Registration of the sorghum multi-parent advanced generation intercross (MAGIC) B-line population ‘MBL’: A source of seed parent genetic diversity

Abstract

Multi-parent populations are capable to dissect complex quantitative traits by capturing multiallelic variation compared to biparental populations. MAGIC B-line (MBL) population is a multiparent advanced generation intercross (MAGIC) population developed at Clemson University using four diverse accessions of grain sorghum [Sorghum bicolor (L.) Moench] that are known to not restore fertility in A₁ cytoplasm. A set of 708 F₇ recombinant inbred lines (RILs) (Reg. no. MP-6, NSL 546930 MAP) were derived from the founders SC630 (PI 533937), SC605 (PI 534096), BTx642 (PI 656029), and BTxARG-1 (PI 561072) using repeated cycles of intercrossing. Each founder was carefully chosen to represent the four prominent sorghum races (kafir, guinea, durra, and caudatum) and capture important traits to segregate in the progeny, including stay-green, plant height, waxy endosperm, and plant/pericarp color. MBL and their founders were phenotypically characterized for plant/pericarp color and plant height, flowering, panicle type, grain yield, and several yield components. The entire population and their founders were genotyped using Diversity Array Technology sequencing (DArTseq) to generate 3751 quality-filtered single nucleotide polymorphisms. Genetic mapping of the MBL led to the discovery of novel marker-trait associations (MTAs) in addition to confirming several known genes. During elucidation of MTAs, there were novel genomic loci that demonstrated pleiotropic effects for agronomic, grain yield, and yield-related traits. With all founders are maintainers (B-lines) of cytoplasmic male sterility, progeny lines serve as genetic resources to improve B-line diversity, which can be limited due to a restricted number of non-restorers in Sorghum bicolor. This population can be further exploited to identify superior alleles to enrich seed parent gene pool.