Tetrazolium Chloride Test for Spring Wheat Seedling Vigor at Low Temperatures¹

Abstract

Low soil temperature is a major environmental factor limiting seedling establishment of early sown spring wheat [Triticum aestivum (L.)]. This laboratory study was conducted to determine if a red pigment, formazan, extracted from tetrazolium chloride (TZ)‐treated embryos could be used as a rapid quantitative test to screen spring wheat cultivars for low temperature seedling vigor. The effects of several factors were considered in developing the screening technique. These were seed size, sample size, length and temperature of the imbibition period, and the correlation of formazan optical density (OD) values with vigor. Seeds of different size categories were imbibed for various time periods at test temperatures (5, 7, or 10°C) prior to the addition of TZ. Formazan was then extracted and OD readings were obtained. Vigor was estimated by measuring shoot length after growth in the dark for 20 days at 10°C or 31 days at 5°C in a water culture medium. Seedling dry weight was also taken after 20 days growth at 10°C. Test results showed that differences among the genotypes for seedling vigor were correlated with formazan OD values. The larger the seed size class the greater the TZ reduction ability. Either five or 10 seeds per genotype were shown to give good genotype separation with low coefficients of variability. Genotypic differences in TZ reduction were apparent after 4 or 5 days imbibition at 5°C or 2 or 3 days imbibition at 10°C. At 7°C, genotypic differences in TZ reduction were apparent at 3, 4, or 5 days. A 4‐day imbibition period at 7°C appeared to. offer the greatest efficiency for genotypic screening. The test promises to be a simple, comparatively rapid, and reliable method for screening wheat genotypes for low temperature seedling vigor.

Tetrazolium Test for Predicting the Seedling Vigor of Rice at Optimal and Low Temperatures

“…Tetrazolium staining has been widely used to evaluate seedling vigor in many crop species (5,9). Instead of using the topographical staining, the quantitative determination of solvent extract of formazan from the tetrazolium salt-stained embryo was also reported to be useful for estimating seedling vigor in wheat (3). Whether this technique can be used in other cereal crops is not reported.…”

Predicting potential field seedling vigour of Canadian six-row barley cultivars

“…Seeds from the CO 2 assay were removed from flasks after the last gas sample was drawn, tied in gauze pouches and placed in beakers containing 10 mL of a solution of 0.2% TZ and distilled water (method modified from Johnston et al [1986], using whole seeds instead of dissected embryos). Beakers were placed in temperature-controlled cabinets for 24 h for the 5 and 10°C assays, and 12 h for the 15 and 20°C assays with air bubbling vigorously through the solution.…”

“…One candidate technique is tetrazolium chloride staining (Kittock and Law 1968), widely applied in the seed industry for viability testing, and adapted as a quantitative method for selecting for low-temperature vigour in spring wheat by Johnston et al (1986). This technique has been successfully applied in rice by Sung and Chen (1988) who were able to identify cultivar vigour differences, with correlations as high as 0.9 between the TZ assay value and seedling dry weight when germinated at 10°C.…”