Quantitative trait loci associated with soybean tolerance to low phosphorus stress based on flower and pod abscission

With 2 figures and 5 tables Abstract Low phosphorus (P) stress limits soybean production. A population of 152 recombinant inbred lines (RILs) derived from a cross between ‘Bogao’ (P sensitive variety) and ‘Nannong 94-156’ (P tolerant variety) and 248 markers were used to map quantitative trait loci (QTLs) for low-P tolerance. Two pot culture trials were conducted and low-P tolerance evaluated using flower and pod abscission rate under low P and normal P. Conditional QTLs and epistasis for tolerance to low P were also analysed. A conditional QTL (near Satt274) on linkage group D1b+W was identified which conferred low-P tolerance epistatic effects and coincided with previously discovered QTLs. An additive QTL, qFARLPG-07, for flower abscission rate under low P was detected with a LOD score of 7.79 and explained 32.3% of phenotypic variation. It was detected at the same interval of the corresponding QTL for other traits across years. This region coincided with two conditional QTLs (cqFARLPG-07 and cqPARLPG-07), from the P-tolerant parent ‘Nannong 94-156’ related to low-P tolerance. These results will provide a basis for further fine mapping and eventual cloning of the P-efficiency genes in soybean.