2018 Solved Old Paper (BOT - 201) New
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Wines are produced from grapes or other fruits by Saccharomyces ellipsoideus with about 14% alcohol concentration. Beer is brewed from barley malt by Saccharomyces cerevisiae with 3-8% alcohol production.
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i. Early Blight of Potato:-
Pathogen:- Alternaria solani
ii. Downy Mildew of Grapes:-
Pathogen:- Plasmopara viticola
iii. Blast disease of Rice:-
Pathogen:- Pyricularia grisea (P. oryzae)
iv. Red Rot of Sugarcane:-
Pathogen:- Glomerella tucumanensis. (Older name = Colletotrichum falcatum)
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Management:-
i. Cultural method:-
> The best way to control red rot is to select setts for planting from healthy plants in a disease- free area.
> The red rot affected field must be rotated with rice for one season and other crops for two seasons.
> Growing of recommended resistant and moderately resistant varieties viz., Co 86032, Co 86249, CoSi 95071, CoG 93076, CoC 22, CoSi 6 and CoG 5.
ii. Physical method:-
> Removal of the affected clumps at an early stage and soil drenching with Carbendazim 50 WP (1 gm in 1 litre of water).
> The cut ends and entire setts should be dipped in a fungicide solution, such as one per cent Bordeaux mixture.
> If the disease is noticed in the field, the leaves and canes should be collected and destroyed by burning.
iii. Chemical method:-
> Adopt sett treatment with Carbendazim before planting (Carbendazim 50 WP (0.5 gm in 1 litre of water) or Carbendazim 25 DS (1gm in 1 litre of water) along with 2.5 kg of Urea in 250 litre of water.
> Use fungitoxic chemicals like Bavistan, Benomyl, Topsin and Aretan at 0.1 per cent for 18 min. at 52ºC for dipping setts which gave almost complete elimination of rot infection.
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Pilobolus:-
1. Classification:-
Kingdom:- Myceteae
Division:- Amastigomycota
Sub division:- Zygomycotina
Class:- Zygomycetes
Order:- Mucorales
Family:- Pilobolaceae
Genus:- Pilobolus
2. Habit and Habitat:-
> Pilobolus, also called hat-thrower fungus, a cosmopolitan genus of at least five species of fungi that are known for their explosive spore dispersal.
> It is also known as conjugation fungi.
3. Thallus structure:-
> The hyphal walls of these fungi contain chitin and fungal cellulose.
> Their mycelium is coenocytic in nature which means that it is multinucleate and aseptate in nature.
4. Reproduction:-
a. Asexual reproduction:-
> It takes place by means of sporangiospores.
> The modes of development of the sporangia, columella and the formation of spores agree closely with those of Mucor mucedo, but the structure of the sporangium represents a special modification of the Mucor type.
b. Sexual reproduction:-
> It takes place by the union of two isogametangia and their coenocytic contents, and resembles essential features of the sexual reproduction of Mucor mucedo. But, in this case, the gametangia are somewhat club-shaped and they meet in such a way that they resemble a pair of tongs.
> A coenocytic zygospore is formed, by their union, at the point of contact, and it appears as a bud and occupies, as if, a terminal position.
> P. crystallius is heterothallic, and the formation of a zygospore is dependent upon the union of mycelia of two sexual strains, ( + ) and (-).
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Annual Reoccurrence of Black Rust of Wheat in India:- In 1933, late professor K. C. Mehta worked on the problem of annual recurrence of rust in India and solved the mystery. He proved that the uredospore’s produced on the hills are responsible for the annual recurrence of rust disease in the plains of India. According to him:
(a) Uredospore’s can survive in the summer in hills (at higher altitude of 1300-2500 metres).
(b) They survive on self sown wheat plants and tillers. The atmospheric conditions on high altitude and the low temperature help for the survival of uredospore’s.
(c) In the hills the wheat crop is sown in September and October, its gets infected very soon whereas in the p’.j -.s of India the wheat crop is sown in the months of October and November. At that time the hilly crop is already heavily infected by rust disease. The wheat plants are infected by the uredospore’s survived during the summer season in hills.
(d) These uredospore’s are easily carried away by wind and first infect wheat crop in January and February. Thus, he concluded that uredospore’s produced on the hilly crops particularly in the region of Himalayas, Nepal hills for northern plains and Nilgiri.
Palni hills and Panchgani of Western Ghats for the southern plains are the causal organisms for the annual recurrence of the rust disease in the plains of India. He also suggested that the rust severity in the plains can be reduced if there is no wheat cultivation on the hills for some time.
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Role of fungi in industries:-
1. Alcohol Production:- Alcoholic fermentation by fungi is the basis of brewing industry. The enzyme zymase of microorganisms like yeast is responsible for alcohol production. Wines are produced from grapes or other fruits by Saccharomyces ellipsoideus with about 14% alcohol concentration. Beer is brewed from barley malt by Saccharomyces cerevisiae with 3-8% alcohol production.
2. Organic acid Production:- Many fungi are used in the commercial production of different organic acids.
3. Antibiotics:- Antibiotics are the metabolic product of some micro-organisms which are active against other microorganism. Wonder drug Penicillin from Penicillium notatum, and drug Fusidin (Fusidic acid) from Fusidium coccineum.
4. Fungi as Food:- Fungi are used as food by humans from a long time ago.
> Fruit bodies of some fungi, like Mushroom and truffles are used as food due to their high protein content (21-30% on dry weight) and have good amount of lysine, an amino acid; minerals like Na, Ca, K and P; Vitamins like B, C, D and K and very little amount of fat. These are recommended as ideal foods for heart patients and diabetes.
> The above-mentioned fungi can grow artificially at the commercial level. Mushroom cultivation has recently gained considerable popularity and has contributed to the national economy in some East Asian
countries.
5. Fungi as Fodder:-
> Yeast that is used as animal feed it is a microbial proteins synthesized by yeast in which digestibility amino acid content higher than an animal routine does has a high biological value as compared to other feed.
> Inactive dry yeast fodder increases bioavailability of protein as they contain essential amino acid.
> Composition of fodder yeast contain 10 essential amino acid. On the content of amino acids fodder yeast similar to proteins of animal origin
> Feed yeast contain Vitamin B (rgulate fat metabolism) rich source of Vitamin D2 (5000-12000 IU/Kg Fd .yst).
> Ash of fodder yeast also contain valuable animals and birds macro and micro elements P, K, Ca, Fe, Mg, S, Na, Cu and others.
> Yeast commonly used commercially strain of Candida utilis,(torula yeast) often called as Torulopsis utilis.
> Other yeast used commerically or studied extensively in laboratory include C.tropicalis and Saccharomyces cerevisea.
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Crop rotations:-
Introducvtion:-
> Crop rotation is the practice of growing a variety of crops in the same area over a number of growing seasons.
> It reduces reliance on a single set of nutrients, pest and weed pressure, and the likelihood of developing resistant pests and weeds.
> It is the process of producing a variety of crops in the same place over the course of several growing seasons.
Criteria for Selection of Crops for Rotation:-
> There should be enough moisture.
> Fertilizer, labour, and machine power are all available.
> Marketing and processing facilities.
> Nutrient availability in the soil.
> The crop's duration—short or long.
Principles of Crop Rotation:-
> Due to fact that legumes fix atmospheric nitrogen into the soil and add organic matter to the soil, they should be planted before non-leguminous crops.
> Crops with tap roots (deep rooted crops like cotton) should be followed by crops with fibrous roots (shallow rooted crops like sorghum or maize). This allows for the proper and uniform use of soil nutrients.
> More exhaustive crops should be followed by less exhaustive crops because crops such as potato, sugarcane, maize, and others require more inputs such as better tillage, more fertilisers, more irrigation, and so on.
Types of Crop Rotation:-
1. One-year Rotation:-
> Crop rotation can be carried out for one year, depending on the size of the available plot of land.
> Following harvest, the soil that is suitable for another specific crop will be planted with that crop for the remaining half of the year.
> One crop would be planted during the first half of the year.
> The planting of maize and then mustard is an example of a one-year crop rotation.
> Another example is the planting of wheat first, then rice.
2. Two Years Rotation:-
> The two-year rotation is essentially identical to the one-year rotation, with the exception that more crop options are available and the crop planting rotation would last for two years instead of one.
> Within the course of a two-year crop rotation, there may be a total of two, three, or four crops planted.
> After the prior crop is harvested, the subsequent crops should have all of the nutrients they need.
> A two-year rotation might involve planting successive crops of corn, mustard, sugarcane, and fenugreek as well as subsequent crops of corn, potatoes, sugarcane, and peas.
3. Three Years Rotation:-
> A three-year rotation, as the name suggests, calls for a number of crops to be planted over the course of three years while addressing all of their nutrient needs.
> On the same piece of land, the crops will be planted one after the other in succession.
> The subsequent crop's nutritional needs will be satisfied by the previously planted crops.
> Some examples of three-year crop rotations include:
i. Rice, wheat, mung, and mustard in succession.
ii. Sugarcane and berseem in succession.
iii. Cotton, oat, sugarcane, peas, maize, and wheat in succession.
Advantages of Crop Rotation:-
i. Improves Soil Condition:- Utilizing various crops, especially those with fibrous or tap roots, can improve the soil's chemical, biological, and physical composition. This increases the amount of organic matter and nutrients in the soil as well as its ability to store water.
ii. Improves Soil Structure:- Rotation helps to preserve and improve soil structure. Crops have various root structures and grow to different depths. Rotating exposes the soil not only to shallow depth crops, but also to deep diggers, which gradually deepen the topsoil.
iii. Reduces Soil Erosion and Water Runoff:- Crop rotation can reduce erosion by enhancing the microbial populations and soil tilth. Surface runoff is reduced as a result of the more stable soil structure created.
iv. Reduces Pests and Weeds:- Pests, plants, and insects can't live without their host for very long. Those pests have no chance if you move your crops around and improve the soil structure at the same time.
v. Control of Insects:- Insects tend to enter your plants' leaves and vines as they prepare to reawaken in the spring in search of their favourite meal. When you rotate, these insects come into contact with a plant that they do not feed on.
vi. Disease Prevention:- Plant diseases can over winter enter in plant leaves, roots, and vines beneath your soil. Crop rotation helps to keep these diseases from returning the following year.
vii. Improvement in Water Quality:- Water quality can be improved by reducing sediment loss, as well as dissolved and sediment-attached nutrient and pesticide losses.
viii. Provides Diversification:- Some crops demand less labor and equipment than others. This implies that the workload can be distributed throughout the year. Additionally, it increases the range of the products that can be sold, preventing from having to "place all your eggs in one basket."
ix. Nutrient Uptake Regulation:- As various crops require different nutrients in different quantities, crop rotation aids in boosting the nutrient uptake by plants from the soil. Crop rotation helps the various crops that are planted within the rotation make the most of all the nutrients in the soil, including the nutrients left over from the previous crop that was planted.
Disadvantages of Crop Rotation:-
i. Involves Risk:- Crop rotation requires a significant financial investment each season to purchase various seedlings of the various crops that will be grown.
> Moreover, particular crops demand specific sorts of equipment, thus farmers may have to invest in different types of machinery.
> This implies that the upfront fees can be higher. However, the success of each crop kind is not assured, and one may wind up losing a harvest.
ii. Requires More Skill & Knowledge:- Crop rotation calls for a broader range of abilities and information regarding each type of crop collected because it involves a variety of crops.
> It also calls for various machinery, the operation of which also takes skill. This implies that learning and perfecting this agricultural method will require more time and effort on the part of farmers.
iii. Difference in Growing Conditions:- For monoculture, or a particular type of crop, some places and their temperatures are better suited.
> The specific type of temperature and soil conditions cannot support the growth of any other crops than that particular type of crop.
iv. Obligatory Crop Diversification:- It is mandatory to plant different crops each time for crop rotation to be effective. However, it prevents a farmer from specializing in a particular crop.
Plant quarantine:- The process of ensuring that seeds, propagules and plant products imported from outside are free from diseases, pests and weeds, is called plant quarantine. The DIP (Destructive Insects & Pests) Act was passed in 1914. There are 4 plant quarantine centres in India -
· NBPGR, New Delhi:- For plant species related to Agriculture and Horticulture.
· FRI (Forest Research Institute), Dehradun:- For forest trees.
· IBS (Indian Botanical Survey), Kolkatta:- For other plants.
· DPPQS (Directorate of Plant Protection, Quarantine and Storage), Faridabad, Haryana:- For food materials.
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Peronospora:-
1. Classification:-
Kingdom:- Myceteae
Division:- Mastigomycota
Sub division:- Diplomastigomycotina
Class:- Oomycetes
Order:- Peronosporales
Family:- Peronosporaceae
Genus:- Peronospora
2. Habit and Habitat:-
> Most of the Peronospora species are highly specific to their hosts and can generally be found anywhere the host plant grows, or is being cultivated.
> It causes downy mildew disease in crops.
i. P. brassicae:- Downy mildew of Mustard.
ii. P. destructor:- Downy mildew of onion.
3. Thallus structure:-
> Well developed and profusely branched mycelium.
Hyphae are aseptate, coenocytic and branched.
4. Reproduction:-
> The first stage in the Peronospora life history is the sporangia.
> The sporangia are small spore-like structures about 65 um long that germinate a germ-tube when they are near a leaf stoma.
a. Asexual reproduction:-
- Asexual reproduction occurs when the air outside is moist making for favourable conditions.
- During asexual reproduction, hyphae on the host plant will form sporangiophores, which will produce conidia.
- The conidia will be dispersed by the wind is able to infect other plants.
- The asexual cycle only takes five to 7 days to complete.
b. Sexual reproduction:-
- Sexual reproduction occurs when the conditions are unfavourable and it needs to withstand harsh environmental conditions.
- During sexual reproduction, the hyphae will undergo meiosis forming antheridia and oogonia, the only haploid structures in the Peronospora life history.
- The antheridia will fuse to the oogonia, initiating plasmogamy and then karyogamy, and will result in the production of many oospores.
- The oospores can then be dispersed by the wind to infect more plants.
- Peronospora is characterized by their ability to produce melanized sporangia, but do not produce zoospores.
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Mushroom cultivation:-
Mushroom:-
> Mushrooms are the eukaryotic, spore bearing organisms, macro-fungi lacking chlorophyll and
grow on dead decomposed matter as saprophytes.
> They derive nutrients through their mycelia. This mycelium forms the fleshy structures, the fruit bodies, which are generally called the mushrooms.
> There are more then 10,000 verities of mushroom out of which only 200 verities identified as edible variety.
Varieties of Mushrooms:- We can grow four varities of mushroom depending upon the climatic condition as:
i. Oyster Mushroom (Sept-April)
ii. Paddy Straw Mushroom (May-Sept)
iii. Milky Mushroom (Sept-April)
iv. Button Mushroom (Nov-Feb)
Cultivation of Button mushroom:- The most popular kind of mushrooms are button mushrooms, often referred to as white mushrooms, baby mushrooms, and cultivated mushrooms. These mushrooms can be consumed raw or cooked, and are frequently added to salads, soups, and as toppings for pizza. In the sixteenth century, button mushrooms were first grown. Button mushrooms make up 85% of the annual production of mushrooms.
Following is a process to grow mushroom:-
1. Compost:-
> The first stage in cultivating button mushrooms is composting.
> This procedure is carried out in public.
> On neat concrete platforms, button mushrooms are raised.
> Compost is prepared in the two types listed below:
a. Natural compost:-
- Natural compost is produced by nature.
- When producing compost for button mushrooms, some natural ingredients are wheat straw, horse manure, gypsum, and chicken manure.
- The compost yard should be evenly covered with a mixture of all the components.
- After that, moisten the prepared compost with a water sprayer.
b. Synthetic Compost:-
- For synthetic compost, we needed urea, gypsum, wheat straw, bran, and ammonium nitrate / ammonium sulphate.
- To begin, trim the staw to a length of 8 to 20 cm.
- Now cover the compost with a fine layer of cut straws and mist it with water.
- You must now thoroughly combine the bran, calcium nitrate, urea, gypsum, and other ingredients.
2. Filling the compost trays:-
> The compost that has been processed is a deep brown tint.
> The compost shouldn't be too damp or too dry when you put it in trays.
> Spray some water on the compost if it's dry.
> Allow some water to evaporate if it is excessively wet.
> You can choose the size of the compost-spreading trays to suit your needs.
> The depth must be between 15 and 18 cm.
> Make sure the trays are constructed of softwood as well.
> Compost must be poured into the trays to the rim and spread out evenly.
3. Spawning:-
> Spawning is the following stage in the cultivation of button mushrooms.
> It entails planting mycelium in the beds.
> There are two methods for spawning:
i. The first is to distribute compost on the tray bed.
ii. The second is to mix mycelium with compost before spreading it on the tray.
> After sprinkling the tray with water and spawning, you must cover it with newspaper to keep the moisture there.
4. Casing:-
> The tray must now be covered with a heavy layer of dirt.
> This soil can be created by mixing garden soil and decomposing cow manure.
> Casing soil is the term for this soil. This casing soil may hold a lot of water.
5. Harvesting:-
> The cap should be gently torn off during harvest.
> To do this, hold it gently between your forefingers, press it into the ground, and then twist it off.
> Cut off the base of the stalk where mycelial threads and dirt granules adhere.
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Mycorrhiza:- It is a symbiotic association of fungi with roots of higher plants. Their major role is to enhance nutrient and water uptake by the host plant by exploiting a larger volume of soil than roots alone can do. the large mass of fungal hyphae acts as a virtual root system for the plants, increasing the amount of water and nutrients that the plant may obtain from the surrounding soil. In reverse, the roots provide essential nutrients for the growth of the fungi.
It is further divied into 2 types:-
Ectomycorrhiza:- It is a type of mycorrhiza, typical of temperate and Boreal trees, in which the fungus forms a layer on the outside of the roots of the plant. Here the fungal hyphae does not penetrate the cortical cells of the plant root. It occur only in about 3 per cent of plant species, majority of which are forest trees. Eg.- Amanita, Boletus, Tricholoma
Endomycorrhiza:- It is a type of mycorrhiza, most common among vascular plants, in which the fungus grow inside the tissues of the roots of the plant. the fungal hyphae penetrates the cortical cells of the plant root and make arbuscules and vesicles, hence also called as Vesicular Arbuscular Mycorrhiza (VAM). Eg.- Glomus
Benefits in agriculture:-
> Mycorrhizae induce plants to absorb more nutrients and water from the soil.
> They also increase plant tolerance ability to various bad environmental stresses.
> In addition to this, Mycorrhizae also play an important role in soil structure process and stimulate beneficial microbial activity.
> We divided functions into two parts:
a. For Soil:-
i. Increase soil’s water & nutrition holding capacity.
ii. Improve soil porosity and permeability.
iii. Develop soil microenvironment, promote higher microbial activity and nutrient cycling.
b. For Plants:-
i. Increase roots establishment and survival at seeding or transplanting.
ii. Improve the plant’s mineral absorption capabilities, access many extra nutrient sources share with colonized plants.
iii. Increase plants resistance ability to soil diseases, virus, drought & salt stress and pests etc.
iv. Increase plants root system healthy development.
Simliar Products:- The optimum supplements to mycorrhizae is Bacillus subtilis, Trichoderma harzianum.
> Mycorrhizae’s ability is to regulate biological diversity in soil, develop positive microenvironment.
> Bacillus subtilis can improve plants uptake nutrients efficiency, increase roots growth and protect roots away from soil pathogens.
> Trichoderma harzianum have super soil adaptability. Good effect on soil conditioner and control soil borne diseases. Also can increase root systems development.
> In general, the more biological diversity of microorganisms, the more advantageous it is for growing.
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Ergot disease of Bajra:-
Pathogen:- Claviceps fusiformis
Symptoms:-
> Small droplets of pinkish sticky fluid oozes out of the spikelets. The affected spikelets turn black and several such dark sticky patches are seen on the earhead.
> Grain formation is inhibited.
> The honey dew contains large number of hyaline single celled conidia.
> Later infected ovaries get converted into sclerotia.
Management:-
1. Seed treatment:-
> Removal of ergot / sclerotia to prevent primary infection Dissolve 1 kg of common salt in 10 litres of water. Drop the seeds into the salt solution. Remove the ergot and sclerotia affected seeds which
will float. Wash seeds in fresh water 2 or 3 times to remove the salt on the seeds. Dry the seeds in shade.
> Treat the seeds with Thiram @ 2g /kg of seed.
2. Spray of Fungicides:- Spray any one of the fungicides like Carbendazim 500g or Mancozeb
1000g /ha when 5 - 10% flowers have opened and again at 50% flowering stage.