T1 locus in cotton is the candidate gene affecting lint percentage, fiber quality and spiny bollworm (Earias spp.) resistance

A genetic linkage map of chromosome 6 was constructed by using 270 recombinant inbred lines originated from an upland cotton cross (Yumian 1 × T586) F₂ population. The genetic map included one morphological (T₁) and 18 SSR loci, covering 96.2 cM with an average distance of 5.34 cM between two markers. Based on composite interval mapping (CIM), QTL(s) affecting lint percentage, fiber length, fiber length uniformity, fiber strength and spiny bollworm resistance (Earias spp.) were identified in the t₁ locus region on chromosome 6. The allele(s) originating from T586 of QTLs controlling lint percentage increased the trait phenotypic value while the alleles originating from Yumian 1 of QTLs affecting fiber length, fiber length uniformity, fiber strength and spiny bollworm resistance increased the trait phenotypic value.     

Dry matter accumulation and partitioning in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) as influenced by potassium fertilization

The effect of potassium (K) supply on dry matter accumulation and partitioning of biomass between different among parts of cotton (Gossypium hirsutum L.) was determined under irrigated conditions. The treatments were four cotton cultivars (CIM-448, CIM-1100, Karishma, and S-12), four K rates (0, 62.5, 125, and 250 kg K ha⁻¹), and two K-fertilizer sources (K₂SO₄, KCl). Sequential harvests were collected at four stages of growth, viz first flower, peak flowering, first boll split, and maturity. The dry weights (DW) of vegetative and reproductive organs were determined. Maximum total DW was obtained at 125 days after planting, and then it declined because of leaf senescence at maturity. Cultivars differed significantly among themselves in the production of total DW and its partitioning between different organs. The addition of K fertilizer increased DW substantially at various stages of growth. Potassium fertilizer stimulated cotton plant to translocate resources towards reproductive organs rather than vegetative organs. Crop receiving 250 kg K ha⁻¹ allocated 77% more dry matter into reproductive organs. The K-sources produced a little effect on the allocation of DW in various parts of the plant. Maximum reproductive–vegetative ratio (RVR) was maintained by cv CIM-448 and minimum in cv CIM-1100. Data showed that a shift in DW allocation into reproductive organs was dependent upon sustained supply of K⁺ throughout the season. There were positive significant correlations (0.86, 0.71, and 0.90) between seed cotton yield and total DW, vegetative DW, and reproductive DW, respectively.     

陆地型长绒棉主要经济性状遗传模式分析

选取两个遗传稳定的陆地型长绒种质系与 3个陆地棉品种按Griffing方法Ⅰ、模式Ⅰ全互交设计配成 5× 5共 2 5个杂交组合。对 9个经济性状进行调查 ,并建立Wr对于Vr的回归方程 ,测验“加性 +显性”模式的符合 ,制Wr对于Vr回归图 ,并估算各遗传参数。结果表明 ,纤维长度、纤维强度、马克隆值、籽棉产量、皮棉产量、单株铃数和单铃重遗传符合Hayman的“加性 +显性”模式 ,非等位基因间相互作用影响不显著。无论图解分析或平均显性度均表明纤维长度、纤维强度、马克隆值F1代为部分显性 ,加性效应方差在这 3个性状总遗传方差中占据相当重要的作用。分析性状中 ,与纤维长度、马克隆值和皮棉产量有关的增效基因 ,既有隐性也有显性 ,位点不同而有差异。纤维长度、纤维强度和马克隆值广义和狭义遗传力均较高。     

Changes in photosynthesis and antioxidant metabolism of cotton (Gossypium hirsutum L.) plants in response to manganese stress

ABSTRACT

This study aimed to assess the physiological and biochemical responses of cotton plants to manganese (Mn²⁺) nutrition. Four cotton genotypes (G1 – TMG 47; G2 – FM 975 WS; G3 – TMG 11 WS and G4 – IMA 8405 GLT) were grown in nutrient solution under two Mn²⁺ concentrations (2 and 200 µmol L^?1) for 10 days. No visible symptoms of Mn²⁺ toxicity were observed in the genotypes tested. All genotypes showed a marked increase in leaf chlorophylls, pheophytins, carotenoids, sucrose and total sugars concentration in response to high Mn²⁺ in a nutrient solution. However, the net photosynthetic rate, stomatal conductance, internal carbon dioxide concentration and transpiration decreased in genotypes G1 and G2 growing under 200 µmol L^?1. Antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased in genotypes G1, G3 and G4. Cotton genotypes showed an increased leaf antioxidant and sugar metabolism as a possible strategy to mitigate oxidative stress. The decrease in the net photosynthetic rate and stomatal conductance; the increased antioxidant enzymes activities (SOD, APX and GR); and the increase in leaf sucrose and total sugar concentration were the main physiological and biochemical responses in cotton plants to Mn²⁺ stress.     

陆地棉(G. hirsutum L.) N-乙酰氨基葡萄糖转移酶基因(GhGnT)的克隆及耐盐性功能分析

在耐盐相关基因芯片基础上,我们筛选到盐诱导显著上调表达(Ratio>2)的N-乙酰氨基葡糖转移酶基因.选取耐盐材料中9806为材料,根据耐盐性抑制消减文库EST序列设计引物,利用RACE及RT-PCR技术获得该基因cDNA全长1970 by,命名为GhGnT.通过Blast比对,发现该基因与蓖麻乙酞氨基葡萄糖转移酶基因...     

陆地棉产量与农艺性状的典型相关和主成份分析

本文运用典型相关和主成份分析方法,对陆地棉品种苏棉2号的产量与农艺性状关系的研究表明:1.产量与产量性状的典型相关高于与生理性状的相关,又高于与形态性状的相关;形态和生理性状对产量性状有重要作用。2.主成份Ⅰ是“产量因子”,主成份Ⅱ是“生理因子”,两者方差贡献累积82%以上。3.影响棉花产量的内在主要因子有总铃数、单铃重、LAI、CGR、结果系数、主茎节距和第一果枝高度。     

棉角斑病对棉花苗、蕾期危害的研究

 近年来,对不同类型棉田角斑病危害调查和以海岛棉为主地病害发生研究,角斑病[Xanthomonas Campestris PV.malvacearum(Smith) Dye]对棉花的危害,以苗、蕾期的顶腐、茎腐最为严重,造成顶梢和茎部黑腐的途径,主要是病菌在棉株组织内的系统侵染。棉子播种试验,毛子播种的棉苗在子叶期就出现病症,脱绒光子的棉苗在真叶3～4片时才出现病害。脱绒光子带有少量的病菌,仍是病害的侵染源,在多雨的气候条件下,可以通过系统侵染和再侵染造成严重危害。     

陆地棉纤维不同强度指标的相关与变异初探

对陆地棉不同纤维强度类型品种的研究表明,单纤维强力,零隔距比强度,3.2毫米隔距比强度与断裂长度4项强度表示的不同指标的差异,品种间变化趋势相似;但环境影响表明,断裂长度与单纤维强力变化趋势相似,而与3.2毫米隔距比强度可能是概念不同的物理量(克力/特克斯),并非决定于同一层次的纤维结构。对纤维强度指标的变异分析证明,除鲁棉6号与PD 9223两品种在一定范围内表现了圆锥体层次愈多,铃期温度愈低。零隔距比强度愈高外,其它品种与其它强度指标的变异与环境和营养条件无关。供试品种中,对环境反应敏感的为鲁棉6号。在4项强度指标中,两项比强度指标仅受胞壁结构影响,变异系数小;单纤维强力与断裂长度受纤维干重与胞壁结构双重影响,变异系数大。     

棉花优良品种中棉所27直接胚胎发生与植株再生

选用我国难培养基因型优良棉花品种中棉所27进行组织培养,研究了该品种体细胞胚胎发生与植株再生能力。该品种体细胞胚胎发生有2种情况:一是由外植体直接诱导获得胚性愈伤组织并形成不同发育时期的胚状体;二是先诱导获得非胚性愈伤组织,再经多次继代培养,获得胚胎发生。不同激素及其组合和浓度配比是影响中棉所27直接诱导获得胚性愈伤组织及体细胞胚胎发生的直接因素。另外,饥饿培养及继代周期对胚胎发生也有重要影响。0.1mg/LKT和0.1mg/LIAA组合、0.1mg/LKT和0.1mg/LZT组合、0.1mg/LZT单独使用,在饥饿条件下培养,均能直接高效诱导获得大量胚性愈伤组织,并有短期内形成不同发育时期的胚状体。胚状体在不含任何激素的MS B5培养基上培养有利于植株再生,并降低畸形苗形成率。另外,还发现不同培养基对中棉所27胚性愈伤组织增殖、体细胞胚形成和萌发的影响不同。     

大丽轮枝菌毒素诱导表达陆地棉cDNA序列的克隆与定位

 为获得陆地棉黄萎病抗性相关候选基因，利用棉花黄萎病菌大丽轮枝菌V991毒素粗提物诱导耐黄萎病陆地棉品种'中棉12'应激基因的表达。在诱导幼根24 h时间点提取总RNA，PCR法合成双链cDNA，应用抑制消减杂交技术[1]，得到了差异表达的180个克隆。经反Northern blot筛选出15个受毒素粗提物诱导应激表达的阳性cDNA克隆，将其命名为Vdrg（response gene induced by toxin of Verticillium dahliae）。本研究对所得阳性cDNA克隆进行了序列分析，并利用Pima S6 与 Acala Maxxa 海陆杂交四倍体棉花F2群体对Vdrg序列进行了棉花基因组定位。