The effect of seed weight and coleoptile tiller development on seedling vigour in tall fescue, Festuca arundinaceaSchreb.
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 INFLUENCE OF SEASONAL CHANGES IN LIGHT ENERGY ON LEAF AND TILLER DEVELOPMENT IN RYEGRASS, TIMOTHY AND MEADOW FESCUE
The importance of leaf area as a determinant of yield in herbage crops is now widely realized. Selection for a rapid increase in leaf area might therefore be a useful approach to the problem of breeding for yield. 
 
 
 
The present paper describes the seasonal changes in two important components of leaf area, rate of leaf and tiller production, in contrasting varieties of ryegrass, timothy and meadow fescue. The regular seasonal variation in these components in the glasshouse is shown to be determined primarily by available light energy, the species and varieties differing in their response to changes in light energy. The possibilities of selection for these components of leaf area are discussed, but it is pointed out that individual leaf size must also be considered.
Testing For Combining Ability in Bromegrass 1
SINCE 1945 extensive use has been made of open-pollination progenies in the evaluation of selections of various perennial grasses at the Forage Crops Laboratory, Saskatoon, Saskatchewan. Open-pollination progenies have been used in preference to polycross progenies, as seed for testing could be obtained directly from the breeding nurseries or from replicated clonal nurseries. As isolation was disregarded and replication of clones limited, some doubt arises as to whether open-pollination progenies uniformly reflect the