Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

The management of ergot of bajra may be possible by adopting Long crop rotations, Keeping seed in 20% salt solution, and Spray of oxychloride + zineb.
Ergot of bajra caused by Claviceps fusiformis is an important and widespread disease in India. The disease causes direct grain yield loss by replacing grains with toxic alkaloid-containing sclerotia, making the produce unfit for consumption.
Management of ergot should include rotation with at least one year between small grain crops. Use crops that are not susceptible to ergot in years when small grains are not grown.

The causal organism of potato scabs is Streptomyces scabies.
Streptomyces scabies is a Gram-positive bacterial pathogen that causes common scab disease in several crops, particularly the potato.
It is a soil-borne pathogen, a very devastating scab pathogen, and difficult to manage in the field.

The black scurf of potatoes is caused by Rhizoctonia solani.
Black scurf is caused by the fungus Rhizoctonia solani, which can exist in the soil in the absence of potatoes. It does not feed on the tubers, and stored tubers with black scurf on them will not decay or deteriorate.
Rhizoctonia causes a variety of symptoms including damping off, stem lesions, stem rot, root rot, crown rot, and aerial web blighting. The infection causes wilting, stunting, and possibly plant death.

The most effective wavelength of light for photosynthesis is Red.
The non-absorbed part of the light spectrum is what gives photosynthetic organisms their colour and is the least effective for photosynthesis in the respective organisms.
In green plants, the action spectrum resembles the absorption spectrum for chlorophylls and carotenoids with absorption peaks in violet-blue and red light.
Photosynthesis measurement systems are not designed to directly measure the amount of light absorbed by the leaf. But analysis of chlorophyll-fluorescence, P700- and P515-absorbance and gas exchange.

Meloidogyne, Heterodera, and Globoderagenus of nematodes have special types of nurse cell systems which serve as a source of continuous supply of nutrients to the nematodes.
The nurse cell-larva complex of nematodes of the genus Trichinella plays an important role in the survival of the larva in decaying muscles, frequently favouring the transmission of the parasite in extreme environmental conditions.

A causal organism that led to the outbreak of the Bengal famine is Helminthosporium oryzae.
Cochliobolus miyabeanus (formerly known as Helminthosporium oryzae) is a fungus that causes brown spot disease in rice.
It is an important plant pathogen because it causes a common and widespread rice disease that causes s high level of crop yield losses. It was a major cause of the Bengal famine of 1943, where the crop yields dropped by 40% to 90% and the death of 2 million people was recorded.

Phages attach themselves to the host tissue through the tail end.
The tail of the bacteriophage includes the tail sheath, base plate and tail fibers, which are made of different proteins. The long tail fibers are used by the bacteriophage to attach itself to the bacterium and the virus then inserts its genetic material inside of the host cell to begin the replication process.
The phage tail is a complex, multiprotein structure that mediates attachment, digestion, and penetration of the cell wall and genome ejection.

Secondary one forms the endosperm.
Endosperm is formed when the two sperm nuclei inside a pollen grain reach the interior of a female gametophyte.
One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell. That cell created in the process of double fertilization develops into the endosperm.
It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in animal diets.

When plants showed partial resistance against all races of pathogens then it is a type of Horizontal 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.
The resistance that is effective at preventing successful attack by all races of a pathogen is called general (or horizontal) resistance.

Magnesium is present in the core of chlorophyll molecules.
Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion.
The molecular formula chlorophyll is C₅₅H₇₀O₆N₄Mg and a structure of (2-formyl)-chlorophyll a was deduced based on NMR, optical and mass spectra.
Most chlorophylls bind magnesium, the axial ligands attached to the Mg²⁺ center are often omitted for clarity.