৪৯তম বিসিএস ⎯ কৃষিবিজ্ঞান [৮০১]

আলুতে সবুজাভ রঙ দেখা দেয় যখন সেগুলো আলোতে উন্মুক্ত থাকে।
এতে ক্লোরোফিল তৈরি হয় এবং সোলানিন এর পরিমাণ বৃদ্ধি পায়।

সোলানিন একটি তিক্ত ও বিষাক্ত পদার্থ, যা আলুর  পুষ্টিগুণ কমিয়ে দেয়।

Alternate bearing may occurred due to-
size and age of shoots, 
C & N ratio, Hormonal
imbalance, 
excess fruits bearing, 
lack of proper management,

The red color of ripe tomatoes is mainly due to lycopene, which is a type of carotenoid pigment. Carotenoids are natural pigments found in many fruits and vegetables that give yellow, orange, and red colors.

Anthocyanins give purple or blue colors in some fruits like grapes or blueberries.
Flavonoids are a diverse group of pigments mostly contributing to yellow and cream colors.
Carotene gives orange or yellow color (like carrots, pumpkins).

Seed Potato: A seed potato is a whole or a cut-up piece of a potato that's used for planting. Each piece must contain at least one "eye," which is a bud from which a new plant will sprout.
True potato seed: True potato seeds are the actual botanical seeds produced by the potato plant's flowers.
Spud is the another name of potato. This name mainly used in UK, Ireland, and North America

The most common method of propagation used for papaya is by seed. This is the traditional and most widely practiced method for commercial cultivation.

Papaya plants are mostly grown from seeds because it is easy, inexpensive, and efficient. For producing uniform and high-quality plants, sometimes methods like grafting or tissue culture are also used . But seed propagation remains the most widely practiced method.

The green leaves and stalks of onion are a good source of vitamin C, which helps boost immunity, and minerals like calcium (for strong bones) and iron (for healthy blood). 

Lycopersicon esculentum - Tomato 
Solanum tuberosum - Potato
Solanum melongena - Brinjal
Musa. paradisiaca -  Banana

Floral Formula 
K = Calyx (sepals)
C = Corolla (petals)
P = Perianth (when sepals and petals are indistinguishable)
A = Androecium (stamens)
G = Gynoecium (carpels)

Bananas are tropical fruits that are very sensitive to cold temperatures. When stored below their optimal temperature range (typically 13°C to 15°C ), they can suffer from chilling injury.
Symptoms of chilling injury: 
Dull, smoky, or grayish skin color.
The inability to ripen properly.

Ethylene damage: Ethylene is a ripening hormone used to control ripening in bananas, not a source of damage in itself.

Sprouting: This is a major problem for tubers like potatoes and bulbs like onions, not for fruits like bananas.

Berry is a fleshy fruit that develops from a single ovary and usually contains multiple seeds. Banana, Tomato
Drupe: A drupe is a fleshy fruit with a stony pit or "stone" in the center, which contains the seed (e.g., peach, cherry, mango).
Siliqua: A siliqua is a dry, dehiscent fruit that splits open at maturity to release its seeds (e.g., mustard, cabbage).  
Legume: A legume is a dry fruit that splits along two seams (e.g., peas, beans). 

Onions are bulbs that are naturally programmed to sprout when conditions are favorable for growth. To inhibit this, the storage environment must be the opposite of what is needed for growth.

Low Humidity: High moisture can encourage mold, rot, and, most importantly, early sprouting. Low humidity keeps the outer skins dry and brittle, forming a protective layer.
Cool, Dry Conditions: Temperatures between 0°C and 4°C (32°F and 40°F) are ideal for slowing down the metabolic processes within the onion bulb. 

Jute: Corchorus olitorius and Corchorus capsularis

Tea: Camellia sinensis

Soybean: Glycine max

Pineapple: Ananas comosus

Actinomorphic means a flower that is radially symmetrical — you can divide it into two equal halves through multiple planes passing through the center, (যেমন পিৎজা কে সমান দুইভাবে বিভিন্ন দিক থেকে ভাগ করা যায়) Sunflower, Mustard, Hibiscus

Zygomorphic, where the flower is bilaterally symmetrical (only one plane can divide it into equal halves). Pea, Orchid, Bean

A ligule is a small, membranous or hairy structure located at the junction of the leaf blade and the leaf sheath. 
এর প্রধান কাজ হল কাণ্ড এবং পাতার খোলের মধ্যবর্তী স্থানে জল, ময়লা এবং পোকামাকড় প্রবেশ করতে বাধা দেওয়া, যা পচন বা অন্যান্য ক্ষতির কারণ হতে পারে।

Banana Variety:
Seedless variety - Amritsagor, Sobri, Agnisor, Cavendish 
Seeded Variety - Alta kola, Manipur
One or two seeded variety - Champa, Zabkathali, Monthan

Curing: is the process of drying the outer leaves, neck, and roots of harvested onions (or other bulb crops) to improve
storage life, reduce rot, and maintain quality.
Grading: This process is done  based on specific quality standards like size, shape, weight, and color.

Sorting:  It involves removing any items that are visibly damaged, diseased, or of poor quality.

Packaging: The final step of placing the sorted and graded produce into containers for storage, transport, and sale.

The chemical most commonly and safely used for the uniform ripening of bananas is ethylene.
It is also called the ripening hormone. 

Regular application of nitrogen (urea) in mango trees is important for promoting healthy growth flushes and flower
production.
✓ Fertilizer should be applied in two splits-
1st one half immediately after harvesting of fruits in June July
2nd Rest one half in September – October at the end of rainy

Auricles are ear-shaped small projections found at the base of the leaf blade, usually clasping or wrapping around the stem. 
They are common in cereal crops like Rice, wheat and barley.

Generally, 4 to 6 irrigations are needed but at least 3
Irrigation: 3 irrigation is required
✓ 1st irrigation is applied 20-25 days after planting
✓ 2nd irrigation is applied 40-45 days after planting
✓ 3rd irrigation is applied 60-65 DAP
✓ Irrigation must be stopped 7-10 days before harvesting

Curing is the process of drying the outer leaves, neck, and roots of harvested onions (or other bulb crops) to improve storage life, reduce rot, and maintain quality.

Aggregate fruits: Fruits derived from a single flower with more than one ovary are called aggregate fruits.
Examples: Strawberry, raspberry, blackberry, custard apple.
Multiple fruits (also called composite fruits)  that develop from the ovaries of multiple flowers in a single inflorescence. 
Examples: Pineapple, Jackfruit, Fig.


সহজে  বুঝার জন্য এটা মনে রাখবেন
Simple fruits → One flower, one ovary.
Aggregate fruits→ One flower, many ovaries.
Multiple fruits→ Many flowers, many ovaries.

Drupes are a type of simple, fleshy fruit that develop from a single ovary and contain one seed enclosed within a hard, stony endocarp.( Mango, Coconut, Peach, Plum)
True berries are a type of simple, fleshy fruit that develop from a single ovary and usually contain multiple seeds embedded within the fleshy pericarp.(Tomato, Grapes, Banana)

Haulm pulling is the removal or cutting of the above-ground part (stems/leaves) of the potato plant 7–15 days before
harvesting.

Earthing up (Hilling): It is the process of heaping or piling soil around the base of the plants as they grow. This is done to cover the lower stems and protect developing underground parts like tubers or roots. 

Br % ⚥ P₂ (lodicules) A₃₊₃ G₁
Explanation:
Br: A bract is present.
%: The flower is zygomorphic (bilaterally symmetrical).
⚥: The flower is bisexual.
P2: There are two perianth parts, which are the tepals (petals and sepals that are indistinguishable).
A3+3: There are a total of six stamens (androecium), arranged in two separate whorls of three.
G3: The gynoecium has a single ovary formed from three fused carpels, with a superior ovary.

Cabbage is a biennial plant, meaning it completes its life cycle in two years. In the first year, it grows the leafy head that we eat. If left to grow, it will flower and produce seeds in the second year before it dies. 
Wheat, sunflower, and corn are all annual plants that complete their entire life cycle from seed to producing new seeds in a single growing season.

⚥ 
​Bract (Br): A modified leaf, usually found just below a flower or flower cluster.

Bristle: A stiff, slender hair-like structure, often found on leaves, stems, or fruits.

Br. % ⚥ P₂ A₃ G₁= Wheat
Br. ⊕ ⚥ K₅ C₅ A∞ G₍₅₎ =Jute
Br. ⊕ ⚥ K_5-7 C₅ A∞ G_(3-5) = Tea
Br % ⚥ P₂ (lodicules) A₃₊₃ G₁ = Rice

Glumes: Two outermost bracts at the base of each spikelet.
Lemma: The outer bract of an individual floret
Palea: The inner bract of a floret, lying opposite to the lemma
lodicule is a small, scale-like structure located at the base of the ovary in the flowers of plants from the grass family, Poaceae.

Grafting is a plant propagation technique in which two different plant parts are joined together so that they grow as a single plant.
The upper part of the graft, which produces the shoots, is called the scion.
The lower part, which provides the root system, is called the rootstock or stock.

Grafting is commonly used for mango because 
High success rate
Faster fruiting
Stronger plants