Application of Exogenous 6‐benzyladenine at the Silking‐Stage Improves the Starch Quality of Waxy Maize Suffering from Post‐Silking Drought Stress
Zhenggang Huo, Huan Yang
Abstract
Abstract The application of exogenous 6‐benzyladenine (6‐BA) can mitigate plant responses to drought stress. The effects of spraying exogenous 6‐BA at the silking‐stage on the waxy maize starch physicochemical properties under post‐silking well‐watered and drought conditions are studied using Jingkenuo2000 (JKN2000) and Yunuo7 (YN7) as materials. The starch granule size in response to drought is enlarged in JKN2000 but reduced in YN7. However, 6‐BA application enlarges the starch granule size of both hybrids under drought conditions. Under both water conditions, 6‐BA application increases the proportion of high‒molecular weight amylopectin branch chains in both hybrids. The amylopectin chain‐length and relative crystallinity in response to 6‐BA application are dependent on hybrid and water condition. The pasting viscosities of both hybrids are improved by 6‐BA application under well‐watered conditions. However, the peak viscosity under drought is improved in JKN2000 and unaffected in YN7 by 6‐BA application. Under drought, 6‐BA application does notaffect the gelatinization characteristics but decreases the retrogradation enthalpy and percentage of both hybrids. In conclusion, exogenous 6‐BA application at the silking‐stage can improve the pasting viscosities under well‐watered conditions and reduce the retrogradation percentage under drought conditions, thereby alleviating the negative influence of post‐silking drought in waxy maize production.