陆地棉四室铃、五室铃棉铃性状及其种子性状的相关研究

2014年在一师十团中棉所试验田种植32个棉花品种,研究陆地棉四室铃和五室铃及其种子性状。结果表明,四室铃在经济系数、种子出仁率、衣分率、子指、衣指方面均高于五室铃,而五室铃单铃重、铃壳重和实数种子数高于四室铃。此外,对四室铃与五室铃及其种子性状的相关分析得出,影响2种铃室及其种子性状的不仅有相同因素,还有不同因素:(1)2种铃室的衣分率均受子指、衣指和不孕籽率的影响,且达到显著水平;四室铃衣分率还受到实数种子数和种子出仁率的影响,且达到显著水平;五室铃衣分率还受经济系数的影响,且达到显著水平。(2)2种铃室的子指受种子不孕率的影响达到极显著水平;四室铃不孕籽率还受衣指、实数种子数、种子出仁率和仁壳比的影响,其中,受衣指影响达极显著水平;受实数种子数、种子出仁率和仁壳比的影响达显著水平。(3)2种铃室的单铃重均受到铃壳重和衣指的影响,且达极显著水平。四室单铃重受子指影响达到极显著水平,而五室铃受实数种子数的影响达极显著水平。     

陆地棉种子品质性状与棉花产量性状的遗传相关性分析

采用包括基因型与环境互作的双子叶作物种子遗传模型和农艺性状遗传模型，分析了陆地棉五个亲本及其Ｆ１、Ｆ２棉子仁的油分含量、油分指数、蛋白质含量和蛋白质指数、棉子的子指、容重、仁壳比和仁指以及棉花植株单株产量、革株铃数、单铃重的两年实验资料，估算了棉仁营养品质性状及棉子物理性状与棉花在艺性状间的各项近传协方差分量。结果表明，棉子仁营养品质和种子物理性状与单株产量遗传相关均不显著，油分含量、油分指数、蛋白质指数、子指、容重和仁指的细胞质效应、母体遗传效应与单株铃数的相应遗传效应存在显著的负向协方差，其互作协方差也为显著的负值。这６个种子性状与单铃重的遗传关系列相反，这些效应均为负相关。衣分与大多数种子性状不存在明显的遗传相关性，仅与蛋白质指数、子指和仁指有明显的细胞质和母体效应的正相关。     

衣分不同陆地棉品种的产量及产量构成因素的遗传分析

选用衣分不同的陆地棉品种配置组合,率先将主基因-多基因联合世代分析与双列杂交试验分析相结合,分别从单个和整体基因水平上对棉花产量及产量构成因素进行了遗传研究。对2个高×低衣分组合的主基因-多基因6世代联合分析结果表明,各产量性状至少在1个组合中检测到主基因的存在,说明产量性状主基因存在的普遍性。由2个组合各产量性状的主基因、多基因遗传率比较得出,产量性状的主基因遗传率比多基因遗传率在不同组合间趋势变化相对较稳定;各性状在2个组合中的主基因、多基因遗传率分量不完全相同。衣分、铃重和籽指在2个组合中分别以主基因遗传为主和以多基因遗传为主;子棉产量和皮棉产量在2个组合中均以主基因遗传为主;衣指在组合I中以多基因遗传为主,在组合II中属于典型的多基因遗传;单株铃数在组合I中属于典型的主基因遗传,在组合II中以多基因遗传为主。双列杂交结果表明,陆地棉产量及产量构成因素都有较高的遗传主效应方差,产量性状受加性效应和显性效应共同控制,其中,衣分、衣指以加性效应为主;子棉产量、铃重和籽指以显性效应为主;皮棉产量和单株铃数以加性和显性效应为主。衣分和衣指的普通广义遗传率和普通狭义遗传率均最高,与联合世代分析两性状的总遗传率平均值结果趋势一致。相关和通径分析一致表明,产量构成因素中单株铃数对皮棉产量的贡献最大,衣分次之,铃重最小。     

海岛棉产量构成因素的遗传模型测验

本试验采用增广NCII设计，对海岛棉单株有效铃数、单株籽棉重、衣指及单铃重等产量构成因素进行遗传模型测验。结果表明：单株有效铃和单株籽棉重符合加性模型，衣分符合加性一显性模型，均存在着极显著的加性效应，单铃重符合加性一显性一上位性模型，存在显著的加性效应和上位性效应。增效、减效等位基因频率在雌、雄亲闯的分配，单株有效铃、单株籽棉重和单铃重有明显差异。单株有效铃、单株籽棉重、衣分和单铃重均为超显性遗传，该4个性状的增效、减效等位基因均可能为显性或隐性，随基因位点而不同。     

棉花抗红铃虫性对产量性状的影响研究

以不同抗性类型的陆地棉抗虫品种(系)和常规棉品种(系)作亲本配制杂交组合,将亲本和F1代杂交种共20个材料在网室、田间进行抗红铃虫鉴定和棉花抗红铃虫性对棉花产量的影响研究,试验表明,具有外源抗虫基因的抗虫棉皮棉产量高,稳产性好,尤其是抗虫杂交棉具有明显的杂种优势。相关分析结果,棉花种子虫害率与皮棉产量、子棉产量、单株成铃数和霜前花率呈极显著负相关;与衣分和僵瓣黄花率成极显著正相关;与单铃重相关性较低。结果表明,利用外源抗虫基因转导的棉花新材料作为杂交亲本,可以培育出丰产高抗棉花害虫的棉花新品种,尤其适合培育抗红铃虫的杂交棉品种。     

气象因子对湖南省棉花经济性状影响的研究

为探索棉花主要经济性状与气象因子之间的量化关系,采用灰色系统和逐步回归法研究了温度、光照时数、空气湿度、降水量对棉花经济性状的影响。结果表明,在湖南气候条件与栽培技术体系下,光照时间、温度与单铃重、籽指关联系数大,与衣分、衣指关联系数小;而降水量、湿度与单铃重、籽指关联系数小,与衣分、衣指关联系数大;温度、光照时间对单铃重、籽指起正作用,降水量在较少的情况下对单铃重起正作用,但超过一定界限后,反而起负作用。降水量对衣分、衣指起正作用。     

陆地棉配合力与杂种优势、遗传距离的相关性分析

 用10个陆地棉亲本进行不完全双列杂交,共配置了45个组合,计算亲本的一般配合力（GCA）、特殊配合力(SCA)、杂种优势,并结合SSR标记研究了陆地棉亲本配合力与杂种优势、遗传距离之间的相关关系。配合力分析发现,10个亲本的一般配合力和特殊配合力存在显著或极显著差异。分析亲本配合力、杂种优势和遗传距离的相关性发现,子棉产量、皮棉产量、衣分的一般配合力和杂种优势呈显著或极显著相关,纤维长度、比强度、麦克隆值、株高、果枝数、单株铃数、铃重、子棉产量、皮棉产量、衣分的特殊配合力和杂种优势均呈极显著正相关,而与遗传距离相关均不显著。单株铃数、铃重、子棉产量、皮棉产量、衣分的杂种优势与遗传距离均为正向显著或极显著相关。在育种实践中这些显著或极显著相关的性状可能具有较高的改良潜力。     

棉花复合杂交育成亲本主要产量性状的杂种优势及配合力分析

为测定利用复合杂交育成的5个亲本的育种应用潜力,将5个亲本与4个推广品种采用不完全双列杂交设计配制20个组合,对组合的产量及相关性状的杂种优势进行分析,并对5个亲本的产量及相关性状进行配合力分析.结果:铃数对产量的贡献最大;A1亲本在铃数,A2亲本在衣分,A3亲本在铃重,A 5亲本在铃重、衣分性状上一般配合力(GCA)为正,A 5亲本是一个较理想的亲本;具有较高特殊配合力效应(SCA)的组合有A5×B3、A2×B2、A3×B1.结论:利用复合杂交培育高配合力亲本是可行的;但不同来源的亲本在同一性状,同一亲本的不同性状间一般配合力(GCA)是不同的;同一性状的不同组合间,同一组合的不同性状间特殊配合力(SCA)效应也都存在大小或方向上的差异.     

基于陆地棉背景的海岛棉染色体片段导入系产量性状QTL定位

棉花产量分为籽棉产量和皮棉产量,其中高皮棉产量总是育种的首要目标。皮棉产量由单株铃数、衣分、单铃重等因素组成。其中衣分在各因素中的遗传率最高,同时也是产量育种中重要的选择指标。育种中利用分离群体对单株铃数、铃重等产量性状选择受环境影响较大。利用染色体片段导入系进行铃数、铃重等产量性状的定位,定向改良产量性状,是棉花分子设计育种的有效方法。本研究利用陆地棉TM-1为轮回亲本和海岛棉海7124为非轮回亲本构建了一套陆地棉背景的染色体片段导入系,并在7个环境的田间试验下,鉴定了它们的产量表现,定位了28个与单株铃数、铃重、衣分和籽指相关的QTL。其中,在Dt亚组染色体上鉴定出的产量性状QTL多于在At亚组染色体上鉴定出的。28个QTL中,加性效应为正的16个,加性效应为负的12个,表明海岛棉不同的导入片段效应不同,有的片段可以提高陆地棉产量,有的则降低陆地棉产量。在6个环境下,导入系IL008(特征标记NAU2573和NAU3576)的衣分均显著高于轮回亲本TM-1,因此IL008可以应用于棉花分子育种,定向改良陆地棉的衣分。     

陆地棉主要经济性状的遗传分析

通过陆地棉主要经济性状的基因效应方差分析,表明产量性状显性方差占表现型变异比率最高,单株铃数显性×环境方差占62．4％,达极显著水平。纤维品质性状中,2．5％跨长、比强度及麦克隆值分别以显性方差、加性方差和加×加上位性方差为主。产量性状普通狭义遗传率、普通广义遗传率最高的均是衣分,最低的都是单株铃数。互作狭义遗传率最高的也是衣分,为11．4％,单株铃数和单铃重互作广义遗传率较高,都在68％以上。2．5％跨长的普通狭义遗传率最低,仅为4．2％,比强度普通狭义遗传率高达55．5％。同时还计算了各对性状基因型相关值。     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Relation between wheat-rye crossability and seed set of common wheat after pollination with other species in the Hordeae

Summary Cultivars of common wheat (Triticum aestivum L. em. Thell.) of high wheat-rye (Secale cereale L.) crossability set more seed with pollen of other related species than did wheats of low wheat-rye crossability. This was found to be true for pollen parents from the genera Triticum, Aegilops, Secale, Agropyron and Elymus.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Breeding apomictic bahiagrass (Paspalum notatum Flügge) with improved turf traits

The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H²) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H² indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Inheritance of fruit colour in a wild Russian red raspberry seedling

Summary A new gene, i, from a self-incompatible wild Russian Rubus idaeus seedling is described. The gene i interacts with the fruit colour gene T, Tii plants having apricot instead of red fruits, and spines, leaves and stems pigmented to varying degrees. A deficit of apricot-fruited seedlings in progenies segregating for i could be explained by linkage between i and the self-incompatibility S locus with a crossover value of approximately 26.7%.Segregations for spine colour in crosses and backcrosses of the Russian seedling with two green-spined (ttII) raspberries selected for their yellow fruit colour, showed that both the latter carried the spine colour intensifier gene P. This suggests that earlier authors were incorrect in attributing the apricot fruit colour developed by some tt plants to a pleiotropic effect of P.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.