Comparative effects of crop residue incorporation and inorganic potassium fertilization on soil C and N characteristics and microbial activities in cotton field

[Background] Crop residue incorporation into the soil is an effective method to augment soil potassium (K) content, and effects of crop residue and K fertilizer on soil K balance have been compared. However, their influences on other soil characteristics such as carbon (C) and nitrogen (N) characteristics and microbial activities have not been quantified. To address this, field experiments were conducted in 2011 at Dafeng (sandy loam) and Nanjing (clay loam) in China with treatments including blank control without crop residue incorporation and K fertilizer application, 0.9 t·ha− 1 wheat straw incorporation (W1C0), 0.7 t·ha− 1 cotton residue incorporation (W0C1), 0.9 t·ha− 1 wheat straw + 0.7 t·ha− 1 cotton residue incorporation (W1C1) and two K fertilizer rates (150 and 300 kg·ha− 1 (K2O)) during the cotton season.

[Results] Compared with control, K fertilizer treatments did not alter soil water-soluble organic carbon/soil organic carbon (WSOC/SOC) ratio, microbial biomass carbon (MBC)/SOC ratio, MBC/microbial biomass nitrogen (MBN) ratio, water inorganic nitrogen/total nitrogen ratio (WIN/TN), the number of cellulose-decomposing bacteria, or related enzymes activities, however, W0C1, W1C0 and W1C1 treatments significantly increased WSOC/SOC ratio, MBC/SOC ratio and MBC/ MBN ratio, and decreased WIN/TN ratio at both sites. W0C1, W1C0 and W1C1 treatments also increased the number of soil cellulose-decomposing bacteria and activities of cellulase, β-glucosidase and arylamidase. Regarding different crop residue treatments, W1C0 and W1C1 treatments had more significant influences on above mentioned parameters than W0C1 treatment. Moreover, MBC/MBN ratio was the most important factor to result in the differences in the number of cellulose-decomposing bacteria and soil enzymes activities among different treatments.

[Conclusions] This study provided a detailed phenotypic diversity description of a population representing a wide range of upland cotton germplasm. Our findings provide useful information about possible elite fibre quality parents for cotton breeding programs.

[Title] Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Authors] HU Wei, SUI Ning , YU Chaoran, YANG Changqin, LIU Ruixian and ZHOU Zhiguo

Journal of Cotton Research2019; 2:24

https://doi.org/10.1186/s42397-019-0040-3

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0040-3

Bt insecticidal efficacy variation and agronomic regulation in Bt cotton

Abstract: The bollworm can be controlled effectively with Bacillus thuringiensistransgenic cotton (Bt cotton) which is being applied worldwide. However, the insecticidal efficacy is not stable. Here we give a summary of research progress for the mechanism of the altered insecticidal efficacy, factors affecting the expression of insect resistance, agronomic practices on regulation of insecticidal efficacy in Bt cotton. To realize the transgenic potential of Bt cotton cultivars, future research may be conducted by increasing synthesis and reducing degradation of Bt protein to maintain high insecticidal ability in the transgenic cotton by agronomic management.

[Title] Bt insecticidal efficacy variation and agronomic regulation in Bt cotton

[Authors] LIU Zhenyu, ELTAYIB H M. A. Abidallha, WU Huimin, ZHOU Mingyuan, ZHANG Xiang, CHEN Yuan and CHEN Dehua

Journal of Cotton Research2019; 2:23

https://doi.org/10.1186/s42397-019-0042-1

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0042-1

Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Background] Evaluating phenotypic traits is very important for the selection of elite lines in Gossypium hirsutum L. Cotton breeders are interested in using diverse genotypes in hybridization that can segregate for traits of interested with the possibility of selection and genetic gain. Information on phenotypic and molecular diversity helps the breeders for parental selection.

[Methods] In this study, 719 global collections of G. hirsutum L. were evaluated for five fibre-related traits during two consecutive years in eight different environments. A series of phenotypic data for fibre quality traits were obtained and the elite accessions were further screened using principal component analysis and phylogenetic tree construction based on single nucleotide polymorphism markers.

[Results] We found that fibre quality traits showed a wide range of variation among the G. hirsutum accessions over 2 years. In general, accessions from outside China tended to have higher fibre length (FL) and fibre strength (FS) than did Chinese accessions. Among different regional accessions in China, North/Northwest accessions tended to have the highest FL, FS and best fibre macronaire. By assessing five fibre quality traits over 2 years with genotypic data, 31 elite germplasms reaching double-thirty quality values (FL ≥ 30 mm and FS ≥ 30 cN·tex− 1) were selected.

[Conclusions] This study provided a detailed phenotypic diversity description of a population representing a wide range of upland cotton germplasm. Our findings provide useful information about possible elite fibre quality parents for cotton breeding programs.
[Title] Evaluation of the genetic diversity of fibre quality traits in upland cotton (Gossypium hirsutum L.) inferred from phenotypic variations

[Authors] SUN Zhengwen, WANG Xingfen, LIU Zhengwen, GU Qishen, ZHANG Yan, LI Zhikun, KE Huifeng, YANG Jun, WU Jinhua, WU Liqiang, ZHANG Guiyin and MA Zhiying
Journal of Cotton Research2019; 2:22

https://doi.org/10.1186/s42397-019-0041-2

https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0041-2

Towards improving drought resistance and lodging resistance in cotton

Abstract: Cotton is one of the most important fiber and oil crop in the world and the fiber yield as well as quality traits are negatively affected by drought and lodging. Improving root gravitropism is a very effective way to enhance the crop resistance to drought and lodging stresses. Recent advance in origin and formation of root gravitropism may provide new insights to increase drought and lodging resistance in cotton.

[Title] Towards improving drought resistance and lodging resistance in cotton

[Authors] LI Fuguang

Journal of Cotton Research2019; 2:21
https://doi.org/10.1186/s42397-019-0037-y
https://jcottonres.biomedcentral.com/articles/10.1186/s42397-019-0037-y