Canola Seed Vigour Ethanol Test

Seed germination, seedling emergence and crop establishment are important aspects of canola production, and are the main components of seed/seedling vigour. A major concern of seed businesses and canola growers alike is loss of seed vigour that may go undetected before planting. Two vigour assays, based on off-gassing of ethyl alcohol from poor vigour seed, are being developed. They are a simple colour test that has been designed for on-farm use, and a technique using a hand-held gas monitor that will be suitable for various applications. Neither technique requires laboratory facilities or training. Assays with both techniques accurately distinguished between highand low-vigour untreated seed. Preliminary work with treated seed is promising. The assays, which normally can be completed in 24 h, can be run at ambient temperatures varying from 19 to 27 °C (66 to 81 °F) and can be used to test seed that is 4.5 to 10.5 % moisture. Hybrid, non-hybrid, genetically modified and mutagenically modified genotypes appear to be equally suitable. Introduction Seed germination, seedling emergence, and crop establishment are important aspects of agricultural and horticultural production, and are important components of seed/seedling vigour. These factors are related to early growth of the crop, and may be related to resistance to early-season stresses and final yield. A major concern of growers is that deterioration of some seed lots, leading to loss of vigour, may be undetected before planting. Current vigour tests vary in reliability and in their applicability to individual crops. Canola is one crop for which a reliable vigour test is not available. Figure 1. Highand low-vigour lots of AC Excel grown hydroponically for 7 d after beginning of seed water uptake (imbibition). High vigour Low vigour Canola seed/seedling vigour can be readily demonstrated by differences in fresh seedling biomass (Figure 1). Relatively little has been published about vigour tests for canola. Germination percentage of seeds in a standard test correlated poorly with field performance, whereas germination after controlled deterioration correlated significantly with plant growth and final yield (Larsen et al. 1998). Thompson, Elliott and Gusta (1999-2000) reported recently that 1) 24-h germination correlated positively with field emergence; 2) smooth spherical dark seed performed better in vigour tests than misshapened, damaged or light-coloured seed; and 3) water uptake by canola seed was correlated with seedling growth. Last year at this conference the need for and interpretation of canola seed vigour tests were discussed (Button 2002) During imbibition, seeds undergo a period of anaerobic metabolism during which ethanol and acetaldehyde are produced. Fairly soon, most seeds shift to aerobic metabolism and the production of ethanol and acetaldehyde drops dramatically or ceases. However, it appears that seeds