Botany lecture notes

Gamma Gardens for Mutation Breeding and Crop Improvement (Advantages and Disadvantages)


atomic garden

Satellite Map of a Gamma Garden at Institute of Radiation Breeding, Hitachiohmiya, Japan

Gamma Gardens (Atomic Gardens)

What are Gamma Gardens or Atomic Gardens?

Gamma garden or Atomic garden is a concept popularized after the Word War 2 for the peaceful use of atomic energy (atoms for peace) for the crop improvement. Gamma gardens or atomic gardens are a type of induced mutation breeding where radioactive sources particularly gamma rays from cobalt -60 or Caesium-137 are used to induce desirable mutations in crop plants. 

Salient features of Gamma Garden

Ø  Gamma gardens are “area subjected to gamma irradiation of crop plants”.

Ø  They are giant structures, enclosed by thick high wall to protect the plants and animals outside.

Ø  The purpose of a gamma garden is to irradiate the whole plants during different stages of development and of varying duration.

Ø  The source of radiation used is Cobalt-60.

Ø  Rarely Caesium-137 is also used as the source of radiation.

Continue reading

Botany lecture notes

Mutation Breeding Technique for the Improvement of Crop Plants (with PPT)


what is mutation breeding

Mutation Breeding
(Induced Mutations for Crop Improvement)

What is mutation?

Mutation is the “Sudden heritable change in an organism”. Mutation may be the change in gene, chromosome or plasmagene (genetic material inside mitochondria and chloroplasts. The mutation produced by change in the base sequence of gene is called point mutation or gene mutation. The gene mutation may be further classified as transition, transversion, deletion, duplication or inversion. Chromosomal mutations are the change in chromosome structure. The change in the structure of chromosome can occur as a result of large deletion, inversion, duplication, translocation and change in chromosome number. Most of the mutations are lethal to the organism. A very small number of mutations are beneficial to the organism. Additionally, by the use of mutation inducing agents, a breeder can induce desirable changes in the genetic constitution of plants and thereby he can improve the performance of a cultivated variety.

Mutation Breeding

Definition: “The utilization of induced mutations in crop improvement is called mutation breeding”

The term mutation breeding was first coined by Freisleben and Lein in 1944 to refer to the deliberate induction and development of mutant lines for crop improvement.

Spontaneous and Induced mutations:

(1). Spontaneous mutation:

Mutation occurs in nature are called spontaneous mutation. Spontaneous mutation occurs in the organism without any treatment at low rate in the nature. The frequency of spontaneous mutation is 10-6 (one in 10 lakhs). Different genes in and organism show different mutation rate.

(2). Induced mutation:

Mutations induced in an organism by treatment with physical or chemical mutagen are called induced mutations. The agents which are used to induce mutation are called mutagens. Certain genes in an organism promote the mutation of other genes nearby in the chromosomes. For example, the gene Dt in Chromosome number 9 of maize increases mutation rate of other genes.

Characteristics of Mutation:

Ø  Mutations are generally recessive; Dominant mutations do occur in nature.

Ø  Mutations are generally harmful to organism; small percentage of mutation is beneficial.

Ø  Mutation occurs at random in the chromosome, may occur in any gene.

Continue reading

Botany lecture notes

Host Selective and Non-Host Selective Toxins in Host Parasite Interactions and Pathogenesis


toxins in plant pathogen interactions

Toxins in Plant Pathogenesis
Toxins in Plant Pathogen Interaction

The process of pathogenesis (the onset of diseased condition) in plants is facilitated by many factors such as virulence of the pathogen, susceptibility of the host, presence of suitable environmental conditions and various enzymes and metabolites of pathogens. Previously we have discussed the importance of different enzymes involved in plant pathogen interactions. These enzymes facilitate the entry of the pathogen into the host and help to colonize inside the host cell. The production of different hydrolytic enzymes may not always result in the establishment of pathogen inside the host tissue. Certain plant pathogen may successfully invade the host tissue area but fail to induce the onset of disease. These findings highlighted the involvement of certain toxins, microbial toxins or aggressins, in the establishment of diseased conditions in plants. The present post describes the Toxins involved in plant pathogen interaction and pathogenesis with examples.

What is meant by ‘toxin’ in Plant Pathology?

Ø  Definition: Any substances produced by a pathogen which is injurious to host and it directly and immediately play a crucial role in pathogenesis.

Ø  Toxins involved in plant parasite interactions are also called as aggressin.

Ø  According to Koch’s postulates, a substance to be called as a ‘toxin’ should follow the following criterions:

@.   The compound must be isolated from the diseased plant

@.   It should NOT be present in the healthy plant

@.   Compound must be chemically characterized

@.   When isolated toxin is reintroduced to a healthy host, it should produce the original symptoms.

Continue reading

Botany lecture notes

Kerala PSC Botany Lecturer Exam 2017 Model Question Paper 3/3


psc botany lecture questions

Kerala PSC Botany Lecturer / Assistant Professor Model Question Paper 2017 Part 3/3

Model/Sample Question Paper of Kerala PSC Botany Lecturer/Assistant Professor Recruitment Examination to be conducted by Kerala Public Service Commission Question for the appointment of Botany Lecturer/Assistant Professor in Government Colleges of Kerala under the Directorate of Collegiate Education, Trivandrum, Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Botany Lecturer Test: Model Questions Set – 3/3

(1). The concept of raising the profile of a particular species to successfully leverage more support for biodiversity conservation of biodiversity is denoted as:

a.       Keystone species concept
b.      Flagship species concept
c.       Umbrella species concept
d.      Indicator species concept

(2). Gelatinous fibres are:

a.       Long sclerenchymatous cells with highly lignified secondary wall
b.      Short sclerenchymatous cells with slightly lignified secondary wall
c.       Fibres with cellulosic secondary cell wall
d.      Fibres with hemicellulosic secondary cell wall

(3). Which of the following is a C3 plant?

a.       Maize
b.      Sugarcane
c.       Sorghum
d.      Rice

(4). The wrong rejection of a true null hypothesis is denoted as:

a.       Type I error
b.      Type II error
c.       Type III error
d.      Type IV error

(5). Carl Woese is best known for his contribution in:

a.       Gene mapping
b.      Three domain system of classification
c.       Genetic engineering
d.      Shotgun sequencing

Continue reading

Botany lecture notes

Botany Lecturer Recruitment Test 2017 by Kerala PSC: Model Question Paper 2/3


botany college lecturer exam by kpsc

Image source: David Hill, Flickr (CC)

Kerala PSC Botany Lecturer / Assistant Professor Model Question Paper 2017 (Set 2/3)

Model/Sample Question Paper of Kerala PSC Botany Lecturer/Assistant Professor Recruitment Examination to be conducted by Kerala Public Service Commission Question for the appointment of Botany Lecturer/Assistant Professor in Government Colleges of Kerala under the Directorate of Collegiate Education, Trivandrum, Kerala. Questions are in MCQ (Multiple Choice Questions) format.

Botany Lecturer Test: Model Questions Set – 2/3

(1). The common intermediate in the synthesis of both adenine and guanine (purines) is

a.       IMP
b.      UMP
c.       AMP
d.      GMP

(2). What is Dobson?

a.       The unit of measure of ozone in the atmosphere
b.      The unit of the measure of thickness of ozone layer
c.       The unit of measure of concentration of CFC to destroy 1 mm of ozone layer
d.      The unit to measure the ozone hole

(3). The metabolite that bridges the gap between Glycolysis and the Kreb’s cycle is

a.       Oxaloacetate
b.      Pyruvate
c.       Acetyl Co-A
d.      Citrate

(4). Which of the following statement correctly describe the internal structure of a monocot root?

a.       Vascular bundles numerous, radial, with endarch xylem
b.      Vascular bundles numerous, radial with exarch xylem
c.       Vascular bundles limited in number, radial with endarch xylem
d.      Vascular bundles limited in number, radial with exarch xylem

(5). Which of the following is NOT a characteristic of K-selected species?

a.       Large number of progenies
b.      Parental care
c.       Delayed reproductive maturity
d.      Limited number of progenies

Continue reading