Resumo

GAIDO, Z. A.  e  DUBOIS, M. E.. Effects of heat stress on breadmaking quality of wheat: progenies with different levels of sensitivity. Agriscientia [online]. 2008, vol.25, n.2, pp.89-96. ISSN 1668-298X.

Periods of heat stress during the grain filling have been observed to influence the baking quality of wheat with a decline in dough strength. The objective of this study was to evaluate the effects of heat stress on bread-making quality of wheat and to identify progenies with different levels of sensitivity. Sixty wheat progenies were analyzed for three consecutive years. The dates of sowing, heading, harvests and the daily maximum temperatures were taken. For each sample, the total heat stress (ETT), defined as the cumulative number of degrees of the episodes of heat stress (at least two consecutive days with temperatures > 30 ºC) happened during the grain filling period, was determined. Three levels of ETT were determined: low, medium and high. The grain protein (PTG), humid gluten (GH) and mixograph variables were measured. The analysis of variance and the Pearson correlation coefficient were performed. For medium and high levels of ETT, PTG, GH and mixograph peak height in all the samples decreased, while the mixograph dough development time (TD_mix), to related with dough strength, diminished in 62% of the samples. This way, genotypes that possess tolerance to heat stress and the greater stability of dough quality were identified.

Palavras-chave : Bread wheat; Bread-making quality; Grain filling period; Heat stress; Heat sensibilit.

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