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Comparison of Different Methods for Phenotyping Preharvest Sprouting in White-Grained Wheat

¹Department of Plant Sciences and Crop Development Centre, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, Canada S7N 5A8. ²Corresponding author. Phone: +1 306 966 4969. Fax: +1 306 966 5015. E-mail address: ravi.chibbar@usask.ca

The objective of this study was to identify a suitable method for phenotyping preharvest sprouting (PHS) resistance in white bread wheat. Forty doubled-haploid (DH) lines derived from a cross between two white-grained spring wheats (Triticum aestivum L.) cultivar Argent (nondormant) and wheat breeding line W98616 (dormant) were evaluated for germination frequency, Falling Number (FN), and α-amylase activity in dry and water-imbibed seeds and spikes. The α-amylase activity in dry seeds or spikes did not differ significantly between parent lines or lines of the DH population. Wetting of seeds or spikes for two days caused a five- to sevenfold increase in α-amylase activity but only in Argent and the nondormant subgroup (49–100% germination) of the DH lines. A positive association (r = 0.60***) was detected between germination frequency and α-amylase activity in imbibed seeds and spikes. Germination frequency could not be correlated to FN or α-amylase activity in dry-harvested seeds. FN showed a strong correlation (r = –0.83***) to α-amylase activity in the dry-harvested seeds but could not be correlated to α-amylase activity in the imbibed seeds. The germination test was the most reliable method for measuring PHS resistance because seed dormancy provides potential resistance to PHS, whereas high α-amylase activity may occur in grains without causing PHS.