秦巴山区玉米杂交组合主要性状与产量间的灰色关联度分析

运用灰色系统理论中杂交组合灰色评判原理与方法,对60个玉米组合的产量和9个产量因素进行灰色关联分析及综合评判,以明确不同玉米杂交组合产量和产量构成因素之间的关系。结果表明:秦巴山区玉米杂交组合产量与主要农艺性状的关联度大小排序为穗粗>百粒重>穗长>穗位高>穗行数>行粒数>出子率>株高>秃顶长。组合46综合性状最好(G=0.881),组合52次之(G=0.861),组合54综合性状最差(G=0.552),综合评判结果与杂交组合在生产实际中表现基本一致。     

灰色关联度分析在棉花新品种综合评价中的应用

采用灰色系统理论中关联度分析法，对2000年江苏省中熟棉花品种区域试验中的8个供试品种(系)进行了多性状的综合评价。结果表明：通9450综合性状最好(r=0．9314)，盐2006次之(r＝0．8967)，泗棉3号综合性状最差(r＝0．7872)。     

灰色系统理论在小麦育种中的应用

根据育种目标,运用灰色系统的理论和方法——杂交组合灰色评判法,对小麦F1代杂交组合的各主要性状,进行综合分析,比较其灰色关联度,确定出优良组合,然后有针对性地进行选择,减少不必要的种植规模,节省人力、物力和财力,有效地提高育种效率,为新品种选育提供科学依据。     

甘蓝型杂交油菜主要农艺性状灰色关联度分析

试用灰色系统理论关联度法对贵州省农科所油料所近年来选育的11个甘蓝型杂交油菜新组合进行单位面积的油菜籽产量等7个主要农艺性状的灰色关联度分析。分析结果表明：不同的杂交油菜组合同一性状与产量的关联度不同；同一组合内的不同农艺性状与产量的关联度也不同。其关联度顺序为：单株产量（r1=09067）＞株高（r2=0．8398）＞林有效分枝数（r3=0.7892）＞用粒数（r5=0．7237）＞林有效角果数（r4=0．4276）＞千粒重（r6=0．3767）。在甘蓝型杂交油菜的组合选育过程中，应注重选择单株生产力高、株高适度、单株有效分枝多的组合，同时要求所选择的组会角粒数，株有效角果数多。千粒重对同一组合材料是相对稳定的，变化幅度小，在育种过程中对千粒重的选择效果不明显。     

杂交组合灰色评判在小麦育种中的应用

运用灰色系统的理论和方法，根据育种目标，对小麦F1代杂交组合的各主要性状，进行综合分析，比较其灰色关联度，确定出优良组合，为小麦品种的选育提供科学依据。     

萝卜杂种优势效应分析及杂交组合的灰色评判

对萝卜15个组合的杂种优势效应分析的结果表明:除里外青×旱红表现为负向优势外,其余各组合均表现为正向优势.多数组合优势效应比较明显,有14个组合的超均亲优势大于28%,10个组合的超高亲优势大于20%,其中最明显的是旱红×四季红3号、大红袍×甜脆青和四季红3号×甜脆青.用灰色评判法对15个杂交组合分析的结果表明:组合3(大红袍×满堂红)、12(旱红×四季红3号)的灰色综合评判值＞0.7000,为优良(一级)组合;组合1、4、6、7、9、11、13的灰色评判值介于0.6000～0.70000之间,为良好(二级)组合;组合2、5、8、10、14、15的灰色评判值＜0.6000,为一般(三级)组合.综合结果分析:旱红×四季红3号为最有价值的组合.     

杂交组合灰色评判在大豆育种中的应用

运用灰色系统的理论和方法,根据育种目标,对大豆杂交组合F1代的各种主要性状,进行综合分析,比较其灰色关联度,确定出优良组合,为大豆品种的选育提供科学依据。     

菜心杂交一代品种的灰色综合评判

用灰色评判法对六个菜心杂交一代品种分析的结果表明:菜心9个性状(单株重、株高、叶柄及叶长、最大叶宽、茎粗、根重、叶柄及叶重、茎薹重、叶片数)的权系数分别为:0.163、0.111、0.118、0.099、0.117、0.093、0.118、0.068、0.112;品种的灰色综合评判值大小顺序为:A5＞A1＞A2＞A4＞A3＞A6;其中A1、A5的灰色综合评判值＞0.789,为一级F1品种;A2、A4的灰色综合评判值介于0.700～0.753之间,为二级F1品种;A3、A6的灰色综合评判值＜0.636,为三级F1品种.     

灰色关联度评判在花生育种中的应用

通过运用灰色系统的理论和方法,对10个花生杂交组合F1代的各主要性状进行综合评判,分析比较其关联度,确定优良组合。结果表明,灰色评判对于花生育种的多配组合、重点选择是一个行之有效的方法和手段     

杂交组合灰色评判在玉米杂交育种中的应用

为了科学、准确的从众多杂交组合中挑选出长势和品质都比较优良的组合,并进行下一年度的种植以及选育,采用杂交组合灰色评判系统对玉米自交系杂交种F1代进行系统评判,根据评判结果划分等级,为F2代的选育工作提供可循信息。应用杂交组合灰色评判方法对本实验中5个自交系亲本的完全双列杂交F1代的农艺性状和品质性状进行综合评价和系统分析。分析结果：将杂交种F1代划分为3个等级,1级组合在下年度要适当扩大种植规模,并在以后的世代中重点选择;2级组合应在下年度进行适当规模种植,进行进一步的优良品种筛选;3级组合若没有特殊优点,应当淘汰。     

Genomics-assisted breeding: The next-generation wheat breeding era

Common wheat provides approximately 20% of the total dietary calorie intake of human beings. Recent technological advances in whole-genome sequencing and their application in wheat and its progenitor species provide new opportunities to uncover the genetic variation of wheat traits and to accelerate the traditional breeding (TB) strategies in the context of genomics-assisted breeding (GAB). Integration of TB, marker-assisted selection (MAS) and genomic selection (GS) with high-density SNP markers is expected to accelerate the breeding process and to further enhance genetic gain. With the assistance of the next- or third-generation sequencing technologies and high-throughput phenotyping platforms, GAB can now realistically be considered in the following area: (i) genome sequencing and high-quality assembly to uncover new variations, (ii) whole-genome sequence-based association studies, (iii) gene function (or functional gene) identification and (iv) integration of whole genomic breeding information, utilizing multi-omics data and different breeding strategies. We argue that GAB is becoming the preferred strategy in pursuit of new wheat cultivars with superior traits on high yielding, high nutritional quality, climate-resilience and so on.     

诱变育种技术在大豆育种中的应用

随着社会的不断进步以及科学技术的不断发展,越来越多的新型技术逐渐地出现在各行各业当中,对于农业来说,使用先进的科学技术手段能够大幅度地增加农产品的产量以及农产品的收获速率,进而带动整体农业的经济发展。基于此,本文针对诱变育种技术在大豆育种中的应用进行研究分析,首先对诱变育种技术在大豆育种中应用的重要性进行阐述,然后对相应的在大豆育种中的诱变育种技术进行分类探讨,最后还对该项技术在大豆育种中应用的发展导向进行展望,以期通过本文的研究与分析,对诱变育种技术在大豆育种中的应用研究起到一定的参考帮助作用。     

Conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops

Summary Monte Carlo computer simulation was used to investigate the conditions favouring doubled haploid breeding over conventional breeding of self-fertilizing crops. Two different systems of doubled haploid breeding and three systems of conventional breeding were compared for two criterion parameters, i.e., the probability of obtaining desirable genotypes and the expected genetic advance of selected lines. It was inferred that the efficiency of production of haploid and doubled haploid plants primarily determines the success of the doubled haploid breeding method. In doubled haploid breeding, about 1/5, hopefully 1/2 as many test plants need to be raised as in conventional breeding to achieve the same level of success. With this condition begin satisfied, the doubled haploid breeding method can efficiently be used when one or more of the following conditions are met: (i) a relatively small number of loci, presumably ten of less, is involved with the breeding objective concerned, (ii) desirable alleles are recessive to undesirable ones at most, if not all, of the segregating loci, and (iii) the genes are not strongly linked. It was confirmed that the doubling of haploids can better be applied to selected F₂ plants rather than to F₁ plants.     

Mutation breeding of Streptocarpus

Summary Leaves of Streptocarpus Constant Nymph have been irradiated with X-rays and fast neutrons. Considering the production of plantlets on the rooted leaf-halves as well as the frequency of mutants among them, the optimal dose for X-rays was found to be 3 krad.Like Saintpaulia ionantha, Streptocarpus produces solid mutants after irradiation, a fact which indicates that each plantlet, developing from an adventitious bud, originates from only one cell. Moreover, a high mutation frequency has been observed as well as a wide variability among the 857 mutants obtained.Application of a heavy X-ray dose (4–5 krad) a few days after colchicine treatment resulted in a frequency of tetraploids which was twice the one obtained after colchicine treatment alone.A number of mutants and (auto)tetraploids have been propagated and tested for their commercial value. Sofar, 5 mutants have been commercialized, viz. Purple Nymph, Mini Nymph, Blue Nymph, Netta Nymph and Cobalt Nymph.     

Mutation breeding of Achimenes

Summary Freshly cut leaves of Achimenes cv. Paul Arnold were irradiated with X-rays or fast neutrons, or treated with colchicine and then allowed to root and form adventitious buds. As found previously in Saintpaulia and Streptocarpus, almost exclusively solid, non-chimeral mutants or tetraploids were, respectively, obtained by using the adventitious bud technique, demonstrating that the apex of such buds originates from single cells.Although the heterozygosity of the original material apparently was not large, a relatively wide mutation spectrum was observed among the mutants produced.After comparative judging, three mutants were awarded a Certificate of Merit and have been commercialized.Two of these are earlier flowering mutants (Early Arnold and Spring time), the third having a more compact form (Compact Arnold).     

Mutation breeding of chrysanthemums

Rooted cuttings of the pot-grown Chrysanthemum variety Hortensien Rose were irradiated with X-rays, fast neutrons, thermal neutrons and electrons. As soon as the plants grew they were topped to stimulated side-shoot formation, often resulting in complete periclinal chimeras (sports). In addition mutation frequency in a given number of plants is enlarged by such a method.Electrons proved to be ineffective, producing only 6–10% mutated plants. The optimum dose X-rays is 1500 Rads. Both fast and thermal neutrons showed a marked higher mutation frequency, the best dose resulting in both cases in c. 28% of mutated plants.The mutation spectra, e.g. the type of mutations induced, showed some variation after the various treatments. But the number of plants irradiated, as well as the number of mutations induced, do not justify the conclusion that a certain treatment results in a specific mutation spectrum, although there was a tendency towards greater variability after neutron irradiation.The mutation spectrum as well as the frequency greatly depends on the genetic constitution of the treated material. Irradiation of the pink-flowering Hortensien Rose, with the maximum number of dominant genes for flower colour, resulted in a great number of different flower colours, as was expected, as well as a number of mutations of flower shape and size. Other pink-flowering varieties showed a similar spectrum, although in some cases the frequency was low or even zero. Chrysanthemum varieties with other flower colours showed a lower mutation rate, most of the flower colour mutations being based on a lower number of dominant genes.Finally, the practical importance and ways of application were discussed.     

Mutation breeding of Alstroemeria

Summary Actively growing young rhizomes of various Alstroemeria cultivars, most sterile hybrids, were treated with X-rays. The optimum dose was about 400 rad for diploid cultivars and 500–600 rad for triploid ones.Although the buds on the rhizomes most certainly have multicellular apices, no X-ray mutant showed any sign of chimerism. Hence only solid(-looking) mutants were obtained. This phenomenon, an unforeseen but advantageous circumstance, could not be explained.Among the rather large number of mutants, several proved to be improvements and have been released to the trade such as cvs. Canaria Stagula, Yellow Tiger Stavero, White Wings Staretto, Harmony Stabroza and Rosita Stareza.     

Plant breeding systems

New concepts in population genetics call for reappraisal of plant breeding procedures; this commentary evaluates certain breeding procedures according to their probable effectiveness in promoting maximum gene recombinations and achieving maximum fitness. Breeding is viewed as an accelerated evolutionary process where appropriate design and control substitute for long duration of complex interactions of genotype with environment in the wild state. Crossing selected sibs in early generations is a means of re-assembling adaptive genes capable of functioning in a balanced polygenic system. The probability that any one individual in early generations after a cross would carry all or most of the potentially co-adaptive genes is very remote; hence strict inbreeding or pure line selection from early generations will not produce the best balanced genotypes. The recombination of two or more partly balanced genotypes by sib crossing magnifies the chance that a maximum number of harmoniously functioning genes will be assembled and through subsequent inbreeding emerge as stable and widely adapted varieties. Breeding procedures are viewed in perspective as they proceed from maximum inbreeding to maximum interbreeding or from pure line selection to bulk selection with natural or enforced sib-crossing.     

Sustainable plant breeding

Plant breeders disrupt Hardy–Weinberg equilibrium through selection, non‐random mating, drift, migration and mutation. Sustainable plant breeding can be defined as productive and competitive breeding that is achieved without loss of genetic diversity in the elite breeding population during the professional career of the breeder. Breeding is often productive but not sustainable. From 1974 to 2000, the animal breeding programme Meatlinc in the United Kingdom had effective population size of 95, population inbreeding of 0.19% per year and generation interval of 2.15 years. Genetic progress in Meatlinc tripled in the 8 years following introduction of best linear unbiased prediction (BLUP) selection (based on the information from relatives) in 1992. Canola breeding in Australia from 1970 to 2000 had longer generation interval (6 years), smaller effective population size (<11) and higher rates of inbreeding (>0.7% per year). BLUP selection in canola was first reported in 2010. Neither programme replaced genetic diversity lost through selection and drift. Most breeding programmes violate conditions of the infinitesimal model, thereby reducing predictability of selection, but breeders can minimize these limitations to sustainable plant breeding.