I have recently learned of an aspect of plant breeding that has been neglected for far too long. Kidd & West (1918) described it:

"IT may not always be fully realised to what a degree the developmental capacity of plants is pre-determined by the action of environmental conditions during the earliest stages of their life-histories. During the course of germination and in the seedling stage, or even earlier during the sojourn of the seed upon the parent and in the dormant period, the 'potentialities' of plants may be affected by actions which only subsequently produce visible results. These results appear during the later stages of development, without reference to the conditions then existing. In this way adverse conditions in the later stages of development may not suppress a vigour of growth which has been pre-determined under favourable conditions during the ripening of the seed in the previous year; or favourable conditions during summer may fail to increase the yield owing to adverse conditions which have previously operated during the period of germination. It is such effects, namely those which are to be traced to the environmental conditions which have operated in the past stage of the plant's life, that we may term effects of physiological pre-determination in order to mark their distinction from those which are due to hereditary causes."

In fact, sometimes the effects are passed along (at least in part) to the next generation, and the effects may be cumulative if each generation receives the same treatment.

In the early 19th century, Van Mons made a name for himself by raising large numbers of superior pears by a method that many writers failed to understand. He collected fruit of wild trees before the seeds were quite ripe, then waited for the fruit to rot before separating the seeds. He also made a point of collecting the first fruit of the seedlings, believing this also helped reduce the coarse vigor of the wild trees and redirect the effort into superior fruit - while making the trees a little shorter and earlier in bearing than the previous.

Goff (1892) planted seeds from unripe tomatoes for several generations. And as with Von Mons' pears, the plants became less vigorous, earlier bearing and more productive - though often shorter lived.

Similar results have sometimes been obtained with old seeds. There was once a rather general understanding that melons raised from old seeds produced smaller vines with fewer branches, but were earlier bearing with fleshier fruit.

I'm collecting more information and assembling it into bibliographies.

Physiological Predetermination

http://www.bulbnrose.org/Heredity/King/PositionEffects.html

Old Seeds/Unripe Seeds

http://www.bulbnrose.org/Heredity/King/OldSeed.html

Other bibliographies are listed on my What's New page.

Karl

Here is a link that might be useful: CybeRose & Bulbs