Integrating Exotic Germplasm into Corn Belt Maize Breeding Programs1
- Arnel R. Hallauer and
- J. H. Sears2
Two procedures were compared for integrating the Colombian ‘Eto Composite’ into our maize (Zea mays L.) breeding program: (i) mass selection for earlier silking and (ii) crossing Eto Composite with six early inbred lines and intermating to form ‘BS2.’ Both procedures were effective for adapting Eto Composite to the central Corn Belt.
Mass selection for early silking decreased the interval from planting to silking by 20 days, for an average decrease of 3.8 days per cycle of selection. A concomitant change with mass selection for early silking was an average decrease of 15 cm per cycle of selection for ear height. The simple correlation between early silking and lower ear height was r = 0.89.*
The (Eto Composite ✕ early lines) crosses averaged 10% heterosis for earlier silking, relative to the midparent. The intermated population (BS2) of the (Eto Composite ✕ early line) crosses showed nearly 50% silk emergence by August 1. The heritability (h2) estimates for silking date (h2 = 59%) and ear height (h2 = 58%), on an individual plant basis, verify that mass selection for early silking is effective for adapting Eto Composite to the Corn Belt.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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