Isogenic Analysis of Productivity in Barley: Interaction of Genes Affecting Awn Length and Leaf-spotting1
- C. W. Schaller and
- C. O. Qualset2
A dominant leaf-spotting mutation (Sp sp) was studied in combination with two genes that control awn development in barley (Hordeum vulgare L.). Eight isogenic lines, normal green and spotted in each of four awn genotypes (‘Awnless’ and ‘Quarter,’ ‘Half,’ and ‘Full-awned’) of ‘Atlas,’ were evaluated in field experiments for 3 years. Leaf-spotting was expressed similarly in all awn genotypes (i.e., about 1.5% leaf coverage in the seedling stage and 15.6% in the adult stage). Mean grain yield was reduced 13.6% in the spotted genotypes compared to green, but the effect decreased linearly with increasing awn length (16.9, 14.7, 13.1, and 10.1% for Awnless and Quarter, Half, and Full-awned, respectively). Kernel size and plant height showed a similar pattern, but the effect of spotting on total and fertile floret numbers was the opposite, being increased linearly with increasing awn development. Tillering was unaffected by either the awn or leaf-spot loci. The developmental effects of leaf-spotting on yield were similar to those caused by stress environments such as drought, disease, or high temperature conditions. Awn development during seedling growth apparently imposes developmental stress, thus long-awned types are detrimental when additional stress conditions are present. However, if stress is applied later in development, the awn with its assimilatory activities, can minimize the stress effects on yield.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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