HYPOCOTYL GROWTH AND SEEDLING EMERGENCE OF WHITE LUPINE (LUPINUS ALBUS L.) UNDER COMPACTED SOIL CONDITIONS

The epigeal emergence of white lupine (Lupinus albus L.) seedlings depends upon their emergence capabilities under stress situations.;Results from the field indicated that the length of white lupine hypocotyls was increased as planting depth increased. In addition, there was an increase in the diameter of the hypocotyl in 1979 and an increase in the swelling index of the hypocotyl in both 1979 and 1980 with increased planting depth.;Shallow-planted seed emerged sooner than deep-planted seed in both 1979 and 1980. In 1980, large seed emerged sooner than small seed. Also in 1979 and 1980, the Hope cultivar emerged sooner than either SWL-17 or SWL-34.;The swelling index and the coefficient of velocity of emergence (C.V.E.) proved to be the two most reliable hypocotyl physical characteristics for determining hypocotyl growth and seedling emergence capabilities in white lupine.;A two-year field study and a controlled environment study were conducted to evaluate hypocotyl growth and seedling emergence under compacted soil conditions. The effects of planting depths, seed sizes, and cultivars on hypocotyl growth and seedling emergence were studied under compacted soil conditions in the field study. In the controlled environment study simulated compaction rates, temperature, seed sizes, and cultivars were evaluated as to their effect on hypocotyl growth.;In the controlled environment studies hypocotyl length increased with increasing temperatures and increasing seed size. Hypocotyl length also decreased in response to increasing weight while Hope white lupine had longer hypocotyls than did SWL-34.;The swelling index increased with increasing temperatures, increasing seed size, and increasing weight or downward force while SWL-34 had a greater swelling index than did Hope.;The hypocotyl elongation rate increased with increasing temperatures and increasing seed size but decreased with increasing weight or downward force. Hope white lupine had a greater hypocotyl elongation rate than did SWL-34.;This study provided evidence that hypocotyl growth was affected by weight or downward force, temperature and depth of planting. Also seed size and genetic differences would indicate possibilities for improvement of emergence capabilities through selection and breeding.