Response of Cotton to Potassium Fertilizer on Effectiveness of Fruiting Sites in Aridisols

Abstract

A field experiment was conducted to assess the effectiveness of fruiting positions along sympodia under varying levels and sources of potassium (K) fertilizer on field-grown cotton in an arid environment. Treatments consisted of four rates of K (0, 62.5, 125.0, 250.0 kg K ha^{? 1}) and two types of K (K₂SO₄ and KCl). Cotton cultivar S-12 (Gossypium hirsutum L.) was used as a test crop. Plant mapping data showed that the total number of fruiting positions, number of intact fruit on sympodia/monopodia, and percent of bolls per position on sympodia differed greatly under different doses of K fertilizer. The percentage of fruit retention was markedly improved under increasing doses of K fertilizer as compared with the K-unfertilized treatment. The percent survival of harvestable bolls for the first five positions along sympodia at the end of the season was 30%, 25%, 18%, 13%, and 8%, respectively. Potassium fertilization stimulated cotton crop in lengthening sympodial branches and retaining more fruit on the first three positions and also at the bottom of the plant during the early reproductive phase. The fruiting pattern was 2–3 and 6–7 d vertical and horizontal fruiting interval, respectively.     

Impact of the use of biofertilizers on cotton ( Gossypium hirsutum ) crop under irrigated agro-ecosystem

High nitrogen fixing, phosphate solubilizing, phytohormones producing isolates of Azotobacter, Azospirillum, Acetobacter and Pseudomonas were used as inoculants for cotton. Important cultures were selected on the basis of their effect on root/shoot length and chemotactic behaviour. Selected bioinoculants were earlier tested for their beneficial properties like nitrogen fixation (ARA), ammonia excretion, IAA production etc. These bio-inoculants were further tested for phosphate solubilization property. Various chosen strains were tested with Desi (HD 123) and American (H 1098) cotton under field conditions (as for wheat). Plant height and boll weight were determined at the time of harvesting whereas survival rate of inoculated bacteria was determined after 30, 80 and 130 days respectively. In the year 2000–01, on the basis of boll number and boll weight plant^?1 AVK 51 (36; 76.2?g plant^?1), HT 57 (27; 56.9?g plant^?1), AC18 (33; 61.5?g plant^?1), Ala 27 (36; 61.4?g plant^?1) and Pseudomonas (34; 71.3?g plant^?1) were identified as significant both for American and desi cotton varieties. Highest survival rate was observed with Mac 68 (33.4 × 10⁵) followed by HT54 (31.5 × 10⁵) after 30 days of sowing, which decreased after 80 days and remained constant up to 130 days. This trend was observed with all the cultures. Similar results were observed in 2001–02. 25?kg ha^?1 N saving was observed with A. chroococcum (AVK51) bioinoculant for cotton crop.     

Chilling Stress Accelerates Degradation of Seed Storage Protein and Photosynthetic Protein during Cotton Seed Germination

Low temperature is one of the major abiotic stresses limiting the productivity and geographical distribution of many important crops. To gain a better understanding of chilling stress responses in cotton ( Gossypium hirsutum L . ), we carried out a comparative proteomic analysis. Cotyledon proteins of 1-week-old cotton seedlings treated with or without chilling treatment at 4 °C were extracted, separated by a two-dimensional gel electrophoresis and compared. Among 1500 protein spots reproducibly detected on each gel, 25 protein spots were down-regulated and 29 were up-regulated. Seven cotton proteins were identified by mass spectrometry analysis as beta-globulin A precursor fragments. One was identified as a Rubisco large subunit fragment, providing evidence of both seed storage protein and photosynthetic protein destruction by chilling stress. The related physiological and biochemical analysis showed that there was a significant increase in endopeptidase activity and activated oxygen generation rate, and an obvious decrease in carboxylation efficiency and maximum net photosynthetic rate of cotton seedlings under chilling stress. Based on the above results, the degradation mechanisms of beta-globulin and Rubisco under chilling stress were discussed. In conclusion, our study provides new insights into chilling-stress responses in cotton and demonstrates the advantages of proteomic analysis.     

陆地棉优质纤维QTL的分子标记筛选及优质来源分析

利用陆地棉优质品系7235、渝棉1号做亲本, 以7235 × 渝棉1号的F2与F2:3分离群体为材料, 开展不同来源棉花高强纤维QTL微卫星标记筛选, 为进一步进行优质纤维QTL聚合育种提供基础。通过5 514对SSR引物对亲本进行多态性筛选, 获得117个多态性标记, 用其中80个标记构建了总长为1 147.8 cM的遗传图谱; 应用复合区间作图法分析了该组合的F2单株和F2:3家系纤维品质性状, 共检测到36个纤维品质数量性状基因座(QTL), 其中与纤维长度、比强度、细度、伸长率及整齐度相关的QTL各6、8、7、8和7个, 分别解释各性状表型变异的3.4%~14.4%、5.0%~42.4%、6.5%~11.7%、5.1%~19.4%和6.9%~14.0%。通过分析来源于7235和渝棉1号高强QTL的染色体分布, 表明两亲本在D7、D8、D9染色体上都存在控制纤维比强度的QTL, 其中存在于D7和D8染色体上来自双亲的QTL紧密连锁, 成簇分布在染色体上的一定区间内。而在D7和D9染色体上也发现双亲完全相同的优质QTL, 其优质供体可能来自陆地棉优质品系PD4381。进一步分析了获得的QTL在聚合育种中的应用潜力。     

陆地棉子叶离体培养诱导不定芽植株再生

以陆地棉种子无菌苗的子叶为外植体材料,研究不同苗龄的子叶、激素组合、硝酸银等对子叶诱导不定芽的影响.试验结果:15 h苗龄的子叶,在附加BAP 3.0 mg/L、IAA 1.0 mg/L、2ip 1.0 mg/L和AgNO3 5.0 mg/L的不定芽诱导培养基上,珂字棉312和泗棉3号的不定芽诱导频率分别为70%和60%左右.     

Application of Gibbereilic Acid on Diploid and Tetraploid Cotton Hybridization

Gibberellic acid growth regulator was used to develop interspecific hybrids between tetraploid and diploid species to increase the genetic variability in cotton.     

新疆棉花子叶节直接诱导多芽发生再生植株的研究

以中国三大棉花产区之一的新疆棉花中长绒陆地棉和特色长绒棉品种为试验材料,采用子叶节作外植体,为防止陆地棉品种外植体褐化的影响,以分步添加6-BA来启动和/或诱导多芽的发生,此时用葡萄糖作为碳源代替通常使用的蔗糖,经过伸长培养后,以1/2 MS培养基添加10 mg/L BA诱导生根,生根率可达72.2;.并通过对不同品种诱导多芽发生的比较,认为以子叶节为外植体直接诱导多芽发生受棉花品种的基因型影响不大,为用农杆菌介导法规模化遗传改良棉花奠定基础.     

国外陆地棉高强纤维种质有关经济性状相关分析

本研究分析了国外高强纤维种质的若干经济性状的相关特征,表明纤维强度与长度存在较大的正向偏相关（r偏＝０．１８１）,麦克隆值与纤维长度呈显著负向偏相关（r偏＝（－０．３４４＊＊）;因此选择长、强、细纤维在实践上是可行的。但是纤维比强度与衣分存在显著负向偏相关＝－０．２８７＊＊）,麦克隆值与衣分存在较大的正向偏相关（r偏＝０．２０３）;因此,在以高强纤维为目标的特用优质棉种中,采用高衣分选择模式须持谨慎态度。     

棉花优良品种中棉所19高频体细胞胚胎发生细胞系筛选与植株再生

选用我国优良棉花品种中棉所19进行组织培养, 研究了该品种的体细胞胚胎发生和植株再生能力。 中棉所19的体细胞胚胎发生有两种情况： 一是由外植体直接诱导获得胚性愈伤组织和体细胞胚; 二是先诱导获得愈伤组织, 再经继代培养获得胚胎发生。 单独使用ZT可在早期诱导胚胎发生, 在该情况下, 对子叶的诱导能力最强, 胚根     

从多毛野生番茄中初步鉴定出一个抗美洲斑潜蝇的显性基因

美洲斑潜蝇(LiriomyzasativaeBlandchard)是危害番茄生产的主要害虫之一,从番茄近缘野生种中挖掘优异的抗斑潜蝇基因,并研究抗虫基因的遗传,是番茄抗虫遗传改良的重要基础。将筛选到的高抗美洲斑潜蝇的野生多毛番茄(L.hirsutum)材料LA2329,与高感美洲斑潜蝇栽培番茄早粉2号杂交,并用早粉2号为母本与杂种F1回交,通过对各世代抗斑潜蝇的人工接种鉴定,初步判定该抗性由单显性基因控制。番茄属中由单显性基因控制的对斑潜蝇抗性,目前尚未见报道。该抗性基因的发现,将为今后番茄抗斑潜蝇育种提供宝贵资源,有望在不远的将来通过标记辅助育种手段而引入栽培番茄,为我国番茄生产中害虫的防治提供环保、经济而有效的科技支撑。