Genetics and Plant Breeding

This cross involves single trait and law of dominance and recessiveness was the result of monohybrid cross.

Linkage is the tendency of genes that are located proximal to each other on a chromosome to be inherited together during meiosis. It was given by Bateson.

Meiosis is a special type of nuclear division which segregates one copy of each homologous chromosome into each new gamete.

A gene that is expressed only when it is present in two copies or if the other copy is missing.

It is one of a number of alternative forms of the same gene or same genetic locus.

It is reproduction from the mating of parents who are closely related genetically. Inbreeding results in increased homozygosity.

It is a gene pair in a heterozygous condition that are both fully expressed.

Here allele of one gene gene suppresses the activity of an allele of another gene.

The genotype is the genetic make up of a cell, an organism, or an individual usually with reference to a specific characteristic under consideration.

It is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele.

Law of independent assortment was explained by dihybrid cross involving two traits.

Moss rose or rose moss, Portulaca grandiflora produces flowers of two colours that is purple and orange as a result of a mutation. The orange is probably the mutant as it is closer to the purple wild type. This is a somatic mutation that may also be passed on in the germ line. Somatic mutation is a genetic mutation that occurs in a somatic cell after conception.

Twins of this type are mostly genetically identical. Subsequently, they are also called identical twins in contrast to fraternal or dizygotic twins, which come from two separate eggs fertilised by different sperms.

Joseph Koelreuter reported hybrid vigor (heterosis) in his tobacco hybridization experiments in the 1760s, making him one of the first to document the phenomenon. While Shull later developed hybrid corn breeding, Koelreuter's work in tobacco came much earlier.