2021 Solved Old Paper (BOT - 201) New

Ans. 
> The somatic phase is represented by a multinucleate apparently naked acellular slimy protoplasmic mass called the Plasmodium.
> The Plasmodium is the product of syngamy, hence a diploid structure.
> The diploid Plasmodium is holocarpic, free living and active. It contains and secretes slime.
> Normally at the fruiting time, the entire Plasmodium is organised into one or more plant­like reproductive structures, the sporangia (sporophores) or under conditions of stress and strains it becomes converted into an irregular hard structure, the sclerotium.
> The reproductive phase is stationary.
> With the exception of three species which are exosporous, all the others are endosporous and produce spores within sporangia.
> The sporangium generally develops a tough non-cellular layer or wall called the peridium which is often studded with tiny crystals of calcium salts.
> Within the peridium is usually an intricate network of fine tube-like structures constituting the capillitium.
> The numerous spores are differentiated from the diploid protoplast of the sporangium by meiosis.
> The encapsulated haploid spores or meiospores are close packed between the fine tubes of the capillitium but are free from them when mature.
> The spore wall is differentiated into two layers, the outer of which is sculptured or spiny.
> On germination, the haploid spores or meiospore give rise either to myxamoebae or biflagellate swarm cells which function as gametes.
> The swarm cells or myxamoebae do not produce slime.
> The sporangium in Physarum thus functions as on organ of sexual reproduction.
> Sexual reproduction is of isogamous type.
> The diploid zygote, by repeated mitoses but no cytokinesis, directly gives rise to multinucleate Plasmodium.
Ans.
1. 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.
2. 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. 

Ans. 
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)
Ans. 
Crop rotation:- 
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.
Ans.
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.
Ans. 
Spermatization:- The mature spermatia are released from the ostiole along with the drop of nectar. Nectar attracts insects due to which spermatia stick to the legs and mouthparts of insects. When these insects come in contact with the receptive fungal hyphae of opposite strain, spermatia stick to it. Due to the desolution of the contact wall, both the nuclei enter the receptive fungal hyphae.
Ans. 
Tundu disease of Wheat:-
Pathogen:- Clavibacter (= Corynebacterium) tritici
Symptoms:-
> The early symptoms of tundu disease are wrinkling of lower and twisting of the middle leaves generally evident when the crop is reaching maturity. This is followed by curling and twisting of spikes.
> What happens actually is that a bright yellow sticky slime exudes mainly from the ear and envelops it. 
> In addition, the slime trickles down to glumes, stem, and leaf sheaths and envelop them. The slimy substance becomes deeper yellow, hard, and dry in dry weather resulting in retardation of plant growth and distortion of stem and ear.
Management:-
i. As soon as the symptoms appear, the infected plants should be uprooted and burnt.
ii. Seeds not contaminated with nematode galls should be sown preferably in non-infected fields. Seeds can be made gall-free by soaking them in strong solution of common salt (solution called ‘brine’) prepared at the rate of 40 lb. salt dissolved in 25 gallons of water. The galls float on the surface of the solution and are removed. This method is the most effective one and recommended strongly.
iii. In tropical countries, summer ploughing helps destroy bacteria and nematodes occurring in soil by heat and desiccation and thus reduces disease incidence in the next season.
Ans. 
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.


Ans. 
Reproduction:-
a. Asexual reproduction:-
> The fungus completes its life mostly in host tissue in the form of resting sporangium. 
> It remains in the soil for a very little period. 
> In the spring season, uniflagellate zoospores are released from the infected tubers and swim to healthy tubers through water. 
> The zoospores come in contact with the new host epidermal cell and dissolve the wall. They enter into the host epidermal cell leaving their flagellum outside. 
> In the host cell, the protoplasm of the zoospore increases in size with large nucleus. Now, it becomes rounded having thick brown wall. This is called as summer spore. 
> The host cell becomes enlarged and hypertrophied. The surrounding cells of infected cell form a rosette of cells around the infected cell. 
> The summer spore now comes to the lower half of the cell and germinates. Its nucleus divides mitotically into 32 small nuclei. This multinucleate structure is called prosorus.
 > Prosorus at the later stage becomes segmented into 4-9 multinucleate chambers, each having many nuclei. 
> Now, the nuclei of each segment divides repeatedly into about 200-300 nuclei. 
> Each segment of the prosorus develops into a sporangium. 
> The protoplast of the each sporangium with a nucleus metamorphoses into a zoospore with a single posterior flagellum. These zoospores are released outside the tuber.
b. Sexual reproduction:-
> Under dry weather when water is scarce, the sporangium behaves like a gametangium. 
> Many uninucleate uniflagellate gametes are produced from each segment. These are called as planogametes, which are similar to zoospores but, smaller in size.
> Uniflagellate planogamete, when comes out from gametangium, meet with another gamete and fuses with it. 
> Fertilization takes place by karyogamy and zygote is formed. 
> Each zygote has two flagella, shared by two individual mating gametes. 
> The biflagellate zygote swims in the water film for some time and then it withdraws flagella. Now it settles on the host surface. Then it pierces the host wall by dissolving it and enters into the host epidermal cell. 
> The protoplast of the zygote settles in the bottom of the cell. It enlarges and becomes thick walled and converts into a resting sporangium. 
> The surrounding cells of the infected cell get activated to divide repeatedly giving rise to a rosette of cells. 
> The resting sporangium becomes dormant in the winter. It becomes active in the next spring season. 
> In the spring season, large numbers of granules appear which act as zoospore primordia. 
> Meiosis was not observed, by Curtis ((1921), but it is assumed that there is reduction division during the formation of zoospores. 
> Zoospores are released outside the host cell.
Ans. 
Ans.
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.
Ans. 
Reproduction:-
> Only sexual reproduction takes place.
> Most of the species are homothallic, but some are heterothallic.
> Plasmogamy takes place by gametangial contact and by trichogyne contact.
> Dikaryophase is in the form of ascogenous hyphae.
> The asci are club shaped which are produced in basal tuft.
> 8 ascospores in each ascus.
Exceptions:-
i. C. hispidum
ii. C. tetrasporum
> Ascus show indirect development in C. brasiliense.
> Pore liberation of ascospores takes place.
> Perithecium:-
- The perithecia of the Chaetomium are produced superficially without a stroma.
- Most distinctive character is presence of numerous long hairs on the peridium that give the genus its name.
Gr.- chaite = long hair, mane 
> Ascospore germination:-
Ans. 
Powdery Mildew of Grapes:-
Pathogen:- Uncinula necator
Symptoms:-
> Powdery growth mostly on the upper surface of the leaves.
> Malformation and discolouration of affected leaves.
> Discolouration of stem to dark brown.
> Floral infection results in shedding of flowers and poor fruit set.
> Early berry infection results in shedding of affected berries.
> Powdery growth is visible on older berries and the infection results in the
> Cracking of skin of the berries.
> It spread through air-borne conidia
> Through dormont mycelium and conidia present in the infected shoots and buds.
> Sultry warm conditions with dull cloudy weather, highly favourable.
Management:- Spray Inorganic sulphur 0.25 % or Chinomethionate 0.1 % or Dinocap 0.05 %.