Gamete selection for macro-nutrient selection of Ca, Mg and K in tall fescue

Authors: Kindiger, Bryan

Submitted to: Journal of Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2021
Publication Date: 10/26/2021
Citation: Kindiger, B.K. 2021. Gamete selection for macro-nutrient selection of Ca, Mg and K in tall fescue. Journal of Horticulture. 8(6). Article 297.

Interpretive Summary: Innovations in plant breeding can achieve advances toward plant improvement by simplifying selection procedures and allowing rapid consolidation of advantageous gene systems. A novel diploid, Lolium multiflorum (Lolium perenne L. subsp. multiflorum (Lam.) Husnot (syn. Lolium multiflorum Lam.) line are seen to induce genome loss and dihaploid generation following hybridization with tall fescue (L. arundinaceum (Schreb.) Darbysh.) (syn.Festuca arundinacea Schreb.)). Grass tetany can cause severe losses from death or reduced performance in grass fed livestock throughout the world. Dietary Mg supplementation adds to the annual cost of labor and production of grazing livestock and does not always ensure that all animals receive adequate amounts of Mg. The research presented here reviews the outcome of the implementation of a new dihaploid breeding and selection approach that can stabilize the complex genetic mineral characteristics of Ca, Mg and K of tall fescue into a homozygous, fixed, non-segregating genetic state. This breeding and selection technique has clear advantages in fixing advantageous gene combinations for other mineral and or forage quality traits. In this study, the dihaploid, gamete selection approach has indicated its value in the rapid and efficient generation of several tall fescue genotypes exhibiting balanced levels of K, Ca and Mg and a low hypomagnesemia ratio. It is anticipated that this approach can be rapidly and efficiently applied toward the selection of additional complex traits.

Technical Abstract: A novel diploid, Lolium multiflorum (Lolium perenne L. subsp. multiflorum (Lam.) Husnot (syn. Lolium multiflorum Lam.) line has previously been observed to induce genome loss and dihaploid generation following hybridization with hexaploid, L. arundinaceum (Schreb.) Darbysh.) (syn.Festuca arundinacea Schreb.). Early observations of chimeral sectors generated in these F1 have indicated a form of mitotic chromosome or genome loss that is responsible for the recovery of the L. multiflorum or L. arundinaceum dihaploids. During the F1 phase, selection for various attributes can be performed on the F1 that will be transferred as a homozygous genetic controlled trait to the resultant tall fescue dihaploid lines. One selection trait that would benefit greatly from this approach would be for producing tall fescue lines that would reduce the occurrence of grass tetany or hypomagnesemia in grazing species. Grass tetany or hypomagnesemia causes severe losses from death or reduced performance in livestock throughout the world. Dietary Mg supplementation adds to the annual cost of labor and production of grazing livestock and does not always ensure that all animals receive adequate amounts of Mg. The production of dihaploid tall fescue seed having balanced levels of Ca, Mg, P and K are generated through this dihaploid inducer approach and the resultant lines may be blended into hybrid synthetics to produce a tall fescue cultivar that will lower the incidence of hypomagnesmia in grazing livestock.