Responses to Selection for Root Dimension in a South European Variety of Perennial Ryegrass)*

摘要

AbstractThe objective of the study was to determine the effect of selection for large root dimension on root and shoot characteristics of an Italian variety ofLolium perenneL. (cv. ‘Vejo’). Two cycles of recurrent restricted phenotypic selection (RRPS) were carried out in 1983 and 1984 at Perugia (Italy). In each cycle, 20 out of 1,500 plants were selected and intercrossed under isolation. In 1985, 120 plants from‘Vejo selected’ and an equal number of plants from‘Vejo’ initial seed‐lot were grown hydroponically for 92 days; at the end of the experiment, the plants were measured for their number of leaves and stems, leaf length, length of the longest root, root volume and shoot and root dry weight.Sufficient genetic variability existed among plants of cv. ‘Vejo’ to allow highly significant responses to selection for root dimension (+25 in root length, +39 in root volume, + 67 in root dry weight and +31 in root: shoot dry weight ratio). Furthermore, two cycles of RRPS for root dimension did not show negative responses of the above‐ground