Effects of postsilking weak‐light stress on the flour quality of spring maize

Abstract

Background and objectives The low sunlight from June to July caused by cloudy weather in Southern China has a detrimental influence on the grain yield and quality of spring maize because this period overlaps with the grain filling stage. A field trial was conducted to study the effects of postsilking shading (30% and 50% light deprivation defined as moderate sunlight [MS] and severe shading [SS], respectively, and with plants under natural sunlight as the control) on grain weight, nutrient contents, pasting, and thermal properties in 2016–2017. Zhengdan958 (ZD958) and Suyu30 (SY30) were used as materials. Findings MS and SS reduced the grain weight by 26.7% and 42.4% for ZD958 and by 17.4% and 25.7% for SY30 in 2016, respectively. In 2017, the decrease was 6.8% and 2.7% for ZD958 and SY30, respectively, and no difference was observed between MS and SS. Shading reduced the starch content and increased the protein content, and the effects were severe when a large amount of sunlight was deprived. SS increased the starch granule size in both varieties and years. MS resulted in an increase in 2016, but no increase was observed in 2017. Peak, trough, and breakdown viscosities decreased under shading. Similar reductions were generally observed between MS and SS. Shading exerted minimal effects on gelatinization and retrogradation temperatures, but the gelatinization enthalpy and peak height index gradually decreased with decreasing sunlight intensity. The retrogradation percentage increased under shading, and this increment was similar for MS and SS in 2016 and gradually intensified with increasing light deprivation in 2017. Conclusions Shading reduced starch and amylose contents and increased protein contents and starch granule size. These effects induced low peak and breakdown viscosities and high retrogradation percentage. The high viscosities and low retrograde of SY30 indicated that it has better grain quality than ZD958. Significance and novelty Shading deteriorates flour viscosity and increases the retrogradation tendency by reducing grain starch content and increasing protein content and starch granule size.

Effects of post-silking low temperature on the starch and protein metabolism, endogenous hormone contents, and quality of grains in waxy maize

“…In the present study, similar declines in PV, TV, FV, and P temp in flour were observed following two environmental LT stresses in both varieties (Table 1). Our previous study found that flour pasting properties are positively correlated with starch content in grains and negatively correlated with protein content and starch grain size (Wen et al, 2019), and this study also found similar results (Figure S2). The increase of protein content under LT stress will limit the swelling of starch in flour under heating, resulting in a decrease in flour pasting properties (Noisuwan et al, 2008).…”

“…The %R of SYN5 was higher than that of YN7 under LT treatment, indicating that the starch of YN7 is more dominant than SYN5 in retrograde tendency. The differences in the functional properties of SNY5 and YN7 grains may be related to their grain component content (Lu et al, 2014b;Wen et al, 2019). Therefore, the present study suggests that post-silking LT stress not only affects physiological and biochemical characteristics but also ultimately affects grain quality.…”

Fertilization time of slow‐release fertilizer affects the physicochemical properties of starch from spring‐sown waxy maize

“…The mean starch content in 2019 (683 mg g −1 ) was higher than that in 2018 (645 mg g −1 ) because the grain development in 2019 1). 36,37 Starch granule size The size distribution of the starch granules presented typical bimodal profiles, with the percentage of small starch granules (d < 5 μm) ranging from 8.68% to 9.02% in 2018 and from 8.88% to 9.12% in 2019 (Fig. 3).…”

Spraying exogenous hormones alleviate impact of weak-light on yield by improving leaf carbon and nitrogen metabolism in fresh waxy maize

“…However, the grain-filling stage is the key period affecting the yield and quality of waxy maize ( Lu et al., 2014 ). Weak-light stress during grain-filling stage led to yield reduction by reducing grain number and weight ( Yang et al., 2016 ; Shi et al., 2018 ; Wen et al., 2019 ), which posed a serious threat to the production safety of maize. Fresh waxy maize is the special maize with the largest planting area in China.…”