[Objective] This research aims to study the effects of delayed sowing on cotton root growth and development characteristics and yield, so as to provide a basis for the timely sowing of cotton in the cotton planting area of the Yellow River Basin. [Methods] A field experiment was carried out at Weixian Experimental Station of Hebei Agricultural University from 2022 to 2023. Two treatments were set as conventional sowing date (15 April) and delayed sowing date (1 May). And the effects of delayed sowing on the root distribution, root growth rate, root-shoot ratio, dry matter accumulation, and yield of a cotton variety Jinongda 23 were analyzed. [Results] Compared with the conventional sowing date, under the delayed sowing condition, the maximum growth rate of cotton root length and root biomass increased by 2.92-5.35 cm·d-1 and 0.40-0.76 mg·d-1, respectively. The proportion of cotton roots in deep soil increased, with root length and biomass in the 30-60 cm soil layer increased by 2.99-3.55 percentage points and 3.94-4.42 percentage points, respectively. There was no obvious difference in aboveground biomass and root-shoot ratio in the late growth stage of cotton. The boll capacity of root system significantly decreased by 6.43%-17.69%. There was no significant difference in seed cotton yield in 2022. In 2023, the number of bolls per unit area and seed cotton yield increased significantly by 9.72% and 7.66%, respectively. Correlation analysis showed that root length density in 0-60 cm soil layer, root biomass density in 0-60 cm soil layer, maximum growth rate of root length, and the proportion of root length in 30-60 cm soil layer are extremely significantly correlated with seed cotton yield. [Conclusion] Delaying the sowing date (1 May) in cotton planting area of the Yellow River Basin can enhance the absorption function of cotton roots by increasing the growth rate of roots, the proportion of root length and biomass in deep soil layers, so as to ensure the accumulation of aboveground dry matter and promote the high yield of cotton.
[Objective] This research aims to investigate the effects of planting density and varieties on the morphological structure of vegetative organs and yield of machine-picked cotton in northern Xinjiang. [Methods] Field trials were conducted in 2022 and 2023 at Wulanwusu Agricultural and Meteorological Experiment Station and Manas Agricultural Experiment Station, respectively. Two varieties, CCRI 127 (V1) and Xinshi 518 (V2), were selected, and three planting densities were designed as 11 plants·m-2 (D1), 22 plants·m-2 (D2), and 28 plants·m-2 (D3), respectively. The effects of different treatments on leaf length, petiole length, petiole diameter, internode length, and internode diameter of cotton main stems and fruiting branches as well as yield traits were compared. [Results] In 2022 and 2023, V1 showed the smallest leaf length, petiole length, and internode length of main stems and fruiting branches under D1 and D2 treatments, respectively. In 2022, V2 showed the smallest leaf length, petiole length, petiole diameter, and internode length of main stems and fruiting branches under D3 treatment. In 2023, V2 showed the smallest petiole length and internode diameter of main stems and fruiting branches under D3 treatment. Leaf length and internode length of main stems and fruiting branches showed V1 ≥ V2 under the same density in 2022. Leaf length, internode length, and internode diameter of main stems and fruiting branches of V1 and V2 were not significantly different under the same density in 2023. The lint percentage of V2 was significantly higher than that of V1 under the same density both in 2022 and 2023. Seed cotton yield and lint yield of V1 and V2 in 2022 as well as that of V2 in 2023 increased with the increase of planting densities. Seed cotton yield of V1D3 treatment was highest in 2022, and relatively higher in 2023. V2D3 treatment had the highest lint yield in 2022 and 2023. [Conclusion] The preferred planting density under the conditions of this experiment was 28 plants·m-2, and the lint yield of Xinshi 518 was higher. The results of this study can provide a support for the improvement of the CottonXL model, and provide a reference for the selection of appropriate varieties and planting densities of machine-picked cotton in the northern Xinjiang.
[Objective] This study aims to provide a theoretical basis for molecular breeding of disease-resistant cotton by cloning Gh_D11G050000 gene, and to analyze its function and mechanisms in cotton resistance to Verticillium wilt. [Methods] Bioinformatic method was utilized to analyze the sequence characteristics and phylogenetic relationship of Gh_D11G050000. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to investigate the expression pattern of this gene, and it's expression level changes after infected by Verticillium dahliae. The function of this gene was validated using virus-induced gene silencing (VIGS) technique. Transcriptome sequencing analysis and the detection of relative expression levels of related genes were conducted to explore the mechanisms of disease resistance. [Results] Gh_D11G050000 exhibited close relationship with Gh_A11G049600 and Gr_11G034620 protein. qRT-PCR analysis revealed that Gh_D11G050000 was highly expressed in cotton roots, and the expression level of Gh_D11G05000 was significantly increased after V. dahliae infection. Gh_D11G050000 silenced cotton plants showed reduced resistance against V. dahliae, characterized by aggravated browning of stem vascular bundles, increased the number of stem segments with bacterial propagation, as well as significantly increased the rate of diseased plants and disease index. Transcriptome analysis combined with qRT-PCR demonstrated that Gh_D11G050000 silenced cotton plants showed decreased transcription levels for several genes in jasmonic acid (JA) signaling pathway, ethylene (ET) signaling pathway, and lignin synthesis pathway. [Conclusion] Gh_D11G050000 positively regulates cotton resistance to Verticillium wilt by influencing the expression of several genes involved in lignin synthesis, JA, and ET signaling pathways.
[Objective] Cotton is a relatively tolerant crop to cadmium (Cd) stress. It is of great significance to breeding and extending the Cd tolerant cotton cultivars for remediation of Cd contaminated soil. This study aims to analysis the inheritance of cotton tolerance to Cd stress and to map the quantitative trait locus (QTL) related to Cd stress. [Methods] In this study, 188 recombinant inbred lines (RIL) called HM188 derived from an intraspecific hybrid between HS46 and MARCABUCAG8US-1-88 were used to study the phenotypic data of germination rate, germination potential, chlorophyll content, plant height, dry and fresh weight at seedling stage under Cd stress, and the Cd stress coefficient of each material was calculated as well. QTL mapping was conducted for each trait and Cd stress coefficient of HM188 population by using complete interval mapping method. [Results] According to the performance and Cd stress coefficient of each trait under Cd stress, MARCABUCAG8US-1-88 was the Cd tolerant parent, while HS46 was a sensitive one. The Cd tolerance of 188 RIL was basically normal distribution, including 23 strong Cd tolerant lines, 49 Cd tolerant line, 67 medium tolerant lines, and 49 sensitive lines. A total of 28 QTL for Cd stress coefficient was identified, which were distributed on 14 chromosomes with explaining of variation of 1.58%~8.41%. Among them, qRFW-13-1 related to root fresh weight was detected in both environments, which explained variation of 7.66% and 7.71%, respectively. [Conclusion] Cd tolerance in upland cotton is a quantitative trait controlled by multiple genes, which was greatly affected by the environment. However, qRFW-13-1 for Cd tolerance may be a stable QTL, which has some application values in molecular breeding for Cd tolerant cotton.
Cotton straw is a by-product of cotton production and an important renewable biomass resource, and the study on its comprehensive utilization is of great significance to optimize energy structure and achieve 'dual carbon' goals. Due to the structural differences, the successful application methods of corn, wheat, and rice straw cannot be directly applied to cotton straw. Traditional treatment and application of cotton straw cause resource waste and environmental pollution. Therefore, it is essential to enhance the comprehensive utilization of cotton straw to improve agricultural waste utilization efficiency, optimize energy structure, and reduce environmental pollution. From the perspective of enhancing the comprehensive utilization efficiency of cotton straw, this article summarizes various utilization modes, including straw returning to the field, using them as feed, energy substrate, and raw material, and prospects the future multiuse of cotton straw which will provide methodological reference and research ideas for the diversified utilization of cotton straw.
[Objective] This research aims to explore the effects of adjuvants during pesticide spraying by plant protection unmanned aerial vehicle (UAV) on droplet deposition characteristics and control efficiency on Aphis gossypii. [Methods] Dajiang T30 UAV was selected to conduct a field spray experiment during the cotton budding stage. The effects of 6 adjuvants (Yaketou, Beidatong, Zhiwusancan, Nongjianfei, Qigong, and Beibeijia) in 39% spirotetramat buprofezin on the size, density, coverage, and deposition amount of droplets and control efficiency on A. gossypii were compared. [Results] Compared with the control without adjuvant, treatments with the adjuvants increased the droplet density, coverage, and deposition amount on the upper, middle, and lower leaves of cotton plant. The droplet size, density, coverage, and deposition amount treated with Beibeijia and Beidatong were all higher; of which the density, coverage, and deposition amount on the upper, middle, and lower leaves of cotton plants were significantly higher than those of the control treatment. The control efficiency on A. gossypii of treatments with adjuvants in the upper, middle, and lower parts of cotton plant was higher than that of the control treatment at 1 d, 3 d, 7 d, and 14 d after application. The control efficiency of the treatment with Beibeijia was the best, followed by the treatment with Beidatong. [Conclusion] The addition of Beibeijia and Beidatong can improve the deposition characteristics of droplets and has a good control effect on A. gossypii. It also has a good synergism on the control of A. gossypii with 39% spirotetramat buprofezin suspension.
