高密度重化控技术对小麦后直播棉花成铃时空分布的调控

以特早熟棉花品种国欣12-1为材料,在江苏省扬州市小麦后直播方式下探讨高密度(1 hm^2120 000～150 000株)配合重化控技术(缩节胺施用量240～480 g/hm^2)对棉花集中成铃的影响。结果表明,在1 hm^2150 000株密度下配合使用240 g/hm^2缩节胺可获得较高籽棉产量,2016年、2017年分别达到3 415.5 kg/hm^2、4 416.3kg/hm^2。在此处理组合下实现棉铃在7月20日至8月30日集中成铃,且成铃部位在棉株顶部向下50 cm内。因此,高密度配合适宜化控技术可实现小麦后直播方式下集中成铃于棉株中上部,从而为机械化采收奠定基础。

Identification and expression analysis of group Ⅲ WRKY transcription factors in cotton

The WRKY proteins constitute a large family of transcription factors in plants containing highly conserved WRKYGQK sequences and zinc-finger-like motifs. To comprehensively study WRKY III genes in cotton, we analyzed the genome sequences of Gossypium hirsutum, G. raimondii and G. arboreum. According to the three genome sequences, 18 group III Gh WRKY genes were identified in G. hirsutum, 12 both in G. raimondii and G. arboreum. Phylogenetic and motif analysis showed that proteins with high similarities could be clustered together and had the same motif components. The ratios of non-synonymous（Ka） to synonymous（Ks） of the Gh WRKY to Gr WRKY or Ga WRKY were lower than 1, which indicated that group III WRKY genes in Gossypium species are under purifying selection. Expression analysis revealed that group III Gh WRKY genes expressed during fiber development and leaf senescence, and most of them could be induced by salicylic acid（SA）, jasmonic acid（JA）, ethylene, abscisic acid（ABA）, mannitol, and Na Cl both in roots and cotyledons. Our study gives a briefly introduction on cotton group III WRKY genes and implicates their potential function in cotton fiber development, leaf senescence and abiotic stresses.

Genome-wide analysis of the calcium-dependent protein kinase gene family in Gossypium raimondii

Plant calcium-dependent protein kinases （CDPKs） play important roles in diverse physiological processes by regulating the downstream components of calcium signaling. To date, only a few species of the plant CDPK gene family have been functionally identified. In addition, there has been no systematic analysis of the CDPK family in cotton. Here, 41 putative cotton CDPK （GrCDPK） genes were identified via bioinformatics analysis of the entire genome of Gossypium raimondii and were classified into four groups based on evolutionary relatedness. Gene structure analysis indicated that most of these GrCDPK genes share a similar intron-exon structure （7 or 8 exons）, strongly supporting their close evolutionary relationships. Chromosomal distributions and phylogenetics analysis showed that 13 pairs of GrCDPK genes arose via segmental duplication events. Furthermore, using microarray data of upland cotton （G. hirsutum L.）, comparative profiles analysis of these GhCDPKs indicated that some of the encoding genes might be involved in the responses to multiple abiotic stresses and play important regulatory roles during cotton fiber development. This study is the first genome-wide analysis of the CDPK family in cotton, and it will provide valuable information for the further functional characterization of cotton CDPK genes.

Genetic Analysis of Earliness Traits in Short Season Cotton (Gossypium hirsutum L.)

Inheritance and interrelationship of phenotype and genotype of earliness traits were evaluated in a diallel analysis involving six early-maturing parents. Date of first square （DFS）, date of first flower （DFF）, date of first open boll （DFOB）, number of node first sympodial branch （NNFSB）, and harvested rate before frost （HRBF） as earliness traits of six parents, 15 F1 hybrids and 15 F2 progenies were investigated from 2005 to 2008. The experiment design was a randomized complete block design with three replications. Additive, dominance and epistasis effects were analyzed with ADAA （additive- dominance-epistasis） model. HRBF, DFF, and DFOB showed significant additive genetic variances. Heritability estimates ranged from 0.088 （HN, narrow sense） and 0.416 （HNE, environment interaction） for HRBF, to 0.103 （HN） and 0.524 （HNE） for DFF, and to 0.187 （HN） and 0.519 （H~） for DFOB. Dominance genetic effects for DFS, DFF, DFOB, and NNSFB were stronger than additive effects. Additive-by-additive epistatic effects for DFS, DFOB, and NNSFB were detected and affected by environment. Correlation analysis showed generally that HRBF had a significant negative genetic and phenotypic correlation with DFS, DFOB, and NNFSB; DFS had significant positive genetic and phenotypic correlations with DFF, DFOB, and NNFSB; significant positive genetic and phenotypic correlations were also detected between DFF and DFOB, DFF and NNFSB, DFOB and NNFSB. The results showed that the lower the node to the first fruiting branch and the shorter the plant, the earlier was the onset of squaring, flowering, and boll opening, the higher was the harvest rate before frost. Heredity of earliness traits among parents and their hybrids were also detected and parents A1, A2, Bl, B2, and B3 could be used to improve earliness traits of short season cotton cultivars.

Architecture of stem and branch affects yield formation in short season cotton

The cotton direct seeding after wheat(rape) harvested is under trial and would be the future direction at the Yangtze River Valley region of China.The objective of this study was to quantify the effects of branch and stem architecture on cotton yield and identify the optimal cotton architecture to compensate the yield loss due to the reduction of individual production capacity under high planting density in the direst seeding after wheat harvested cropping system.The characteristics of the stem and branch architecture and the relationships between architecture of the stem and branch with yield formation were studied on eight short season cotton cultivars during 2015 and 2016 cotton growth seasons.Based on the two years results,three cultivars with different architectures of stem and branch were selected to investigate the effect of mepiquat chloride(MC) application on the architecture of the stem and branch,boll retention,and the yield in 2017.Significant differences were observed on plant height,all fruiting nodes to branches ratio(NBR) in the cotton plant,and the curvature of the fruiting branch(CFB) among the studied cultivars.There were three types of stem and fruiting branch structures: Zhong425 with stable and suitable plant height and NBR(about 90 cm and 2.5,respectively),high CFB(more than 10.0),and high boll retention speed and seed cotton yield;Siyang 822 with excessive plant height and NBR,low CFB,and low boll retention speed and seed cotton yield;and other studied cultivars with unstable structure of stem and branch,boll retention speed,and seed cotton yield across years.And MC application could promote the appropriate plant height and NBR and high CFB and thus resulted in high boll retention speed and the yield.The results suggested that the suitable plant height and NBR(about 90 cm and 2.5 respectively),and high CFB(more than 10.0),which was related to both genotype and cultural practice,could promote the higher boll retention speed and seed cotton yield.

Analysis of MIKC^C-Type MADS-Box Gene Family in Gossypium hirsutum

MIKCC-type MADS-box genes encode transcription factors that are involved in plant developmental control and signal transduction. Few Gossypium hirsutum MADS-box genes have been reported thus far. Recently, the genome of Gossypium raimondii, considering the contributor of the D subgenome to G. hirsutum, was sequenced and provided a valuable resource to identify and analyze multiple MADS-box genes in G. hirsutum. Here we comprehensively analyzed 53 MIKCC-type MADS-box genes, including 34 newly cloned genes. Phylogenetic analysis of these genes with those from Arabidopsis and grapevine showed that the FLC and AGL12 subfamilies were absent in G. hirsutum. Proteins within a gene subfamily tended to share conserved motifs, and large differences occurred among subfamilies. Expression analysis in multiple tissues and lforal organs implied differing roles for the subfamilies in G. hirsutum. At nine loci, two or three genes co-occurred, indicating that they came from different subgenomes; these groups had similar expression patterns. The identiifcation of MIKCC-type MADS-box genes in G. hirsutum provides a valuable resource for further research into lfowering time, lfower development and ovule development in this important crop plant.

Cloning and Expressing of a Gene Encoding Cytosolic Copper/Zinc Superoxide Dismutase in the Upland Cotton

In this study, a gene encoding a superoxide dismutase （SOD） was cloned from senescent leaves of cotton （Gossypium hirsutum）, and its expressing profile was analyzed. The gene was cloned by rapid amplification of cDNA ends （RACE） method. Northern blotting was used to show the profile of the gene expression, and the enzyme activity was mensurated by NBT deoxidization method in different growth periods. The full length of a gene of cytosolic copper/zinc superoxide dismutase （Cu/Zn-SOD） was isolated from cotton （GenBank Accession Number： DQ445093）. The sequence of cDNA contained 682 bp, the opening reading frame 456 bp, and encoded polypeptide 152 amino acids with the predicted molecular mass of 15.03 kD and theoretical pI of 6.09. The amino acid sequence was similar with the other plants from 82 to 87%. Southern blotting showed that the gene had different number of copies in different cotton species. Northern blotting suggested that the gene had different expression in different tissues and development stages. The enzyme activity was the highest in peak flowering stage. The cotton cytosolic （Cu/Zn-SOD） had lower copies in the upland cotton. The copper/zinc superoxide dismutase mRNA expressing level showed regular changing in the whole development stages; it was lower in the former stages, higher in latter stages and the highest at the peak flowering stage. The curve of the copper/zinc superoxide dismutase mRNA expressing level was consistent with that of the Cu/Zn-SOD enzyme activity. The copper/zinc superoxide dismutase mRNA expressing levels of different organs showed that the gene was higher in the root, leaf, and lower in the flower.