Soybean resistance and yield response to southern root-knot nematode
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Soybean represents the largest and most concentrated segment of global agricultural trade. Despite its consistent yearly yield increment around the world, biotic stresses can limit soybean yield potential. Meloidogyne incognita (SRKN) is one of the most yield-suppressing pathogens in soybean in the United States and around the world. With limited chemical and cultural management options, the use of genetic resistance is the most efficient management approach. The major QTL on chromosome 10 is the primary source of SRKN resistance in soybean cultivars, however, limited studies evaluated its efficacy in minimizing yield suppression under field conditions. Additionally, limited QTL regulating resistance were identified in the soybean genome. Therefore, the objectives of this study were to evaluate the yield performance of SRKN resistant and susceptible soybean lines in field conditions with variable levels of SRKN pressure and perform a genome-wide association study to identify QTL regions regulating resistance. In environments with high SRKN pressure, resistant lines yielded on average 21.2 [percent] higher than the susceptible group. The presence of the major resistance QTL on chromosome 10 reduced yield losses by approximately 6-fold in comparison to the susceptible group (-0.0011 [percent] against -0.0062 [percent] per 1 SRKN second stage juvenile in 100 cm-3). Across all phenotypic inputs, a total of 37 significant SNPs that were associated with soybean resistance to M. incognita were identified on chromosomes 8, 9, 10, 13, 14, and 19. We identified nine regions across the soybean genome significantly associated with M. incognita resistance, including seven regions not previously reported in the literature.