Selection for heading date synchrony in wild rice.

Half-sib families of Zizania palustris were evaluated at 2 Minnesota sites in 1984 and 1985. Two measures of flowering synchrony of main stems and tillers were used. 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, the 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) indicated that a long-term selection effort would be required to achieve synchrony. A random population (control) and a selected population (from one cycle of half-sib family selection) were evaluated at 4 plant densities. 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 synchrony favoured yield selection as the better choice for long-term yield gain.