (Zucc.) Trotter] is an annual C4 grass crop that originated in Ethiopia. The average grain yield of this crop is low; averaging < 0.8 Mg ha-1 in farmer’s fields of the semi arid conditions.Productivity can be increased to a considerate extent through the improvement of management practices alone, particularly sowing time with appropriate weed control. The objective of this study was to identify the growth and yield performance of tef as affected by cultural manipulation of date of sowing and weed removal time at semi arid region in Alem tena in Ethiopia. Tef was planted at three sowing dates, recommended sowing date, 7 and 15 days delay after the recommended date. The fiveweed removal time were included as weedy check (W1), weeded two weeks (W2), four weeks (W3), six weeks (W4) after crop emergence and weed-free check (W5). All data were subjected to analysis by ANOVA, principal component analysis (PCA) and correlation/regression analysis. Weed removal time played a minor role compared to sowing time. Irrespective of weeding dates, delayed tef sowing time was very critical. Plant height reduced by 23 to 32%, panicle length by 45.51 and 55.11% crop biomass by 34.39 and 35.53% and grain yield 60 to 68%, when sowing was delayed for 7 and 15 days, respectively. The relationship between plant height and grain yield and crop biomass and grain yield oftef was very strong and quadratic, whereby, as the plant height as well as crop biomass increased, the yield also increased. All these relationships clearly indicate the high competitive ability of tef against nutsedge. Nutsedge competition during the first 6 weeks after crop emergence reduced tef biomass by more than 30%. Keeping the tef field free of weeds for at least six weeks for early and late sown tef is essential to give the crop advantage of growing faster to enhance crop yields

Introduction to robotics agriculture in pest control: a review

Agriculture is one of the latest industries that uses robotic technologies. Cultivation of crops with high yield and quality can be enhanced when technological sustenance is involved. Pests are nuisance and cannot be completely eliminated, but with effective control and management. damages caused by pests could be minimized below economic threshold. Automation in agriculture is stable and accurate and is mainly incorporated in mechanized farming system. However its numerous application in different agricultural practices is not well noticed. Hence this paper attempts to provide profound awareness on robotic technology in agriculture. Robots could have a specific or multiple functions and, most commonly, they are made up of five basic components; sensors, effectors, actuators, controller and arms. Use of automation in weeding, weed mapping, micro spraying, seeding, irrigation and harvesting are progressions which promote sustainable agriculture and food security. In future, solar robots with battery inverter may be invented

Effect of Exserohilum monoceras (Drechslera) leonard & suggs on the competitiveness of Echinocloa cruss-galli (L.) P. Beauv

The use of bioherbicide to reduce interference by barnyard grass in rice cropping system has been suggested but has not been reported. Against this conceptual background, a mini-plot study was conducted to simulate the efficacy of Exserohilum monoceras to reduce competitiveness of barnyard grass in rice using replacement series experiment. The effect of E. monoceras on rice was negligible, as it did not cause any infection. Severe infection was observed on barnyard grass inoculated with this fungus at all plant densities as indicated by high AUDPC values (ranges from 610.35-468.28 unit2) and fast disease progress rates (r L= 0.48 logit/day). Rice biomass in mixture with diseased weed was higher than in the presence of healthy weed, and is not significantly different from rice biomass in the non-weedy control. In the inoculated experiment, at lower weed density, competition between barnyard grass and rice was not apparent despite the fact that the weed growth was reduced. As the weed density increased, rice continued to grow, but barnyard grass was suppressed; the growth difference was bigger and more measureable. In the non-inoculated control, the interaction between barnyard grass and rice was observed at 2:2 ratio, but at 3:1 in the inoculated experiment, indicating that rice was more competitive over barnyard grass. It took three barnyard grass to equal the shoot dry weight of one rice plant. This study provides strong evidence of the ability of E. monoceras in reducing the competitive ability of barnyard grass and thus provides new opportunities for the future of biological weed control in Malaysia

Effect of inoculum concentration, wetness duration and plant age on disease development by Exserohilum prolatum in itchgrass (Rottboellia cochinchinensis)

Exserohilum prolatum, a fungus isolated from diseased itchgrass plants in Peninsular Malaysia, has been considered as a potential agent for biological control of this serious grass weed. Inoculum concentration, wetness duration and itchgrass age significantly influenced disease development by E. prolatum in itchgrass when evaluated in glasshouse experiments. Disease development increased with increasing inoculum concentration from 2x104 to 2x107 conidia/ml. As wetness duration increased, disease development increased. Complete kill of itchgrass at 3 to 4 leaf stage was obtained at 2x106 conidia/ml and a 24 hr dew period. However, when formulated in 0.01% Tween 20 and 2% palm oil, E. prolatum reduced wetness duration requirement, and exposure to 12 hr dew period resulted in 80% reduction in itchgrass shoot dry weight. Susceptibility of itchgrass to the fungus decreased with increasing plant age. Itchgrass at two to six leaf stages were the most susceptible to fungus infection. يعتبر فطر(Exserohilum prolatum)&nbsp; والذي تم عزله من عشبة أم بليلة في شبه جزيرة ماليزيا وسيلة مكافحة إحيائية فاعلة لهذه العشبة النجيلية الضارة. عوامل تركيز اللقاح ، فترة الرطوبة وعمر النبات أثرت معنوياً على تطور المرض بواسطة (E. prolatum) في عشبة أم بليلة عندما قيّمت بتجارب داخل صوبة زجاجية. وقد تلاحظ أن تطور المرض قد إرتفع إرتفاعاً معنوياً مع إرتفاع معدل تركيز اللقاح منx 2&nbsp; 104 وإلى 2 x 107 كونيديا/مل. من ناحية أخرى تلاحظ أن شدة الإصابة بالمرض إزدادات معنوياً بإزدياد فترة الرطوبة. هذا وقد حدت موت كلي للعشبة عمر 2-3 ورقات عندما تمت معاملتها بواسطة تركيز لقاح 2x106 كونيديا/مل وفترة رطوبة 24 ساعة. أدى إستخدام عامل إنتشار Tween 20 بنسبة 0.01% وزيت النخيل بنسبة 2% إلى تقليص الحاجة إلى فترة رطوبة ممتدة (24 ساعة) حيث إنخفض الوزن الجاف للمجموع الخضري بنسبة 80% عند معاملة العشبة بفترة رطوبة بلغت 12 ساعة. أبانت النتائج أن قابلية العشبة للإصابة بالفطر قد إنخفضت مع تقدم عمر النبات وأن الأعشاب عمر 2-6 ورقات كانت أكثر قابلية للإصابة

Growth response of eight tropical turfgrass species to salinity

Irrigation seawater of different salinity levels (0, 24, 48 and 72 dSm-1) were applied to experimental plants grown in a plastic pots filled with a mixture of sand and peat (9:1). The results were analyzedusing SAS and treatment means were compared using LSD Test. The results indicated that Paspalum vaginatum (seashore paspalum) (SP), Zoysia matrella (manilagrass) (MG), Pasplaum vaginatum local(SPL), Cynodon dactylon (common bermuda) (CB), Cynodon dactylon (bermuda greenless park) (GLP), Eremochloa ophiuroides (centipede) (CP), Axonopus compressus (cow grass) (CG) and Axonopusaffinis (narrowleaf carpet grass) (NCG) experienced a 50% shoot growth reduction at the EC of 39.8, 36.5, 26.1, 25.9, 21.7, 22.4, 17.0 and 18.3 dSm-1, respectively, and a 50% root growth reduction at the ECof 49.4, 42.1, 29.9, 29.7, 26.0 24.8, 18.8 and 20.0 dSm-1, respectively. The ranking for salinity tolerance of selected grasses was  SP>MG>SPL>CB>GLP>CP>NCG>CG. The results indicate the importance of the selection of turfgrass varieties according to the soil salinity and seawater salinity levels to be used for irrigation