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Hello dear researcher,
I am very eager to participate in writing part of your research, if possible, and do whatever my scientific ability allows. My favorite topics are plant nutrition, environmental stresses and other aspects of crop physiology. Thank you very much.
AHAD MADANI
Ph.D in Agronomy.
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How to Find a Research Collaborator
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In between Genetic and plant breeding, plant physiology, agriculture biotechnology and plant pathology which one subject have maximum contribution in crop improvement? Which one is better for research?
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Among the research areas of Genetic and plant breeding, plant physiology, agriculture biotechnology and plant pathology all of them have contribution in crop improvement but I thing Genetic and plant breeding has maximum contribution in crop improvement. Agriculture biotechnology is also better but it has to follow conventional breeding.
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I am analysing physiological data (transpiration rate, biomass production, silica content…) coming from plants cultivated in an experimental field with the aim of understanding if (1) water-treatment; (2) species; (3) variety have an effect on the silica content of leaves samples.
I would like to know an extra opinion on some issues: (a) can the experimental design (explication below) be considered a split-split plot design? If yes, is it correct to consider the block as the one year-experiment, the pplot as the treatment, the splot as the species and the ssplot as the variety? Do you have some suggestion to implement this design in R considering I have available, so far, only the data coming from one replication (one year of experimental field)?
Each plant grew inside a lysimeter (a cylindric tube placed inside a concreate pit which allowed me to control the water regime and the transpiration rate while it simulated the real field conditions as for example the soil profile). I am investigating 3 crops: Sorghum (S), Pearl millet (PM) and Finger millet (FM), 10 varieties for each crop, and I tested 2 different water treatments for each crop: water-stress (WS) and the control well-watered (WW). For each treatment I tested the same 10 varieties with 5 pseudo-replicas for each variety. I organized the field (file attached) into 6 plots: 1. FM- WS, 2. PM-WS, 3. S-WS, 4. FM-WW, 5. PM-WW, 6. S-WW. Each plot was filled with 50 cylinders (10 varieties x 5 pseudo-replicas) divided into 10 rows. The 50 plant-samples have been randomize separately (each plot has its own randomization). Therefore, in each plot I tested simultaneously 3 variables: (1) treatment; (2) species; (3) variety: each plot is characterized by 1 treatment and 1 species and 10 randomized-placed varieties and treatments have not been mixed in the same plot.
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In strip plot/split block design, each block is divided into as many column (vertical strip) as levels of factor 'A' and as many row (horizontal strip) as the levels of factor 'B'. Levels of factor 'A' are assigned randomly to vertical strips and levels of factor 'B' are assigned to horizontal strips randomly. So in each strip, vertical or horizontal, level of one factor remain same throughout the different levels of second factor. In case of split plot design, formation of main plot and randomization of treatments remain similar to strip plot design. However, different levels second factor are accommodated randomly in relatively smaller plots within the main plot. Thus randomization of second factor and plot size are different from those adopted for strip plot design. Similarly, third factor which requires relatively smaller plots are accommodated as sub-sub plots in each subplot of the main plot. Again here randomization does not remain similar to strip plot design. Experimental details also indicate about different levels of precision and plot sizes for different treatments. Thus, looking over the experimental layout provided in the post, split-split plot design seems to be more pertinent than the strip plot design.
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Dear Andrea
I send you an example of calculation for chill hours and chill units. Any question I can answer, please use lmorales@uchile.cl.
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If yes,which fertilizer have more impact?
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NA
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Cereal crops mostly depend on rainwater and thus are more influential. As for the legume crops that they mostly depend on irrigation, so they have less impact and this concerns my country, Iraq.
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My data for fungicide treated replication shows higher RMSE and R-square but less CV compared to the untreated replication for a regression between vegetation indices and yield. How correct is it? Both the replications had 49 genotypes of wheat.
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Dear Rahul Raman As I understand, CV expresses standard error as the percentage of mean. Higher is the CV, larger is the experimental error and, lower is the reliability of experiment. It (CV) may vary from experiment to experiment.
Thanks!
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Development of apical meristem in bread wheat is central to both sides, but how about rye?
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Hello Sir,
Did you manage to find your answer to the above question? If yes, is it ok for me to direct message you in regards to some questions about the apical meristem? Thank you in advance.
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Green beans were infested with rhizoctonia Solani though not sure what AG is
Said this because nothing is really reliable when artificial inoculation happens and the three points triangle is really a matter of circumstances in that case
Thank you
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the koch postulate and anastomosis help a lot in diagnosing the infected beans roots
Thank you
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Foliar fertilization is a quick and efficient way to improve crop nutrient status during periods of high nutrient demand in the crop, or soil-applied fertilizers less available to the plant.
My questions what is an appropriate time to supply nutrients as foliar for sugarcane crop. The nutrient contains nitrogen, phosphorus, potassium, Sulfur, Calcium, Magnesium, zinc, iron, manganese, and copper when we added as a single or combined system.
. it is critical to determine the effect of crop load on the capacity of properly timed foliar fertilizers to increase the yield of sugarcane.
The question for researchers in the fields of soil science, plant nutrition, crop physiology and agronomist specialized in sugarcane crop.
Therefore, my request is to provide me with any practical suggestions to increase my knowledge concerning these issues, besides the literature review, technical report and articles also are needed.
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The best timing is when the plant has the biggest foliage unless there is a need to spray earlier than that (i.e. to cure nutrient deficiency)
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During water deficit stress, plant shows several responses. If fertilizers or other chemicals are applied, how their absorption will be affected, is there any reference please?
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I agree with the explanation of Youssef Sassine
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Is it possible that, plants with a better vegetative growth can show lower reproductive growth, whereas, plants showing lower vegetative growth can give a better reproductive growth? Let me explain, If we get a better vegetative growth but lower reproductive growth from application of fertilizer with higher available N, and vise versa from application of fertilizer with less available and slow release N, then is it meaningful to say that, in case of fertilizer with higher available N, N is immediately assimilated in development of vegetative growth leaving little for reproductive stage and thus showing a lower reproductive growth? On the other hand, in case of the fertilizer with less available N and slow N release, N becomes available during reproductive development, resulting in lower vegetative growth but a better reproductive growth.
My query is based on our findings on crop growth experiment, but I am not very sure how to explain these. Can anyone please help me with the possible explanation for such results?
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Shifting between vegetative growth and reproductive growth is determined by the balance between nutrients after the plant accomplish its accumulated heat hours. that is why the fertilization recipe is changing according to plant age. For example we fertilize vegetable plants with NPK 20-20-20 in the first two weeks after transplanting then with 15-30-15 until flowering then 12-12-36 during flowering and fruiting. With indeterminate crops, when the shoot is badly infected and we had to remove most of the leaves, we go back to the first recipe to renew the shoot.
in your case, plenty of N encourage the plants to continue in vegetative growth.
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  1. Plants in the controlled conditions grow isolate but its not the same case in field.
  2. Volume of soil available to the roots within a pot is considerably smaller as compared to field condition. 
  3. Volume of water and amount of nutrients is also less.
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Controlled experiments are different that field experiments. that is why when you extrapolate the results of controlled experiments you find always overestimation than actual results. you may get one relation of these experiment like relation between light intensity and photosynthesis to use it as a component in a bigger model but you can't relay on the results of those experiment on estimating a crop yield in a region for example.
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In animals, small and weak often feel stress from the tall and strong ones?
so, in plants, did they could feel the differences, except for they will competing for CO2, water, nurtrion and fertilizer.
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Different plant heights affect the amount of light intercepted specially for short plants. this results in slower photosynthesis rate for the latter ones and low assimilate production hence smaller shoot and root size. eventually, those smaller plants may not be able to continue specially if they are light-deficient sensitive.
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Rootstocks are considered as the major via- medium for regulating the performance of scion with regard to whole range of parameters , starting from simple growth to multiple resistance against pests and diseases , besides expending the harvesting window of scion. In a combination of compatible  rootstock-scion , no genetic transformation takes place either  mutualistically or otherwise  , it is simply the characters of rootstock in question , translate into the performance of scion. What do you think , when such permanent changes do not  take place in such combination , how come , the flow of various  signals takes place  from rootstock to scion and vice-versa  , much to the benefit of  scion only .  
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Root-stocks are essential to overcome some problems in the soil such as salinity, water logging or diseases where the variety of the scion can not produce or success. for example, some mango varieties are grafted on some others to overcome salinity problem of the soil. in some other cases, root stock promotes better growth and production and better fruit quality of scion
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I have been using the AquaCrop model since its introduction with version 3.1. I have recently modeled some potato cultivars subject to deficit and full irrigation in a dry and hot climate in south of Iran. I used the latest version 6. Based on my several experiences in calibration and validation of the AquaCrop model (trial and error approach to calibrate the model), I have some suggestions for the model developers in order to improve the model performance in its the future versions.
We know that the AquaCrop model is basically developed for simulating irrigation managements, and it is a water-driven model for simulating yield and biomass of field crops. Incorporating more parameterization options that consider the physiology of crop would help for more accurate simulation. Below I would like to share my thoughts with those who are interested in modeling with AquaCrop and have experiences with it or are going to use it in future. I would be happy to learn from you and your experiences in what has been reflected below, or other options based on your experiences.
1) I think that the latest version is good for no water stress but still it needs more improvements for simulation under water stress, especially in hot and dry climates with high VPD (>3-4 kPa). Maybe some deficit irrigation in moderate and temperate climates (low to moderate VPD)  would still provide good conditions for simulation of deficit irrigation. I think that VPD plays a major role when we simulate deficit irrigation levels (mild, moderate, severe). 
2) The model still has shortcomings in modeling senescence and it is not able to physiologically simulate senescence particularly under high water deficit. The model cannot match well the biomass and yield accordingly. In such conditions, soil water is not simulated so good as the ones in earlier times of growth period.
3) It is better to allow the user to assign multiple values  of calibrated WP* during the growing stages instead of just one WP*. This is most important for the later stages for biomass simulation, and assigning a single calibrated WP* may not allow full performance of the model when crop mature. At least 2-3 WP* values should be considered depending on the length of growing period.
4) The interaction of water stress and heat stress is very important particularly in the arid and semi-arid areas where climate change may have higher sever effect on crop physiology. For example, for tuber crops such as potato, secondary growth may happen in later time of the season for which biomass may jump after the crops have experiences high heat and water stress during the middle of growth stages.   
5) The recommended WP* ranges for the C3 and C4 crops as outlined in the manual andthe model may not work well in hot and dry climates and deficit irrigation practices. For potatoes we chose calibrated values below the recommended one, and also in a very recent publication (Agricultural Water Management 203 (2018) 438–450), the authors have assigned WP*=21 for seed production of maize (C4) under full and deficit irrigation that is far below the recommended one. Therefore, it seems that in hot and dry climates WP* is lower than the recommended values for both C3 and C4 crops specially if crops are subject to deficit irrigation. 
Thank you and look froward to hearing more from the other AquaCrop model users!  
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We have been testing Aquacrop in my country. We will be happy to share our results with you as soon as we finish.
Thank you for your contribution
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I have the following results:
Number of tubers/plant
Average weight of tubers/bag
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I am afraid it is not possible because the extrapolation of your results will hugely shift from the real facts. your pot experiment excluded the competition between plant for all resources, nutrients, water, and light. So don't expect that you will have the same results when you carry out the same experiment in the field.
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Available theories and papers suggest that increase in grain starch content and decrease in grain protein leads to a higher grain yield. But, what might be the reason for high grain yield in few corn and sorghum genotypes with high grain protein and slightly low (below average) grain starch content?
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good
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We have been trying to extend soybean in northern Bangladesh in Kharif II (Avg. Temp 30-35°C) and Rabi (Avg. Temp 18-25°C) seasons for several years. We are getting fluctuating yields often due to variations in environmental and climatic factors. We need to choose a suitable variety of soybean. We have come to know that crop heat unit (CHU) indexing system is used in temperate countries like Canada to select suitable crop varieties for a region. We are trying to find out whether such a system can be used in the subcontinent.
We would like to know:
· Can this system be appropriately adapted for tropical and subtropical countries?
· Is such a system in use India or any other country of Southeast Asia?
· Can this system be used to select crop varieties to avoid heat damage of excessively hot periods of summer?
· In case this system is used in this region, what are crop heat unit (CHU) values for different soybean varieties?
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Crop Heat Units (CHU) provides an indexing system to assist farmers to select the most suitable hybrids and varieties for their area. This indexing system was originally developed for field corn and has been discovered in Ontario and is useful in many other countries for more than 30 years. The crop heat unit ratings are based on the total accumulated crop heat units (CHU) for the frost-free growing season in each area of the province. It describes how much CHU are available in different regions and how hybrids and varieties of some warm-season crops are rated.
The rate of development of crops from planting to maturity is dependent mainly upon temperature. Cool temperatures slow down the progress to maturity and warm temperatures hasten maturity. Other environmental factors – such as photoperiod (daily period from sunrise to sunset), soil fertility and available water in the soil – can also influence the rate of crop development.Air temperatures are usually expressed in terms of the daily minimum (min) and maximum (max).
Daily crop heat units are calculated from these min and max temperatures. There are separate calculations for day and night. The daytime relationship uses 10 °C as the base temperature and 30 °C as the optimum because warm-season crops do not develop when daytime temperatures fall below 10 °C and they develop fastest at about 30 °C. The nighttime relationship uses 4.4 °C as the base temperature and does not specify an optimum temperature because nighttime minimum temperatures very seldom exceed 25 °C.
he most common calculation for accumulated heat for corn in Canada is the ‘Ontario Crop Heat Unit’ (CHU). This calculation is based on the maximum (Tmax) and minimum (Tmin) daily temperature in degrees Celsius. This index reflects that growth rate of corn:
1. increases proportionately to minimum daily temperature (usually night-time temperature), at all temperatures above 4.4°C (40°F)
2. increases at increasing rates with maximum daily temperature (usually daytime temperature) from 10 to 30°C (50 to 86°F), then at decreasing rates to 50°C (122°F).
Agricultural Meteorology
Volume 26, Issue 3, May 1982, Pages 201-213📷
Research paperHeat units in relation to corn maturity in the Atlantic region of Canada,https://doi.org/10.1016/0002-1571(82)90031-0Get rights and content
Abstract: Field trials were conducted at five locations in the Atlantic region of Canada over seven years to determine relationships between climate and corn (Zea mays L.) maturity. Ear moisture at harvest was correlated with Corn Heat Units (CHU), growing degree-days above 10°C and soil temperature (r2 = 0.32 to 0.49, P ⪯ 0.01). Day/night temperature range and a latitude factor were also significant in regressions, although not likely due to ‘cause and effect’ relationships. Locally recommended hybrids required 2300–2500 CHU's to reach 30 to 35% whole plant dry matter, and 2500–2700 CHU's to achieve 35% kernel moisture. Corn grown at one location required an additional 150 CHU's to achieve maturity in comparison with the other test sites possibly due to coastal influences on climate.
Long-term weather records were used to calculate available CHU's and to construct a CHU zonation map for the region. Average CHU's available for silage corn production ranged from over 2500 in large inland valleys in New Brunswick and Nova Scotia, to less than 1900 in northern New Brunswick, the south shore of Nova Scotia, and Cape Breton Island. Production of silage is presently limited to regions with 2100 CHU's or more before frost, and grain corn to regions with 2400 CHU's or more before frost Coastal regions require an additional 150 CHU's for both silage and grain corn production.
📷
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Hi All,
I really need an assay(s) that can test how efficient a plant is using water? Thus far, my method for measuring this have been by using a porometer, and a simple assay where you put plant cuttings in a tube and measure how much water they remove (via transpiration).
I have several compounds that I need to screen to see if they help plants take up water more. I'd be great if there was a simple assay out there that could do this.
All thoughts/ideas/comments are welcomed!
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Thanks Svetoslav - Sorry for long delay. I'll definitely try this out!
Best,
Christian 
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Could same plant species collected from different environmental conditions - relative humidity, temperature, water stress, atmospheric carbon dioxide etc. vary in their stomata/trichome densities? Which is expected to have higher stomata/trichome densities - the less or extreme condition?
Thanks
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Interesting question..
The results indicate a dynamic system in which stress treatments of large A. annua plants had a minor promoting effect on the initiation of GT in developing leaves, and a maturing effect of GT later in the lifetime of the individual GT. The hypothesis that applying stress can induce larger GT or more numerous GT was rejected..PDF enclosed 
Another study.. Results also showed that the conical and globular-headed trichomes’ densities decrease as leaf age increases. Th e leaf petioles of the 2 variants are dominated by globular-headed trichomes. On the abaxial surface, analyses showed that there were 28% and 58% more stomata on the young leaf compared to semiold
and old leaves, respectively. Further studies into the physiologically mediated mechanisms that are responsible for these observations in T. cucumerina are crucial..PDf enclosed
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Salt toxicity is a common problem in high pH saline soils. The problem is aggravated by applying poor quality underground water to fruit plants.  
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We need to establish first , whether it is salinity or sodicity . If it is salinity , no need to apply gypsum or any chemical amendment . the question of applying gypsum as a chemical amendment comes only , when ESP is more than 15 and soil pH more than atleast 8.5..For removing salt from saline soils, we need only waterlogging followed by flushing /leaching of salts. For a sensitive crop like citrus ( hopefully kinnow mandarin raised on Jatti khatti rootstock) ) , any soil EC value more than 0.50-1.00 dS/m would be adversely affecting the growth as well as performance of the crop. USDA salinity standards would no longer aid in solving the salinity -induced adverse affects in citrus. 
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Leaf gas exchange measurement on leguminous crops
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Yes. Those are definitely more tolerent to water deficit than many of the C3 plants
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The paper should deal with physiology of modern corn and sorghum cultivars. How it differs from physiology of traditional corn and sorghum? I am in need of few papers related to the above mentioned aspect.
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Ok, now I get it. Thanks for clarifying.
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Soil and plant nutrition
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Thank you all for the suggestions and papers uploded
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references
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We are interested in measuring the light availability for coffee plants under a range of different adaptation practices (shade, cover crops etc). We want to ensure that the measurement can be automated (i.e. a sensor that can be left for a number of months) and covers the three relevant aspects of light for plant growth. That would be quality (the wavelength), quantity (intensity/concentration) and duration. 
Does anyone have any recommendations based on their research?
Many thanks for any advice
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Multiple sensors based on PAR will serve your purpose.
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Some species are resistant to high levels of aluminum in the soil. Tea (Camellia sinensis) has this ability in very acid soils where ion pairs "Al-P" are formed and absorbed by the roots.
Tea can accumulate aluminum by complexification with organic acids and flavonols and also benefit phosphorus absorbed with him. This phenomenon of absorbing "Al-P" pairs also explains the stimulatory effects on growth of low alumium levels for many crops.
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Interesting discussion . One of the most conspicuous effects of Al-toxicity is the suberisation of root hairs , thereby , impairing with nutrients translocation . The tolerant cultivars efficiently took up and utilized Ca and P in the presence of aluminium. The susceptible (Al-sensitive) and intermediate cultivars exhibited less Ca and P uptake and utilization. An interesting PDF is enclosed for further reading , please..
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we are working on improving salinity tolerance of crop plants using exogenous application of silicon. i would like to know the normal range of the concentration of silicon in crop plants?
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Nice discussion ....Some exerpts from the paper entitled Silicon: A Beneficial Substance by Joseph Heckman published in Better Crops ( Better Crops/Vol. 97 (2013, No. 4)...
Plant tissue Si concentrations will vary widely depending on plant species and the soluble Si concentration in the soil. It is not unusual to fi nd Si concentrations in plants at levels comparable to or above those for macronutrients (up to a few
percent of dry weight). Grasses and monocots generally accumulate higher concentrations of Si than dicots (approx. 0.1% Si). Concentrations as high as 10% Si are possible in some plant species such as Equisetum (Horse tail).
Optimum Si concentrations have not been established for most crops. Research conducted on soils in New Jersey indicates concentration ranges that may occur for some crops. For example, adding supplemental Si increased concentrations in pumpkin leaf tissue from 700 to 3,500 mg Si/kg, in corn stem tissue from 1,300 to 3,300 mg Si/kg, wheat fl ag leaves from 1,530 to 11,750 mg Si/kg, and Kentucky bluegrass leaves from 4,200 to 7,200 mg Si/kg. Different parts within the same plant can also show large differences in Si accumulation. For example, polished rice contains 0.5 g Si/kg, while the rice hull may contain 230 g Si/kg (Currie and Perry, 2007).
PDF enclosed for further reading..
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I am looking for some information on the effect of doubled haploids on inbreeding depression in crop plants. Attaining homozygosity through several cycles of selfing leads to inbreeding depression in many crops. What is the inbreeding depression observed in plant made homozygous through anther/microspore culture?  Haven't had much success in finding relevant literature through web search. Any help/guidance will be much appreciated.
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Dear Hafiz, I agree with what Luke said. Tracing the nature of inbreeding depression in DH lines is indeed difficult because those plants hardly survive the variations. We have been involved with the development of some rice DH lines and have observed that, while it responded well with some Japonica rice lines, microspore culture exhibit a very low frequency with the Indica genotypes. This is mostly because of recalcitrant effect of the existing variations within a group of genotypes.. 
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This is one of the treatments in a factorial experiment involving different species, drought and fire. Any ideas on a fire protocol that might work best will be highly appreciated. 
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fire promotes some species to regrowth but suppresses the majority. Usually thick barks and seed teguments, or below ground structures ensure this capability. In a green house some experiment can be run only by treating seeds or thich root sections or lignotubers with fire in a set with unburnt control. Trays with soil and vegetetables can be placed outside with suitable temperature checks inrange with actual accurrences like in http://firearchaeology.com/Direct_Effects_files/Beadle_1940.pdf
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In short rotation tree crops for industrial use in agroforestry need to develop a growth models for comparison of growth in sole plantation and in under agroforestry plantations. What are the essential parameters to be monitored or variables to taken for development of growth models of such tree species. 
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Thanks Klemens. I will see the project details and text send by you.
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I developed some summer onion mutants. These mutants produce sufficient roots when grown in winter. But when these are grown during March and onward, they produce very little roots which causes severe seedling death after transplanting. To suggest the grower I need cheap and available source of hormone/substance so that the grower can afford the cost and get easily in the market; parallelly which can enhance rooting to check seedling deaths.
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Use of Cytozyme @ 0.2% as root dipping spray at 15 and 45 days after transplanting, dipping seedling roots for 20 minutes before transplanting and foliar sprays are found more effective in bulbs development and higher yield of kharif onion.
Use of MH to check premature bolting and sprouting in storage is recommended. MH @ 2000 ppm applied 75 DAP for kharif onion and @ 2500 ppm just before neck fall in rabi onion are recommended.
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I am working with a group of kiwifruit orchards that have leaves with severe chlorosis. The leaf iron is very high at 240ppm, Manganese, magnesium and nitrogen are all in the normal range. The symptoms are identical to severe manganese deficiency. The irrigation water has high Bicarbonate content.
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Phillip , i have seen both leaf graph and symptoms , apparently the symptoms look like Mn-deficiency , but 80 ppm of  leaf Mn will not induce any deficiency symptoms such as these.   Soil pH is also within the managable range. How  about the spatial distribution of these symptoms  across the whole field, is it sporadic in distribution or uniform  distribution ?
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Acutally i need methodology and reference for fruit crops.
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Determination of Proline (Bates et al. 1973)
1.     Plant Dry matter(0.05 g) is homogenized in 5 ml of 3% aqueous sulfosalicylic acid.(can be determined in fresh tissue as well (0.25g) in 10 ml of 3% aqueous sulfosalicylic acid).
2.     Leave for 3hrs for extraction to complete
3.     Centrifuge at 1500 g for l0 min.
4.     2 ml of supernatant is added to 2ml Glacial Acetic acid and 2 ml Acidic Ninhydrin.
(Warm 1.25 g ninhydrin in 30 ml of GAA + 20 ml (6M) H3PO4 with agitation until dissolved)
5.     Boil at 100oC in a Water Bath for 60 min.
6.     Stop the reaction by placing in an ice path.
7.     Add 4 ml of Toluene and mix vigorously.
8.     Let warm to r. t.
9.     Read at 520 nm, using toluene as blank.
10.   At 4 0C, the reagent is stable for 24 h.
11.   Use a standard curve for concentration from 0- 512 µL (20-100 µg/ml) of L-Proline.
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Sir,
Suppose LAD values calculated based on leaf area index values are 70.6, 80.2, 50.8, 90.7 for greengram genotypes g1, g2, g3 and g4 respectively and expressed as (m2/m2). days. Whether I should keep the units or not in the table. How the above values could be explained?
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Madam LAD is the ability of the plant to maintain the green leaves over unit area of land throughout its life . It is expressed in days
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is it days after full bloom, color, size of individual fingers or shape of the fingers?
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Dear Micheal, as subjective index I would indicate number of days after flowering (opening of the last set of fingers from the bunch at the time the remaining of the rachis - also termed the heart - should be removed) is the most appropriate. If your bananas (Grand Naine group) are grown in a more tropical climate then it will take from 9 to 12 weeks to the fingers to be ready to harvest. However in a more subtropical or chilly environment then it might take up to 7 months to the fruit to ready to harvest. Other methods such as fruit color are less trustworthy, since weather variations (more cloudy days versus more sunny days, for example) could strongly influence color development.
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Biuret content in urea is maximum permissible at 1.5% 
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Dear Gaurav Singh,
Urea is suitable for all crops and soils. Being non-polart, this is an ideal Fertilizer, but urea having more than 1.2% Biuret it is very harmful for certain crops like pineapple, Citrus, Tobacco and coffee which are sensitive to Biuret, urea with a lower Biuret content of 0.5 to 0.8% is preferable for application as a foliar spray. Chlorosis occurs on the leaf of the plants, when Biuret more than 1.5%.Fertilizer grade urea   contains the impurity biuret which is toxic to the plant especially when applied as a leaf dressing. Biuret more than 1.5 % can damage the root of the plant and also useful bacteria and chock the capillary of the root cell, Nitrogen carrying capacity will be reduced.
The biuret formed at following conditions in Urea process.
1.       High Temperature.
2.       High Concentrations
3.       High residence time
Formation of biuret takes place when urea is heated to its melting point it starts decomposition with evolution of ammonia preumably,urea first isomerizes which dissociates into isocynic acid and ammonia.
•          CO(NH2)2    =  NH4CNO       +              NH3.
•          (UREA)           (AMM.CYNATE) 
•          The isocynic acid reacts with urea to form biuret.
•          NHCO  +  CO(NH2)2    =    NH2CONHCONH2
•          In the presence of excess ammonia biuret is formed at substantially lower rate by direct reaction between urea molecules.
•          2CO(NH2)2 =  NH2CONHCONH2+NH3.
•             (UREA)                    BIURET                      AMMONIA
•          BIURET + UREA    =   TRIURET  + AMMONIA
Regards,
Prem Baboo
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It's a facultative CAM plant. If this machinery is transfered to crop plants they can easily withstand salt and water stress.
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Cam cycle is fitted to drought tolerance and uses photosynthesis in futile paths. This is paid off by slow growth and a complex regulation of carboxylases activation, vacuole  carriers and malate PEPCO2ase insensitivity. Photosynthetic efficiency per leaf unit mass is low and multiple cassettes are involved in an hypotetical transfer but this topic is already under scrutiny, as in Dr Xiaohan Yang, a staff scientist in the Biosciences Division at Oak Ridge National Laboratory, which would be the right person to get involved, http://www.scientificamerican.com/article/does-agave-hold-the-secret-to-drought-resistant-farming/
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How can I estimate the physical loss of standing crop residue (like rice or wheat or maize) from the soil surface from a no-till plot?
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Dear Dr Mohanty,
In similar work we are estimating residue dry weight/unit area at different time intervals. Bedsides, it is hypothesized that since residues would undergo decomposition, the changes in specific compound (cellulose for rice), nutrient (say C for cereals) contents or ratio (e.g. C:N ratio) would be good indices. More information and suggestions would be highly appreciated.
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which physiological process does the wild species of our food crops had, C3 / C4 / CAM physiology ?
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The most common metabolic pathway for photosynthesis is C3. C4 and CAM metabolisms are thought to be an evolution of the C3 pathway.
You may choose your species according to the environment you live. In certain environments C4 are more efficient than C3 or CAM. For instance, the water use efficiency (i.e. amount of carbohydrates produced per unit of water) is definitely higher in CAM plants compared to C4 and C3, respectively. This means that you would probably choose CAM plants in arid environments.
Wild species did not change their photosynthetic pathway due to a direct connection with domestication. They were likely to change their metabolism because of a change in their original environment, which could have been due to domestication or to other factors (e.g. colonization).
I hope I was helpful.
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I have came across some publications about CERES, AFRCWHEAT2, WE models. But other crop models, for example STICS and APSIM, have also module for phenology simulation. Is there a nice review about this topic?
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Hi: The precision of phenology prediction is dependent on both, model structure and the data base and the method of parameterization. We published a paper on wheat phenology simulation using a quite large data base for the parametrization.
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I want to test the pollen viability against heavy metal stress. If you can send me a  low cost simple protocol, I would like to test it.
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Check:
Searcy, K. B., & Mulcahy, D. L. (1985). Pollen tube competition and selection for metal tolerance in Silene dioica (Caryophyllaceae) and Mimulus guttatus (Scrophulariaceae). American journal of botany, 1695-1699.
Searcy, K. B., & Mulcahy, D. L. (1985). Pollen selection and the gametophytic expression of metal tolerance in Silene dioica (Caryophyllaceae) and Mimulus guttatus (Scrophulariaceae). American Journal of Botany, 1700-1706.
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Webworld of microbes in soil fertility transformation is distinctly visible on various kinds of crop responses. But , responsiveness of such microbial inoculation is often claimed to be bit time consuming . And annual crops are often debarred from such benefits compared to perennial crops. Very often , we keep talking of source specific microbes, crop specific microbes, native microbes and so on ...In this background, i have few very pertinent quarries to be responded by my learned colleagues . These are as follows:
* How far soil microbes compare with plant endophytic microbes?
*Is there any crop specific study to establish the superiority of soil microbes over plant endophytic microbes and vice-versa?
* Is there any tissue specific microbes more accountable to crop response?
* What kind of microbes are more favored in studies on plant endophytic microbes?
* What kind of inoculation procedures should be adopted for plant endophytic microbes?
* Is there any possibility of having plant endophytic microbial consortium for elevated crop response?
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Dr Deka , so  far researches accrued on this issue , it is claimed bacteria of endophytic origin are more efficient compared to rhizophere origin , they are supposed to be metabolically more like a part of plant functioning . But , I wonder how to inoculate them ?. Shall we adopt soil inoculation or seed inoculation , very often seed inoculation finds difficulty in generating good plant response.
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I made an experiment with several tomato cultivars. I measured chlorophyll content at one middle leaf by using SPAD 502. The result showed that plant with dense leaves (high number of internodes) had lower chlorophyll contents compared to the ones with less dense leaf (Lower number of internodes).
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Plant has dense canopies usually being more shaded by leaves from upper side. That trigger different rate of photosynthesis between lighted leaf and covered leaf. The upper side leaf provide better amount of photosynthesis products than shaded leaf which it also has higher total number of covered leaf than lighted leaf. The shaded leaf is not only becoming a producer but also consuming higher carbon complex to maintain their life.
The higher respiration rate than photosynthesis rate which also lead to chlorophyll breakdown to provide more energy and also transport mobile element such as Mg, P, N directly to new leaf. It has been believed that dicotyle plant which have sympodial growth provide more leaf to maintain the stability between production and consumption of carbon complex.
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DSSAT/INFOCROP to a limited take care of the soil conditions as influenced with tillage and other management options. 
Lot of work has been done in recent past to evaluate effects of zero/minimum tillage, bed planting, other RCTs on suggesting management options and also assessing growth and yield of crops. 
Transfer functions generated to a limited extent, long term consequences missing to a greater extent.
we need to include these transfer functions within the body of the crop growth model, or evolve a simple soil health module to include the mediated effects
some work in understanding of the entire system, which subsequently aids in developing a sub-routine
regards
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The main tillage induced soil property is aeration. It is for increasing aeration tillage is carried out. But one of the natural property that tillage destroys is soil structure through destruction of water stable aggregates and biological constructions.
Zero tillage operations increase the biological activity and naturally the structure will be properly retained leading to good aeration. Structure is a complex physical quality, which primarily determines aeration and indirectly influence soil biotic activity and thus the fertility.
There is no single direct measurement by which the tillage induced damage can be measured; perhaps the best of single measurement that can reveal tillage induced soil degradation is that of 'bulk density'
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I have worked on a tomato variety trial and it might not be possible to harvest tomato plants and oven-dry them to determine above ground dry matter due to too many tomato plants. I am wondering if it is also possible to calculate Harvest Index by using fresh weight, considering that we also consume tomato fruits in fresh.
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HI units are functional to their use as marketable units. If the destiny of ypur tomatoes is dry fruit one you should take dried fruit mass relative to plant dry mass. Grains are meausred in dry basis but tomatoes HI are given in fruit fresh weight per plant fresh weight. Pruning and management with chemicals like off-shoot-O modify sensibly HI, as in http://www.ncbi.nlm.nih.gov/pubmed/11541684
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DEAR ALL, i going to use sago - gelatinized edible starch powder as geling agent in potato micropapogation give any refrance or suggestion were well come ....also i need suppler of same from india...
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Dear Marney Cereda , Thanks.. sir  what % of tapioca (cassava starch) ... and for which crop u are using it ?
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Source-sink relationship What are the main factors determining the source capacity in legume crops at flowering stage?
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and also, percent of abnormal seeds( those which are fertile but can not be grown). in some cases we had 30% abnormal seeds.
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in my point of view, physiological, phenological and water relations should be look at.
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In a citrus rootstock trial planted in South Australia in 1997, the combination of Navelina 7.5 (Spanish clone) on C35 citrange started to fail after around 15 years.  Of the original 9 trees, 7 have died, and the 2 that are still alive are in poor health. They show a clear crease under the bark at the bud union, indicating incompatibility (see photo).
These are some of the oldest trees of this combination in Australia, but I have been told by some in the industry that reports of a similar problem have emerged from overseas, although I can find no literature to confirm this.  Can anyone provide a published paper, or failing that some unpublished information showing this problem happenning elsewhere?
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Mark can you supplement some information on nature of soil that is used. the photograph , you have provided is not sufficiently displaying incompatibility , since ratio rootstock -to-scion ratio seems to perfectly alright . Do you feel it is a typical incompatibility issue or any other issue.
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I would like to find a good function to fit kinetic data of leaf senescence (few and meaningful parameters). So far I have chosen a Gompertz function to explain green area index over thermal time. Do you use the function properties (Gompertz or any else), or do you estimate senescence onset as the time for an empiric percentage of senescence threshold?
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We have used photothermal time in preference to just thermal time.    The PhD thesis of Rizaldi Boer at Sydney University deals with this aspect.   The thesis was entitled 'Climatic Constraints on anthesis of wheat in a major wheat growing area of Australia'.
    In eastern Australia, the rate of senescence is fairly linear even with thermal time;  it deviates if very hot conditions prevail say 35+ C.
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Applying fertilizer along with maize seed planting, would it be a best strategy of applying the fertilizer for efficient use of the maize seedlings since the maize plant is monocotyledon? what happen to the endospalm  of the seed?
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placement of fertilizer P may promote early plant growth, however the amounts placed have to be accounted in the total fertilizer balance of a crop. HAve a look at: http://www.ipni.net/publication/bettercrops.nsf/0/43A9E1C1969501668525798000820189/$FILE/Better%20Crops%201999-1%20p34.pdf
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Gas exchange of water vapor and CO2 are controlled by stomata. In many plants, when CO2 increases, there is a reduction of stomatal conductance.
But many species are known to grow more when Co2 increases. How do we reconciliate the two facts ?
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I would like to add that, under drought, C4 crops indeed benefit from elevated atmospheric CO2 to roughly the same extent as C3 crops. Probably, this is due to a stomatal limitation of photosynthesis that also occurs in C4 crops if drought leads to increased stomata closure and a consequently decreased Ci.
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The tree is oil palm ,and I know it depends on the age of the tree and the extend of the root ,but I want to know when is the best time for sampling leaves to determine whether the amount of fertilizers applied was enough? Do we have any role for that?
I want to take a picture by satellite and UAV to compare between nitrogen content in aerial images and ground data that's why I want to know when is the best time for leaves sampling after applying nitrogen in soil. generally not exactly
Thanks in advance.
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 Ana and Racio  , both have responded very nicely to your very intriguing question .  . Mohamad , in perennial crops , best premise of taking leaf samples is the period where leaves are about to enter into the phase of source ( Supplying accumulated nutrients to developing fruits )  from initial period of sink ( Period for which leaves continue to accumulate nutrients ) , so it is the time of intersection of sink-to-source. And this period needs to be standardized according to your crop , soil , management practices and agroclimate . The time of soil sampling should then commensurate with the time of leaf sampling.
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what is the effect of phosphorus and potash application on day to tasseling, silking and physiological maturity of maize crop?
please attach the research paper with the response.
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In research involving biological materials like maize vis-a-vis effects of P and K fertilizers, ready made, straight, precise and reproducible results do not exist in any part of the world. Diverse and uncontrollable factors operate in producing a crop yield that keeps on changing with climatic factors as well. There is no point in asking questions for which none can provide ready and reliable answers. 
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Contamination is rare on plates and morphological characteristics are also as usual Rhizobia but chemical test making me ambiguous. Can you help me by giving any helpful information.
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Dear Ali
They may be fast growing and salt stress resistant Bradyrhizobium thats why they grow so fast.....
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experimental design 
 CRD in factorial experiment ..4 sesame land-races and one improved drought tolerant variety +3 drought stress levels (0%; 5% and 10% PEG Mr 6000) replicated 4 replications.
what amount of  PEG will i need and other essential apparatus to complete this experiment?
what step should i take from step one to produce significant results,especially the how to mix culture media and PEG?
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PEG medium is a good choice for study of drought  stress potential at germination stage in crops as well as forest tree species.
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Crop physiology
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Dear Florence , there could be a possibility of some relation  salinity tolerance and iron toxicity in rice . The presence of salinity, I feel  will reduce the toxic level of iron to accumulate in the soil under paddy grown preferably under waterlogged conditions. Greater is the salinity of the soil , lesser will be the ferrous iron to accumulate , since salinity -induced oxidation of iron will be more pronounced  , but waterlogging will gradually neutralize the effect of salinity depending upon the texture  and duration of submergence .
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I'm writing a term paper about stay-green phenotype. Such suggestions will be a big help. Thank you!
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I tried GA treatment and HNO3 (scarification) but was in vain.
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Dear Mr. Prasad,
First, incubate the seeds (Hulled and de-hulled) at 50 degree C for 48 hours. Then put in pettridishes with cotton for  more than 96 hours. I have found 98% germination. Please proceed.
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Dear Friends
Regular application of fertilizers to annual crops will give immediate response as well as returns. With respect to perennial crops like mango, cashew and sapota etc., application of fertilizers at regular intervals are not giving immediate response as well as returns why it is so?. Based on my experience in cashew, no significant difference was observed with respect to yield with application of fertilizers and without application of fertilizers. Then i have collected the biomass of the well matured cashew orchard and weighed. Around 5 tonnes of cashew biomass collected from one hectare area. Then started analysing the nutrient content of the biomass and observed that enough nutrients are available in that biomass for meeting the requirement for cashew. 
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Tree crops require nutrients, but because of the amount of nutrient stored internally and the delay between application and uptake, the effects of fertiliser application are delayed
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For the first time it looks like herbicide damage. Young leaves growth retardation and yellowing have been noticed at the same plot last year, but at later stage of plant development. This year, the symptoms appeared after transplantation. There was no any herbicide applied here at least for last 3 years. Water for irrigation is obtained from underground sources. Soil is rich (Krasnodar black soil  region). 
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Yes Alex, tomatoes are extremely sensitive to phenoxyacid herbicides at soil levels even below 10ppb and the limits of detection of the most sensitive residue tests. Incorporation of a heavy application of organic matter once the spring thaw has occurred can assist the soil microbes to reduce the carryover residues more rapidly. A green manure crop of a suitable legume ploughed in can  do this job. A summer season of fallow with this organic matter incorporation might allow a more rapid return to the tomato crop. And of course tomatoes and corn, sweet potatoes for example don't like repeat year after year planting due to soil disease build up, but once again the organic matter incorporation assists with combating these fungal diseases and even nematodes.
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In chickpea crop production, there is wet substance which appears on leaves called axalic or maleic acid, the question is, are there any genotypic differences in the production of oxalic acid and maleic acid? 2. Do management practices affect the production of these acids? 3. Do these acids have any beneficial effects on the plants themselves?
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There are genotypic differences in chickpea. An un-planned "evaluation" was done by rabits that invaded one of my experiments: The kabuli chickpea cultivar Gharb2 remained untouched, while cultivar Gharb3 (low axalic acid) was eaten and  almost grazed to the ground.
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Tomato hybrid plants show slight yellowing and deformation of younger leaves. The symptoms occur from seedlings to maturing stage. Affected plants grow slower.  Is it mild virus or genetic feature? It has no relation to my previous question...
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Since you said some plants are showing symptoms, this rules out genetic. In case of Genetics, all plants should be that way. Looks nutritional deficiency. STEM (soluble trace elements mix) spray at 8 oz/100 gallon works well for my plants (but my plants are not tomato) .
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The symptoms shown in the slide appear only after approx. one month during storage (not in the field) and only on the peel and not in the fruit flesh. Therefore it cannot be due to calcium or boron deficiency. Any idea ?
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Calcium deficiency. the rind of the fruit, and tissue die under these spots and turn to brown, over time, these spots become a bit deep color fabric becomes beneath dark brown and dry then become Vllah.
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Now I research about if different crop system could affect herbivore induced plant volatiles like methyl salicylate effeciency for attract nature enemies.
Does  anyone know the paper about it, thanks for your help?
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I am not clear with your statement "herbivore induced plant volatiles like methyl salicylate effeciency for attract nature enemies." - volatiles are used by the host plant for protection and signaling - protection from potential pathogens and signaling to beneficial organisms in more ways than one. Methyl salicylate is one such defense signal.
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Plant nutrition research very  often neglects the most important aspect of change in shelf life of fruits in response to nutrient composition of edible part . We always believe that an improvement in plant nutrition will expunge the free radicals accumulated in the fruits while storage . And , the abundance of dismutases as a function of nutrients like Fe, Zn , B, Ca could come very handy in scavenging the excess presence of free radicals , thereby , resonating the palnt defense tool to become doubly active in offering the extended shelf life of fruits . Unfortunately , there are miniscule evidences on these aspects . I , invite researchers  worldover to express their take on the subject . 
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Dear Theresa, that's the problem .There are still conflicting research outcomes . Although , theoretically , it sounds so convincing . And , interestingly , you will see little data on this very important aspect of plant nutrition vis-a-vis shelf life of edible plant part.  There is only some inroads made  into the role nutrients like K , Ca .... Why not you expect some improvements in shelf life through better acquisition  of nutrients like Fe , Zn , Mn  which are the integral part of dismutases, which are so well known in detoxifying  reactive oxygen species.  
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Source to sink distance varies among species. Please explain its effects on the yield of plants. If there is some reference, it would be helpful for me.
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Different researches have presented variable and conflicting views regarding source-sink relationship and impact of this relationship on growth and yield of crops as well as individual plants. However as far as agricultural crops are concerned, researches have pointed towards the source-sink relationship intensity and strength of source in making sugars available at sinks.
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What compounds/measures/characteristics determine the quality of Pinot Noir grape berries? Brix+ph+titratable acidity are pretty standard, but what else influences the decision to harvest?
Cheers,
Iain
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The three parameters you mention all change during fruit ripening, and are therefore useful for following ripening. However, they won't tell you a priori  whether it is time to harvest. Granted, there is a practical range for each of these parameters required for wine stability. However, simply getting into that range is not at all sufficient for establishing commercial quality.
When it comes to the important subjective question of what constitutes better wine, instrumental measurements become more difficult. With Pinot noir, the subtlety of the flavors and aromas and mythology surrounding their origin probably make it the most difficult winegrape variety of all for which to identify an objective harvest parameter. 
In practice, Pinot noir winemakers figure out--for each vineyard--which harvest parameters tend to give them the result closest to what they desire.  Some winemakers have identified  flavor or texture characteristics in the berries that they find to be useful predictors of harvest time. But those vary greatly among individuals and are difficult to describe to others. Viticultural and enological scientists have expended great effort trying to make that process more predictable.
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Xylem and phloem pH might differ among species and environmental conditions. Is this pH affect the mobility of nutrients within plant body? If Yes then Why... Explain please....
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Some studies shown that nitrate and total ionic concentrations (cations+anions), and the proportion of cations influenced xylem pH such that xylem pH increases as nitrate and total ionic concentrations decrease, and the proportion of cations increases (DOI:10.1093/jxb/err370). Also osmotic stress conditions can influence the pH of the xylem. The pH value of xylem sap increased under osmotic stress.
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Many exotic plantations are being promoted in wet lands particularly close to paddy-rice agroecosystems. It will be interesting to know the possible impact of popyphenols on the morphology, physiology, energy partitioning and  molecular  level.
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Several agroforestry solution were tested in rice asfor Vetiver-rice combination. This is supported by FAO ICRAF in the philippines. As far testing biocompatible solutions you may try to use pot trials with and without active charcoal up to 6% in volume. This agent will remove root exidates and if the soil was taken under the trees you like to test, the rice seedling growth rate will be higher in amended soil.
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a colleague is interested in assessing yield penalty for groundnut cultivars having multi resistance to diseases such as leaf miner, rosette, leaf spot, and tolerant to drought
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thank you very
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Considering the crisis in availability of irrigation water in future, even in South Asian countries, rice production should be made in system (s) where water requirement is less; for example, aerobic method of rice cultivation consumes less water; however, the nature of variations in crop physiology due to the shift from anaerobic to aerobic rhizosphere is not understood clearly.   
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I am sorry I cannot  provide any knowledge  to this subject.
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In wheat crop, usually we observe that the middle seeds in the spike are bolder compared with the grains on the top and bottom of the spike. What are the genetic and physiological reasons for this phenomenon? Explain please.....
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You should look up the papers by HM Rawson from the late 1960s and early 1970s; the CSIRO did a huge amount of work assessing growth of wheat spikelets, whole plants, photosynthesis, etc. Mostly published in Australian Journal of Biological Sciences, but some of the other CSIRO Journals as well. The link is to a paper specifically on grain position.
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Traditional maize (zea mays) has evolved from teosinte (Zea Mexicana). Maize grains can synthesize and store lipids. Can teosinte grains do so?
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Gaber,  That was nt the suggestion as I see it.  Maize may well have oils in their seed that can serve as sources of energy that the seed can use until it is able to photosynthesize.  
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Is there any software or through lysimetric method
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Well if you are interested in estimation of actual evapo-transpiration for a large scale then it is expensive to use lysimeter or other eddy covariance measurement instruments. So could you let us know your spatial and temporal resolution and I personally believe that fitted model for particular area may vary. for Arid and sub-arid region SEBAL (surface energy balance algorithm ) is very suitable choice and could give you about 80% accuracy in estimating Actual ET. to apply SEBAL there are many ways and If I am not wrong then you can use ILWIS which has builtin algorithm or ERDAS. good luck!
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