The occurrence of high temperature (HT) in crop production is becoming more frequent and unpredictable with global warming, severely threatening food security.  The state of an organ’s growth and development is largely determined by the temperature conditions it is exposed to over time.  Maize is the main cereal crop, and its stem growth and plant architecture are closely related to lodging resistance, and especially sensitive to temperature.  However, systematic research on the timing effect of HT on the sequentially developing internode and stem is currently lacking.  To identify the timing effect of HT on the morphology and plasticity of the stem in maize, two hybrids (Zhengdan 958 (ZD958), Xianyu 335 (XY335)) characterized by distinct morphological traits in the stem were exposed to a 7-day HT treatment from the V6 to V17 stages (Vn presents the vegetative stage with n leaves fully expanded) in 2019–2020.  The results demonstrated that exposure to HT during V6–V12 accelerated the rapid elongation of stems.  For instance, HT occurring at V7 and V12 specifically promoted the lengths and weights of the 3rd–5th and 9th–11th internodes, respectively.  Meanwhile, HT slowed the growth of internodes adjacent to the promoted internodes.  Interestingly, compared with control, the plant height was significantly increased soon after HT treatment, but the promotion effect became narrower at the subsequent flowering stage, demonstrating a self-adjusting mechanism in the maize plant in response to HT.  Importantly, HT altered the plant architectures, including a rising of the ear position and increase in the ear position coefficient.  XY335 exhibited greater sensitivity in stem development than ZD958 under HT treatment.  These findings improve our systematic understanding of the plasticity of internode and plant architecture in response to the timing of HT exposure.

In China, farmers have increasingly adopted the direct-seeded rice (DSR). While the impacts of DSR have been investigated, there is little evidence on the impact of DSR adoption on pesticide use. In this study, the impact of DSR adoption on pesticide use is examined using data from a 2018 survey of 982 rice farmers in the Yangtze River Basin in China. The endogenous treatment-regression and switching regression models are employed to address the self-selection issue. The results show that, after accounting for the self-selection issue, the DSR adopters spend 401.72 CNY ha^-1 more on pesticides compared to the non-adopters. While DSR adoption significantly increases the use of insecticides, fungicides and herbicides, its positive impacts on insecticide and herbicide expenditures are the greatest and smallest, respectively. The robustness is confirmed by replacing the dependent variable, winsorizing the research sample and altering the estimation method. The heterogeneous analysis illustrates that DSR adoption has a greater positive impact on pesticide expenditure for farmers aged below 60 years, with at least 6 years of education, and with rice sown area less than 2 ha. Based on these findings, this study proposes that efforts should be made to enhance the complementary techniques for DSR, popularity of DSR cultivation technologies, and the socialized services. In summary, this study provides a more comprehensive view of the advantages and disadvantages of DSR with a focus on its impact on pesticide use, which has important policy recommendations for pesticide reduction.

Genetic improvement of meat production traits has always been the primary goal of pig breeding. Geographical isolation, natural and artificial selection led to significant differences in the phenotypes of meat production traits between Chinese local pigs and Western commercial pigs. Comparative genomics and transcriptomics analysis provided powerful tools to identify genetic variants and genes associated with skeletal muscle growth. However, the number of available genetic variants and genes are still limited. In this study, a comprehensive comparison of transcriptomes showed that ribosomal protein S27-like (RPS27L) gene was highly expressed in skeletal muscle and up-regulated in Chinese local pigs when compared with Western commercial pigs. Functional analysis revealed that overexpression of RPS27L promoted myoblast proliferation and repressed differentiation in pig skeletal muscle cells. Conversely, the knockdown of RPS27L led to the inhibition of myoblast proliferation and the promotion of differentiation. Notably, a 13-bp insertion-deletion (InDel) mutation was identified within the RPS27L promoter, inserted in Chinese local breeds and predominantly deleted in Western commercial breeds. Luciferase reporter assay suggested this InDel modulated RPS27L expression by influencing transcription factor 3 (TCF3) and myogenic differentiation antigen (MYOD) binding to promoter. Furthermore, a positive correlation was observed between the expression of RPS27L expression and backfat thickness. Association studies demonstrated this InDel was significantly associated with the body weight of pigs at the age of 240 days. Together, our results suggested that RPS27L was a regulator of skeletal muscle development and growth, and was a candidate marker for improving meat production traits in pigs. This study not only provided a biomarker for animal breeding, but also was helpful for understanding skeletal muscle development and muscle-related disease in humans.