大刍草×玉米G综合种分离自交系的遗传效应和配合力分析

用一年生墨西哥大刍草（Zea Mexican Schard）与玉米G综合种远缘杂交选育的10个自交系作母本，以7个骨干自交系为父本，按10×7不完全双列杂交设计组配70个杂交组合为供试材料，研究了远缘杂交选系主要农艺性状和经济性状的遗传组成、遗传力和配合力效应。结果表明，抽丝期、株高、茎粗、穗长和百粒重主要受加性基因效应影响，狭义遗传力高，适合早代选择；茎强度、穗粗、穗行数和行粒数受加性基因和非加性基因效应同等影响；而穗位高、穗重、穗粒重和出籽率主要受非加性基因效应影响，狭义遗传力低，宜晚代选择。一般配合力效应分析结果，GT107可以作为很好的早熟、矮杆、抗倒和高产育种潜力亲本。     

低酚陆地棉育种亲本配合力的研究

选择８个现代低酚陆地棉育种亲本（包括４个高酚棉和４个低酚棉品种），按４×４不完全双列杂交设计，对１６个组合的Ｆ×进行了双列分析。结果表明，在所研究的１０个性状中，子棉产量、皮棉产量和纤维整齐度主要受非加性基因控制，单铃重、衣分、比强度、２．５％跨长和麦克隆值则主要由加性基因控制，衣指由加性和非加性基因共同控制，而子指受环境的影响较大；在大多数性状上，高酚棉亲本的加性遗传方差比低酚棉亲本贡献大，而在２．５％跨长和麦克隆值２个性状上，低酚棉亲本的加性遗传方差起着更重要的作用；中７８８６是综合性状比较理想的亲本材料，冀合２２５是较好的高产亲本，冀无２５２和中无１５１是较好的优质低酚棉亲本。综合一般配合力和特殊配合力分析结果，组合中７８８６×冀无２５２可具较好的育种潜力。     

大刍草×玉米G综合种分离自交系的遗传效应和配合力分析

用一年生墨西哥大刍草(Zea Mexican Schard)与玉米G综合种远缘杂交选育的10个自交系作母本,以7个骨干自交系为父本,按10×7不完全双列杂交设计组配70个杂交组合为供试材料,研究了远缘杂交选系主要农艺性状和经济性状的遗传组成、遗传力和配合力效应。结果表明,抽丝期、株高、茎粗、穗长和百粒重主要受加性基因效应影响,狭义遗传力高,适合早代选择;茎强度、穗粗、穗行数和行粒数受加性基因和非加性基因效应同等影响;而穗位高、穗重、穗粒重和出籽率主要受非加性基因效应影响,狭义遗传力低,宜晚代选择。一般配合力效应分析结果,GT107可以作为很好的早熟、矮杆、抗倒和高产育种潜力亲本。     

几个小麦品种（系）主要农艺性状配合力与遗传力分析

本文采用不完全双列杂交设计,对15个小麦品种(系)的8个主要农艺性状的配合力与遗传力进行了分析。结果表明,所有的8个性状(单株籽粒产量、单株生物产量、单株穗数、收获指数、株高、抽穗期、穗粒数、千粒重),其广义遗传力都较高,可在早代进行选择;株高与抽穗期的遗传主要受基因加性效应控制;其余性状(产量性状)的遗传除受基因加性效应控制外,非加性效应(显性效应和上位性效应)的影响更大。F1代的表现,同时受到双亲GCA的与SCA的影响。选择单株生物产量与单株穗数GCA较高、性状互补的亲本,才有可能选出单株籽粒产量高的强优势组合。从亲本的表现型不能推断其一般配合力效应的大小。本文同时对各材料的特点进行了分析。     

冬小麦水旱品种间杂交主要性状的遗传分析

利用水地和旱地两种生态型的品种 ,采用 4× 4不完全双列杂交试验 ,对水旱品种间杂交主要性状的配合力和遗传表现进行了研究。结果表明 ,水地亲本的一般配合力效应对杂种后代主要性状的影响 ,除千粒重外 ,均达到显著或极显著水平 ;旱地亲本的一般配合力效应主要对株高、穗下节长、单株穗数、收获指数等与抗旱性有关的性状影响明显 ,且除株高和收获指数外 ,其余性状P1的方差均大于P2 的方差。说明水地亲本对杂种后代产量性状影响大 ,旱地亲本主要影响抗旱性状 ,水旱两种生态型杂交 ,实现了抗旱与丰产的有机结合。株高、穗下节长、穗粒数、单株产量、单株生物产量和收获指数以加性效应为主 ,而显性基因对单株穗数、千粒重、单穗重的影响较大。旱地小麦产量性状遗传力均较低 ,而株高、穗下节长、收获指数等与抗旱性有关的性状遗传力较高     

玉米穗部性状的基因效应分析

由８个亲本组成的双列杂交试验,分析了穗长、穗粗、穗行数、百粒重、单株籽粒产量的基因效应。Ｗｒ／Ｖｒ和Ｄ、Ｈ、（Ｈ／Ｄ）分析表明,除单株产量存在显著的上位性,不符合加性—显性模型外,其余４个性状均符合加性—显性模型。穗粗、穗行数以加性效应为主,穗长、百粒重、单株产量显性效应和上位性起主要作用;穗粗隐性基因为增效,显性基因为减效,其余性状均为显性基因增效,隐性基因减效;穗长、穗粗、穗行数的狭义遗传力较高为５０．８％～８７．９％,百粒重、单株产量较低为２１％左右;平均杂种优势效应按强弱顺序是单株产量＞百粒重＞穗长＞穗粗＞穗行数。     

小黑麦产量性状的遗传和相关分析

以6个小黑麦品种（系）为亲本材料，按GriffingⅡ方法配制杂交组合，对亲本、F1、F2的产量性状进行了遗传分析，结果表明：千粒重的遗传由加性效应和显性效应共同控制，株高由加性效应起主要作用，而单株产量、每穗粒数和穗下节间长除由加性效应和显性效应控制外，还可能受上位性效应和环境效应控制。除新小黑麦4号外，其它亲本的大部分性状的显性效应预测值达到了负的极显著水平，预示着这些亲本杂种后代的产量性状将有明显的自交衰退现象。新小黑麦3号、新小黑麦4号的单株产量、千粒重、株高和穗下节间长的加性效应达到了极显著水平，因此这两个品种宜作为改良产量性状的骨干亲本。性状相关分析表明，大多数成对性状的各项相关系数为正值，且多以加性遗传相关为主，提高每穗粒数和千粒重可以有效增加产量。     

小麦耐热性的配合力分析

利用６×６完全双列杂交材料，通过测定膜热稳定性大小（ＲＩ％）对冬小麦的耐热性进行了配合力分析。结果表明，亲本之间耐热性的一般配合力效应（ＧＣＡ）、特殊配合力效应（ＳＣＡ）和反交效应（Ｒ）均达到极显著水平；该性状的遗传以加性基因效应占优势，但非加性基因效应和反交效应也起比较重要的作用，狭义遗传力估计大小为４２．２％。     

非等试验设计水稻产量构成性状基因型×环境互作的遗传分析

研究表明各产量构成性状不仅普遍存在加性效应和显性效应，而且还普遍存在基因型×环境互作。但是不同性状其加性效应和显性效应所起的作用不同。其中多数性状，如穗实粒数、穗总粒数、千粒重、粒长、粒宽、籽粒长宽比、穗长及株高等性状的加性效应大于显性效应，只有单株有效穗数和单株产量两性状的显性效应大于加性效应。所     

大麦若干经济性状的遗传特性分析

按Hayman方法对8×8完全双列杂交F_1的6个性状进行基因效应分析与模型检验,株高、穗长、实粒数符合加性-显性模型.株高、实粒数为部分显性,加性方差和显性方差均显著,基因的加性效应比显性效应更重要;穗长为超显性,显性基因效应比加性基因效应更重要.对杂交F_1、F_2进行配合力效应值分析表明,一般配合力方差和特殊配合力方差对所研究性状均重要,多数性状为加性基因效应占主导.亲本85G63、81-18、82-14为最佳配合者,其主要经济性状一般配合力好.杂交F_1各性状均有明显杂种优势,组合间和性状间的优势具有显著差异,以单株籽粒产量优势最强,其余依次为实粒数、穗长、株高、小穗粒数和千粒重.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

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.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

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.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...