Wild Rice Populations Research Articles

Patterns of variation in Ontario wild rice ( Zizania aquatica L.) 4. Influence of regional and local environmental factors on variation within and among field populations

Analyses of covariance were used to examine morphological and productivity data from 17 indigenous wild rice populations in six empirically defined climatic regions. Statistical compensation for effects of local environmental factors (principal components of sediment nutrient concentrations, water depth and other emergent macrophytes) permitted direct comparisons of populations in different regions. there was a general trend of increasing stem and root weight, leaf width, and pistillate floret number with decreasing climatic severity. Tiller production was greatest in populations from intermediate climatic regimes. These results were consistent with those obtained in greenhouse experiments. Seed length and weight did not appear to be systematically related to climatic regime, and plant height was primarily a function of local environmental factors, especially water depth.

The domestication of American wildrice

The expansion in wildrice (Zizania palustris) production and the associated research efforts represent the largest modern effort to domesticate a cereal grain. Wildrice growers brought the species under cultivation, but plant breeding and agronomic research have accelerated the domestication process. The domestication and commercialization of this diploid (2n = 30), protogynous, cross-pollinated, annual, aquatic cereal present an opportunity to examine crop evolution and domestication theory. Traits associated with the domesticated cereal grains are shattering resistance, tiller synchrony, and increased seed size. This syndrome of traits may result from automatic selection, the selective force applied by repeated cycles of planting of harvested seed. Positive responses from deliberate selection for these traits in wildrice populations indicate that a domestication ideotype is attainable through plant breeding and that founder effect in this diploid species may be negligible. Continued commercial production of wildrice in the Great Lakes region is not likely to further the domestication process, whereas automatic selection may be initiated in the emerging California wildrice industry.

Patterns of variation in Ontario wild rice ( Zizania Aquatica L.).2. Differential responses of populations to varying cultivation conditions

Wild rice plants from four seed sources were grown in two greenhouses and one lake that did not previously support wild rice. Morphometric responses of the plants to the varying cultivation conditions differed among the seed sources. One population was particularly sensitive to the different environments, and appeared to have a superior capacity to exploit favourable conditions for improved productivity. It is argued that differential phenotypic plasticity among wild rice populations may be adaptive and related to climatic factors. The implications of the results for breeding wild rice for lake production are discussed.

Patterns of variation in Ontario wild rice ( Zizania Aquatica L.). 3. Similarity between source and introduced populations pairs under experimental and field conditions

Morphometric similarities between source wild rice populations and populations introduced to other sites from those sources were examined in two studies. Progeny of two populations, 5 and 50 years after introduction, were compared with progeny of the common source population over 8 water depth/fertilizer treatment combinations. In a field study, five introduced populations and their three sources were compared 5 or 10 years after establishment of the new stands. Source and introduced population pairs appeared to be genetically similar after 50 years of reproductive isolation. It is suggested that phenotypic plasticity buffers these populations from directional selection pressures, and that the degree of plasticity itself may be subject to natural selection.

Selection for Heading Date Synchrony in Wild Rice1

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.

Secondary succession of weed communities in lowland habitats of Taiwan in relation to the introduction of wild-rice (Oryza perennis) populations

Wild-rice (Oryza perennis Moench) populations were introduced into abandoned lowland fields (and a ditch) at five sites in Taiwan. The weeds arising after clearance and tillage of the fields were observed with regard to various attributes of the community during three years. Among a total of 84 identified species, Leersia hexandra had the highest relative frequency. With secondary succession, the percentage biomass of perennial species, particularly of grasses, gradually increased and the dominance index (1-H′/H′ max) also increased. Species present in the buried seed pool in soil samples showed a different pattern of successional changes. With species classified into grass, sedge, and dicot groups and their percentage of biomass data compared with corresponding data for the density of plants from buried seeds, a negative correlation was found which suggested differences in behavior among the plant groups. Experiments on the effects of weeding and inundation suggested that the niches of Oryza perennis and of Leersia hexandra largely overlap, and differed from that of Panicum repens. The wild-rice populations declined as Leersia dominated. This relationship was demonstrated by principal component analysis and standard partial regression analysis of the data.

Differentiation of perennial and annual types due to habitat conditions in the wild riceOryza perennis

Populations of the common wild rice of AsiaO. rufipogon Griff. (=Oryza perennis Moench) were studied with regard to interrelations between life-history traits and habitat conditions. They showed a perennial-annual continuum and differed in reproductive allocation and many other traits. Perennial populations were found in deep swamps, while annual populations were in shallower, temporary swamps which were parched in the dry season. The perennial and annual types tended to be in association with other perennial and annual plants, respectively, suggesting their niche differentiation. Intermediate perennial-annual populations were in communities with a high species diversity. In one population, plants growing on the periphery of the swamp were of annual and those in deeper center were of perennial type. Another population seemed to be differentiated into an annual and an intermediate type in accordance with different degrees of habitat disturbance. The small genetic distances found between the sub-populations suggested their differentiation within a gene pool.

Growth, Mortality, and Biomass Partitioning in Freshwater Tidal Wetland Populations of Wild Rice (Zizania aquatica var. aquatica)

WHIGHAMI, D., and R. SIMPSON. (Biol. Dept., Rider Coll., Lawreniceville, New Jersey, 08648). Growtth, mortality, aiid bioiiiass partitioiiliig in freshlwater tidal wetland populatioiis of wild lice (Zizania aquatica var. aqutatica). Bull. Toirey Bot. Club 104: 347-351. 1977.-Wild rice is a common aniiual in Delawaare River tidal wetlands. Net productioln wvas as high as 20.9 g m-2 day-1 amid varied seasonially. The lowest productioii rates occurred duriiig the seedling phenophase ancd the highest followed seedling establishmenit. On a percenitage basis, more biomass was allocated inito root productioii during the seedling phemiophase. Populationi mortality was coiistanit betweeni May and early August.

Directions of Differentiation in Populations of Wild Rice, Oryza perennis and O. sativa f. spontanea

Directions of Differentiation in Populations of Wild Rice, Oryza perennis and O. sativa f. spontanea

DIRECTIONS OF DIFFERENTIATION IN POPULATIONS OF WILD RICE, ORYZA PERENNIS AND O. SATIVA F. SPONTANEA

Journal Article DIRECTIONS OF DIFFERENTIATION IN POPULATIONS OF WILD RICE, ORYZA PERENNIS AND O. SATIVA F. SPONTANEA Get access Hiroko Morishima, Hiroko Morishima Search for other works by this author on: Oxford Academic Google Scholar Hiko‐Ichi Oka, Hiko‐Ichi Oka Search for other works by this author on: Oxford Academic Google Scholar Wen‐Tsai Chang Wen‐Tsai Chang Search for other works by this author on: Oxford Academic Google Scholar Evolution, Volume 15, Issue 3, 1 September 1961, Pages 326–339, https://doi.org/10.1111/j.1558-5646.1961.tb03158.x Published: 01 September 1961 Article history Received: 16 September 1960 Published: 01 September 1961