Oil Yield Components of Maize Crops Exposed to Heat Stress during Early and Late Grain‐Filling Stages

Abstract

Heat stress frequently limits grain yield of summer crops. Most research on maize (Zea mays L.) has analyzed heat stress effects on crop physiology and kernel set but little attention has been given to kernel weight and its composition. The objectives of this work were (i) to assess the response of maize oil yield components (kernel number and weight, embryo oil concentration, and embryo/kernel ratio) to postflowering heat stress and (ii) to explore changes in the sensitivity to this constraint across developmental stages and genotypes. Hybrids with different kernel types (flint, popcorn, and semident) were exposed to contrasting temperature regimes (nonheated and heated: air temperature at ear level > 35°C) during early or late stages of the effective grain filling. Oil yield was affected by early (up to −60%), and to a lesser extent, late (up to −40%) heat‐stress episodes. These effects were mediated by lighter kernels (r2 = 0.94; P < 0.001) and lower kernel oil concentrations (r2 = 0.80; P < 0.001). Reductions of kernel weight were related to shorter grain‐filling periods (r2 = 0.48; P < 0.01), and those of kernel oil concentration were mainly associated with lower embryo oil concentrations (r2 = 0.64; P < 0.001). Kernels of semident hybrids were the most prone to alter their weights and oil concentrations in the face of a wide range of heat stress intensities. Variations in kernel oil concentration due to high temperature became notorious when kernel weight reductions were larger than 20%.

Climate Variability and Change in Bihar, India: Challenges and Opportunities for Sustainable Crop Production

“…This also indicates that for every 1 • C rise in temperature, the yields of wheat soybean, mustard, groundnut and potato would decline by 3-7% in India [49]. Maize is also highly susceptible to heat stress during the reproductive stage [7,[50][51][52], and it is reported that each degree increase in a day where the temperature exceeds 30 • C reduces the final yield of maize by 1% under favorable growing conditions, and by 1.7% under drought-stressed conditions [53]. This shows that heat stress will be a major climate risk for crop production across Bihar, particularly for winterand spring-sown crops when higher temperatures coincide with the reproductive phase of the crops.…”

Heat Stress during Grain Filling Modifies Kernel Protein Composition in Field‐Grown Maize

“…Treatments included a combination of four maize hybrids (H) with distinctive endosperm types (Flint: orange-flint; Pop: popcorn; Te: temperate semi-dent, and TeTr: temperate × tropical semi-dent) and two temperature regimes (TR) applied at daytime hours (non-heated control and heated) during two different growth stages (GS) of the effective grain-filling period (early and late) of 15-d duration. More details about the crop husbandry can be found in Mayer et al (2014). In both Exp, a single stand density of 9 plants m -2 was used.…”

“…Kernel starch or protein concentration (in mg g -1 ) was expressed on a dry weight basis. More details about TRs can be found in Table 1 in Mayer et al (2014). After near infra-red transmittance analysis, at least a 20-g bulk of kernels from each sample was used to determine individual endosperm weight.…”

“…everta), and semi-dent (ssp. More details about the heating system can be found in previous works (Cicchino et al, 2010a;Mayer et al, 2014;Rattalino Edreira et al, 2011). Fig.…”

Yield of forage, grain and biomass in eight hybrids of maize with different sowing dates and environmental conditions

“…These results are consistent with previous reports that indicated that rainfall directly influenced the total production of maize due to increases in the distribution, density and depth of the roots (37) . Moreover, extreme temperatures affect directly the grain weight (38,39) and yield (40)(41)(42)(43) . Heat stress reduced maize grain weight due to proportional losses in grain composition (starch, protein and oil contents) and due to its direct effect during the grain-filling period, which caused a cessation of grain filling (43)(44) .…”