Explanining the vigor (relative and absolute) in seeds: the biological meaning behind the mathematician

Vanderley José Pereira

doi:10.14393/bj-v36n0a2020-48957

Abstract

Seed vigor is the totality of all properties that determine a rapid and uniform emergence and development of normal seedling under a wide range of conditions. However, the physiological quality within a seed lot is not homogeneous, generating a quality gradient between seeds. Thus, the vigor expressed by the final percentage of normal seedlings tends to underestimate the quality of the batch, considering the total number of seeds. One possible method for correcting such an effect would be to weight vigor by germination, generating an index called relative vigor. The index reflects the “success” of viable seeds in maintaining their potential under stress. In this context, this review article proposes the possibility of using a new measure for vigor and new interpretation of relative vigor, as well as providing the mathematical basis for its use.

Highlights

Seed vigor is the sum of all properties that determine the fast and uniform emergence and development of normal seedlings under different conditions
The vigor expressed by the final percentage of normal seedlings tends to underestimate the quality of the lot, because it considers the total number of seeds
The present review article talks about the possibility of using a new measure, for the vigor, and a new interpretation, the relative vigor, as well as giving the mathematical basis for its use, based on a bibliographical survey and inferences

Summary

INTRODUCTION

Seed vigor is the sum of all properties that determine the fast and uniform emergence and development of normal seedlings under different conditions. The resulting value would be the “success” of viable seeds in maintaining their germination in the face of stress An outline of this formula was made in 1995 by Egli; Tekrony, to verify the suitability of the vigor test for field emergency. The Z value, measures the synchrony, or the degree of germination overlap (RANAL; SANTANA, 2006) These adaptations for the germinal process reinvigor the viability of the new interpretation for the expression of Egli; Tekrony (1995), aiming to determine relative vigor. Relative vigor was calculated as a percentage, which, from a practical point of view, facilitates interpretation (EGLI; TEKRONY, 1995) This approach is correct because both absolute vigor and germination are given in percentages of normal seedlings and, in making the ratio, resulting in a dimensionless index converted to a percentage by multiplying by one hundred (Equation 1). In the latter case it is expected that due to sampling (BRASIL, 2009) the addition of the maximum theoretical limit will be small, so it is recommended to convert the percentage to 100% (maximum limit)

How does relative vigor relate to absolute means?

Soja Milho

Findings

FINAL CONSIDERATIONS