Can plants recognize their relatives?

    As unlikely as it might seem, recent research has shown that some plants are capable of recognizing if other plants growing nearby are related to them or not, in a process called kin recognition. Even more remarkable, they can then change their growth patterns accordingly.
    If growing near relatives, they often grow in a less competitive way, knowing that their relative will respond similarly and that both neighbors will benefit from sharing common resources without wasting energy on competing for them. If the neighbor is not related, however, they will grow more aggressively, attempting to out-compete the other plant and prevent it from getting access to water, light and other resources.
    Most of the plants that are known to do this so far are wild plants with no particular economic importance. They can recognize other plants that are related to them at the level of half-siblings or cousins and grow less competitively next to these relatives than they would near nonfamily.
    Competitive growth usually takes one of two forms. Some plants will grow taller or grow more leaves than they would otherwise need, in order to shade out their competitors. Others show extra root growth in an attempt to get access to soil nutrients or water before their neighbor can. The energy required for this competitive growth takes away from the energy available to make seeds, however, and often results in lower yields under competition.
    While kin recognition has not been thoroughly examined in crops yet, we know that at least rice and soy are capable of it. The uniform genetics of modern crop varieties mean that all plants within a particular variety or hybrid are very closely related and have a high potential to show kin recognition.
    A recent study clearly demonstrated this in soybeans. It compared commercial soybeans grown in single variety stands to those grown in mixes with other varieties, with a wild soya bean and with dry bean. All of the modern soy varieties tested recognized each other as relatives when grown together and had normal growth patterns.

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