Gamete-Seed Transmission of Alfalfa Mosaic Virus and Its Effect on Seed Germination and Yield in Alfalfa Plants

Abstract

LEAN. 1977. Gamete-seed transmission of alfalfa mosaic virus and its effect on seed germination and yield in alfalfa plants. Phytopathology 67: 576-579. The percentage of alfalfa mosaic virus (AMV)-infected conditions, there was a reduction of 30.8-34.6% in seeds was determined in the commercial production of seven germination and a reduction of 45.1-68.6% in yield of seed by different cultivars of alfalfa. Seed transmission of AMV AMV-infected alfalfa. No systemic infection from the ranged from 0.6 to 10.3%. The transmission of AMV through infected pollen in the normal or male-sterile female parents pollen and the ovules of the infected alfalfa plants was shown. was detected. The susceptibility of two different cultivars of Ovule transmission ranged from 0.5 to 6.0% and pollen alfalfa, Sonora 70 and Mesa Sirsa 034, to AMV is compared. transmission varied from 1.0 to 14.0%. Under greenhouse Alfalfa mosaic virus is a widespread and truly 24-26 C and 70% relative humidity (RH). Alfalfa seeds cosmopolitan virus that attacks alfalfa (Medicago sativa from new crops were obtained from the Cooperative L.) and several other crops (1, 2, 3, 13, 17, 18, 19). Its Extension, Agronomy, University of California, Davis. existence has been known since 1931 (21). Three-hundred seeds of each cultivar were planted in In 1962, Belli (1) reported for the first time that AMV steam-sterilized metal pots. Four-wk-old seedlings of was transmitted through the seeds of alfalfa. Zschau (22) alfalfa were used for virus assay. The seedling infection studied two strains of AMV and showed both to be seedwas detected by assaying the seedlings on cowpea (Vigna transmissible. Frosheiser found 1-4% seed transmission sinensis L.) (2) and on Red Kidney bean (Phaseolus of AMV in 13 of 15 seed lots of alfalfa tested (6). He vulgaris L.) as the test plants. This was done because of recently reported 0.5 to 26.5% transmission of AMV masking of AMV symptoms in some cultivars of alfalfa through pollen and 0.0 to 9.5% transmission through the (2, 4, 8). Inoculum for mechanical inoculation was ovules of infected alfalfa clones (8). prepared from each alfalfa seedling by grinding it in a Several reports relate to the economic importance of sterile mortar and pestle with a few milliliters of 0.05 M AMV and its effect on dryor fresh-matter yields of potassium phosphate buffer, pH 7.2. The prepared alfalfa plants. The conclusions of various investigators inoculum was used to inoculate six four-leaved cowpea relative to the economic importance of AMV are quite and Red Kidney bean plants. Prior to inoculation, the contradictory (5, 7, 9, 10, 12). Zschau (22) reported that leaves of these plants were dusted with corundum latent AMV infection generally damaged alfalfa less in powder. Between 140 and 159 seedlings of each alfalfa the vegetative stage than in the reproductive stage, cultivar were randomly assayed and the percentage of thereby affecting seed yield. However, he did not report seed transmission was noted (Table 1). any actual loss data. Ovule and pollen ...

Seed transmission of Papaya meleira virus in papaya (Carica papaya) cv. Maradol

“…The high percentage of infection in plants grown from diseased seeds is consistent with values obtained in other studies, which demonstrated that the probability of plant infection through seed transmission (i.e. when infected seeds are used) is high, although not 100% (Hemmati & McLean, 1977;Johansen et al, 1994).…”

Cytopathology of Mature Ovaries from Lettuce Plants Infected by Lettuce Mosaic Potyvirus

“…Similar results have been reported in the study of seed transmission of AMV, FROSHEISER (1974) and HEMMATI and MCLEAN (1977) demonstrated in crossing experiments that AMV was transmitted to the embryo through the ovules. Despite these observations, Wu-COXSON et al (1975), using conventional thin-section electron microscopy, were unable to find particles of AMV in the ovules of alfalfa.…”

“…FROSHEISER (1974) and HEMMATI and MCLEAN (1977) reported that alfalfa mosaic virus (AMV) was transmitted to alfalfa embrj-os through the ovules, but WILCOXSON ct al. (1975) were unable to find AMV particles in thin-sections of 50 ovules from infected alfalfa plants by conventional electron microscopy.…”

Symptoms and Host Range

“…In a few instances, for example, in tulip color-adding virus, infection results in increased pigmentation in some areas of the petals (Matthews, 1991). Virus infection may reduce pollen production and decrease seed set, seed size, and germination (Hemmati and McLean, 1977) (Figure 4.3). The effects of virus infection on these nectar guides and on the behavior of honeybees do not appear to have been studied.…”