Crop variety improvement - class-VIII

After the hybridization of two selected parent plant species, the recombinants with the desired combination of characters are selected. These hybrids are then self-pollinated for several generations so that they reach a state of uniformity or homozygosity so that the desired characters will not segregate in the progeny.

Pusa Gaurav is an insect resistant variety of Mustard or Brassica that shows resistant against the aphids.

(D) 27 varieties of documented basmatic rice are grown in India. It is known for excellent cooking and eating qualities and many improved varieties using plant breeding are developed which give tolerance to many disease or climate also increased yield.

• Processes like the crossing of plants that have a pure line character, selection of plants that have desirable qualities and their artificial selection, obtaining a better yield of crops to improve nutrition and resistance to diseases are all parts of plant breeding. 

• Hybridization is defined as the process of interbreeding between two individuals of different plant species to obtain a hybrid that contains the genes of both the parent species due to genetic recombination. 
• The process of developing a new variety by changing the genome through X-ray or UV radiation is known as mutation breeding. It is a quick method to obtain genetic variation. 
• These are the two techniques that can be used for the development of the plant variety which gives high yield and resistance to diseases. 

• The selection is the oldest method of plant breeding in which the two plants are selected on the basis of the superior characters. This method helps in the elimination of undesirable characters. The two plants are selected in order to preserve the favorable traits. This method involves the preservation of the plants which have superior characters. 

Many different management programs are undertaken in order to improve the yield of the crop plants. The crop protection, production, and variety improvement are the management programs which help to enhance the yield of the crop. The transport management is not a part of crop yield increase. 

The crossing between genetically different plants to produce a new variety is called as hybridization. Genetically modified crops can be produced by insertion of genes with desired traits by the process of hybridization. The parents are allowed to perform hybridization and the offspring is known as the hybrid. The hybrid is allowed to self-pollinate in order to maintain a pure breed of the hybrid. The hybrid varieties are used for better crop production. There is the mating of two different plant species which results in genetic variation. There is the recombination of the characters of both the parent plants. 

The crossing between two plants of different species to produce a new variety is called hybridization. The new plant which is produced is known as the hybrid which possesses superior characters of both the parent plants. The traits which are considered for hybridization are resistance to pests, insects and diseases, an increase in the productivity and high yielding, tolerance to adverse conditions, etc. The hybrid is called as hybrid vigor which has better characteristics when compared to the parental types. 

Hybrid plants can be developed by the breeding of the plants of different species. This is known as the process of hybridization. The parents are genetically different plants. There is segregation of the characters which results in the formation of offspring which have superior characters when compared to the parents. There is recombination which introduces certain new genes in the offspring. Due to genetic recombination, variations are produced. The offsprings are genetically different from the individual parents. 

Hybrid plants can be developed by the breeding of the plants of different species. The parents are genetically different plants. Iris albicans is the sterile hybrid which is developed by breeding of two different species. This is known as interspecific hybridization. This is a sterile plant which spreads by rhizome division.

Answer is option A i.e. "Hybridisation"
The biological species concept defines a species as members of populations that interbreed in nature. According to this concept, organisms belong to the same species if they can interbreed to produce viable, fertile offspring. Reproductive isolation, natural selection and gene pool are applicable to one species.
Hybridisation, on contrary, occurs due to process of combining two different species of organisms to create a hybrid.
Hence, "hybridisation" is not applicable to biological species concept.

In angiosperms, one meiotic division produces 4 microspores, but only one functional megaspore is formed from one megaspore mother cell. For 100 grains, 100 meiotic divisions are needed for the male side (pollen) and 100 for the female side (ovule), totaling 200. However, if the question implies the standard formula (n + n/4), it is 125.

Both Sharbati Sonora and Pusa Lerma are amber-colored wheat varieties derived from Mexican wheat breeding programs.

Pulses are generally deficient in sulfur-containing amino acids, specifically cysteine and methionine.

The National Seed Corporation (NSC) is responsible for the production and distribution of certified seeds, ensuring their purity and quality.

Paraguay tea is obtained from leaves of evergreen tree Ilex paraguariensis. 

Soya Bean, Sonora-64, and Tanchung native-1 are all varieties introduced to other regions for cultivation.

Cultivated cotton (Gossypium hirsutum) evolved through the hybridization of two different species followed by polyploidy (allotetraploidy).

Haploids are useful in plant breeding because they can be doubled (diploidized) to produce completely homozygous lines in a single generation.

Hybrid rice production relies on the three-line system: the CMS (Cytoplasmic Male Sterile) line, the Maintainer line, and the Restorer line.

Hybridisation is defined as the process of interbreeding between two genetically divergent individuals or two individuals of different species. Therefore, the statement (i) is correct.
Interspecific hybridisation means cross mating between two different species but sharing same genera. For example, a cross breed between a lion and a tiger, they both are from same genus Panthera but different species. So the statement that cross between two varieties is called interspecific hybridisation is wrong.
I am a brinjal farmer, my brinjals are being infected by some beetles every year. I spend a huge sum of money on insecticides and pesticides to protect my crop. Then, a biotechnology company approaches me with a new strain or variety of brinjal plants which have the capability to produce a natural pesticide that makes it resistant to the beetles. My crop is not only saved, but  I also get good yield of brinjals now and earn a lot of money. I do not have to spend extra money on pesticides and insecticides. Basically, I got a brinjal plant with gene of desired character and got a desired genetically modified brinjal plants. Therefore, the statement (iii) is correct.
When the parent plants cross bred are from the same species, but of different variety is called intervarietal hybridisation. For example, a cross bred between two different varieties of wheat plant. They belong to the same species but they are of different variety. Therefore, the statement (iv) is wrong.
Hence, we can conclude that (i) and (iii) are correct statements.

The  method of altering the genetic pattern of plants to increase their value and utility for human welfare, is called crop improvement or plant breeding. It is a purposeful manipulation of plants to create desired plant types that are better suited for cultivation, give better yield and are disease resistant. iit is purely depends on domestication.

So the given statement is true.

The cochineal insect are introduced into the (Opuntia) prickly pear. The insect destroy the weeds without harming the crop plants. Its one of the biological method as well.

Yeast ferments the sugar present in the dough into carbon dioxide. The ${ CO } _{ 2 }$ released from the yeast fills the dough and increases its volume. Once, the bread has baked, the heat causes the bubbles to break and makes the bread light and fluffy.

• Triticale is a man-made crop developed by crossing wheat and cereal rye. It is probably the only new man-made crop in commercial production. 
• Triticale was found to be more efficient than wheat in utilizing and absorbing nitrogen from the soil. 
• It also produces a 30% higher yield on acid soils and is superior to wheat on copper-deficient soil.

• Plant breeding aims to improve the characteristics of the plant so that they become more desirable agronomically and economically. 
• Thus, the chief objective of plant breeding is to develop such improved varieties of crop plants that will be commercially successful. 

Pure breeding varieties are the one that carries same allele for a particular character and pass the trait without change from one generation to next upon selfing (for example, pure breeding tall (TT) plant carries two copies of “T” allele). Hybrids are the one which carries contrasting allele of a particular gene e.g., hybrid tall plant’s genotype is “Tt”. Incomplete dominance refers to the conditions where none of factors of a gene is dominant; the phenotype of heterozygous dominant individual is blend of dominant and recessive traits. Thus, it is an exception to Mendel’s principle of dominance. Heredity is genetic transmission of characters from parent generation to progeny. Alternative forms of a gene are called alleles e.g., alleles for gene for plant height are “T” and “t”. Thus, the correct answer is option A.

• Plant breeding is the art and science of changing the traits of plants in order to produce desired characteristics. 
• Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular techniques. 
• Plant breeding aims to improve the characteristics of the plant so that they become more desirable agronomically and economically. 
• Thus, the chief objective of plant breeding is to develop such improved varieties of crop plants that will be commercially successful. 
• Generally, a successful variety is one with a total balance of traits that makes it more profitable for growers. 
• Quality characters vary from one crop to another, e.g., grain size, colour, milling and baking qualities in wheat (Triticum aestivum), cooking quality in rice (Oryza sativa), malting quality in barley (Hordeum vulgare), size, colour, and flavour of fruits, keeping quality of vegetables, protein content in cereals and legumes, lysine content in cereals, methionine and tryptophan contents in pulses, etc.

• Plant breeding aims to improve the characteristics of the plant so that they become more desirable agronomically and economically. 
• Thus, the chief objective of plant breeding is to develop such improved varieties of crop plants that will be commercially successful. 

Presence of three or more sets of chromosomes in an organism is called polyploidy. It is often seen in plants and very rare in animals. It is caused due to the non disjunction of the sister chromatids during the recombination (at meiosis). It can be induced in plants and cell cultures with the help of some chemicals like colchicine. Polyploidy causes variation, as it adds new genomes into a species. It has been widely used in producing hybrids of wheat. Ploidy level also effects some characteristics of plants. For example, higher ploidy leads to the larger cell size. So, the correct answer is B.

In crop improvement programme, haploids are important because they form perfect homozygous lines. Homozygous are the pure line selection plants resulting from self pollination. In this way, considerable homozygosity is obtained. Haploids are those plants which possess a gametophytic number of chromosomes. Haploids are used in plant breeding, especially for the production of homozygous plants and in their studies in the detection of mutation.

The widespread adoption of high-yielding, uniform varieties leads to the replacement of local landraces, thereby reducing genetic diversity.