EFFICIENCY OF UTILIZATION OF ASELECTION INDEX IN ASSESSMENT OF DRYDOWN OF CORN GENOTYPES (Zea mays L.)

Utilization of a reliable, large scale, fast, non-destructive methods for assessing the speed of corn grain dry-down rate (DDR) (speed of loosing water from grain between physiological maturity and harvest) in early stages of the breeding program, to identify real differences among genotypes, is proposed. Non-destructive determinations of the grain moisture of individual plants with a wooden moisture (Voltcraft FM-200 Humidity meter) were performed for a large number of genotypes, hybrids and inbred lines from Romanian Pioneer corn breeding program, during 2010-2012. Calibration curves (issued on the basis of successive determinations of the grain moisture by using in parallel the wooden moisture and standard gravimetric method) were used to transform the wooden moisture readings in estimated% grain moistures (EPGM). A synthetic selection index (DDIND), represented by the slopes of the linear regression line between EPGM and measurement timing were computed. DDIND computed as describe above was used to compute ANOVA analysis. Preliminary results showed that DDIND had a large degree of precision; a significant part of the DDIND variation was due to genotypic variations in all analyzed experiments, suggesting that real differences in genotype with regard to DDIND could be detected by this method. Additional studies are necessary to determine if selection on the basis of DDIND would results in releasing of superior commercial hybrids with fast DDR.