Tester Performance Level for the Evaluation of Lines for Hybrid Performance1
- J. H. Lonnquist and
- M. F. Lindsey2
A total of 348 S1 lines of corn, Zea Mays L., (116 from each of three sources) were topcrossed to a high- and a low-yielding tester. Based upon topcross performance, a high- and a low-yielding group of lines were selected within each source for each topcross series. Subsequently, these selected groups of lines were evaluated in crosses with four elite lines as testers. In these latter trials the difference (H-L) averaged greater for lines selected originally on the basis of the low-yielding tester. Furthermore, lines selected as high yielding on the basis of crosses with the low tester averaged 5% higher yielding in testcrosses with the elite lines than those selected high on the basis of topcross performance with the high tester. The data substantiate previously published suggestions based upon theoretical considerations relative to the value of low-yielding testers for line evaluation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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