Efficacy of growth regulators in a lodging-sensitive wheat cultivar: grain yield, crop economic profitability and flour industrial quality

Abstract

Growth regulators in annual crops such as wheat are being used for reducing plant lodging. Thus, this study aimed to assess the effects of applying different growth regulators on grain yield, industrial quality of flour, and the economic viability of a lodging-sensitive wheat cultivar, namely TBIO-Pioneiro. The RDB experimental design consisted of five treatments and nine replicates. The treatments used the following regulators: trinexapac-ethyl (T1), ethephon (T2), prohexadione calcium (T3), chlormequat chloride (T4) and a control (untreated) (T5). The rates were determined according to the manufacturer’s recommendations for other crops. Plant height was reduced with application of regulators, for example, trinexapac (93.1 cm), and control (100.7 cm). This same growth regulator tested increased TGW (36.2 g) over the control (33.6 g) making plant lodging lowest (from 34%-control to about 10%-treated). Grain yields with application of growth regulators were higher than control (3.1 t ha-1), ranging from 148.9 to 158.9% (means regulator-treated of 4.8 t ha-1). Regarding grain alveograph indices, there was an increase in gluten strength (W) with the use of ethephon (309 10-4J), prohexadione (309.3 10-4J), and chlormequat (309 10-4J), compared with control (240.3 10-4J). The economic return on investment was higher than the control, of up to 35.7%. It is concluded that application of prohexadione, ethephon and chlormequat changes the gluten strength of wheat grains and that the growth regulators tested are efficient in controlling lodging, reducing plant height and increasing grain yields, thus providing productive stability and higher financial returns in wheat cropping.