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.     

Evaluation ofFusarium wilt-resistance in primitive races ofGossypium hirsutum L.

Seven primitive races ofGossypium hirsutum L.punctatum, marie-galante, richmondi, latifolium, morrilli, palmeri, mexicanum and five F₁ crosses were inoculated withFusarium f. sp.vasinfectum physiological strain I. in the wilt field of Cixi Cotton Institute in 1987. There were highly significant differences among these primitive races.Punctatum andpalmeri were highly resistant. The resistances ofmarie-galante andmexicanum was similar with that of cultivar ‘Simian2’;richmondi, latifolium andmorrilli were susceptible. The disease incidence of F₁ in five primitive races hybridized with cultivar ‘Simian2’ was generally higher than that of mid-parent value. Inheritance of wilt resistance was partially dominant. In addition, 178 accessions of eight primitive races were evaluated for their resistance as before in 1989. There were significant differences in resistance among races and intra-race accessions. There were wilt resistance accessions among primitive races in which disease incidence was below 10%–25%. Inpalmeri, marie-galante, richmondi andpunctatum, one accession was immune with 0% disease incidence, respectively; 22.7–77.4% accessions were susceptible with 50% disease incidence. It showed that primitive races were mixed populations. They should be evaluated and screened for their utilization in cotton breeding program. Some best plants were selected from F₂ of two crosses, ‘Simian2’ ×palmeri and ‘Simian2’ ×mexicanum, based on the resistance toFusarium wilt and the response to photoperiod. 11 lines had been obtained with good fiber quality and relatively high potential production by backcrossing improvement. These lines are now being tested.     

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.     

Response of cotton (Gossypium hirsutum L.) to different tillage systems and intra-row spacing

The earliness is of great importance to cotton production in Mediterranean-type environments due to detrimental effects of autumn rainfall on lint quality. However, farmers commonly avoid early sowing due to risks of cold soil temperature and waterlogging after sowing in spring. Ridge-tillage system is one approach to increase soil temperature and mitigate adverse effects of waterlogging. The ridge-tillage system is also advantageous in reducing inputs in tillage operations. However, a limited experimental data are available about the effects of ridge-tillage system on earliness of harvesting, lint yield and quality of cotton in the Mediterranean-type environments. Thus, the objective of this study was to determine how ridge-tillage (RT)-planting system and intra-row spacing affect cotton lint yield, earliness and fiber quality compared with conventional tillage (CT)-planting system. Field experiments were conducted on a clay soil (Vertisol) in Hatay province (36°39′N–36°40′E, 83 m a.s.l.) in the Eastern Mediterranean Region of Turkey during 2000 and 2001. The experiment was laid out as a split-plot with three replications with tillage systems as main plots and intra-row spacings (13, 17, 21 and 25 cm) as subplots. The effects of tillage systems on lint yield and earliness were inconsistent among years. The RT-planting system resulted in 13.5% higher lint yield and 14.5% more earliness in 2001 when abundant rainfall occurred after sowing, while significant effects of tillage systems were not observed in 2000. The intra-row spacings significantly affected lint yield and earliness in both years. The earliness increased with closer spacing, while the highest lint yield was obtained from 17 cm intra-row spacing in both years. However, the fiber quality parameters were not significantly affected by tillage systems, intra-row spacings and tillage system × spacing interaction in both years. Finally, the results suggest that RT-planting system with 17 cm intra-row spacing can be used in cotton production instead of CT-planting system in the Eastern Mediterranean Region of Turkey. Ridging in 17 cm intra-row spacing also seems to be suitable to mechanical harvesting.     

Agronomic traits at the seedling stage,yield, and fiber quality in two cotton (Gossypium hirsutum L.) cultivars in response to phosphorus deficiency

ABSTRACT

Cotton is critical for phosphorus demands and very sensitive for its deficiency. However, identifying the effect of low-phosphorus tolerance on cotton growth, yield, and fiber quality by reducing phosphorus consumption. This may help to develop phosphorus-tolerant high-yielding cotton cultivars. In a two-year repeated (2015 and 2016) hydroponic experiment (using 0.01 and 1 mM KH₂PO₄), two cotton cultivars with phosphorus sensitivity (Lu 54; a low-phosphorus sensitive and Yuzaomian 9110; a low-phosphorus tolerant) were screened on the base of agronomic traits and physiological indices through correlation analysis, cluster analysis and principal component analysis from 16 cotton cultivars. Low phosphorus nutrition reduced the plant height, leaf number, leaf area, phosphorus accumulation and biomass in various organs of seedlings. The deficiency negatively affected the morphogenesis of seedlings, as well as yield and fiber quality. Further, these screened cultivars were tested in a pot experiment with 0, 50, 100, 150, 200 kg P₂O₅ ha^?1 during 2016 and 2017. It was found to have a significant (P< 0.05) difference in boll number, lint yield, fiber strength, and micronaire at the harvest. Furthermore, after collectively analyzed the characteristics of Lu 54 and Yuzaomian 9110, there were six key indices that could improve the low phosphorus tolerance of cotton cultivars. These were root phosphorus accumulation, stem phosphorus accumulation percentage, leaf and total biomass of seedlings, seed cotton weight per boll and fiber length.     

Effect of nitrogen and wheat residue on cotton (Gossypium hirsutum L.) yield and weed control

Wheat (Triticum aestivum L.) residues and nitrogen (N) management are the major problems in the southern part of Iran where irrigated wheat–cotton (Gossypium hirsutum L.)–wheat rotation is a common practice. A 2-year (2009–2011) field experiment was conducted as a split plot design with four replications at a cotton field (Darab), Fars Province, Iran, to determine the influence of different rates of wheat residue (0%, 25%, 50%, and 75%) incorporation and N rates (150, 200, 300, and 400 kg ha^?1) on weed suppression, yield, and yield components of cotton. Results showed that a higher residue incorporation and a lower N rate improved weed suppression in both years. For treatments receiving 150 kg N ha^?1 and 75% of wheat residues (2250 kg ha^?1), weed biomass and density were significantly lower compared to treatments receiving 400 kg N ha^?1. The highest cotton lint yield (about 2400–2700 kg ha^?1) was obtained by 300 kg N ha^?1 in the absence of residue application, in both years. Incorporation of 25% of wheat residue (750 kg ha^?1) and application of 300 kg N ha^?1 are recommended to guarantee an optimum level of cotton lint yield and weed suppression in a wheat–cotton–wheat rotation in this region.     

A-genome cotton as a source of genetic variability for Upland cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis>)

Since Upland cotton (Gossypium hirsutum) is known to have relatively low levels of genetic diversity, a better understanding of variation and relationships among possible sources of novel genes would be valuable. Therefore, analysis of genetic variation of the genus Gossypium, especially the diploids, which are the putative donors of the A and D genomes for the commercially important allotetraploid cottons (AADD), G. hirsutum and G. barbadense, could provide important information about the feasibility of using these genetic resources for cotton improvement. The primary objective of this study was to analyze the genetic diversity in A-genome diploid cotton species, G. herbaceum (A1) and G.␣arboreum (A2) by using microsatellite markers. Forty-one A-genome germplasm accessions were evaluated with 32 microsatellite loci. Genetic similarities between A1 and A2 ranged from 0.62 to 0.86 with a mean of 0.70. Within each A-genome species similarities ranged from 0.80 to 0.97 with a mean of 0.89 for A1 and from 0.82 to 0.98 with a mean of 0.89 for A2. A UPGMA tree and principal coordinate analysis based on genetic similarity matrices showed distinct clusters consistent with the genomic groups.     

Evaluation of Gossypium arboreum L. Germplasm for resistance to thrips

Summary As part of a project to assess the U.S. Asiatic Cotton Germplasm Collection as a source of genes for pest resistance, forty-three accessions of Gossypium arboreum L. were evaluated for resistance to thrips. Thrips, Thysanoptera spp., are a minor, but widespread pest on cotton, G. hirsutum L. and G. barbadense L. Accessions were planted in free-choice field tests in 1988, 1989, and 1990 at the Cotton Branch Experiment Station, Marianna, Arkansas. Damage ratings, based on a scale of 0 (no damage) to 7 (severe damage), were made approximately one month after planting. Relative score was computed by dividing the rating of each accession by the rating of the reference, G. hirsutum Stoneville 506. The relative score averaged over all G. arboreum accessions by year varied with the year, but was less than 100 (relative score for Stoneville 506) in each case. When data were combined for all three years, twenty-five accessions were significantly better than Stoneville 506. Introgression of the better accessions into G. hirsutum is now in progress.Abbreviations NPGS National Plant Germplasm System - STV 506 G. hirsutum Stoneville 506     

膜下高频滴灌对土壤温湿环境及棉花产量的影响

以田间试验为基础,对高频覆膜滴灌条件下土壤水分、温度以及棉花的耗水过程和生长状况进行了观测。结果表明,高频滴灌条件下,灌水次数及灌水量分别比对照多20次和596.2mm,土壤含水率水平较高,棉花根系吸水阻力小,耗水强度大,可达7.4mm/d。各生育阶段高频滴灌的土壤温度比对照低,而且根系分布浅。另外,高频滴灌棉花地上营养器官生长旺盛,叶面积指数很大,可达到6.6。然而,高频滴灌棉花产量比对照低111.34kg/hm2,水分利用效率低。试验认为高频滴灌的生产意义不显著。     

Variability Among Maize (Zea mays L.) Inbred Lines for Seed Longevity

Genotypes conserved in active collections may suffer genetic erosion and modifications. The objective of this work was to investigate changes in germination and vigour in maize (Zea mays L.) inbred lines during cold storage in an active collection. Seeds of 16 maize inbreds produced along 16 years were evaluated for emergence and seedling vigour in a growth chamber. Linear and quadratic regressions of vigour and viability-related traits over seed age were calculated and tested for homogeneity. The seed of five production years of five inbreds that behaved differently in the regression analysis was multiplied in 1998, and original and renewed seed were evaluated in a growth chamber in 1999. Viability and vigour decreased linearly with age for most inbreds, particularly for B84 and EP10, varied at random for a few inbreds, and remained high for EP56 and A295. Aging caused reduction of vigour and loss of viability in most inbreds. There was variability for seed longevity among inbred lines; longevity was highest for inbred EP56. During storage, some seeds of each inbred died, while enduring seeds, when multiplied, produced new seed with enhanced viability and vigour compared to the average seed of the inbred, suggesting natural selection for viability and vigour during storage within inbred lines.     

施氮量对不同开花期棉（Gossypium hirsutum L.）铃纤维细度和成熟度形成的影响

为兼顾试验的重复性和生态区域性,选用高品质棉（科棉1号）和常规棉（美棉33B）品种为材料,于2005年分别在江苏南京（118o50E, 32o02N,长江流域下游棉区）和江苏徐州（11711E, 3415N,黄河流域黄淮棉区）设置施氮量（低氮:N 0 kg/hm2;适氮:N 240 kg/hm2;高氮:N 480 kg/hm2）试验,研究施氮量对不同开花期棉铃纤维细度、成熟度和马克隆值形成的影响。结果表明:（1）施氮量显著影响棉纤维细度、成熟度和马克隆值的形成过程,但三者在不同开花期对氮素水平的响应不同,施氮量与开花期对棉纤维细度、成熟度和马克隆值的形成存在互作效应。8月10日前开花的棉铃,铃期［花后0～50 d （DPA）］日均温在23.3 oC以上,纤维细度、马克隆值以N 0 kg/hm2施氮量下最大,棉纤维马克隆值与纤维细度的相关性较大;8月25日开花的棉铃（铃期日均温在20.8～23.3 oC之间）,纤维成熟度、马克隆值以N 240 kg/hm2施氮量下最大;9月10日开花棉铃（铃期日均温低于20.8 oC）,纤维细度、成熟度和马克隆值均以N 480 kg/hm2最大,棉纤维马克隆值与纤维成熟度的相关性增强。（2）影响不同开花期间纤维细度、成熟度和马克隆值的主要因素是铃期日均温,最终纤维细度、成熟度和马克隆值在不同施氮量之间的变异与不同开花期（铃期日均温不同）间的变异比较,前者显著小于后者。综上,因开花期不同而形成的铃期日均温是决定细度、成熟度和马克隆值的最重要因素,施氮量可通过对位叶叶氮浓度NA影响棉纤维细度、成熟度和马克隆值的形成过程,增加施氮量可减小上述指标在不同开花期间的差异。     

Genetic Diversity of Asian Cotton (Gossypium arboreum L.) in China Evaluated by Microsatellite Analysis

Asian cotton (Gossypium arboreum L.) was once widely cultivated in China. It has also been a valuable source of genetic variation in modern cotton improvement. In this study, the genetic diversity of selected G. arboreum accessions collected from different regions of China was evaluated by microsatellite (simple sequence repeats, SSRs) analysis. Of the 358 microsatellite markers analyzed, 74 primer pairs detected 165 polymorphic DNA fragments among 39 G. arboreum accessions examined. Twelve accessions could be fingerprinted with one or more SSR markers. With the exception of two accessions, DaZiJie and DaZiMian, genetic similarity coefficients among all accessions ranged from 0.58 to 0.87 suggesting high level of genetic variation in the G. arboreum collections. The UPGMA dendrogram constructed from genetic similarity coefficients revealed positive correlation between cluster groupings and geographic distances. In addition, comparison of the microsatellite amplification profiles of the diploid G. arboreum and tetraploid Gossypium hirsutum L. found that size distribution of amplified products in G. arboreum was dispersive and that of G. hirsutum was relatively concentrated. The information on the genetic diversity and SSR fingerprinting from this study is useful for developing mapping populations for constructing diploid cotton genetic linkage map and tagging economically important traits.Diqiu Liu, Xiaoping Guo: These two authors contributed equally to this work.     

基于GGE分析的西北内陆棉区纤维品质生态区划分

本文选用2005—2014年我国棉花区域试验西北内陆早熟棉区7个和早中熟棉区10个试验点作为试验环境进行纤维品质区域分布分析。运用GGE模型划出双标图,研究西北内陆棉区的试验环境与参试品种纤维品质性状互作模式,对参试品种性状选择适宜的生态区进行探讨与划分,并基于GGE双标图对纤维物理性能指标相关性进行研究,为西北内陆棉区棉花品种区域化种植和理想试验环境选择提供依据。结果表明:(1)棉花各纤维品质性状相互之间存在着一定的相关关系,纺纱均匀性指数与长度、比强度和整齐度指数表现极显著或显著正相关。(2)西北内陆棉区早熟组纤维品质性状可划分为3个生态区:优质棉纤维生态区(精河)、普通优质纤维生态区(兵团第六师昌吉、乌苏)、普通纤维生态区(兵团第七师125团、兵团第八师121团、石河子以及敦煌)。(3)西北内陆棉区早中熟组品质性状由优质到普通亦可划分为3个生态区:优质纤维生态区(莎车、轮台、巴州、库车、疏附、兵团第一师阿拉尔13团以及新疆塔河10团)、普通优质纤维生态区(麦盖提和兵团第三师喀什)、普通纤维生态区(阿克苏)。因此西北内陆早熟棉区应在注重品种早熟性选育的基础上,注重优质纤维综合品质性状的培育,提高纤维的长度和比强度。南疆的早中熟棉区,注重推选适合机采棉的长度和比强度的棉花品种外,应精准掌握合理的棉花采摘期,提高纤维成熟度,但要注重降低马克隆值,划分优化种植区域为棉纺企业合理用棉提供多层次的原棉材料。     

On the specific status of Gossypium lanceolatum Todaro

Summary Gossypium lanceolatum comprises a group of laciniate-leaved commensal cottons from the Mexican states of Oaxaca and Guerrero. This geographically restricted, morphologically distinct group of perennial cottons has been considered conspecific with G. hirsutum, with which it is sympatric. In addition to its questionable specific status, G. lanceolatum has added importance because it represents the focal point of an hypothesis that New World tetraploid Gossypium have a polyphyletic origin—an hypothesis that conflicts with the more widely accepted view that New World tetraploid Gossypium have a monophyletic origin. To reassess the systematic and genetic relationships between G. lanceolatum and G. hirsutum, historical data were reconsidered in the context of recently published molecular marker based data. Chloroplast and nuclear DNA markers fail to discriminate G. lanceolatum from G. hirsutum, uniting both into a single phylogenetic lineage. A new analysis of allelic variability at 50 allozyme loci in 11 G. lanceolatum and 527 G. hirsutum accessions demonstrates that G. lanceolatum has no unique alleles relative to G. hirsutum. Genetic identity estimates were uniformly high (> 0.96) among G. lanceolatum and geographically adjacent, mainland Mesoamerican groups of G. hirsutum accessions. Multivariate analyses demonstrated that G. lanceolatum is genetically embedded within geographically adjacent populations of G. hirsutum. These data, in conjunction with the complete interfertility between the two taxa and previous evidence for conspecificity, lead to the conclusion that G. lanceolatum does not warrant specific status. Rather, it is more properly recognized as a locally developed, domesticated form of G. hirsutum, i.e., G. hirsutum race palmeri.     

基于GGE双标图和马克隆值选择的棉花区域试验环境评价

棉纤维马克隆值是与纤维成纱品质密切相关的重要品质指标,也是长江流域棉花品质改良的主要制约因子。选择利用对目标环境代表性强的试验点进行区域试验布局有助于提高马克隆值育种效率和节省试验成本。GGE双标图是进行试验点代表性评价和选择最有效的统计和图形展示工具,已经在多种作物区域试验中用于品种稳定性和试验环境相似性分析,但在基于马克隆值选择的棉花区域试验环境评价中应用报道较少。本文采用GGE双标图方法对2000—2010年期间27组长江流域国家棉花区域试验中的15个试验环境基于马克隆值选择的鉴别力、代表性和理想指数进行综合评价与分析。结果表明:各试验环境依理想度指数优劣排序为荆州市>黄冈市>南通市>九江市>岳阳市>射洪县>常德市>安庆市>武汉市>南阳市>南京市>慈溪市>襄阳市>简阳市>盐城市;从中筛选出最理想试验环境为湖北省荆州市,较理想试验环境为湖北省黄冈市、江苏省南通市和江西省九江市,这些试验环境对以长江流域为目标环境的广适性新品种选育和作为区域试验点鉴别理想品种的效率最高;而位于江浙沿海棉区的江苏省盐城市和浙江省慈溪市不适宜作为针对长江流域的马克隆值选择与推荐环境。本研究充分展示了GGE双标图在区域试验环境评价方面的应用效果,也为以长江流域棉区为目标环境的广泛适应性和特殊适应性品种的马克隆值选择和应用提供理论依据。     

Sampling a Core Collection of Island Cotton (Gossypium barbadense L.) Based on the Genotypic Values of Fiber Traits

A genetic model, including effects of environments, genotypes, and genotype by environment interaction, was employed to analyze five fiber traits of Island cotton (Gossypium barbadense L.). Genotypic values of 304 accessions were predicted by the adjusted unbiased prediction (AUP). Genetic similarities between different accessions were measured by Mahalanobis distances based on genotypic values. Appropriate sampling strategies, linkage rules in stepwise clustering, and sampling proportion were evaluated. To form a core collection of Island cotton, 60 accessions were sampled by the deviation sampling strategy combined with single linkage rule of hierarchical clustering. The genetic variation and structure captured by the core collection were examined in means, variances, ranges and coefficients of variation, correlation coefficients of quantitative traits, and the accessions distribution plotted by first two principal components between two collections. It was showed that the initial collection was well represented by the core collection for exploiting the Island cotton germplasm. These authors contributed equally to this work.     

膜下滴灌条件下棉株温湿度微环境

通过对膜下滴灌棉花根区土壤温度、水分、冠层叶温、气温及冠层空气湿度的观测,分析了该灌水条件下棉花土壤水、热关系,冠层温、湿度关系,结果发现:棉花根区土壤水分与温度之比在深度方向上近似呈线性关系,冠层叶—气温差与空气饱和差也呈线性关系,说明膜下滴灌技术能够为棉花根系提供良好的吸水环境,有利于棉花生长。     

基于GGE双标图和比强度选择的棉花品种生态区划分

由于农作物品种区域试验是品种审定和推广应用的前提,而区域试验中基因型与环境的互作效应是普遍存在的,因而探索和利用试验环境在鉴别基因型遗传差异和对品种在目标环境中的平均表现代表性方面的作用以辅助品种选育和推广的问题,越来越受到植物育种家和农技推广人员的高度关注。我们采用GGE双标图分析方法对2000—2010年期间27组长江流域国家级棉花品种区域试验的目标环境中可能存在的基于棉纤维比强度选择的品种生态区进行探索与划分,并对品种生态区划分结果进行信息比(IR)校正,以提高品种生态区划分的可靠性。结果表明:(1)基于纤维比强度选择的GGE双标图分析的总体有效拟合度为68.4%,其中有13次出现过度拟合或拟合不充分现象,总体拟合可靠性一般。而基于IR-GGE模型的总体拟合度为73.7%,比GGE双标图的有效拟合度提高6.0%,说明采用IR对双标图分析的结果进行优化和校正可以提高品种生态区划分的可靠性。(2)根据GGE双标图分析结果,我国长江流域棉区大致可划分为4个基于纤维比强度选择的品种生态区,第1个品种生态区包括安庆、襄樊、南通和岳阳,第2个品种生态区包括常德、九江和武汉,第3个品种生态区包括慈溪、南京、黄冈、荆州和盐城,第4个品种生态区包括南阳、简阳和射洪。而基于IR较正的GGE模型则可划分为3个品种生态区:第1个为主体品种生态区,包括安庆、武汉、九江、襄樊、南阳、岳阳、常德、黄冈、荆州、南京和慈溪11个试验点,第2个品种生态区包括南通和简阳,第3个品种生态区包括盐城和射洪。IR校正后长江流域棉区的品种生态区划分更准确可靠,地理区域特性也更明显,说明地理环境因素对纤维比强度的选择效果仍然有很大的影响力,四川盆地棉区和江苏沿海棉区并不适宜开展针对整个长江流域棉区的广适性棉花纤维比强度选择,从而为长江流域棉区棉花纤维比强度的选择和推荐策略提供了科学的决策依据。     

基于同异性分析的不同类型棉花品种纤维品质特征与分类评价

为精确分析中国棉花纤维品质的区域特征、分布规律及综合性评价,以2005-2014年国家棉花品种区域试验531个参试品种纤维品质数据为材料,运用作物育种同异性分析理论对杂交棉和常规棉品种的纤维品质进行综合评价。结果表明：1）常规棉品种纤维品质符合审定标准Ⅰ型、Ⅱ型和Ⅲ型的品种数分别占参试常规棉品种数的1.58%、28.42%和14.74%,杂交棉纤维品质符合审定标准Ⅰ型、Ⅱ型和Ⅲ型的品种分别占参试杂交棉品种数的0.59%、19.94%和10.56%。黄河流域常规棉品种、杂交棉品种纤维品质综合同一度分别为0.869 3和0.888 8,长江流域杂交棉纤维品质综合同一度为0.864 3,西北内陆棉区常规棉纤维品质综合同一度为0.890 5。2）不同棉区常规棉与杂交棉纤维品质性状比较表明,西北内陆棉区常规棉品种纤维品质性状优于黄河流域杂交棉;而黄河流域杂交棉又优于黄河流域常规棉和长江流域杂交棉,黄河流域常规棉与长江流域杂交棉纤维品质性状差异不显著。可见,黄河流域棉区适宜种植推广中长绒、高比强和高马克隆值的常规棉品种;长江流域棉区适宜种植中长绒、高比强度和高马克隆值的杂交棉品种;西北内陆棉区适合种植长强细的优质常规棉品种,可作为棉纺工业纺中高支纱的优质棉生产基地。本研究对优化我国优质棉区域布局和种植结构调整有重要参考价值。     

Identification of double/twin bolled and bicolor unit ‘cluster’ in <Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L. cotton

Cultivated tetraploid Gossypium hirsutum L. (Malvaceae) cotton has been characterized as having one flower at a primordia. In a strain (CSH-13) of Gossypium hirsutum cotton, four plants out of 103 had two to three double bolls or twin bolls/plant during 2003–2004 crop season at CICR regional station, Sirsa, Haryana, India. Progeny evaluation in 2004 and 2005 crop seasons indicated that plants raised from seeds harvested from double bolls/twin bolls produced plants bearing double bolls only and plant progeny raised from the seed of single bolls from these mutant plants produced two to three double bolls per plant similar to the parent. Progeny testing revealed that double boll formation is the result of spontaneous mutation and environment does not influence its expression. The mutant is early in maturity by 10–15 days, naked seeded and possesses comparable agronomic characters with normal plants. Another spontaneous mutant of Gossypium hirsutum having more than three appendages originating from primordia.: four bolls one leaf, three bolls one leaf, two bolls two leaves, one boll three leaves were obtained from the population of CISV-13 strain in crop season 2003. These appendage groups have been described as bicolor unit by Clemens Bayer, [Zur Infloreszenzmorphologie der Malvales. Dissertations Botany 212 (1994)] and cluster mutant by Russell and Luther [J Cott Sci 6 (2002) 115]. One to three bolls in a cluster or bicolor unit were observed without formation of seeds and lint. About one-third of the total bolls on the mutant plant were of this type. In progeny testing during 2004 and 2005 crop seasons, this mutant produced plants exclusively with more than three appendages revealing that plants identified in 2003 were due to spontaneous mutation. This mutant was also early and naked seeded. Many of the other characters of the mutant plants were comparable with the wild type plants of the strain. Both the mutants were observed having economic impact due to their better yielding ability as compare to respective parents.