Domanda interessante! Tieni presente che il termine trifoglio copre un'ampia varietà di specie del genere Trifolium. Il trifoglio - un simbolo popolare della Trinità cristiana in Irlanda - è spesso associato al trifoglio minore (Trifolium dubium) o al trifoglio bianco (Trifolium repens). Per il resto di questa risposta, userò il trifoglio bianco come specie vegetale di riferimento.

Prima di tutto, dobbiamo chiederci cosa causa la differenza nel numero di foglioline sul trifoglio - fondamentalmente, il tratto è genetico o no (il tratto è ereditabile)? È influenzato dall'ambiente? Se è influenzato dall'ambiente, quali sono i fattori che controllano il numero di foglioline, e in che misura prevalgono sulla componente genetica (se c'è)?

Il laboratorio di Wayne Parrott dell'Università della Georgia fa alcune ricerche sul trifoglio bianco. In 2010, he published a paper in Crop Science studying the genetics behind three different morphological traits in the white clover. His team observed that warmer conditions favored the development of four-leaf clovers. Furthermore, they found that at least one gene in the linkage group H1 controls the trifoliolate trait - in other words, there are genetic elements responsible for the development of three-leaf clovers.

Parrott Lab at the University of Georgia

For more information, check out this article from WIRED - The Mysterious Genetics of the Four-Leaf Clover.

Coming back to your question, is it possible to create a four-leaf clover field by cutting all three-leaf clovers? Highly unlikely, especially if the gene(s) regulating clover development use a three-leaf variant as a default state, as suggested by the aforementioned study. However, here are some strategies you could implement to potentially increase the proportion of four-leaf clovers in a field:

• You could provide the right environmental conditions (e.g. warmer temperatures) that favor the development of the four-leaf variant. This can be done by growing your clovers in a greenhouse.
• You could also try to find a way to alter the expression pattern of the genes controlling the trifoliolate trait. For example, in a simple scenario, if there was only one gene controlling this trait and high
• An even more ambitious approach would be to directly modify the genes controlling leaflet count such that the clover plant develops a four-leaf clover morphology as its default state. I am not a plant biologist so I cannot comment on the technologies available for gene modification/editing in clovers such as T. repens.

Best of luck creating your four-leaf clover field. May your blessings outnumber the shamrocks that grow, and may trouble avoid you wherever you go. :)