Root characteristics in pea in relation to compaction and fusarium root rot

Differences in pea root length, root surface area, and diameter were rapidl y determined using the WinRhizo computer program. Repeatable differences we re measured both in the laboratory and in the field. Large-rooted lines, as measured in the laboratory, also were the largest-rooted lines in the fiel d. Large-rooted lines produced more roots and had more root surface area wh en exposed to a 1.6 g cm(-3) bulk density compacted layer with the presence of the Fusarium root rot pathogen (Fusarium solani f. sp. pisi). Also, lar ge-rooted lines regenerated more roots when one-third or two-thirds of the root system was removed or when one cotyledon was removed from 5-day-old pl ants. Large-rooted pea lines should have an advantage in growing under adve rse conditions of compaction and the presence of Fusarium root rot.