Exploration of the Genetic Basis of Taro Leaf Blight Resistance in Breeding Populations.

Abstract

Taro (Colocasia esculenta) is a clonally propagated root crop that is a staple of Pacific Islanders. Production of taro is reduced by the Taro Leaf Blight (TLB) disease that is present in most of the taro growing regions of the world. Genetic resistance has been identified in taro populations from Palau, Indonesia and Papua New Guinea. In this study, I explore the genetic architecture of TLB resistance in three breeding populations with the resistant material being incorporated into the existing University of Hawaii taro breeding program. A linkage map based on a F1 population using single nucleotide polymorphism (SNP) markers was developed to identify quantitative trait loci (QTL) linked with TLB resistance in laboratory assays. Sixteen QTL with major and minor effects were identified on different linkage groups. In addition to the mapping populations, 295 genotypes of taro were evaluated for yield attributes using a Hierarchical Bayesian Model. Yield data were collected for six years from 2013 to 2018, with the breeding cultivar 1025-181 being most promising in terms of yield. The QTL identified in this study can be used in Marker Assisted Selection (MAS) of taro for TLB resistance. The promising genotypes for yield and TLB resistance should be included as parents in future breeding programs.