Genetic Dissection for Maize Forage Digestibility Traits in a Multi-Parent Advanced Generation Intercross (MAGIC) Population

Abstract

Forage feedstock is the greatest source of energy for livestock. Unfortunately, less than 50% of their fiber content is actually digested and assimilated by the ruminant animals. This recalcitrance is mainly due to the high concentration of plant cell wall material and to the limited digestion of the fiber by the microorganisms. A Genome-Wide Association Study (GWAS) was carried out in order to identify Single Nucleotide Polymorphisms (SNPs) associated with forage digestibility traits in a maize Multi-Parent Advanced Generation Intercross (MAGIC) population. We identified seven SNPs, corresponding to five Quantitative Trait Loci (QTL), associated to digestibility of the organic matter, 11 SNPs, clustered in eight QTLs, associated to Neutral Detergent Fiber (NDF) content and eight SNPs corresponding with four QTL associated with Acid Detergent Fiber (ADF). Candidate genes under the QTL for digestibility of the organic matter could be the ones involved in pectin degradation or phenylpropanoid pathway. Transcription factor genes were also proposed for the fiber QTL identified, in addition to genes induced by oxidative stress, or a gene involved in lignin modifications. Nevertheless, for the improvement of the traits under study, and based on the moderate heritability value and low percentage of the phenotypic variability explained by each QTL, a genomic selection strategy using markers evenly distributed across the whole genome is proposed.

Genetics of Germination and Seedling Traits under Drought Stress in a MAGIC Population of Maize

“…The targeted phenotypic traits are considered important for the study of drought tolerance at seedling stage and in breeding programs. The germination percentage is the most representative trait at this stage, as noted by Grzesiak et al [ 55 ]. The germination rate under drought stress can indicate the germination ability of drought resistance of various varieties and lines, and root length and density are good indicators of drought tolerance in cultivated crops [ 56 ].…”

Precision Mapping of a Maize MAGIC Population Identified a Candidate Gene for the Senescence-Associated Physiological Traits

“…This multiparent population was developed as described in Butron et al (2019) and Jiménez-Galindo et al (2019) , and it is formed of 672 recombinant inbred lines (RILS) over six cycles of recombination in an eight-way cross synthetic. The diverse genetic base and the significant number of RILs allows for a high resolution of putative QTL-associated regions as shown in other studies, for example, corn borer and fusarium ear rot resistance ( Butron et al, 2019 ; Jiménez-Galindo et al, 2019 ), forage digestibility ( Lopez-Malvar et al, 2021 ), maize stover yield and saccharification efficiency ( López-Malvar et al, 2021 ), and early development in cold conditions ( Yi et al, 2020 ).…”

Different Efficient Responses of Sorghum and Maize Varieties to Different Irrigation Systems

“…Irrigation efficiency refers to the mass of dry matter or the output per unit (m 3 ) of water consumed by the plant. The total energy required for the production of the two plant species studied in the six major groups, including machine equivalent energy, fuel consumption (Erdal et al, 2007), irrigation (Hatirli et al, 2006), manpower (Ozkan et al, 2004), seed (Mokhtarpour et al, 2000), Pesticides and fertilizer (Lopez-Malvar et al, 2021). For this purpose, all inputs and outputs were converted into equivalent energy using standard conversion coefficients as shown in Table 2.…”