Browsing by Author "Bäckström, Hanna"

The growth and development of barley (Hordeum vulgare L.) is affected by photoperiod and temperature. Photoperiod has various signalling functions affecting reproductive development and its rate. It also affects the rates of leaf area extensions and dry matter production. Increase in photoperiod hastens the plant developmental processes and affects the leaf area and tiller formation. Primary tillers form from axillary buds in the leaf nodes on the main culm and increase the leaf area of the plant. Under favourable conditions, initiated tillers grow to separate culms with grain bearing ears. However, the environmental conditions during the growing season in northern latitudes affect tiller formation. The aims of the experiments were to investigate the effects of photoperiod on barley leaf and tiller development. Other aims were to compare the differences expressed by the two row-types and tillering habits. Seven barley accessions, differing in tillering habit and row-type, were used in the experiments. Three pairs of near-isogenic accessions six-rowed ‘Morex’ and ‘Uniculm Morex’, ‘Kindred’ and ‘Uniculm Kindred’, two-rowed ‘Ingrid’ and ‘3-503’, differing in tillering habit, and two-rowed ‘Saana’ were grown in growth chamber at humidity of 60/70 % and at temperature 18/12 ºC (day/night), in three different photoperiods (15 h, 18 h and 21 h). The leaf length and width were measured from the full-grown leaves. The samples to identify main culm and tillers were taken after the plants reached the 4-leaf-stage. The effects of photoperiod, accession, tillering habit and row-type on the plant, leaf and tiller growth were statistically analysed. Increase in photoperiod hastened the plant development as well as leaf and tiller emergence rates. The leaf size and main culm leaf area decreased as the photoperiod increased. The number of tillers increased as photoperiod increased. The uniculm accessions had larger leaves and a larger main culm leaf area than the conventional tillering accessions. Six-rowed accessions had larger leaves and a larger main culm leaf area than the two-rowed accessions. The two-rowed accessions had a faster tiller emergence rate and a higher tiller number compared to the six-rowed accessions. Photoperiod treatments affected the leaf and tiller growth and development as expected apart from the number of tillers produced in the longest, 21h photoperiod. Differences between the two tillering habits and row-types were also as expected, although some exceptions occurred. Potentials and limitations of uniculm growth habit in agricultural production were also discussed.