Selection for Heading Date Synchrony in Wild Rice1
- P. M. Hayes and
- R. E. Stucker2
Heading date synchrony, the uniform flowering of mainstems and tillers, was characterized and used as a selection criterion in half-sib family populations of wild rice (Zizania palustris L.). Greater intraplant synchrony would reduce the opportunity for mainstem shattering and increase harvestable yield. Principle objectives were to characterize heading date synchrony, estimate its heritability, and determine its association with other agronomic traits. A secondary objective was to measure the effect of plant density on heading date synchrony expression. Two synchrony indices, synchrony range and synchrony measure, were computed based on mainstem and tiller heading dates of individual plants sampled within half-sib families. Half-sib families were evaluated in four replicates of blocks-in-replicates designs in paddies at Grand Rapids and Excelsior, MN in 1984 and 1985. The families were derived from single plants: 100 selected for synchrony, 40 for asynchrony and 40 chosen randomly. Compared to reported values for domesticated cereals, wild rice populations showed considerable asynchrony of heading date. Heritable variation for heading date synchrony was not correlated with other agronomic traits. Estimates of predicted gain (3.4 to 6.7% per cycle) indicate that a long-term selection effort would be required to achieve synchrony in these populations. The random population (control) and the selected population (from one cycle of half-sib family selection) were evaluated at four plant densities at two locations. Plant density did not have a significant effect on heading date synchrony expression. Comparison of expected gain from selection for yield per se to gain from selection for tiller synchrony favored yield selection as the better choice for long-term yield gain in wild rice.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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