Effects of barley yellow dwarf virus on the growth and yield of single plants and simulated swards of perennial rye‐grass

Abstract

Irish perennial rye-grass plants infected with barley yellow dwarf virus (BYDV) showed inconspicuous leaf symptoms but were more stunted and yielded less total herbage, but more early spring herbage, than healthy plants. During a period of 2 years, infection did not decrease plant survival; infected plants produced more tillers and gave a higher ratio of vegetative to fertile tillers than healthy plants. BYDV caused a greater loss of yield in simulated rye-grass swards cut twice a year than in those cut four times. Swards in which half the plants were infected gave yields intermediate between those of healthy and infected swards. Infected plants tended to dominate healthy ones in swards cut four times, but in those cut twice a year the initial status quo was maintained. In swards containing rye-grass and white clover, the clover yielded more for most of the year when with BYDV-infected than with healthy rye-grass, but this trend was reversed in spring.The different effects of barley yellow dwarf virus on rye-grass plants and of cocksfoot streak virus on cocksfoot seem reflected by the different effects of the viruses on the competition between infected grass, healthy grass and white clover plants, when these are grown in different combinations.

Effects of barley yellow dwarf virus on simulated swards of Nui perennial ryegrass

“…Possibly a combination of the higher nitrogen status and less frequent defoliation of the British swards accounts for the different effects of BYDV on herbage yields in the two trials. Catherall (1966) also reported that BYDVinfected ryegrasses not only began growth 2-3 weeks earlier and outyielded healthy plants in spring but they also tillered more than did healthy plants. These observations were made on individually grown plants and so they cannot be compared with our data obtained from simulated swards.…”

“…The effect of BYDV on ryegrass in simulated swards was first studied by Catherall (1966) at the Welsh Plant Breeding Station, Aberystwyth. It is therefore germane to compare our data with that from the British trial, bearing in mind the differences in c1imate, strains of BYDV, and plant varieties used.…”

“…Catherall (1966), using a simulated sward technique, found that BYDV caused a 17.4% loss in annual herbage yield from swards of perennial ryegrass cut twice a year and 8.4% loss from those cut four times a year. He also noted that the pattern of seasonal growth was alte red by the virus.…”

Risk assessment of genetically engineered crops: fitness effects of virus‐resistance transgenes in wild Cucurbita pepo

“…Virus infections can be ubiquitous in wild plant populations (MacClement and Richards 1956, Yahara and Oyama 1993, Malmstrom et al 2005, can cause significant reductions in vegetative and reproductive performance (Friess and Maillet 1996, Funayama et al 1997, Power 2002, and can alter intra-and interspecific 3 E-mail: kdl24@cornell.edu competitive interactions in plant communities (Catherall 1966, Catherall and Griffiths 1966, Friess and Maillet 1997, Power and Mitchell 2004. Few studies, however, have comprehensively measured fitness impacts of viruses or directly assessed the impact of virus-resistant transgenes on plant fitness (but see Fuchs et al 2004b).…”

Breeding Forage Plants in the Genome Era

“…BYDV infection in ryegrasses reduces dry matter yield by as much as 24% (Catherall 1966;Wilkins and Catherall 1977). RMV infection in ryegrasses results in dry matter reductions of 5 -50% (A 'Brook and Heard 1975;Jones et al 1977;Eagling et al 1992).…”