Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

The role of inorganic nutrients in plant growth and metabolism was first discovered by Knop.
Wilhelm Knop was a German agrochemist and co-founder of modern water culture. Nitrogen, Phosphorus, Sulfur, Potassium, Calcium, Magnesium, and Iron are identified as essential elements of plant nutrition by him along with Von Sachs.
They were the first to use standardized nutrient solutions in experimental plant physiology.

Khaira disease of rice is due to the deficiency of Zinc.
Khaira disease of rice is a micro-nutritional (Zn) deficiency characterized by the presence of dusty brown patches on leaves which ultimately undergo necrosis.
This is one of the most common diseases in rice. As it affects the leaf of the plant-the rate of photosynthesis decreases which ultimately causes (25 - 30)% production loss.

Mad cow disease is caused by Prion.
Mad Cow Disease is a progressive neurological disorder of cattle that results from infection by an unusual transmissible agent called a prion.
CWD is a prion disease that affects deer, elk and moose in some areas of North America, South Korea and Norway.

Water drops present on leaf margins of Tropaeolum, Balsam and grasses in the early morning are due to Guttation.
Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation generally happens at night.
At night, transpiration usually does not occur, and when there is a high soil moisture level, water will enter plant roots, because the water potential of the roots is lower than in the soil solution. The water will accumulate in the plant, creating a slight root pressure. The root pressure forces some water to exude through special leaf tip or edge structures, hydathodes or water glands, forming drops.

The black heart of potatoes is the result of High temperature during transit, Poor ventilation in the store, and High temperature of soil during growth and maturation of tubers in the crop field.
The black heart occurs primarily in storage when the tubers do not receive enough oxygen. Blackening of the tuber center follows acute oxygen deficiency associated with either low temperature in confined storage or high field soil temperatures. The tissue dies from the inside out and turns jet black.

a. Nitrate-N causes Methemo-globinemia.
Drinking water with high nitrate can cause a potentially fatal disorder called methemoglobinemia. Methemoglobinemia is a condition in which more than one percent of the hemoglobin in red blood cells takes the form of methemoglobin.
b. Nitrous oxide affects the Ozone layer.
Air pollution in the form of Nitrogen oxides (NO_x) can harm the ozone layer which protects the surface of the Earth from harmful radiation.
c. Nitrogen and phosphorus lead to Eutrophication.
An overabundance of nutrients-primarily nitrogen and phosphorus-in water starts a process called eutrophication. Algae feed on the nutrients, growing, spreading, and turning the water green.
d. Cadmium as a contaminant in Zinc and Phosphatic fertilizers causes Heart and Kidney disease.
Cadmium has been associated with kidney disease, bone disease and cardiovascular disease. With chronic exposure, cadmium accumulates in the epithelial cells of the proximal tubule, resulting in a generalized reabsorptive dysfunction characterized by polyuria and low-molecular-weight proteinuria.

In the case of Zn deficiency of paddy, 25 kg zinc sulphate should be applied to one hectare of soil.
Zinc is one of the essential elements in paddy plants as it involves nitrogen assimilation and protein metabolism. And at the same time, the availability of zinc is lower in submerged fields like paddy plantations in comparison to normal upland fields. So, it is required to add zinc-rich fertilizers to the paddy fields approximately 25 kg per hectare.

When the chromosome number in leaf cells of an angiosperm is 22, 11 in gametes is the correct option.
The angiospermic leaf cell is diploid in nature that is 2n, therefore, if the chromosome number in the leaf cell is 22, that means, each gamete will have half the number as gametes are haploid.

Chromosome numbers in a flowering plant can be Haploid diploid or polyploid.
Most flowering plants are polyploid, and many are distinct in combining the diploid nuclear genomes from two or more different ancestral species or genera (allopolyploids).
Spore mother cells within the anther pollen sacs form four haploid pollen grains.

Horizontal resistance is also known as Field resistance.
In genetics, the term horizontal resistance was first used by J. E. Vanderplank to describe many-gene resistance, which is sometimes also called generalized resistance. This contrasts with the term vertical resistance which was used to describe single-gene resistance.
In the first round of breeding for horizontal resistance, plants are exposed to pathogens and selected for partial resistance. Those with no resistance die, and plants unaffected by the pathogen have vertical resistance and are removed.