Development of Multi-Parent Advanced Generation Intercross (MAGIC) Mapping Population for QTL Analysis in Rice

Abstract

A major advantage for researchers in plant and animal genetics lies in the ability to create experimental populations. Such populations mix well characterized founder genomes in controlled pedigrees, and facilitate the investigation of both the genome itself and its relationship with traits and the environment. Traditional experimental populations combine the genomes of two parents with contrasting phenotypes to identify regions of the genome affecting the trait. However, each of these populations captures only a small snapshot of the factors affecting the trait due to the narrow genetic base. It is only possible to detect those genomic regions which differ between the two founders, and all alleles occur with high frequency in the population. Recently, a multi-parent advanced generation intercross (MAGIC) strategy has been proposed to interrogate multiple alleles and to provide increased recombination and mapping resolution. The main objective of developing MAGIC populations is to promote intercrossing and shuffling of the genome, thus increased precision and resolution with which QTLs can be detected due to the increased level of recombination. The Global MAGIC is an attempt to combine traits from several gene pools that have been adapted to different environments. In addition to being a source of potential novel variation, the Global MAGIC population provides useful materials for studying the relative contributions from different crop ecotypes and the level of recombination among exploited genomes constituting this population. An eight Parent-based rice MAGIC population was initiated to develop by employing 2-way, 4-way and 8-way cross along with 8-way intercross hybridization. Nonetheless, the 2-way (Single cross), 4-way (Double cross hybrid) cross has completed during the first year of research program (2018-2019) and subsequently, 8-way cross giving rise to 2 sets (8-wcp set1) having genome ABCDEFGH and 8-wcp set-2 with genome EFGHABCD) of 8-way cross F1 genotypes has accomplished at Aman season of second year (2019-2020) of the project. The eight-way crosses of set 1 (8-wcp set-1) were further intercrossed (Boro 2019) with the reciprocal eight-way crosses set 2 (8-wcp set -2) for establishing altogether 85 eight-way intercross combinations (ABCDEFGH/EFGHABCD) and then, we render this 1-85 group as BUMpop (Bangabandhu University Mapping Population). Progeny from each of the eighty-five 8-way intercrosses were grown, keeping ~ 4 offspring per cross constituting the population size as 85 × 4 = 340 lines. The seeds of BUMpop were progressed to the F6 generation via single seed descent (SSD) method in the field.