Plant Pathology MCQ Question and Answer | Agriculture MCQ Question

The fungus of Drechslera oryzae produces toxins that are highly toxic to rice seedling name of such toxin is ophiobolins. Neither ABA, trimethyl amine nor isobutylene.
Drechslera oryzae causes brown leaf spot disease in rice (Oryza sativa L.). This fungal pathogen produces a series of ophiobolins that cause some of the characteristic symptoms of the disease when applied to rice leaves at 10^-4 and 10^-5 M.

Maximum photosynthesis occurs in White light.
Most organisms that use oxygenic photosynthesis use visible light for the light-dependent reactions, although at least three use shortwave infrared or, more specifically, far-red radiation.
Photosynthesis range from 400 to 700 nm, and it absorbs the Violet, Blue and Red colour of Light. In white light all the colour spectrum energies are involved so, maximum photosynthesis is taken place in white light.

Bacteria leaf blight of rice caused by Xanthomonas oryzae is commonly controlled by seed treatment and foliar spray of the Streptocycline chemical in India.
Bacterial leaf blight of rice (BB) is a disease caused by the Gram-negative bacterium Xanthomonas oryzae. It causes wilting of seedlings and yellowing and drying of leaves.
Spray Streptomycin sulphate + Tetracycline combination 300 g + Copper oxychloride 1.25 kg/ha. If necessary repeat 15 days later. The application of bleaching powder @ 5 kg/ha in the irrigation water is recommended in the kresek stage.

Maximum transpiration occurs in Mesophytic plants.
Mesophytes are terrestrial plants that are neither adapted to particularly dry nor particularly wet environments.
They usually have broad, flat, and green leaves, an extensive fibrous root system to absorb water; and the ability to develop perennating organs such as corms, rhizomes and bulbs to store food and water for use during drought. These conditions allow the maximum rate of transpiration.

Sugarcane plant shows chloroplast dimorphism.
The occurrence of two different types of chloroplasts in the leaves of C₄ plants is referred to as chloroplast dimorphism. It is a characteristic feature of C₄ plants like sugarcane.
The vascular bundle sheath cells of sugar cane contain starch-storing chloroplasts lacking grana, whereas the adjacent mesophyll cells contain chloroplasts that store very little starch and possess abundant grana.

The gummosis disease of citrus which is caused by Phytophthora palmivora is identified by observing Oozing of gum.
An early symptom of Phytophthora gummosis is sap oozing from small cracks in the infected bark, giving the tree a bleeding appearance.
The gumming may be washed off during heavy rain. The bark stays firm, dries, and eventually cracks and sloughs off.
This disease is commonly seen in mandarin, sweet orange, lemons and other citrus fruits.

Young pollen grains produce androgenic haploids in anther cultures.
The term androgenesis refers to plant regeneration directly from microspore culture under in vitro conditions. The underlying principle of androgenesis is to stop the development of pollen cells, which normally become sexual cells, and to force their development directly into a complete plant.
The androgenic method of haploid production is from the male gametophyte of an angiosperm plant i.e., microspore (immature pollen).
Young pollen grains produced androgenic haploids in anther cultures while the anther wall, a tapetal layer of the anther wall and connective tissue are the parts of the anther.

FYM contains 0.5% N.
Farmyard manure refers to the decomposed mixture of dung and urine of farm animals along with litter and leftover material from roughages or fodder fed to the cattle. On average well decomposed farmyard manure contains 0.5 percent N, 0.2 percent P₂O₅ and 0.5 percent K₂O.

The process by which excess energy is lost is Fluorescence.
Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence.
Fluorescence occurs when an excited molecule, atom, or nanostructure, relaxes to a lower energy state (usually the ground state) through the emission of a photon without a change in electron spin.