Predicting seedling emergence of cabbage and onion using vigour tests

Abstract

Predicting seedling emergence using standard and non-standard germination temperatures, standard accelerated ageing (AA) and saturated salt accelerated ageing (SSAA) tests, were investigated. Germinations were performed at temperatures of 10o, 20o, 20o/30o and 30oC for cabbage (Brassica oleracea var. capitata L.) and 10o, 15o, 20o and 30oC for onion (Allium cepa L.). Seeds were aged using relative humidities of 32% (RH32), 43% (RH43), 75% (RH75) and 100% (RH100). Emergence trials were conducted at a range of temperatures (winter, 15o/25o and 30oC) and growth media. Most SSAA vigour tests were useful in differentiating seed lots based on their physiological stage of deterioration. In the SSAA tests, the seed moisture content remained below 14% and no fungal growth occurred. For cabbage, highly significant correlations were obtained between 10oC and RH32 and all emergence trials. For onions highly significant correlations with emergence percentage were obtained with germinations at 15o and 30oC. Mean germination time (MGT) and germination energy (GE) were valuable in categorising seed lots with moderate vigour levels, however, only GE revealed good correlation with winter emergence trial of onions.