UV COLOR SORTING TO IMPROVE BRASSICA GERMINATION

Abstract

The purpose of color sorting by fluorescence was to upgrade seed quality by removal of fluorescent coatings that were attributed to sinapine leakage from nonviable seeds. Nine seed lots (three seed lots each of broccoli, cabbage and cauliflower) were custom coated. Seed samples were pretreated prior to coating with or without 1.0% NaOCl for 10 minutes to enhance leakage. Fluorescence, as measured by fiber optic spectrometry, was expressed from 400 to 560 nm with peak emission being from 430 to 450 nm. A UV color sorter was employed to separate fluorescent (reject) from non-fluorescent (accept) coatings. The percent non-fluorescent coatings (averaged over seed lot and NaOCl pre-treatment) before and after sorting was 89.5 and 95.9, respectively. There was a six percent loss of non-fluorescent coatings after sorting (averaged over all treatments). An increase in the percent germination was recorded in 8 of the 9 seedlots following color sorting and the greatest improvement was obtained with seed lots of medium quality. The germination of three medium quality lots was increased from 10 to 15 percentage points. The average increase in germination with or without NaOCl pre-treatment was 8.2 and 5.5 percentage points, respectively. In conclusion, the combination of coating technology with seed conditioning by UV color sorting was effective in improving Brassica seed performance.