Space-planted and Mass-seeded Progeny Tests for Seed Yield and Seed Size in Tetraploid Crested Wheatgrass1
- H. M. Schaaf2
Twenty-four tetraploid crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.] genotypes were evaluated as clones (parents), open-pollination (OP) progenies, and topcross (TC) progenies. Parents and OP's were grown in replicated spaced plantings and assessed for spikes/plant, seeds/spike, seed yield, and seed size (mg/100 seeds). Mass-seeded OP's and TC's were evaluated for seed yield and seed size in replicated singlerow plots.
Although space-planted and mass-seeded progenies provided similar evaluations of seed-yidd potential, method of culture caused sizable shifts in the expression of seed size. When seeking simultaneous improvement of both characters, selecting parents on the basis of spaced-progeny performance appeared to retain some undersirable genotypes, the effects of which could decrease the efficiency of recurrent selection. The heritability of all four characters was lower for the spaced progenies than for the seeded progenies. In addition, space-planting altered the relationship of seed size to spikes/plant, seeds/spike, and seed yield.
Correlations of 0.83 and 0.85 (P < 0.001) for seed yield and seed size, respectively, demonstrate close similarity of OP and TC performance in mass-seeded tests.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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