Genetic variability and QTL mapping of morphological traits and inflorescence prolificacy in African bermudagrass

Abstract

AbstractAfrican bermudagrass (Cynodon transvaalensis Burtt‐Davy) (2n = 2x = 18) has unique morphological characteristics such as finer leaf blades and shorter internodes that are important to improving turf qualities (i.e., texture and density) as compared to other Cynodon species. It has been extensively used to cross with common bermudagrass (Cynodon dactylon Pers. var. dactylon) in developing high‐quality interspecific [C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] F1 hybrid cultivars for turf use. However, the molecular basis of its morphological variation is unknown. Accordingly, the objectives of this study were to estimate the heritability and identify quantitative trait loci (QTL) associated with morphological and reproductive traits. A first‐generation self‐pollinated (S1) population of 109 individuals was evaluated for plant height (PH), leaf blade width (LBW) and leaf blade length, stem internode diameter and length, and inflorescence prolificacy (IP) in a replicated field trial over three seasons (2018–2020). The broad‐sense heritability estimates ranged from 0.31 (PH) to 0.80 (IP). Twenty‐four QTL were identified and nine of them were consistent ones. Fifteen candidate genes were found at a major and consistent QTL region associated with LBW. Frequent QTL colocations were found among morphological traits and between morphological traits and IP, partially explaining the significant correlation. The findings provide critical information and resources toward understanding the genetic basis associated with morphological and reproductive traits within C. transvaalensis and could contribute to marker‐assisted selection for breeding new turf‐type bermudagrass cultivars.