Comparison of diagnostic testing with phenotypic expression of parent and hybrid Brassica varieties

Abstract

Many seed companies and producers use diagnostic testing to determine the genetic purity of their seed. Diagnostic labs, such as isoelectric focusing and isozyme electrophoresis, are able to verify a variety's genetic purity within a few days of extracting the proteins from the seed. Growout testing can also be used to determine genetic purity of a seed variety; however, it can be months before a seed company can obtain results. The purpose of this experiment was to collectively use isoelectric focusing and isozyme electrophoresis technologies with a growout method to analyze the genetic purity of parent and hybrid varieties for three Brassica oleracea species: broccoli, cabbage, and cauliflower. Two varieties were used with three variables consisting of five female, five male, and twenty hybrid seeds for each crop. A total of 180 pots were placed in a controlled environment; and benches were blocked by crop and sub-blocked by variety. Plants were cared for daily and visually inspected for phenotypic differences. Data measurements of height and leaf spread were collected weekly and final mass and weights of the yield were assessed at the end of the experiment. Tissue samples were also collected from each plant and sampled by both isoelectric focusing and isozyme electrophoresis. The comparison of the growout with lab results verified the accuracy of 98.89% for Brassica oleracea genetic purity testing. Results indicated not only accuracy but also identified useful polymorphic stains and created a nomenclature for Brassica oleracea species which can be used for future research.