Discrimination of individual seed viability by using oxygen consumption technique and headspace gas chromatography-ion mobility spectrometry

It is crucial to identify and select high-quality seeds for improving crop yield. The purpose of this study was to improve the selection of crop seeds for separating vital seeds from dead seeds, by predicting the potential germination ability for each seed, and thus improve seed quality. The oxygen consumption (Q) of seed and the headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) were evaluated for identifying single seed viability. Firstly, the oxygen consumption technique was the hope, for the difference was found among values relative to respiratory characteristics across seeds vital or not, in final oxygen consumption (Q₁₂₀), which was achieved not only on sweet corn seeds but also on pepper and wheat seeds. Besides, a new variable, Qₜ, was established to shorten the measuring process in the Q2 procedure, which was significantly related to the viability of individual seeds. To minimize seed damage during measurement, the timing for viability evaluation was pinpointed at the 12th, 6th and 9th hour for pepper, sweet corn, and wheat seeds based on the new variable concerning oxygen consumption (Q₁₂, Q₆ and Q₉), respectively. The accuracies for viability prediction were 91.9, 97.7 and 96.2%, respectively. Dead seeds were identified and hence discarded, leading to an enhancement in the quality of the seed lot regarding an increase in germination percentage, all from 86.6, 90.9, and 53.8% to 100%. We then tried the HS-GC-IMS to determine the viability of single sweet corn seed, for corn seed has a heavier weight to make the volatile gas components most likely to be detected. A total of 48 peaks were identified, of which 38 target compounds were characterized, including alcohols, aldehydes, acids and esters. However, there were no significant difference between the vital and dead seeds, due to the trace amount volatile composition difference among individual seeds. Furthermore, the PCA based on the signal intensity of the target volatile compounds obtained lost its effectiveness, unable to distinguish those two types of sweet corn seeds. These strategies can provide a reference for rapid detection of single seed viability.