Assessment of one maize hybrid lot uniformity by UPOV morphological and protein markers

Abstract

Monitoring genetic uniformity and identity is very important in maize breeding and seed production. Due to practical reasons, molecular and biochemical methods for the determination of genetic purity and uniformity should reliably reflect genetic differences associated with traditional morphological traits, even when they are not agriculturally important. A comparison of genetic purity and uniformity of one maize hybrid lot, based on morphological UPOV markers and the UTLIEF (Ultrathin-layer isoelectric focusing) method is performed in this research. Tested hybrid samples expressed uniform protein markers profiles, but on the other hand, unsatisfactory uniformity of morphological markers in the field, indicating some laches in seed production. Although the UTLIEF method, standardized by ISTA rules, provides enough accurate distinction between F1 seed and self-pollinated maternal seed, a "clean" isozyme or protein profile will not necessarily correlate with morphological homogeneity. It is most likely that the non-uniformity of the tested hybrid lot originates from the non-uniformity of one of the parental lines. Therefore, to establish where the laches occurred, it is necessary to perform post-control tests with reference samples of maize hybrid and parental lines, as well as, the insight into their official descriptions according to the UPOV descriptor. Thus, it is very important to require the deposition of referent samples of hybrids and varieties whose seed production is allowed in Serbia, as well as to have harmonised protocols for conduction of laboratory and field post-control tests.