Effect of Genetically and Environmentally Induced Heading Date Differences on Yield and Adaptation of an Isogenenic Barley Pair1
- V. W. Samail,
- R. F. Eslick and
- E. A. Hockett2
Early maturity has long been recognized as crucial to crop adaptation in norther climates. This study was conducted to determine the specific effect of early maturity on yield and morphological character responses over a large number of environments. ‘Betzes’ spring barley (Hordeum vulgare L.) and its early heading backcross isotype ‘Erbet’ were grown in 214 environments. The effect of the mean 8- day reduction in heading dates on agronomic character responses in each environment was determined by using paired T-tests, correlation analysis, and stability linear and curvilinear regression analysis. Betzes was 8 days later to head, 3 days later to mature (to 15% grain moisture), higher yielding (0.19 Mg/ha), had 75 g/kg more thin kernels, 125 g/kg fewer plump kernels, lower kernel weights (2.0 mg) 9 kg lower protein content, and taller plants (6.5 cm) than its early isotype Erbet when averaged over all environments. Correlation and linear stability regression analysis of the effect of early vs. normal heading date indicated that plant height and yield were primarily pleiotropically decreased by genetically reduced growth duration. Kernel weights, percent plump, and thin kernels, which all expressed a curvilinear response, were increased in the early line. In low yielding environments (increased stress), Erbet yielded as well as Betzes, and their yield patterns were correlated. Erbet yield patterns were not correlated to Betzes yield patterns in the higher (>4640 kg/ha) yielding environments.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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