Differences in the field emergence of seed lots with high laboratory germination or in germination after storage are referred to as seed vigor (Dornbos, 1995; TeKrony, 2003), a concept that comprises various aspects of quality and indicates the stage of seed deterioration.
Low-vigor lots (i.e., highly deteriorated) having poor field emergence may not necessarily be detected by standard germination. Vigor tests thus provide additional information on the relative emergence potential and longevity of seed lots (Powell and Matthews, 2005; TeKrony, 2003). Several such tests have been used to indicate emergence potential and longevity in crop seeds among which controlled deterioration (CD) and accelerated aging (AA) are widely used (Hampton and TeKrony, 1995). Both these tests are based on differentiating seed lots by testing their germination after a period of controlled aging. Standard aging conditions proposed for a number of crop seeds in CD were 45 °C and 20% mc for 24 h (Matthews, 1993) and in AA at 41 to 43 °C for 48 to 72 h (Hampton and TeKrony, 1995).
Although various studies have been conducted in cucurbit seeds (Pesis and Ng, 1983; Torres and Marcos-Filho, 2005), no consistent aging environment has been proposed for predicting cucurbit seed longevity. These studies compared the vigor of seed lots but did not correlate the results with emergence and longevity. Recently, we identified vigor test regimens that were well correlated with field emergence potential (Mavi and Demir, 2007a, 2007b), but these were not evaluated as predictors of longevity.
The use of transplanted modules in cucurbit production places more emphasis on high germination to maximize the efficiency of module production. If carryover seeds are used for transplant production, the vigor may be lower, although the standard germination remains high. Rapid emergence and uniform seedling growth are important attributes in modular plant production and they have also been shown to depend on seed vigor in peppers (Basak et al., 2006) and Brassica spp (Matthews, 1980; Powell et al., 1991). Therefore, information about the vigor of the seed lots before storage is valuable for producers. Several studies as mentioned have ranked the vigor of cucurbit seed lots by means of CD and AA tests, but there is little work to correlate these tests with seed storage potential. The work described here was conducted to fill this information gap and thus improve the management of seed stocks for the benefit of seed companies and plant producers. The objective of the study was then to find the optimum CD and AA duration to rank the seed lots and to correlate laboratory germination (radicle emergence) after AA and CD test with relative storage longevity.
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