Title:

Kentucky Bluegrass as an aid to the establishment of crop management systems

Objectives:

1. Develop maximum genetic and biological potential by identifying specific morphological-anatomical features associated with floral induction (specific research area 3A)
   1. Identify morphological indicators of the juvenile to adult transition and develop a growth stage model for floral competency of tillers based on the results. Methods of scanning electron and epifluorescence microscopy are used (in progress)
   2. Identify biochemical differences in wax composition using methods of thin layer and/or gas chromatography. (not relevant based on findings from Objective 1a) Compare five cultivars that show variation in timing of floral induction and density of tiller production using the features defined for the juvenile to adult transition. (in progress)
   3. Compare developmental changes in tillers of each of the cultivars before and after mechanical residue removal in the field. (modified & in progress)
2. Develop sustainable grass seed cropping systems by improving methods of crop management (specific research area 1A).
   1. Develop a practical means for the grower to assess leaf stage as it reflects floral state.

Investigator:

Anne W. Sylvester, Dept. of Biological Sciences, UI

Cooperators:

Glenn Murray, Dept. of Plant Sciences, UI
Jeff Griffin, Dept. of Plant Sciences, UI
Vickie Parker-Clarke, Agricultural Extension Agent, Kootenai County

Abstract:

Our current research shows that anatomical features of vein number and sclerification, rather than wax and hair distribution, correlate with the floral transition in seedling year plants and in established tillers. Furthermore, new fall tillers are not present in sufficient numbers to account for the panicles produced the next summer. Tillers that emerged the previous spring appear to be the future panicle-producers. Consequently, we hypothesize that spring tillers may be the significant panicle-producers the second year after their emergence. The juvenile threshold, significant for panicle production, may thus occur in tillers emerging in the spring rather than the fall.

Justification:

The practice of post-harvest open-field burning is used routinely to reduce pest and weed problems and to stimulate yield of bluegrass seed the following year. Alternatives to the practice must be economically feasible because grass seed production is an integral part of the agricultural economy of the Inland Northwest. Mechanical removal of grass residue is currently being investigated as a favorable alternative to the burning practice. It is evident that, regardless of the fall treatment, seed production is enhanced only in tillers that have passed a certain developmental threshold, termed the juvenile phase. Understanding when this developmental phase occurs is essential to the appropriate design of residue management systems. For example, cultivar selection can be optimized and field treatments can be planned based on the developmental parameters of a field. The research presented here determines which tillers are receptive to floral induction and are thus responsible for optimal panicle production. The primary goal is to identify specific plant features that are indicators of the readiness to flower. This information will be used to design a means of identifying developmental stages in the field. The research will thus contribute to the cooperative effort to provide alternatives to open field burning by identifying morphological indicators of the flowering state.