In the face of agricultural labor shortages, reducing labor and costs in rice production while meeting demand or increasing yield is crucial for sustainable agricultural development.  Using crop straw boards and raising seedlings at a high-density can reduce labor demand and enhance rice yield.  This study investigated the effects of seeding density and transplanting age on tillering patterns, panicle formation rates, and yield to determine the optimal cultivation practices for maximizing rice yield.  Two-year field experiments were conducted in Sihong County, Jiangsu Province, China, using the japonica rice variety Nanjing 5718.  Five seeding densities (150–350 g/tray) and four transplanting ages (10–25 days) were evaluated to assess their impacts on tillering patterns, panicle formation rates, and yield.  Innovative crop straw boards were employed to enhance planting efficiency and reduce dependence on soil for raising seedlings.  This approach also lessened tillage layer destruction, promoting sustainable practices.  The results indicated that increasing seeding density significantly altered tillering and panicle formation patterns by reducing the occurrence and panicle formation rates of lower-position tillers.  Although the occurrence of middle- and high-position tillers increased, the overall number of panicles per hill decreased, especially at higher densities, negatively affecting yield.  Reducing the transplanting age promoted the emergence and panicle formation of lower-position tillers, thus mitigating these negative effects.  Specifically, compared to traditional methods (150 g/tray, 20-day seedlings), the higher seeding density (300 g/tray) and reduced transplanting age (15-day seedlings) increased total panicle number by 3.79–4.73% and yield by 3.38–5.05%.  Combining higher seeding densities with reduced transplanting ages offers significant advantages over conventional practices by enhancing resource utilization and improving tillering efficiency.  These findings provide actionable recommendations for optimizing rice cultivation practices and contribute to sustainable agricultural development.

The H9N2 subtype avian influenza virus (AIV) hemagglutinin (HA) protein is a major immunogen in which HA1 is a genetic variant and HA2 is relatively conserved.  Identifying broad-spectrum antigen epitopes targeting HA1 is crucial for vaccine design and detection.  Based on the phylogenetic and serological analyses, we identified 2 antigenic groups and 3 representative viruses: A/chicken/Jiangsu/JY040218C/2019, A/pigeon/Jiangsu/JY020616/2019, and A/chicken/Jiangsu/WX090312/2018.  An overlapping peptide library was synthesized using HA1 amino acid sequences of the viruses as templates.  Through peptide scanning of the sera against different strains of H9N2 subtype AIV, we identified peptides from 4 regions (H9-2/3, H9-20/21, H9-26, and H9-29/30/31) that demonstrated broad-spectrum reactivity.  Immunological assay results demonstrated that H9-21 (²¹⁹RIFKPLIGPRPLVNGLMGRI²³⁹), H9-26 (²⁶⁹SGESHGRILKTDLKMGSCTV²⁸⁹), and H9-30 (³⁰⁹YAFGNCPKYI GVKSLKLAVG³²⁹) effectively induced antibody generation and conferred partial protective efficacy against the parent virus JY040218C.  The results of lymphocyte proliferation and ELISpot assays indicated that peptides H9-15 (¹⁵⁹MRWLTQKNNAYPTQDAQYTN¹⁷⁹), H9-22 (²²⁹PLVNGLMGRINYYWSVLKP G²⁴⁹), and H9-23 (²³⁹NYYWSVLKPGQTLRIKSDGN²⁵⁹) could effectively stimulate the expression of interferon-gamma in peripheral blood lymphocytes of chickens immunized against different strains of H9N2 AIV.  Collectively, 5 novel cell epitopes H9-15, H9-22, H9-23, H9-26, and H9-30, including the best B cell epitope H9-26 and the best T cells epitope H9-22, were identified that could be targeted for vaccine design or detection approaches against H9N2 AIVs.

The high labor demand during rice seedling cultivation and transplantation poses a significant challenge in advancing machine-transplanted rice cultivation.  This problem may be solved by increasing the seeding rate during seedling production while reducing the number of seedling trays.  This study conducted field experiments from 2021 to 2022, using transplanting seedling ages of 10 and 15 days to explore the effects of 250, 300, and 350 g/tray on the seedling quality, mechanical transplantation quality, yields, and economic benefits of rice.  The commonly used combination of 150 g/tray with a 20-day seedling age in rice production was used as CK.  The cultivation of seedlings under a high seeding rate and short seedling age significantly affected seedling characteristics, but there was no significant difference in seedling vitality compared to CK.  The minimum number of rice trays used in the experiment was observed in the treatment of 350–10 (300 g/tray and 10-day seedling age), only 152–155 trays ha–1, resulting in a 62% reduction in the number of trays needed.  By increasing the seeding rate of rice, missed holes during mechanical transplantation decreased by 2.8 to 4%.  The treatment of 300–15 (300 g/tray and 15-day seedling age) achieved the highest yields and economic gains.  These results indicated that using crop straw boards can reduce the application of seedling trays.  On that basis, rice yields can be increased by raising the seeding rate and shortening the seedling age of rice without compromising seedling quality.