Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 28, 1997
Publication Date: N/A
Interpretive Summary: Efficient breeding methods are needed to reduce time requirements and increase precision in selecting superior parents for improved cultivars of cross-pollinated forage crops. Evaluation of clonal lines to determine the breeding value of potential parents would require less time than progeny tests, but other investigators have reported that progeny tests are emore accurate. We tested clonal lines of intermediate wheatgrass in vegetatively propagated plots that simulated a solid-seeded planting and found that clonal line performance provided a good indication of parental performance. However, resources required to establish these clonal plots were too great to allow evaluation of large numbers of potential parents. Thus, we recommend use of small clonal plots to assess plant characteristics with high heritability in initial screening tests followed by progeny tests to assess complex characters such as dry-matter yield. This study establishes the value of clonal plots in selecting superior parents for improved, cross-pollinated forage cultivars. This information can be applied to other plant breeding programs involving cross-pollinated species.
Technical Abstract: Efficient testing procedures are needed to identify superior parents for improved cultivars of cross-pollinated forage species. The primary objective of this study was to compare clonal and open-pollinated progeny testing in the selection of parents from an intermediate wheatgrass [Thinopyrum intermedium (Host) Barkw. & Dewey] population. A second objective was to examine experiential error control from a partially-balanced lattice design and a nearest-neighbor analysis relative to a randomized complete block statistical design. Based on 3-yr means from one location, narrow-sense heritability estimates from 81 parent clones and their respective open-pollinated progenies averaged 50% for heading date, 45% for plant height, and 69% for dry matter yield. Extreme high- and low-ranked entries for all three traits generally were in common for clonal and progeny tests. A lattice design and nearest-neighbor analysis reduced experimental error but did not improve rank correlations between parent clones and their progenies or heritability estimates compared to a randomized complete block design. Both clonal and open-pollinated progeny tests should be used to select superior parents, as both test procedures have unique attributes. Clonal tests are useful in selecting for traits with relatively high heritability, while extensive progeny testing is more appropriate for complex traits such as dry-matter yield.