New approaches to seed vigor testing

Abstract

Among the principles used for the evaluation of seed vigor, two approaches are predominant: seed resistance to stresses and the direct or indirect identification of the "current" state of the seeds, e.g., enzymatic activity, integrity of the cellular membranes, growth parameters. In this presentation recent innovations are discussed in procedures for seed vigor evaluation emphasizing the methodologies of accelerated aging with salt saturated solutions, controlled deterioration and potassium leachate tests. These tests, performed at seed the laboratory of ESALQ/USP, in function of their simplicity and efficiency, deserve the attention of seed technologists.

Electrical conductivity testing of corn seeds as influenced by temperature and period of storage

“…The lots used also showed at least 97% germination, i.e., above the minimum standard established (85%) for certified corn seeds in Brazil. On this basis, for lots with similar germinability, the identification of differences in physiological potential has become the basic objective for vigor tests (Marcos-Filho, 1998).…”

“…Although these tests are internationally standardized for these two species, they continue to require adjustments of methodology for application to other species; their efficiency in determining seed vigor of other species also needs additional research (Marcos-Filho, 1998). …”

Vigor-S, a new system for evaluating the physiological potential of maize seeds

“…In this respect, in addition to minimizing the interference of the analyst to make corrections of nondemarcated parts of the seedlings and reduce the time of analysis, the Vigor-S system showed the possibility for better utilization of the results obtained from the same evaluation, automatically supplying the lengths of the primary root, the shoot, and the seedling in total, as shown in Figures 2A and B. Consequently, it is a more detailed and precise evaluation, which, among others, is an important argument towards the acceptance of the system by seed analysts (McDonald, 1975;Hampton, 1993;Marcos-Filho, 1998). The SVIS showed significant higher precision when compared with manual measurements of seedlings, as reported by Hoffmaster et al (2003).…”

Assessment of Potato Mother Tuber Vigour Using the Method of Accelerated Ageing

“…In this test, seeds are exposed to two stress factors: high temperature and high air humidity. Its modified version for small seeds of other plant species is an accelerated ageing test in a saturated salt solution (SSAA) (Rodo and Marcos-Filho, 2003;Contreras and Bardos, 2005) and a controlled deterioration test (CD) (Marcos-Filho, 1998;Dąbrowska et al, 2000;Rodo and Marcos-Filho, 2003;Grzywacz and Orzeszko-Rywka, 2007).…”

“…They can be divided into three groups: tests based on germination, including the modernized form based on a computer analysis of digital photographs of germinating plants (Sako et al, 2001;Oakley et al, 2004), physiological and biochemical tests (Marcos-Filho, 1998;Carvalho and Marcos-Filho, 2002) and complex tests (Grzywacz and Orzeszko-Rywka, 2007). Since 1950 more than 60 different tests have been proposed but the International Seed Testing Association (ISTA) Committee for Vigour Evaluation concentrated mainly on nine of them (Grzywacz and Orzeszko-Rywka, 2007); that is, growth tests, cold-test, cool-test, complex stress vigour test, Hiltner test, accelerated ageing test, controlled deterioration test, electric conductivity test and tetrazolinum test.…”