Difference Between Geitonogamy and Xenogamy

The key difference between Geitonogamy and Xenogamy is that Geitonogamy is the transfer of pollen onto the stigma of another flower of the same plant while Xenogamy is the transfer of pollen onto the stigma of another flower that belongs to a genetically different plant. Geitonogamy is a type of self-pollination whereas xenogamy is a type of cross-pollination.

Angiosperms rely on pollination for fertilization and production of seeds. Pollens from anthers transfer into the stigma of pistils during the pollination. Pollination can happen between male-female parts of the same flower or between two flowers of the same plant or between two flowers of the different plants. If pollination occurs between two flowers of the same plant, it is known as geitonogamy while if it occurs between two flowers of the different plants, it is known as xenogamy.

CONTENTS

1. Overview and Key Difference
2. What is Geitonogamy
3. What is Xenogamy
4. Similarities Between Geitonogamy and Xenogamy
5. Side by Side Comparison – Geitonogamy vs Xenogamy in Tabular Form
6. Summary

What is Geitonogamy?

Geitonogamy is a type of self-pollination that occurs between two flowers of the same plants. It is the process of transferring pollen from one flower to stigma of another flower of the same plant. When multiple flowers are present in a plant, geitonogamy is highly feasible and it occurs naturally due to the action of pollinators.

With regards to function, geitonogamy could be defined as a type of cross-pollination, but in the context of genetics, it is regarded as a type of self-pollination. Because the flowers involve with this process are genetically identical. Therefore, this process results in genetically identical offspring in contrast to xenogamy. Geitonogamy is common between flowers that share a single stem. Maize is a plant that shows this mode of pollination.

What is Xenogamy?

Xenogamy refers to the union of two gametes of two genetically different individuals of the same species. With respect to angiosperms, xenogeny is the pollination that occurs between flowers of two genetically different plants. Since xenogamy occurs between two genetically different parents (two genotypes), it increases the genetic variability of offsprings. Thus enhances the overall fitness of a species.

In nature, xenogamy is an evolutionary important process, because it produces more fit organisms. More fitness organisms will continue to survive in the environment and it is important for the evolution of a species. And also it is an important process to reduce homozygosity in breeding populations in agriculture. Furthermore, it allows the reintroduction of alleles or introduction of new alleles into a population.

What are the Similarities Between Geitonogamy and Xenogamy?

• Both Geitonogamy and Xenogamy are types of allogamy.
• Both come under cross-fertilization.
• In both processes, two individual flowers are involved.
• Both processes occur due to vectors such as pollinators, wind etc.

What is the Difference Between Geitonogamy and Xenogamy?

Geitonogamy refers to the pollination between two flowers of the same plant. Xenogamy refers to the pollination between two flowers of different plants. Therefore, the flowers are genetically similar in geitonogamy while the flowers are genetically different in Xenogamy. Further, geitonogamy is a type of self-pollination unlike xenogamy, which is a type of cross-pollination.

Geitonogamy involves only one plant, unlike Xenogamy that involves two genetically different plants. Also, the seeds are genetically identical in geitonogamy but the seeds are genetically different in xenogamy. Moreover, geitonogamy is not possible in dioecious plants. However, xenogamy is possible in dioecious plants. Geitonogamy produces less fit offsprings. On the contrary, xenogamy produces more fit offsprings. Overall, geitonogamy is not evolutionary important but xenogamy is evolutionarily important.

Summary – Geitonogamy vs Xenogamy

Geitonogamy and Xenogamy are two types of allogamy. Two flowers involve in both processes. But in geitonogamy, two flowers come from the same plant while in xenogamy two flowers come from two different plants. Hence geitonogamy is a type of self-pollination whereas xenogamy is a type of cross-pollination. Genetic variability among the offspring is high in xenogamy in contrast to geitonogamy that produces genetically identical offspring. This is the difference between geitonogamy and xenogamy.

Reference:

1.“Geitonogamy – Embibe.” Embibe: AI Powered Learning and Score Improvement Platform for Any Exam. Available here  
2.“Xenogamy.” Species, Genetic, Alleles, and Homozygous – JRank Articles. Available here   

Image Courtesy:

1.’4378439971′ by jonny goldstein (CC BY 2.0)  via Flickr