[Objective] Heat damage is the most important meteorological disaster during the flowering and boll setting stage of cotton, which severely limits the safe production of cotton in Xinjiang. The evolution characteristics of heat damage in this area are clarified, which provides a reference for the scientific formulation of disaster prevention and mitigation measures. [Methods] This research used the daily maximum air temperature of 55 national basic meteorological stations in Xinjiang cotton planting areas from 1961 to 2022, and the observation data during the flowering stage and boll opening stage of 24 cotton meteorological observation stations from 1991 to 2022. Combined with the monitoring indices of high temperature and heat damage during flowering and boll setting stage of cotton, this research revealed the temporal and spatial variation of high temperature and heat damage with different grades during cotton flowering and boll setting stage by climate tendency rate and Mann-Kendall mutation test. [Results] The results showed that the maximum air temperature, extreme high temperature(daily maximum temperature ≥38.0 ℃) and cumulative days of the extreme high temperature during the flowering and boll setting stage of cotton in Xinjiang showed a significant upward trend from 1961 to 2022, with trend rates of 0.16 ℃·(10 a)-1, 0.07 ℃·(10 a)-1 and 0.45 d·(10 a)-1, respectively. The frequency and intensity of high temperature and heat damage during the flowering and boll setting stage of cotton in Xinjiang have increased. From 1961 to 2022, the years of high temperature and heat damage during flowering and boll setting stage with different intensities in the cotton planting area of eastern Xinjiang subregion accounted for more than 96.0%, and the mild and moderate heat damage in the cotton planting area of southern Xinjiang subregion accounted for 88.7% and 51.6%, respectively. And the frequency of mild heat damage during the flowering and boll setting stage of cotton in the northern Xinjiang subregion was 64.5%. [Conclusion] The frequency and intensity of heat damage during flowering and boll setting stage in Xinjiang cotton planting area showed the regional characteristics of "strong in the east and weak in the west, more in the south and less in the north". Therefore, more attention should be paid in Xinjiang cotton planting areas to the breeding and application of high temperature resistant varieties, rationally adjustment of the cotton planting layout, strengthening the monitoring and early warning of meteorological disasters, and ensuring the safe and stable development of cotton production.
[Objective] This study aims to understand the changes in the agglomeration level of cotton production in China and its influencing factors. These findings hold practical significance for optimizing the layout of the cotton industry, promoting high-quality development of the cotton industry, and enhancing regional economic development. [Methods] Using the location quotient index to measure the agglomeration level of cotton production in China from 2001 to 2022, comparing the agglomeration growth and competitive status changes of cotton production in major producing provinces using the competitive state model, and finally empirically analyzing the factors affecting agglomeration changes. [Results] From 2001 to 2022, the cotton production aggregation level in inland regions of Northwest China has been consistently higher than that in the Yangtze River basin and the Yellow River basin, and has continued to rise. The production aggregation level and competitiveness of cotton in Xinjiang have been continuously strengthened. However, the production aggregation level and comprehensive competitiveness of cotton in other major cotton-producing provinces have notably declined. Factors affecting the changes in cotton production aggregation in China include conflicts between grain and cotton for land, water resources, the quantity of agricultural labor, agricultural technology levels, transportation costs, the synthetic fiber industry, and cotton target price policy. [Conclusion] For the sustainable development of the cotton industry, it is recommended to scientifically promote the allocation of resources for cotton production, implement the cotton industrial policies in accordance with local conditions, improve the technical level of cotton production, improve the cotton production infrastructure, promote the development of related industries and improve target price subsidy policies.
[Objective] To improve the yield of summer direct seeding cotton in the Yangtze River basin, this study focuses on the effects of nitrogen (N) and potassium (K) application frequency on cotton. [Methods] Field experiment was conducted in 2021 and 2022 under a randomized complete block design in a split-plot arrangement, where K fertilizer (210 kg·hm-2) application frequency K1 [pre-plant fertilizer (PP) 100%] and K2 [PP 50% + first flowering fertilizer (FF) 0 d 50%] were kept in the main plot, and the sub-plots were allocated with N fertilizer (210 kg·hm-2) application frequency: N2 [PP 20% + FF 0 d 80%], N3 [PP 20% + FF 0 d 60% + FF 21 d 20%], and N4[PP 10% + FF 0 d 50% + FF 7 d 30% + FF 21 d 10%]. The effects of different treatments on cotton dry matter accumulation and allocation, N and K accumulation and allocation, yield and yield components, and nutrient utilization efficiency were studied. [Results] The dry matter mass and the accumulation of N and K at plant removal stage, and the duration and average accumulation rate of the rapid accumulation period of dry matter in cotton plant, source, flow, and sink organs under K2N3 treatment were lower than those of K2N4 treatment, but the distribution ratio of dry matter, N, and K in the sink organs were higher than those of K2N4 treatment. K2N3 resulted in higher seed cotton yield and lint cotton yield, which were 31.4% and 31.9% significantly higher than the lowest yield treatment K1N2, respectively. However, further increase of N application times (K2N4 treatment) did not result in significantly higher cotton yield. There is no significant difference in the partial productivity of N and K between K2N3 and K2N4 treatments, but both are significantly higher than the other treatments. Principal component analysis showed that the main difference in cotton yield comes from the number of bolls, and promoting the allocation of biomass, N and K nutrients to sink organs is beneficial for improving yield. [Conclusion] For the direct seeding cotton after wheat in the Yangtze River basin, two times of K application combined with three times of N application can increase the absorption of N and K, promote dry matter as well as N and P distribution to sink organs, thus increase the number of bolls, and improve cotton yield.
[Objective] This research aims to investigate the impact of different nitrogen (N) fertilizer rates on cotton under the machine picked with(66 + 10) cm row spacing, so as to provide scientific basis for improving the high-yield cultivation technology of cotton. [Methods] N top-dressing experiments was carried out in Korla of Xinjiang during 2021 and 2022. A field experiment was conducted using Ba 43541 as the test material, and four pure N application levels were set: 0, 112.5, 225.0, and 337.5 kg·hm-2. Canopy structure characteristics, yield traits, and N use efficiency of cotton in middle position of the wide line (MW), middle position of the narrow line (MN), adjacent to plant (AP) and intermediate position of the adjacent two membranes (MC) were compared under different treatments. [Results] Under different treatments, with the advancement of growth process, leaf area index (LAI) of cotton at the four test sites increased first and then decreased, while photosynthetically active radiation (PAR) decreased first and then increased, but mean leaf angle (MLA) and gap fraction transmission coefficient (GFTC) showed different change trends. During the full budding stage, the LAI was lower, while MLA, PAR, and GFTC were higher in MC. The differences of LAI, PAR, and GFTC among the four test sites gradually decreased from the flowering and boll setting stage to the boll opening stage. During the full boll setting stage and boll opening stage, MLA were higher in MN and AP. Applying N 112.5 kg·hm-2(N1) obtained appropriate LAI, MLA, PAR, and GFTC during the full boll setting stage, the boll number of per unit area increased. In 2021 and 2022, compared with the other three treatments, seed cotton yield of N1 increased by 1.38%-16.50% and 1.66%-11.57%, and lint yield increased by 1.57%-16.37% and 0.59%-12.40%, respectively; partial productivity and agronomic utilization of N were also increased. In terms of cotton LAI and PAR, there were extremely significant positive correlation among the four test sites. Overall, the best positive correlation of cotton canopy structure index was found among AP and MW, AP and MN. [Conclusion] Under the same N application rate, the change trends of LAI and PAR at four test sites were consistent, while the change trends of MLA and GFTC were inconsistent. The application of 112.5 kg·hm-2 N could promote the high yield of Ba 43541, and improve the N use efficiency of cotton.
Cotton is an important economic crop in the world, occupying a significant position in the national economy. Cottonseed, as the main product of cotton production, is rich in high-quality protein and oil. Against the backdrop of the current shortage of protein and oil resources, fully exploring and utilizing the protein and oil resources in cottonseed can ensure the safety of edible oil supply and alleviate food security issues. With the increasing attention paid to the comprehensive utilization of cottonseed, the research on the genetic improvement of cottonseed nutritional quality is gradually increasing. This review provides an overview of the common methods for determining cottonseed protein and oil content, and summarizes the genetic characteristics and influencing factors of these traits. The relationships among cottonseed protein and oil content and fiber yield as well as the fiber quality traits were analyzed. A total of 335 quantitative trait locus (QTL) for oil content and 196 QTL for protein content were collected to construct a consistent physical map. In addition, the research progress of cottonseed protein and oil related synthetic pathways and regulatory genes were introduced, and the future research directions of biological breeding for cottonseed nutritional quality was prospected, which can provide a reference for the genetic improvement of nutritional quality in cottonseed.
Cotton is the most important natural fiber crop in the world, as well as also an important cash crop and raw material for textile industry in China. The change of fruit branch angle directly or indirectly affects the canopy structure, light energy distribution, boll formation structure and mechanical characteristics. In order to provide reference for the improvement of cotton plant architecture breeding and further promote cotton breeding, this paper reviews the current research status of cotton fruit branch angle from the perspective of cultivation and molecular, summarizes the previous research results and probes into the research trend of cotton fruit branch angle.