Abstract
BackgroundThe identification of lines resistant to ear diseases is of great importance in maize breeding because such diseases directly interfere with kernel quality and yield. Among these diseases, ear rot disease is widely relevant due to significant decrease in grain yield. Ear rot may be caused by the fungus Stenocarpella maydi; however, little information about genetic resistance to this pathogen is available in maize, mainly related to candidate genes in genome. In order to exploit this genome information we used 23.154 Dart-seq markers in 238 lines and apply genome-wide selection to select resistance genotypes. We divide the lines into clusters to identify groups related to resistance to Stenocarpella maydi and use Bayesian stochastic search variable approach and rr-BLUP methods to comparate their selection results.ResultsThrough a principal component analysis (PCA) and hierarchical clustering, it was observed that the three main genetic groups (Stiff Stalk Synthetic, Non-Stiff Stalk Synthetic and Tropical) were clustered in a consistent manner, and information on the resistance sources could be obtained according to the line of origin where populations derived from genetic subgroup Suwan presenting higher levels of resistance. The ridge regression best linear unbiased prediction (rr-BLUP) and Bayesian stochastic search variable (BSSV) models presented equivalent abilities regarding predictive processes.ConclusionOur work showed that is possible to select maize lines presenting a high resistance to Stenocarpella maydis. This claim is based on the acceptable level of predictive accuracy obtained by Genome-wide Selection (GWS) using different models. Furthermore, the lines related to background Suwan present a higher level of resistance than lines related to other groups.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-016-0392-3) contains supplementary material, which is available to authorized users.
Highlights
The identification of lines resistant to ear diseases is of great importance in maize breeding because such diseases directly interfere with kernel quality and yield
The inbred lines were clustered into distinct genetic groups through a Principal Component Analysis (PCA) analysis based on the relationship data
Subgroups Amarillo Dent, Tropical Flint and Suwan, which were clustered in the tropical genetic group in the principal component analysis (PCA), were differentiated from the Non-Stiff Stalk Synthetic (NSSS) and Stiff Stalk Synthetic (SSS) groups by the hierarchical clustering technique
Summary
The identification of lines resistant to ear diseases is of great importance in maize breeding because such diseases directly interfere with kernel quality and yield. Among these diseases, ear rot disease is widely relevant due to significant decrease in grain yield. Ear rot may be caused by the fungus Stenocarpella maydi; little information about genetic resistance to this pathogen is available in maize, mainly related to candidate genes in genome. The harmful economic impact of this disease increases every year and is driven by increases in the use of irrigated areas as well as by the use of no-tillage systems These factors contribute to the propagation and survival of S. maydis in farming areas because of its necrotrophic nature. Ear rot occurs in both tropical and dos Santos et al BMC Genetics (2016) 17:86 temperate regions; it is a disease of global importance [4, 36]
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