HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by McClain, E. F. Search for Related Content PubMed Articles by McClain, E. F. Agricola Articles by McClain, E. F.

Effects of Generation and Method of Synthesis on Performance of Orchardgrass Cultivars¹

Commercial Syn-1 seed produced by pollination among S₁ or S_1F1 (first-generation increase of an S₁ family in isolation) families of the parental clones of a conventional synthetic to produce generations designated here as 1-Syn-1 and 2-Syn-1, respectively, might more fully utilize heterosis. Effects of increased inbreeding in the parental populations, however, theoretically are not completely eliminated in the autotetraploid F₁. Applicability of these considerations to orchardgrass (Dactylis glomerata L.) for forage yield, panicle production, and rust (Puccinia spp.) reaction was assessed by comparing Syn-1, Syn-2, Syn-3, 1-Syn-1, and 2-Syn-1 generations of 29 experimental synthetics (clonal combinations) in three tests. Tests I, II, and III contained primarily two, four, and two parents per clonal combination, respectively.

Generation means expressed as percent of the Syn-1 and based on 2-year forage yields were 91.3 (Syn-2), 87.3 (Syn-3), and 88.2 (1-Syn-1) in Test I and 100.2 (1-Syn-1) in Test II. Mean yields of the 1-Syn-1 and 2-Syn-1 as percent of the Syn-3 were 113.3 and 107.1, respectively, in Test III. No consistent change occurred in panicle production or rust scores. Significant interactions for clonal combinations with generations occurred in Tests I and III for yield and rust and in Tests I and II for panicle production. Correlation coefficients between generations generally were significant only for panicle production and rust score. Although yield depression generally increased as inbreeding increased, selection of clonal combinations with attenuated inbreeding depression appears possible. However, selection of such combinations would tend to exclude the more productive Syn-1's

Key Words: Dactylis glomerata L. • Forage yield • Panicle production • Rust • Puccinia • Synthetic cultivar • Inbreeding depression • Heterosis • Combining ability

² Associate professor of agronomy and soils, Clemson Univ., Clemson, SC 29631.

Received for publication April 16, 1982.