Chromatin accessibility plays a vital role in gene transcriptional regulation.  However, the regulatory mechanism of chromatin accessibility, as well as its role in regulating crucial gene expression and kernel development in maize (Zea mays) are poorly understood.  In this study, we isolated a maize kernel mutant designated as defective kernel219 (dek219), which displays opaque endosperm and embryo abortion.  Dek219 encodes the DICER-LIKE1 (DCL1) protein, an essential enzyme in miRNA biogenesis.  Loss of function of Dek219 results in significant reductions in the expression levels of most miRNAs and histone genes.  Further research showed that the Heat shock transcription factor17 (Hsf17)-Zm00001d016571 module may be one of the factors affecting the expression of histone genes.  Assay results for transposase-accessible chromatin sequencing (ATAC-seq) indicated that the chromatin accessibility of dek219 is altered compared with that of wild type (WT), which may regulate the expression of crucial genes in kernel development.  By analyzing differentially expressed genes (DEGs) and differentially accessible chromatin regions (ACRs) between WT and dek219, we identified 119 candidate genes that are regulated by chromatin accessibility, including some reported to be crucial genes for kernel development.  Taken together, these results suggest that Dek219 affects chromatin accessibility and the expression of crucial genes that are required for maize kernel development

Assessment of yield stability is an important issue for maize (Zea mays L.) cultivar evaluation and recommendation. Manyparametric procedures are available for stability analysis, each of them allowing for different interpretations. The objectiveof the present study was to assess yield stability of maize hybrids evaluated in the National Maize Cultivar Regional Trialsin southwestern China using 20 parametric stability statistics proposed by various authors at different times, and toinvestigate their interrelationships. Two yield datasets were obtained from the 2003 and 2004 national maize cultivarregional trials in southwestern China. A combined analysis of variance, stability statistics, and rank correlations amongthese stability statistics were determined. Effects of location, cultivar, and cultivar by location interaction were highlysignificant (P<0.01). Different stability statistics were used to determine the stability of the studied cultivars. Cultivarmean yield (Y) was significantly correlated to the Lin and Binns stability statistic (LP, r=0.98** and 0.97** for 2003 and 2004trials, respectively) and desirability index (HD, r=0.38 and 0.84** for the 2003 and 2004 trials, respectively). The statisticsLP and HD would be useful for simultaneously selecting for high yield and stability. Based on a principal componentanalysis, the parametric stability statistics grouped as four distinct classes that corresponded to different agronomic andbiological concepts of stability.