VIEW ARTICLE

Germination of Fusarium solani f. sp. pisi Chlamydospores in the Spermosphere of Pea. G. E. Short, Graduate Assistant, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824; M. L. Lacy, Associate Professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824. Phytopathology 64:558-562. Accepted for publication 5 November 1973. DOI: 10.1094/Phyto-64-558.

A method was developed for directly determining amount of spore germination in pea spermospheres in 1-mm increments of distance from the seed coat. The greatest distance at which Fusarium solani f. sp. pisi chlamydospores germinated was established within 24 h at 22 or 30 C, and never exceeded 7 mm under any conditions tested. More spores germinated, and the spermosphere was larger at 50% than at 20% soil moisture. More germination occurred near the emerging radicle than in other areas of the spermosphere. Greatest distances from seeds at which spores germinated decreased with increasing temp at 50% soil moisture. At 20% soil moisture, a higher percentage of spores germinated at 22 than at 10 or 30 C. The wrinkle-seeded pea cultivar 'Miragreen' supported more spore germination in the spermosphere than did the smooth-seeded cultivar 'Alaska'. If Miragreen seeds were soaked in aerated water for 48 h prior to planting, spores germinated only in the millimeter of soil nearest the seed and percentage germination was one-sixth that of spores in the same zone near unsoaked seeds.