If you just want a specific plant to get its growth on before letting it bloom, that’s fine. Tests on garden peppers, precocious flowering plants, showed that those forced to remain “juvenile” longer, also produced more fruit by the end of the season. Of course, the unmollested plants had the earliest fruit.
However, there is evidence that plants flowering for the first time produce more variable offspring than they will when they are a few years older. Van Mons discussed this in his “theory” (or system) of plant breeding. It apparently served him well, considering how many pears he introduced.
This is the sort of thing that would have made Mendelianists laugh scornfully, if they had ever bothered to read anything published before Mendel invented plant breeding. But then one of their own, Calvin Bridges (1927, 1929), made the startling discovery that the same is true of fruit flies. Young flies produce more diverse offspring than they do when mated again just a few days later. A few days in the life of a fruit fly is comparable to a few decades in the life of a pear.
Then, Prokofyeva-Belgovskaya (1947) worked it out that heterochromatin (the condensed or silenced portion of chromosomes) increases with age. Heterochromatin reduced crossover frequency. Therefore, if two genes happen to lie on the same chromosome and fairly close together, we are more likely to find them separated while the parents are young, rather than after they become old and set in their ways.
Linkages to be considered are, for instance, between the bright yellow flower color of Rosa foetida and short-lived, black-spot prone leaves. Is the deep crimson color necessarily linked to a weak neck, or can the linkage be broken.
It is important to note that P-B also found that the degee of heterochromatization is partly inherited. That is, the offspring of old fruit flies start their lives with more heterochromatin than their siblings born to the same parents a few days earlier.
So, to break a linkage one may need to raise two or three generations from the first fruits.
Another useful possibility: Michurin found that plants flowering for the first time tend to be more tolerant of foreign pollen. First flowers of a seedling may be somewhat defective. This defectiveness may extend to incompatibility. Michurin also noted that once the virgin specimen had been “tricked” into accepting foreign pollen, it continued to accept that pollen in later years. That seems reason enough to get fruit as soon as possible from our seedlings, if we have any intention of breeding from them.
Karl