Relationship between line and topcross performance under drought and non-stressed conditions in tropical maize
1997
Betran, F.J. | Banziger, M. | Beck, D.L.
Maize grain losses due to drought in the tropics may reach 24 m tons per year. 'Tuxpeno Sequia C6' (TS6) and 'La Posta Sequia' (LPS) are two white-grained tropical populations that have been improved for drought tolerance at flowering and grain filling, using a recurrent S1 selection scheme under three water regimes: well-watered, intermediate drought stress and severe drought stress. Population improvement accomplished by recurrent selection has shown that increased grain yield under drought stress is highly associated with reductions in anthesis-silking interval (ASI) and barrenness. The objective of this study was to estimate the relationships among yield and secondary traits under managed stress environments between S3 lines derived from TS6 C1 and LPS C3 and their topcrosses with Tuxpeno and non-Tuxpeno testers. Phenotypic correlations between topcross grain yield and line grain yield, ASI and barrenness, as well as high heritabilities for these traits (0.50), suggest that selection for a reduction in ASI and barrenness in the lines, together with line per se yield performance under drought, could be used to select stress tolerant hybrids.
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