Molecular Plant Breeding 2025, Vol.16, No.4, 211-220 http://genbreedpublisher.com/index.php/mpb 216 Figure 2 Effects of different high-temperature stress regimes on kernel characteristics of waxy maize (Adopted from Guo et al., 2021) Image caption: (A) Schematic diagram of the different temperature treatments. NN, normal day/normal night; NH, normal day/hot night; DH, hot day/normal night; and DNH, hot day/hot night. The stress treatments were imposed during the period 1~15 d after pollination (DAP), and the plants were kept under NN conditions at all other times. (B) Changes in kernel dry weight and (C) and kernel water content with time. (D) Starch content of grains at maturity. Data are means (±SE) of n=3 replicates. Significant differences compared with the NN were determined using Student’s t-test: *P<0.05 (Adopted from Guo et al., 2021) 7.2 Gene expression changes under different sowing-density scenarios The changes in sowing time and planting density can affect whether pollen release is synchronized, whether nutrient distribution is balanced, and the distribution of hormones, all of which can influence the expression of genes related to kernel development. Multi-omics studies have found that the gene expression patterns of kernels vary greatly 10 and 25 days after pollination, involving functions such as starch synthesis, hormone signaling, and some transport proteins (Guo et al., 2021). At the junction of the kernel and the parent, some transcription factors, such as MADS-box, control the transport of sugar, amino acids and ions, thereby affecting whether the kernel can fill (He et al., 2024). In addition, an epigenetic modification called N6-methyladenosine (m6A) can also affect the expression of genes related to kernel development, thereby influencing the size and quality of kernels (Wu et al., 2024). 7.3 Molecular markers related to pollination synchrony and kernel traits Whether pollination is synchronized will directly determine the quantity of kernels and whether their development is uniform. From a molecular perspective, transcription factors of the BES1/BZR1 family (such as ZmBES1/BZR1-5) are related to kernel size and weight, and their SNP loci can also serve as molecular markers for improving kernel traits (Sun et al., 2020). In addition, the KIL1 gene in the NAC family controls the senescence of filaments, affects the length of the pollination window, and thereby influences the seed setting rate (Ishka, 2022). During kernel development, genetic changes related to glucose metabolism, hormone signaling and transport proteins can also be used as molecular markers to help select high-yielding maize varieties with coordinated kernel development (He et al., 2024). 8 Case Study: Field-Based Evaluation of Sowing Date ×Density on Glutinous Maize Yield 8.1 Site and hybrid description In field trails, typical plots from different regions are usually selected and conducted together with multiple hybrid varieties of glutinous maize. There are obvious differences among different hybrids in terms of tillering ability, panicle position differentiation and kernel development. Some varieties have many tillers and panicles. These characteristics can help them maintain relatively stable yields in low-density or adverse environments (Parco et al., 2022; Rotili et al., 2022). 8.2 Experimental design and pollination synchronization results In the experiment, different sowing times were set, such as early sowing, mid-sowing and late sowing. Several planting densities were also combined, such as 4 or 8 plants per square meter. The purpose of doing this is to
RkJQdWJsaXNoZXIy MjQ4ODYzNA==