Effects of delayed sowing and planting date on starch RVA profiles of different <italic>indica</italic> hybrid rice in the sub-suitable region of ratoon rice

Abstract

<p indent=0mm>In order to explore the effect of sowing and planting date on the RVA profiles characteristics of <italic>indica</italic> hybrid rice, a two-factor split plot design with two <italic>indica</italic> hybrid rice varieties (Chuanyou 6203 and Yixiangyou 2115) and two sowing and planting date was conducted in Longchang and Qianwei in Sichuan province. The results showed that ecological condition, sowing and planting date, variety, and the interaction between sowing and planting date with ecological condition and variety had marked impact on the starch RVA profiles characteristic values of <italic>indica</italic> rice. In the sub-suitable region of ratoon rice, delayed sowing and planting date decreased the temperature, sunshine hours, and rainfall during grain filling period of rice, which resulted in the reduction in peak viscosity, hot paste viscosity, cool viscosity and breakdown viscosity, but increased in setback viscosity and peak time. Compared to ratoon rice, late sowing and planting date treatment increased peak viscosity and breakdown viscosity, and decreased cool viscosity, setback viscosity, consistence viscosity, peak time, and pasting temperature. The effect of sowing and planting date on the RVA spectrum of starch was different with ecological condition. Sowing and planting date leaded to greater variation in peak viscosity, setback viscosity, and breakdown viscosity in Qianwei compared with that of Longchang. Compared with Chuanyou 6203, sowing and planting date had greater influence on the peak viscosity and breakdown viscosity of Yixiangyou 2115. Overall, the starch RVA profiles characteristics of delayed sowing and planting date treatment was closer to the ratoon rice, which resulted in better cooking and eating quality of rice.