Asociation between agronomic and molecular marker variation in genotype evaluation

BALZARINI, M.; ARROYO, A.; BONAMICO, N.; DI RENZO, M.

Alemania

Simposio; International Symposium Agricultural Field Trials -Today and Tomorrow.; 2007

A series of agricultural applications of discrete discriminant analysis (DA) to combine molecular marker and agronomic data from cultivar field trials, has suggested a connection between quantitative trait loci (QTL) analysis and marker selection. The idea is to identify markers significantly associated with the classification of genotypes into groups of extreme performance regarding a given agronomical trait. In this work, we use the RELIEF-F filter instead of DA to identify DNA markers able to classify well molecular maize phenotypes in phenotypic groups defined from agronomic data of multiple-environment trials (MET). The RELIEF-F filter provided a value of relevance (discriminatory power) for each marker that facilatate marker selection. To illustrate the procedure we use a data set containing genotype evaluation of Mal de Rio Cuarto (MRC) disease in Argentina. A group of 130 maize RIL derived from a cross between a  susceptible inbreed line (Mo17) and a partially resistant inbreed line (BLS14), was evaluated for several agronomic traits involved in the calculation of disease index, in six environments. The RIL were F2:6 descendents from the early generation population where in MRC-QTL were first identified. DNA profiles were obtained for each RIL using 60 SSR markers selected over 4 maize chromosomes. The molecular variance analyses found significant statistical differences between the two extreme groups conformed for each agronomical trait. The classification of lines using the selected markers produced low cross-validation error rates. These markers were also analyzed using results from previous QTL mapping experiments for MRC disease. We conclude that candidate markers associated with agronomical performance from MET can be effectively detected using the procedure.