无膜滴灌栽培条件下不同棉花品种、密度和播期对其生长的影响

【目的】研究无膜滴灌栽培条件下不同棉花品种、密度和播期对其生长的影响,为新疆南疆棉花无膜滴灌栽培技术提供数据支持和理论依据,筛选出适宜的品种、密度和播期。【方法】分别在库尔勒、阿拉尔、图木舒克进行试验,采用无膜滴灌栽培方式和裂-裂区试验设计,研究品种、密度、播期3个因素对棉花生育期、产量构成、农艺性状、干物质积累、纤维品质的影响。【结果】品种和播期对棉花生长影响较大,生育期较短的早熟棉花品种子棉产量较高;播期推迟造成生育期延长,并使子棉产量、单株铃数、衣分、霜前花率逐渐下降,对农艺性状和纤维品质造成一定影响;密度增加造成单株铃数、株高、单株果枝数、单株果节量逐渐下降,对子棉产量、纤维品质未造成显著影响。【结论】棉花品种中619熟性较早,产量较高,可作为新疆南疆无膜滴灌栽培的适宜品种;适宜的播期为4月15~25日;密度22.5×10~4株/hm^2的子棉产量在3个密度中最高,为适宜的种植密度。

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.

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.

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.

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.