Genetic Variation of Kikuyugrass in California, Hawaii, and Australia.

Kikuyugrass (Pennisetum Clandestinum Hochst. ex Chiov.) is a warm-season turfgrass that originated from east Africa.  Since its introduction into California in the 1920s, little research has been done on its genetic variation within California and abroad as a basis for improving the species.  Samples were collected throughout California from residential, private, golf course, and wild areas.  Collections of kikuyugrass were also sampled in Hawaii and Australia.  A total of 375 genotypes were collected and their genomic DNA was isolated and sent to Diversity Arrays Technology in Bruce, Australia.  An Illumina HiSeq 2500 platform with a combination of restriction enzymes was used to isolate and sequence low copy sequences from genomic DNA.  From these sequences 20,336 SNP and 12,500 SilicoDArT markers were developed and used to determine relatedness among the three collections.  All three geographic locations analyzed together show 2 major clusters with one having two sub clusters.  Genotypes from the Australian collection and from California predominantly clustered together.  The two sub clusters consist of lines created by the University of California, Riverside and the Hawaiian collection.  Small branch length among genotypes suggests a low level of polymorphism within each cluster, with larger variation seen only between the two major clusters. It appears that genetic improvement of turf-type kikuyugrass for California will require importation of germplasm from abroad.