Plant Pathology - Study Mode

[#346] Stage-II of rust fungi is marked by
Correct Answer

(D) Urediniospores

Explanation

Solution: Stage II of rust fungi are marked by Urediniospores. Urediniospores are thin-walled spores produced by the uredium, a stage in the life cycle of rusts. Urediniospores usually have two dikaryote nuclei within one cell. In mass, they are usually pale brown in contrast to teliospores which are generally dark brown.

[#347] Who is regarded as father of phytopathology?
Correct Answer

(D) Anton de Bary

Explanation

Solution: Anton de Bary is regarded as the father of phytopathology. Heinrich Anton de Bary was a German surgeon, botanist, microbiologist, and mycologist. He is considered a founding father of plant pathology (phytopathology) as well as the founder of modern mycology. Plant pathology is the science that studies the causes of plant diseases, the mechanisms by which diseases develop in individual plants and plant populations, and the ways and means by which plant diseases can be managed or controlled.

[#348] Kisan khad (CAN) contains
Correct Answer

(B) 25 - 28% N

Explanation

Solution: Kisan khad (CAN) contains 25 - 28% N. Calcium ammonium nitrate or CAN, also known as nitro-limestone or nitrochalk, is a widely used inorganic fertilizer. Locally it is also known as Kisan khad. Fertilizer grade CAN contain roughly 8% calcium and 21 - 27% nitrogen. CAN is preferred for use on acid soils, as it acidifies soil less than many common nitrogen fertilizers.

[#349] Gemini virus is
Correct Answer

(A) ss DNA

Explanation

Solution: Gemini viruses are a group of plant viruses known for their single-stranded DNA (ssDNA) genome . They belong to the Geminiviridae family , which is named after their characteristic geminate (twin) particle morphology . These viruses are circular, single-stranded DNA viruses that primarily infect plants, causing severe diseases in economically important crops. Structure and Genome: Gemini viruses have two joined icosahedral capsids , forming their unique twin structure. Their genome consists of either a monopartite or bipartite ssDNA , depending on the genus. The two major genera are: Begomovirus – Bipartite genome (DNA-A and DNA-B components) Mastrevirus and Curtovirus – Monopartite genome (single DNA component) Replication: Unlike RNA viruses, Gemini viruses replicate using a rolling-circle replication mechanism within the nucleus of host plant cells . They rely on the host's DNA replication machinery to propagate. Transmission: These viruses are primarily transmitted by whiteflies (Bemisia tabaci) , which act as vectors and spread the virus from infected to healthy plants. Some members of this family can also be transmitted by leafhoppers. Diseases and Economic Impact: Gemini viruses are responsible for devastating plant diseases, leading to significant yield losses in crops such as: Tomato – Tomato Yellow Leaf Curl Virus (TYLCV) Cotton – Cotton Leaf Curl Virus (CLCuV) Cassava – Cassava Mosaic Virus (CMV) Maize – Maize Streak Virus (MSV) These viruses cause symptoms like leaf curling, yellowing, stunted growth, and reduced productivity , making them a major concern in agriculture. Management and Control: Controlling Gemini viruses is challenging due to their efficient transmission by insect vectors . However, management strategies include: Vector control – Using insecticides and biological control methods to reduce whitefly populations. Resistant crop varieties – Developing and planting virus-resistant or tolerant crops. Cultural practices – Crop rotation, removal of infected plants, and use of virus-free planting material. Genetic engineering – Developing transgenic plants with virus resistance genes. Due to their significant impact on agriculture, continuous research is being conducted to develop better management strategies and resistant crop varieties to mitigate the effects of Gemini virus infections.

[#350] In plants, the common symptom caused by the deficiency of K, P, Ca and Mg is the
Correct Answer

(D) Appearance nectrotic areas in the leaves

Explanation

Solution: In plants, the common symptom caused by the deficiency of K, P, Ca and Mg is the appearance of necrotic areas in the leaves. Necrosis is the death of a circumscribed area of plant or animal tissue as a result of disease or injury. Necrosis is a form of premature tissue death, as opposed to the spontaneous natural death or wearing out of tissue, which is known as necrobiosis. Deficiencies of the nutrients nitrogen, phosphorus, potassium, and magnesium result in chlorosis (yellowing) and eventual necrosis (death) of older mature leaves.