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Optimizing the configuration of row spacing and the dosage of 1,1-dimethyl-piperidinium chloride (DPC) in machine-picked cotton is an important means for constructing a reasonable individual and group structure for cotton and increasing yield. 'Yuanmian 11' was used as planting material and a split-plot experimental design was adopted. Under the condition of consistent density, the main plot was set with 2 plant row spacing configurations including 76 cm equal row spacing and (66+10) cm wide and narrow row spacing; the sub-plot was set with 4 doses of DPC, which were 270, 410, 550 and 690 g•hm-2, respectively. The effects of different treatments on the growth rate of the main stem of cotton, plant structure, canopy characteristics and yield components were studied. The results showed that under the same DPC treatment, 76 cm equal row spacing mode increased the daily growth rate and internode length of the main stem of cotton, increased the angle of the lower fruit branches and the length of the upper fruit branches, reduced the length of the lower fruit branches and the angle of the upper fruit branches, and had a reasonable distribution of leaf area index in the vertical direction of the canopy, which improved the number of bolls per plant, single boll weight and seed cotton yield. Under the same planting mode, the daily growth rate of the main stem of cotton, the internode length of the main stem at various parts, and the length of the first fruit internode of the upper fruit branches were all inversely proportional to the dose of DPC.The angle of fruit branches at various parts increased first and then decreased with the increase of DPC dose. Increasing the dose of DPC could reduce the leaf area index of cotton to a certain extent. Based on the comparison and analysis of cotton plant type and yield in this experiment, it was recommended that cotton with 76 cm equal row spacing configuration mode should be sprayed with 550 g•hm-2 DPC during the whole growth period, while cotton with (66+10) cm mode should be sprayed with 410 g•hm-2 DPC to obtain an ideal yield. Above results provided a theoretical basis for the selection of plant row spacing configuration and the application of chemical control management measures for machine-picked cotton in Xinjiang. [ABSTRACT FROM AUTHOR]

Optimizing the efficiency and effectiveness of light utilization is crucial for increasing cotton (Gossypium hirsutum L.) yields. However, how to increase light use efficiency and yield by improving canopy structure has not been fully verified and quantified through field trials, especially at different test sites. To explore this issue in greater depth, split-plot field experiments were conducted from 2019 to 2021 in Dongping and Jinxiang counties, Shandong, China. The effects of different planting densities and cotton varieties on the leaf area index (LAI), PAR interception rate (In), photosynthetically active radiation-use efficiency (PARUE), plant nutrient uptake, and seed cotton yield in a cropping system in which cotton was planted directly after garlic (Allium sativum L.) harvest were studied. The results revealed that increasing the planting density from the lowest value of 6.8×104 plant·ha−1 to 11.3×104 plant·ha−1 resulted in increases of 4.4–14.7 % in the cotton LAI, 2.5–12.4 % in the net photosynthetic rate (Pn), 5.0–6.8 % in the PAR interception rate, 16.0–53.2 % in the PARUE, and 5.2–13.4 % in the seed cotton yield. Notably, compared with those of Demian 15, the Lumian 532 variety presented greater LAI, Pn, PAR interception rate, PARUE, nutrient uptake, and seed cotton yield at D11.25 in the 2020 experiment in Jinxiang County. Specifically, on D11.25, Lumian 532 had the highest seed cotton yield, reaching 3939.0 kg·ha-¹. The LAI had a direct positive effect on nutrient uptake in cotton, with a value of 0.8. In addition, according to the Mantel test (p < 0.05), the primary driving factor influencing seed cotton yield was the Pn. This factor was significantly and positively correlated with the PAR interception rate and seed cotton yield (p < 0.01). Additionally, the PARUE was most significantly influenced by planting density (R=0.82, p < 0.01), with an increase of 2.0×10−4 g·MJ-¹ for each additional planting density. In conclusion, increasing the planting density of direct seeded short-season cotton plants after garlic harvesting can increase cotton light interception and utilization efficiency and improve plant nutrient uptake. This increase can result in increased seed cotton yield. Ultimately, the Lumian 532 variety performed optimally at D11.25. These results are essential for improving and managing cropping systems involving the planting of cotton in the Yellow River Basin of China and similar regions. • Denser planting increased cotton light interception (5 %–6.8 %) and utilization (16.0 %–53.2 %). • Increasing density improved both nutrient uptake and seed cotton yield (5.2 %–13.4 %). • The impact of density on photosynthetic radiation use efficiency (R=0.8) surpassed that on variety. • The Lumian 532 variety optimal at a planting density of 11.3×104 plants·ha−1. • The primary driving factor of increased seed cotton yield is the net photosynthetic rate. [ABSTRACT FROM AUTHOR]

Coronatine, an analog of Jasmonic acid (JA), has been shown to enhance crop tolerance to abiotic stresses, including chilling stress. However, the underlying molecular mechanism remains largely unknown. In this study, we investigated the effect of Coronatine on cotton seedlings under low temperature using transcriptomic and metabolomics analysis. Twelve cDNA libraries from cotton seedlings were constructed, and pairwise comparisons revealed a total of 48,322 differentially expressed genes (DEGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified the involvement of these unigenes in various metabolic pathways, including Starch and sucrose metabolism, Sesquiterpenoid and triterpenoid biosynthesis, Phenylpropanoid biosynthesis, alpha-Linolenic acid metabolism, ABC transporters, and Plant hormone signal transduction. Additionally, substantial accumulations of jasmonates (JAs), abscisic acid and major cell wall metabolites were observed. Transcriptome analysis revealed differential expression of regulatory genes, and qRT-PCR analysis confirmed the expression patterns of 9 selected genes. Co-expression analysis showed that the JA-responsive genes might form a network module with ABA biosynthesis genes or cell wall biosynthesis genes, suggesting the existence of a COR-JA-cellulose and COR-JA-ABA-cellulose regulatory pathway in cotton seedlings. Collectively, our findings uncover new insights into the molecular basis of coronatine--associated cold tolerance in cotton seedlings. • Coronatine can alleviate the damage caused by low temperature to cotton. • Coronatine promote JAs, abscisic acid (ABA), and cell wall metabolites accumulations. • Coronatine may affects JA-cellulose or JA-ABA-cellulose regulatory pathways. [ABSTRACT FROM AUTHOR]