Sowing Date in Egypt Affects Chia Seed Yield and Quality

Abstract

Core Ideas Bivariate linear mixed models should be used to estimate correlations between traits in designed experiments. The fourth sowing date resulted in highest seed yield and harvest index with high PUFA/SFA ratio and content of PUFA and protein. Under later sowing, protein content and saturated fatty acids increased whereas oil content and PUFA decreased. Sowing chia in Egypt is recommended between the middle and end of September to achieve higher yields and good quality. Chia (Salvia hispanica L.) has recently been rediscovered as functional “superfood” for human nutrition. Chia is a short‐day plant and it naturally grows in tropical and subtropical environments. It can cope with water stress and thus could also be cultivated in arid regions. The aim of this study was to determine the suitable sowing date (SWD) for chia in Egypt. Therefore, the effect of six different sowing dates (August to October) on agronomic traits like seed yield (SY), plant height, seed yield per plant (SYP), harvest index (HI) and quality traits such as protein, oil, mucilage content, and fatty acid profile was evaluated. The last SWD resulted in a significantly lower SY (125.91 kg ha−1), HI (0.11), oil content (27.08%), content of polyunsaturated fatty acids (PUFA) (81.46%), and ratio of PUFA to saturated fatty acids (7.24), but higher thousand kernel weight (TKW) (1.51 g), protein content (26.03%), and higher content of saturated fatty acids (SFA) (8.21%) compared with the other SWDs. The maximum observed SY (664.94 kg ha−1) was recorded for SWD 4 (3 Oct. 2015). In this study, the thermal time at onset of flowering and the corresponding prevailing daylength showed a strong positive relationship for daylengths higher than 10.4 h that corresponded to about 600°C d (between SWD 5 and 6). Considering the obtained results and the possible risk of high temperature stress for very early sowings (SWD 1 and 2), sowing dates between middle and end of September are recommended to achieve a marketable seed quality and higher yields.