The effect of seed weight and coleoptile tiller development on seedling vigour in tall fescue, Festuca arundinaceaSchreb.

Abstract

INDEX WORDSFestuca arundinacea, tall fescue, seed weight, coleoptile tiller, seedling vigour, selection criterion. SUMMARYTwo characters, previously shown to influence the rate of seedling growth in tall fescue, were studied in detail in three distinct populations as part of a programme to improve seedling vigour in the species. The effect of seed weight was found to be confined to the very early stages of growth and was apparent in seedling dry matter yield but not in tiller number. The development of a tiller in the axil of the coleoptile, which varied significantly between populations, had a far greater and more permanent effect both in terms of dry matter yield and tiller number. The increase in tiller number attributable to the coleoptile tiller and its derivatives increased geometrically in step with the total tiller number, so that the intitial difference of 28~ in the first harvest remained practically unchanged in the subsequent three harvests. Similarly, the percentage difference in dry matter yield between plants with and without a coleoptile tiller remained more or less constant at about 22~ from the second harvest onwards.It is concluded that the development of a coleoptile tiller may prove to be a useful selection criterion in the breeding of this species.

The effects of ploidy and seed mass on the emergence and early vigour of perennial ryegrass (Lolium perenne L.) cultivars

“…Variation in embryo size has been shown to be an important determinant of early vigour among a number of cereal species (López-Castañeda et al 1996) and seedling leaf breadth has been shown to be an effective selection criterion to increase the early vigour of bread wheat (Rebetzke and Richards 1999). Genetic variation in seedling vigour independent of seed mass has been observed in seedling yield of sand bluestem (Glewen and Vogel 1984) and in early tiller development in tall fescue (Lewis and Garcia 1979).…”

“…Shoot characteristics such as coleoptile tiller development (Lewis and Garcia 1979) and coleoptile and mesocotyl length and thickness (Andrews et al 1997) have been shown to be important characteristics related to the early vigour of forage grass species, especially in stress environments. Our data demonstrate that when seed mass effects are removed there is still considerable variation for a range of seedling vigour components in perennial ryegrass cultivars.…”

Effect of seed mass on germination and growth in three dominant species in southern Brazilian coastal dunes

“…Seed size also affects seedling biomass (Zimmerman & Weis, 1983): usually, the seedlings from large seeds are larger than those from small seeds, especially in the early stages of growth (Schaal, 1980;Saverimuttu & Westoby, 1996). The initial seedling size differences may persist until maturity (Schaal, 1980;Weis, 1982) or become imperceptible with time (Zimmerman & Weis, 1983) because of the differential relative growth rate among seedlings from differently sized seeds (Lewis & Garcia, 1979;Zhang & Maun, 1990). Some studies (Zimmerman & Weis, 1983) indicate that a higher relative growth rate of seedlings from small seeds exists only in the early stages of development, and/or that the RGR may be reduced in competitive conditions .…”

Tall fescue in Australia and New Zealand

“…Badoux did not comment, but tiller number can be recorded for many more seedlings in a given time than seedling weight. The presence of a coleoptile tiller on seedlings grown in a glasshouse at 20-25°C was closely correlated with plant weight and tiller number at later stages (Lewis & Garcia 1979), and tall fescue populations varied in the frequency of this trait. Seed weight has been suggested by several authors as a likely indicator of seedling vigour, but Lewis & Garcia found it had a very ephemeral effect.…”