Does self pollination of a flower produce offspring with genetic variation?Watch
1. During prophase 1, homologous chromosomes align and recombine (swap homologous sections of the chromosome). This results in some of the alleles previously separated (one on the maternal chromosome and one on the paternal chromosome) now being joined on the same chromosome. Later, when the daughter chromosomes segregate, you end up with gametes that have chromosomes carrying a new combination of alleles. You have a new linkage groups, but not new alleles. So recombination plus independent segregation does generate some genetic variation.
This is what makes self-pollination different from cloning, where you are simply reproducing the exact same DNA, arranged on the chromosomes in the exact same way
2. As in all DNA replication, there is always a small error rate, so occassionally a spontaneous error may occur that results in some variation in the progeny (I would stress that the error rate is exceedingly small though)
PS after many generations of self-pollination, the population tends to get less healthy. You are no longer introducing any new alleles, just mixing up the same alleles into different linkage groups. In effect, you "run out" of variations to try, so if the environment changes a lot, you have much less adaptability available