甘肃彩色棉花抗旱性农艺性状指标的筛选鉴定

以抗旱性不同的白棉、棕棉和绿棉品种(品系)为试验材料, 通过水分亏缺控制试验, 采用主成分分析和逐步回归分析方法, 调查其主要农艺性状指标与抗旱性的关系。结果表明, 干旱胁迫下, 各彩色棉花的籽棉产量、株高、叶片数、单株成铃数、有效果枝数、果节数、收获指数、茎粗、籽指和上半部分纤维长度均相应的降低; 抗旱指数与株高、果节数、单株成铃数、花铃期叶片数、有效果枝数、籽指、单铃重、收获指数、茎粗呈极显著正相关; 单株成铃数、单铃重和花铃期叶片数可作为不同色彩棉花简单、直观的抗旱性鉴定指标, 有效果枝数、株高、果节数、收获指数和籽指也可作为彩色棉花抗旱评价指标。     

抗虫基因导入对棉花形态、产量性状及生理特性的影响

 从棉花形态性状、产量性状和生理特性三个方面较系统地研究了抗虫基因导入对棉花生长发育的影响。结果表明,转基因抗虫棉的单株结铃数、成铃率高于其受体品种;单株果枝数、单株果节数、铃重、衣分低于受体品种。还在棉花不同发育时期对其生理、生化特性进行了测定。 结果表明,在7月8日以前,转基因抗虫棉的光合强度和叶绿素含量低于其受体品种,从7月8日以后,转基因抗虫棉的光合强度和叶绿素含量高于其受体品种。研究还表明,转基因抗虫棉抗环境胁迫能力差,容易早衰。全生育期内,转基因抗虫棉MDA 含量均高于其相应的受体品种,SOD、POD 和CAT酶活性均比其受体品种低。     

种植密度与播期对江汉平原短季棉成铃空间分布的影响

在不同密度、播期处理条件下,研究荆早棉1号的成铃空间分布,结果表明:密度增加,叶枝数、叶枝成铃数、主茎果枝数、果枝成铃数、单株成铃数减少;播期延迟,叶枝数、叶枝成铃数明显增加,果枝数、果枝成铃数及单株成铃数明显减少。各处理不同部位果枝、果节上成铃数占单株总铃数的比率总体表现为:1~5果枝6~10果枝11~15果枝16及以上果枝;1~2果节3~4果节5节及以上果节。1~10果枝、1~2果节的成铃数占全株铃数的比率高,则产量表现好;反之,则产量表现差。     

高品质棉与抗虫棉杂交株型性状的遗传及与产量性状的关系

采用增广NCⅡ设计,以5个高品质陆地棉品种（系）为母本,5个转基因抗虫棉品种（系）为父本组配的25个杂交组合为材料,研究主要株型性状的遗传效应、杂种优势及与产量性状的相关性。结果表明,株高、始果枝高、果枝数和果节数的平均中亲优势较小,但不同组合间差异较大,均符合加性遗传模型。遗传相关分析表明,株高与株铃数、单株皮棉重呈极显著正相关;果枝数与株铃数呈极显著正相关,与铃重呈极显著负相关;果节数与株铃数、衣分和单株皮棉重呈显著正相关。株型性状与产量性状间的关联性主要是由果节数与株铃数、铃重的相关引起。研究结果为高品质抗虫棉理想株型性状的选育与调控具有一定的指导意义。     

鲁棉6号三系杂交优势的研究

通过回交对杂种后代进行测交筛选,育成恢复能力完全的恢复系.对育成的恢复系与不育系配制的杂种优势与保持系、正反交的遗传效应研究表明,总果节数及单株铃数上具有显著的杂种优势,部分组合在产量表现和农艺性状上没有显著的不良影响.     

不同播期与打顶时间对麦(油)后直播短季棉产量及纤维品质的影响

【目的】探索播期与打顶时间对麦(油)后直播短季棉产量、产量特性及纤维品质的影响。【方法】以中棉所50为材料,采用裂区设计,研究不同播期(月-日)(S_1,05-25;S_2,06-10)和打顶时间(月-日)(T_1,07-30;T_2,08-07;T_3,08-15)对长江流域下游植棉区麦(油)后直播短季棉产量和纤维品质的影响。【结果】播期间,皮棉产量和霜前花率及铃数、铃重和衣分均以S_2条件下较低;果枝数和果节数以S_2条件下较低而成铃率以S_1较低。打顶时间间,皮棉产量和霜前花率随打顶时间推迟而降低;果枝数、果节数及节枝比随打顶时间推迟增加而成铃率降低。互作显示,皮棉产量与霜前花率均以S_1T_1处理较高;果枝数和果节数以S_1T_1、S_1T_2和S_1T_3处理较高,成铃率以S_2T_1和S_1T_1较高。相关性分析表明,皮棉产量与果枝数、果节数、铃数显著正相关,但与节枝比、成铃率相关不显著。此外,播期间,以S_2条件下棉株下部和中部果枝成铃分布比例较高而上部较低;打顶时间间,下部和中部果枝成铃分布比例随打顶时间推迟降低而上部增加。就棉铃纤维品质而言,S_1T_1处理不同果枝部位棉铃的纤维长度、纤维比强度和中部马克隆值均较优。【结论】长江流域下游植棉区,麦(油)后直播短季棉于5月25日播种、7月底打顶有利于其高产、稳产和优质。     

机采棉主要农艺性状与密度相关性分析

为研究棉花适宜机采农艺性状与密度的相关性,明确通过密度塑造适宜机采株型的方法,采用大田试验,以K836为试验材料,设计3×10 ⁴、6×10 ⁴和9×10 ⁴株/hm ² 3个密度处理,研究密度对机采棉子棉产量的影响及其与机采棉主要农艺性状的相关性分析。结果表明,在本研究密度范围内,棉花株高、果枝长度、果枝第一节位长度、果枝节数、单株果枝数和单株干物质量随着密度的增加而下降,密度对第一果枝节位和果枝夹角没有显著影响。与低密度（3×10 ⁴株/hm ²）相比,高密度处理（9×10 ⁴株/hm ²）棉花单铃重降低,衣分提高,单株铃数降低,总铃数增加,密度对子棉产量没有显著影响。除第一果枝高度外,株高、第一果枝节位、果枝长度、果枝第一节位长度、果枝节数、果枝夹角、单株果枝数与单株干物质量和单株铃数呈正相关,与单铃重和子棉产量呈负相关,其中果枝长度和单株果枝数呈极显著正相关。因此,适当增加种植密度使棉花株高降低,果枝变短,株型更为紧凑,可以通过密度塑造适合机械采收的株型,冀南地区高密度（9×10 ⁴株/hm ²）处理棉花株型符合机采要求。     

棉花最佳成铃模式的研究

本文在1987年试验基础上,1988年继续应用二次正交旋转组合设计的方法,对密度、氮素、单株果枝数及缩节安化控四项农艺措施进行综合研究,根据研究结果建立了产量、成铃分布、亩果节回归模型。通过数学模型筛选出亩产子棉225kg以上的优化农艺措施组合方案,给出了该优化组合最佳的成铃模式和分布特点。此外,还给出了该优化组合的亩果节数、蕾铃脱落率的动态变化曲线,为该优化方案实施时提供诊断指标和参数。     

丰抗棉10号杂交优势的研究

通过对杂交后代的测交筛选,育成恢复能力完全的恢复系.对育成的恢复系与不育系配制的杂种优势与保持系、正反交的遗传效应研究表明,生长势、抗逆性、果节数及单株铃数,都具有显著的杂种优势,部分组合在产量上的表现和农艺性状没有显著的不良影响.     

长江流域麦/油后直播棉花播种时间下限研究

【目的】晚播、增密、减氮是长江流域棉花生产通过缩短生产周期来降低人工成本和物化成本的有效途径,适宜的播种时间是麦/油后直播棉花产量形成的重要影响因子,但是适宜的播期及晚播下限的研究未见报道。【方法】2018年和2019年在湖北省主产棉区4个试验点进行播期试验,试验设5个播期处理,分别为5月20日、5月25日、5月30日、6月4日、6月9日,在高密度、低氮条件下,研究不同播种时间对棉花生育进程、田间长势长相、产量和品质的影响。【结果】推迟播种可通过缩短播种出苗期和苗期加速棉花生育进程,全生育期缩短,纤维品质稳定。但是,随播期推迟,伏桃数量、单株铃数、单位面积成铃数、籽棉产量及成熟期吐絮率下降。特别是过迟播种,单位面积成铃数、10月20日吐絮率及产量会显著下降。【结论】长江流域相似棉区麦/油后直播模式最适播期建议在5月25日左右,以不晚于6月4日为宜。     

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.     

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.     

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.     

Flag Leaf Senescence, as Evaluated by Numerical Image Analysis, and its Relationship with Yield under Drought in Durum Wheat

Senescence was evaluated at different stages of the grain‐filling period in eight durum wheat varieties using numerical image analysis (NIA). The varieties were grown under early, severe drought conditions on the high plains of Sétif in Algeria. After flowering, three different irrigation treatments were applied. Treatment effect was small, while a genotypic effect was noted for most of the senescence parameters. Senescence correlated to biomass, while the maximal rate of senescence, V_smax, correlated to thousand‐kernel weight. The potential of the method of numerical image analysis for monitoring flag leaf senescence, detecting genotypic variability and selecting genotypes with delayed senescence is discussed.     

Cowpea (Vigna unguiculata): Genetics,genomics and breeding

Cowpea, Vigna unguiculata (L.), is an important grain legume grown in the tropics where it constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. A review of the genetics, genomics and breeding of cowpea is presented in this article. Cowpea breeding programmes have studied intensively qualitative and quantitative genetics of the crop to better enhance its improvement. A number of initiatives including Tropical Legumes projects have contributed to the development of cowpea genomic resources. Recent progress in the development of consensus genetic map containing 37,372 SNPs mapped to 3,280 bins will strengthen cowpea trait discovery pipeline. Several informative markers associated with quantitative trait loci (QTL) related to desirable attributes of cowpea were generated. Cowpea genetic improvement activities aim at the development of drought tolerant, phosphorus use efficient, bacterial blight and virus resistant lines through exploiting available genetic resources as well as deployment of modern breeding tools that will enhance genetic gain when grown by sub‐Saharan Africa farmers.     

Screening for resistance to take-all in wheat,triticale and wheat-triticale hybrid lines

Summary Fifteen triticale and wheat-triticale hybrid lines were evaluated for resistance to the take-all fungus Gaeumannomyces graminis var. tritici and compared with five wheat and two rye lines in inoculated field and pot trials. The triticale and wheat-triticale hybrid lines varied in rye chromosome number and degree of resistance expressed. One line, Venus with seven pairs of rye chromosomes consistently showed levels of resistance intermediate between wheat and rye. A trend was observed where increasing rye chromosome content led to greater resistance but exceptions showed that variation within triticales could not be ascribed to rye chromosome content alone.     

Insect resistance in potatoes: sources,evolutionary relationships,morphological and chemical defenses,and ecogeographical associations

Summary The past 25 years, 1686 potato accessions, representing 100 species in the genus Solanum L., subgenus Potatoe, section Petota, were evaluated for field resistance to one or more of the following insect pests: green peach aphid, Myzus persicae (Sulzer); potato aphid, Macrosiphum euphorbiae (Thomas); Colorado potato beetle, Leptinotarsa decemlineata (Say); potato flea beetle, Epitrix cucumeris (Harris); and potato leafhopper, Empoasca fabae (Harris). Accessions highly resistant to green peach aphid were identified within 36 species, to potato aphid within 24 species, to Colorado potato beetle within 10 species, to potato flea beetle within 25 species, and to potato leafhopper within 39 species. Resistance levels were characteristic within Solanum species. Insect resistance appears to be a primitive trait in wild potatoes. Susceptibility was most common in the primitive and cultivated Tuberosa. Insect resistance was also characteristic of the most advanced species. The glycoalkaloid tomatine was associated with field resistance to Colorado potato beetle and potato leafhopper. Other glycoalkaloids were not associated with field resistance at the species level. Dense hairs were associated with resistance to green peach aphid, potato flea beetle, and potato leafhopper. Glandular trichomes were associated with field resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Significant correlations between insect score and altitude of original collection were observed in six of thirteen species. Species from hot and arid areas were associated with resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Species from cool or moist areas tended to be resistant to potato aphid.Abbreviations EBN Endosperm Balance Number     

A self-fertile trigeneric hybrid in the Triticeae involving Triticum,Hordeum, and Secale

Summary A self-fertile trigeneric hybrid in the Triticeae involving species from the Hordeum, Triticum and Secale genera has been produced. The trigeneric hybrid was obtained by crossing octoploid triticale (x Triticosecale Wittmack) with octoploid tritordeum (H. chilense × T. aestivum amphiploid). The trigeneric hybrid presented a genome constitution AABBDDRH^ch and 2n=8X=56 chromosomes. The cytogenetical analyses showed no chromosome instability nor homeologous pairing between Hordeum and Secale chromosomes. In the F₂ generation the chromosome number ranged from 42 to 52. Within this range, the plants with smaller numbers of chromosomes were more frequent. A preferential transmission of rye chromosomes could be inferred.     

Evolving gene pools in crop plants

Summary The three gene pool system can be applied usefully to the whole range of crop plants. The primary gene pool (GP1) show varying degrees of fragmentation. No morphological discontinuity is apparent between wild and cultivated Lathyrus sativus but clear discontinuities have developed between conspecific wild and cultivated Phaseolus and Vigna species. Further discontinuities can develop in cultigens where disruptive selection has been practiced, as in Beta vulgaris, Linum usitatissimum and Brassica oleracea where more than one distinct crop has evolved within a single biological species. Each such crop has developed its own distinctive gene pool.