MAPPING FUSARIUM EAR ROT RESISTANCE USING RECOMBINANT HYBRIDS DEVELOPED FROM THE MAGIC MAIZE POPULATION

Maize is one of the most produced cereals worldwide. Many studies have been\r\nconducted to decipher the genetic basis of several traits of agronomic\r\nrelevance. In crops such as maize, where the commercial varieties are F1\r\nhybrids, the optimal populations to screen would theoretically consist of\r\nhybrids. However, researchers often use populations composed of inbred\r\nlines, which are arguably insufficient for understanding the mechanisms\r\nthat play a role in hybrid performances. In this study, we have developed a\r\nrecombinant intercross (RIX) population by crossing pairs of recombinant\r\ninbred lines (RILs) belonging to a multi-parental Advanced Generation Inter-\r\nCross (MAGIC) population to perform QTL mapping using a hybrid genetic\r\nbackground. We phenotyped 214 RIX genotypes along with the MAGIC founder\r\ninbreds for 10 agronomic traits, including Fusarium Ear Rot (FER)\r\nresistance indexes in two consecutive years. The genotypes of RIXs were\r\nreconstructed in silico starting from the corresponding RILs’ reconstructed\r\ngenotype probabilities. For this task, we used a panel of about 74K SNP\r\nmarkers obtained using Single Primer Enrichment Technology (SPET).\r\nResults of the QTL mapping in the hybrid population revealed several\r\ngenomic regions associated with agronomic traits and FER resistance.\r\nSuggestive candidate genes were identified in the mapped intervals. The\r\nunderstanding of their role is currently ongoing. Our findings represent a\r\nproof-of-concept that RIX populations are potentially outstanding materials\r\nto understand the genetic control of complex quantitative traits in hybrid\r\ngenetic backgrounds. This kind of resource and the information gathered\r\nwould provide a future platform to support and accelerate maize improvement.