Inbreeding is the result of mating between close relatives or occurs when a flower is pollinated by pollen from the same plant ( selfing ) Selfing is the most extreme form of inbreeding . During seasons where flowering is poor or pollination vectors ( insects, birds and bats ) are not active , seed crops with high levels of inbreeding may be produced. In ideal circumstances the outcrossing rates for eucalypts should range from 40% to 90%. Inbreeding reduces the survival rate and vigour of seedlings and limits the number of new combinations on which future genetic diversity depends.
Reports of declining bee populations are a concern , if pollinating agents are scarce or absent during a flower period , a highly inbreed seed crop can result. Yesterday I went to check flowering yellow box trees on our place and was surprised to find them covered in these small beetles. The scent of the blossoms was strong and these beetles appeared to be sipping the nectar in an almost intoxicated state. Today they had disappeared , moved on to the next flowering yellow box to do a little outcrossing I hope.
Linda Broadhirst from CSIRO is concerned about the genetic health of Australia’s yellow box populations. She fears they are close to genetic collapse. You can help her reasearch by collecting seed sample for genetic profiling (Look at the post on www.strathbogierangescmn.com for details)