Genetic variability and QTL mapping of winter survivability and leaf firing in African bermudagras

Authors: YU, SHUHAO - Oklahoma State University; SCHOONMAKER, ASHLEY - Oklahoma State University; YAN, LIULING - Oklahoma State University; Hulse-Kemp, Amanda; FONTANIER, CHARLES - Oklahoma State University; MARTIN, DENNIS - Oklahoma State University

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2022
Publication Date: 10/26/2022
Citation: Yu, S., Schoonmaker, A., Yan, L., Hulse-Kemp, A.M., Fontanier, C.H., Martin, D.L. 2022. Genetic variability and QTL mapping of winter survivability and leaf firing in African bermudagras. Crop Science. https://doi.org/10.1002/csc2.20849.
DOI: https://doi.org/10.1002/csc2.20849

Interpretive Summary: Bermudagrass is a widely-used warm season grass across the southeast; however, in the more northern parts of the growing area it becomes susceptible to winterkill which is undesirable for property owners. A special type of bermudagrass that comes from Africa, referred to as African Bermudagrass, has often been used as a parent for creating popular bermudagrass lines that are higher quality and more resilient particularly to drought. Little information is known about the genetics of the African bermudagrass that provide these desirable traits, which are the focus of this study. We used a population of lines that were descended from an African bermudagrass parent that differed in their display of desirable traits to integrate traits with the genetics of the lines to better understand what genetic regions are important. Traits that were studied include ability of plants to become green again in the spring after winter cold, amount of winterkill, and drought resistance. We found that multiple genetic regions are important for different traits, including some regions that are implicated across traits. This information will help us to dig further into the genetics and build tools for breeders developing new lines with African bermudagrass to speed up their programs.

Technical Abstract: Turf-type bermudagrass is susceptible to winterkill when grown in transition zone climates. Minimizing water use in turfgrass management is of societal significance. African bermudagrass (Cynodon transvaalensis Burtt-Davy) has been extensively used to cross with common bermudagrass (C. dactylon Pers. var. dactylon) in the creation of F1 hybrid cultivars that are popular in the turf industry. Little information regarding the molecular basis of winter survivability and drought resistance in African bermudagrass is available. Accordingly, the objectives of this study were to quantify genetic variability and identify quantitative trait loci (QTL) associated with winter survival traits [spring greenup (SG), spring greenup percent green cover (SGPGC), winterkill (WK)], and leaf firing (LF) in African bermudagrass. A total of 109 first-generation self-pollinated (S1) progeny of C. transvaalensis ‘OKC1163’ were evaluated in a field trial in a randomized complete block design with three replications for four seasons. Significant genetic variation existed for all the traits examined, and the broad-sense heritability estimates ranged from 0.36 to 0.52 for the winter survival traits and was 0.81 for LF. Eight QTL were identified for winter survivability and two for LF in analyzing the phenotypic data on a preexisting high-density linkage map. Six of the 10 QTL were consistently identified at least in two environments. The co-location of two QTL, one for winter survival and another for LF suggests the possibility of improving both traits together. Findings provide new insights to the genetic control of winter survivability and LF, and contribute genetic resources for marker-assisted selection in turf-type bermudagrass improvement.