How does allopolyploidy occur in plants?

Allopolyploidy occurs in plants specifically through hybridization between different species. This process begins when two distinct species produce hybrid offspring. The hybrid may have an irregular number of chromosomes because each parent contributes a different set of chromosomes. In many cases, these hybrids are initially sterile due to this chromosomal mismatch. However, allopolyploidy can happen when the hybrid undergoes a series of genomic doubling events, resulting in a stable organism with chromosomes from both parent species. This doubling creates a new species that has multiple sets of chromosomes derived from each parent, leading to increased genetic variation and sometimes new traits that can be advantageous in certain environments.

Environmental adaptations, intra-species mutations, and somatic cell doubling, while relevant to plant biology, are distinct processes and do not directly lead to allopolyploidy. Environmental adaptations refer to how organisms change in response to their surroundings, intra-species mutation involves changes within a single species' genetic makeup, and somatic cell doubling results in cells having extra sets of chromosomes but does not involve hybridization between different species.