Plant Pathology - Study Mode

[#901] Which of the following micronutrients mostly deficit in Indian soil?
Correct Answer

(A) Zn

Explanation

Solution: Zn is the micronutrient that is mostly deficit in Indian soil. About 48.1% of Indian soils are deficient in diethylene-triaminepentaacetate (DTPA) extractable zinc, 11.2% in iron, 7% in copper and 5.1% in manganese. The total Zn content in soil depends upon the parent rock, weathering, organic matter, texture and pH. The most quoted range of total Zn in normal soils in 10 - 300 mg kg -1 .

[#902] The yellow rust of wheat is caused by
Correct Answer

(A) Puccinia striformis

Explanation

Solution: The yellow rust of wheat is caused by Puccinia striformis. Wheat yellow rust, also known as wheat stripe rust, is one of the three major wheat rust diseases, along with stem rust of wheat and leaf rust. Stripe (yellow) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a serious disease of wheat occurring in most wheat areas with cool and moist weather conditions during the growing season. Yellow rust, or stripe rust, takes its name from the appearance of yellow-colored stripes produced parallel along the venations of each leaf blade. These yellow stripes are characteristic of uredinia that produce yellow-colored urediniospores.

[#903] Which of these is endoparasitic Powdery mildew fungus?
Correct Answer

(A) Leveillula

Explanation

Solution: Leveillula is an endoparasitic Powdery mildew fungus. Leveillula taurica is an obligate fungal pathogen, from the phylum Ascomycota, which causes powdery mildew. Under favorable climatic conditions, the chasmothecia open and release ascospores, which are wind-dispersed. The ascospores enter the host through its stomata, germinate, and colonize the host's tissues with their mycelia. The pathogen then begins to produce its asexual conidia, either singly or on branched conidiophores. The conidia exit through the host’s stomata and serve as a secondary inoculum to spread disease after initial infection. It affects the host from the inside, thus it is endoparasite.

[#904] The causal organism of bunchy top of banana is transmitted by
Correct Answer

(A) Pentalonia nigronervosa

Explanation

Solution: The causal organism of the bunchy top of the banana is transmitted by Pentalonia nigronervosa. Banana bunchy top is a viral disease caused by a single-stranded DNA virus called the banana bunchy top virus (BBTV). It was first identified in Fiji in 1879. Banana bunchy top virus (BBTV) is a plant pathogenic virus of the family Nanoviridae known for infecting banana plants and other crops. It is aphid transmitted. It is known that Banana aphid (Pentalonia nigronervosa) transmits the virus from infected to healthy plants by feeding. Aphids feed on the plant phloem tissues by injecting their thin, flexible style into the epidermis of the plant tissue until it reaches the phloem of the leaves.

[#905] Factor which is not normally limiting in photosynthesis is
Correct Answer

(A) Chlorophyll

Explanation

Solution: Among the given options, the factor which is not normally limiting in photosynthesis is Chlorophyll. Chlorophyll is any of several related green pigments found in cyanobacteria and the chloroplasts of algae and plants. Chlorophyll allows plants to absorb energy from light. Chlorophylls absorb light most strongly in the blue portion of the electromagnetic spectrum as well as the red portion.