Munkvold G P, Carlton W M
Assistant Professor.
Research Associate, Department of Plant Pathology, Iowa State University, Ames 50011.
Plant Dis. 1997 Feb;81(2):211-216. doi: 10.1094/PDIS.1997.81.2.211.
Two greenhouse and two field experiments were conducted in 1994 and 1995 to quantify the incidence of maize kernel infection resulting from systemic infection of maize plants by Fusarium moniliforme. Seeds were infected by two methods: (i) spray-inoculation of maize silks during seed development (field-infected), and (ii) soak-inoculation of mature seeds in a spore suspension (laboratory-infected). Plants were grown from infected seeds and assayed for systemic infection by the seed-inoculated strain, determined by vegetative compatibility of recovered isolates with the original strain. The seed-inoculated strain was recovered from stalks and kernels of plants grown from both types of infected seed. Mature plants grown from field-infected seeds had a higher percentage of their kernels infected with the seed-inoculated strain compared with plants from laboratory-infected seed. Mean incidence of infection by the seed-inoculated strain was 9.9 to 29.4% of all kernels (33.0 to 55.9% of F. moniliforme-infected kernels) in the plants grown from field-infected seed. Some plants from infected seed were subsequently silk-inoculated, and the silk-inoculated strain was recovered from a much higher percentage of kernels (26.5 to 37.5% of all kernels or 77.9 to 78.4% of F. moniliforme-infected kernels) than was the seed-inoculated strain; furthermore, silk inoculation significantly reduced incidence of kernel infection by the seed-inoculated strain. Seed infection by F. moniliforme resulted in systemic infection of plants and kernels. However, local infection (via silks) was a more important pathway to kernels than was systemic infection, and strains infecting the silks competed successfully against those entering the kernels through systemic development.
1994年和1995年进行了两项温室试验和两项田间试验，以量化由串珠镰刀菌对玉米植株进行系统感染而导致的玉米籽粒感染发生率。种子通过两种方法进行感染：（i）在种子发育期间对玉米花丝进行喷雾接种（田间感染），以及（ii）将成熟种子浸泡在孢子悬浮液中进行接种（实验室感染）。用感染的种子培育植株，并通过种子接种菌株的系统感染进行测定，该测定通过回收分离株与原始菌株的营养亲和性来确定。从两种感染种子培育的植株的茎杆和籽粒中都回收了种子接种菌株。与实验室感染种子培育的植株相比，田间感染种子培育的成熟植株中，其籽粒被种子接种菌株感染的百分比更高。在田间感染种子培育的植株中，种子接种菌株的平均感染发生率为所有籽粒的9.9%至29.4%（串珠镰刀菌感染籽粒的33.0%至55.9%）。一些由感染种子培育的植株随后进行了花丝接种，从花丝接种菌株中回收的籽粒百分比（占所有籽粒的26.5%至37.5%或串珠镰刀菌感染籽粒的77.9%至78.4%）远高于种子接种菌株；此外，花丝接种显著降低了种子接种菌株对籽粒的感染发生率。串珠镰刀菌对种子的感染导致了植株和籽粒的系统感染。然而，局部感染（通过花丝）是籽粒感染比系统感染更重要的途径，并且感染花丝的菌株比通过系统发育进入籽粒的菌株竞争更成功。
