Effect of Genes for Photoperiodism, Semidwarfism, and Awns on Agronomic Characters in a Wheat Cross

The effects of genes for photoperiodism, semidwarfism, and awns on agronomic characters in wheat (Triticum aestivum L.) vary depending on environment. Few data are available for the Canadian prairies. The objective of this study was to measure the effects on wheat of these genes under the long day, short growing season conditions in Saskatchewan and to determine the optimum combination of them. A cross was made between ‘Glenlea’, a photoperiod insensitive, tall, awnletted cultivar, and ‘Era’, a photoperiod sensitive, semidwarf, awned cultivar. A random sample of F₆ lines was generated by a single seed descent procedure and tested for response to a 10-h photoperiod. The results indicated that a single gene was segregating for photoperiod response. Twenty-four sensitive and 22 insensitive F₇ lines plus the parents and another check were tested at Saskatoon in 1983, and Saskatoon and Elrose in 1984. Measurements were made on days to heading, days to maturity, height, straw strength, yield, kernel weight, test weight, protein concentration, and SDS (sodium dodecyl sulfate) sedimentation value. The photoperiod insensitive lines tended to be slightly earlier (0.7 days), shorter (3.7 cm), and lower yielding (2.1%) than sensitive lines. Semidwarf lines were slightly earlier to head (0.5 days) and considerably higher yielding (17%) than tall lines. They also had smaller kernels (1.9 g/1000) and lower protein concentration (0.6 g kg⁻¹). Awned lines were slightly earlier to head (0.6 days), higher yielding in the two Saskatoon tests (5%) but lower yielding at Elrose (6%), and had larger kernels (1.6 g/1000) than awnletted lines. Protein content was negatively correlated with yield and days to heading was negatively correlated with days to fill. Based on the results of this cross, it appears that to obtain high yield a cultivar should combine semidwarfism, awns, and photoperiod sensitivity.