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1.
John E. Bradshaw 《Euphytica》2017,213(3):60
Plant breeders can help farmers increase food production by breeding new cultivars better adapted to their chosen farming systems, but these must be capable of providing the necessary plant inputs for the required levels of crop production in 2050. Until 200 years ago the farmers themselves were the plant selectors. Plant domestications, extensive crop dispersions and farmers’ selections produced thousands of locally adapted landraces of cultivated plants. During the twentieth century these were largely replaced by relatively few high yielding cultivars and the natural habitats of many of their wild relatives became endangered. Hence in situ and ex situ conservation, and evaluation and use of plant genetic resources is vital for future plant breeding. The development of scientific breeding from the beginning of the twentieth century was based on understanding the mechanism of inheritance and the mating systems of crop plants. The types of genetically uniform, high yielding cultivars that have been bred from genetically heterogeneous landraces were determined by the mode of reproduction and mating system of the cultivated plant species: inbred line (wheat) and hybrid (rice) cultivars for inbreeding species, hybrid (maize) cultivars for outbreeding species, and clonal (potato) cultivars for vegetatively propagated species. When genetically heterogeneous crops are desired, mixtures of cultivars and synthetic cultivars can be produced. Future progress in crop improvement will come from three complementary approaches: use of hybridization and selection in further conventional breeding, base broadening and introgression; mutation breeding, cisgenesis and gene editing; and genetically modified crops. 相似文献
2.
In the Andean region, the Preduza project and its partners combined breeding for durable disease resistance using locally
adapted cultivars and farmer participatory methods. The approach taken resembles participatory variety selection (PVS). Farmers
participated in the selection of advanced materials, rather than finished cultivars. This paper describes this approach and
reports experiences with farmers–breeders collaboration.
As breeders involved farmers as participants, they learned more about the most important criteria of male and female farmers
for preferred cultivars in the marginal environments of Andean cropping systems. This approach encouraged the use of locally
adapted cultivars (often landraces), made the breeders less dependent on foreign materials, and has resulted in selection
and development of new wheat, barley, common bean, quinoa, potato and maize cultivars.
Breeding programmes based on crossing locally adapted cultivars followed by selection by the breeders in the early phases
of the breeding programmes and by participatory selection with the farmers in the more advanced stages of the breeding programmes
appeared successful. It became clear that breeders must be well acquainted with the farmer preferences such as the requirements
for specific agronomic, storage, processing and marketing traits.
Over a period of five years the centralized formal breeding approach predominantly based on material produced by the international
institutes was replaced by decentralized breeding approaches based largely on local germplasm with extensive farmer participation. 相似文献
3.
Achievements and limitations of contemporary common bean breeding using conventional and molecular approaches 总被引：1，自引：0，他引：1
Common bean (Phaseolus vulgaris L.) improvement programs have been successful using conventional breeding methods to accomplish a wide array of important
objectives. Specific achievements include the extension of range of adaptation of the crop, the development of cultivars with
enhanced levels of disease and pest resistance and breeding lines that possess greater tolerance to drought. The most effective
breeding method depends on the expression and inheritance of the trait to be selected and the target environment. Many bean
improvement programs use molecular markers to facilitate cultivar development. In fact, several recent germplasm releases
have used molecular markers to introgress and or pyramid major genes and QTL for disease resistance. Related species (P. coccineus and P. acultifolius) via interspecific hybridizations remain an important albeit long-term source for resistance to economically important diseases.
Slow progress has been made in the improvement of traits such as adaptation to low soil fertility and tolerance to high levels
of soluble Al in the soil using conventional breeding methods. The inability to directly measure root traits and the importance
of genotype × environment interaction complicate the selection of these traits. In addition, symbiotic relationships with
Rhizobium and mycorrhiza need to be taken into consideration when selecting for enhanced biological N fixation and greater or more
efficient acquisition of soil P. Genomic examination of complex traits such as these should help bean breeders devise more
effective selection strategies. As integration of genomics in plant breeding advances, the challenge will be to develop molecular
tools that also benefit breeding programs in developing countries. Transgenic breeding methods for bean improvement are not
well defined, nor efficient, as beans are recalcitrant to regeneration from cell cultures. Moreover, if issues related to
consumer acceptance of GMOs cannot be resolved, traits such as herbicide tolerance in transgenic bean cultivars which would
help farmers reduce production costs and decrease soil erosion will remain unrealized. 相似文献
4.
A. Ross Ferguson 《Euphytica》2007,154(3):371-382
Genetic diversity provides the raw material for breeding and plant improvement. Breeders of plant species that have little
or no history of improvement tend to make the greatest use of collections of raw or unimproved germplasm. Kiwifruit (Actinidia) are one such crop in that they have been subjected to little selection pressure and are still very similar to plants in
the wild. To take advantage of the diversity in the genus Actinidia, breeders need to know the extent of the diversity and also need to be able to identify the plants with which they are working.
Voucher specimens should be prepared for all plants used in experimental studies. A good understanding of the reproductive
biology of Actinidia should facilitate incorporation of wild germplasm into kiwifruit breeding programmes. The HortResearch Actinidia collection has already proved its worth with the development of valuable new kiwifruit cultivars. 相似文献
5.
Pedigree analysis of the origin of manganese tolerance in Canadian spring wheat (Triticum aestivum L.) cultivars 总被引：1，自引：0，他引：1
Summary Breeding wheat (Triticum aestivum L.) for tolerance to manganese (Mn) might be in some cases more feasible and economical than use of soil amendments. As part of research on the heritability of Mn tolerance, a study on the level of Mn tolerance in Canadian wheat cultivars and its probable origin was accomplished by analysis of cultivar pedigrees and drawing phylogenetic maps to discern filial relationships. Cultivar tolerance to Mn was determined by relative root weight (RRW) in solution culture in the presence of 500 M Mn. A total of 91 cultivars were screened, 76 of which were Canadian. These data, together with data from another 28 cultivars reported in the literature, were used to draw two pedigree maps, a map for Canadian cultivars only, and a map for the Mn-tolerant Canadian cultivars Norquay and Laura. Results indicated a range of tolerance to Mn among Canadian cultivars. Manganese tolerance, found in either Canadian or foreign germplasm, and of either recent or older selection or origin, seems to have originated from land races from Rio Grande do Sul, the southernmost state of Brazil. Tolerance may have been introduced into Canadian germplasm directly by the use of Brazilian cultivars as parents, or indirectly by the introduction of Mexican germplasm with Brazilian parentages. This information will help the plant breeder to develop plant breeding systems, and may also help in the study of the mechanisms for Mn tolerance in wheat. 相似文献
6.
Jaime Prohens Pietro Gramazio Mariola Plazas Hannes Dempewolf Benjamin Kilian María J. Díez Ana Fita Francisco J. Herraiz Adrián Rodríguez-Burruezo Salvador Soler Sandra Knapp Santiago Vilanova 《Euphytica》2017,213(7):158
The need to boost agricultural production in the coming decades in a climate change scenario requires new approaches for the development of new crop varieties that are more resilient and more efficient in the use of resources. Crop wild relatives (CWRs) are a source of variation for many traits of interest in breeding, in particular tolerance to abiotic and biotic stresses. However, their potential in plant breeding has largely remained unexploited. CWRs can make an effective contribution to broadening the genetic base of crops and to introgressing traits of interest, but their direct use by breeders in breeding programs is usually not feasible due to the presence of undesirable traits in CWRs (linkage drag) and frequent breeding barriers with the crop. Here we call for a new approach, which we tentatively call ‘introgressiomics’, which consists of mass scale development of plant materials and populations with introgressions from CWRs into the genetic background of crops. Introgressiomics is a form of pre-emptive breeding and can be focused, when looking for specific phenotypes, or un-focused, when it is aimed at creating highly diverse introgressed populations. Exploring germplasm collections and identifying adequate species and accessions from different genepools encompassing a high diversity, using different strategies like the creation of germplasm diversity sets, Focused identification of germplasm strategy (FIGS) or gap analysis, is a first step in introgressiomics. Interspecific hybridization and backcrossing is often a major barrier for introgressiomics, but a number of techniques can be used to potentially overcome these and produce introgression populations. The generation of chromosome substitution lines (CSLs), introgression lines (ILs), or multi-parent advanced inter-cross (MAGIC) populations by means of marker-assisted selection allows not only the genetic analysis of traits present in CWRs, but also developing genetically characterized elite materials that can be easily incorporated in breeding programs. Genomic tools, in particular high-throughput molecular markers, facilitate the characterization and development of introgressiomics populations, while new plant breeding techniques (NPBTs) can enhance the introgression and use of genes from CWRs in the genetic background of crops. An efficient use of introgressiomics populations requires moving the materials into breeding pipelines. In this respect public–private partnerships (PPPs) can contribute to an increased use of introgressed materials by breeders. We hope that the introgressiomics approach will contribute to the development of a new generation of cultivars with dramatically improved yield and performance that may allow coping with the environmental changes caused by climate change while at the same time contributing to a more efficient and sustainable agriculture. 相似文献
7.
Decentralized selection and participatory approaches in plant breeding for low-input systems 总被引：1，自引：0，他引：1
Heterogeneous environments make it difficult to apply consistent selection pressure because often it is difficult to identify
a single or a few superior genotypes across all sets of conditions. However, when the target system is characterized by heterogeneity
of environmental stress, varieties developed in high-yielding conditions may fail to satisfy farmers’ needs. Although this
type of system is often found in marginal environments of developing countries, heterogeneous environmental conditions are
also a feature of organic and low-external-input systems in developed countries. To meet the needs of these systems, breeding
programs must decentralize selection, and although decentralized selection can be done in formal breeding programs, it is
more efficient to involve farmers in the selection and testing of early generation materials. Breeding within these target
systems is challenging, both genetically and logistically, but can identify varieties that are adapted to farming systems
in marginal environments or that use very few external inputs. A great deal has been published in recent years on the need
for local adaptation and participatory plant breeding; this article reviews and synthesizes that literature. 相似文献
8.
Participatory plant breeding (PPB) has been suggested as an effective alternative to formal plant breeding (FPB) as a breeding
strategy for achieving productivity gains under low input conditions. With genetic progress through PPB and FPB being determined
by the same genetic variables, the likelihood of success of PPB approaches applied in low input target conditions was analyzed
using two case studies from FPB that have resulted in significant productivity gains under low input conditions: (1) breeding
tropical maize for low input conditions by CIMMYT, and (2) breeding of spring wheat for the highly variable low input rainfed
farming systems in Australia. In both cases, genetic improvement was an outcome of long-term investment in a sustained research
effort aimed at understanding the detail of the important environmental constraints to productivity and the plant requirements
for improved adaptation to the identified constraints, followed up by the design and continued evaluation of efficient breeding
strategies. The breeding strategies used differed between the two case studies but were consistent in their attention to the
key determinants of response to selection: (1) ensuring adequate sources of genetic variation and high selection pressures
for the important traits at all stages of the breeding program, (2) use of experimental procedures to achieve high levels
of heritability in the breeding trials, and (3) testing strategies that achieved a high genetic correlation between performance
of germplasm in the breeding trials and under on-farm conditions. The implications of the outcomes from these FPB case studies
for realizing the positive motivations for adopting PPB strategies are discussed with particular reference for low input target
environment conditions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
10.
Rooting patterns, biomass production, tillering, and yield formation of four winter wheat cultivars in a low external input system Growth conditions of winter wheat in agricultural low external input systems, e.g. ecological agriculture differ from those in conventional agriculture with regard to nutrient flow, impact of diseases, and weed competition. Knowledge of the dynamics of yield formation of winter wheat cultivars is very important for further development of such systems. During two growing seasons root growth, above ground biomass production, tillering, and yield formation were studied with four winter wheat cultivars of different periods of release at two ecologically managed farms in Northern Hessia. The results can be summarized as follows: – In general, plant breeding did not lead to a reduced development of root systems or above ground biomass production in winter wheat (Stöppler et al. 1989 a). Modern wheat varieties develop an extensive root system in greater depth, which means better drought resistance. – Not only root length densities, total root length, characteristics of tillering, and yield formation showed clear genotypic differences between the winter wheat cultivars, but also the development of root systems and above ground biomass production. – Winter wheat cultivars with a high plant density seem to have a retarded root growth after tillering due to intra-plant-competition and late root growth during grain filling, whereas cultivars with a high ear weight develop an extensive root system before the grain filling period. At the beginning of this period, a great root length per culm seems to be most important to achieve a high ear weight. The results indicate that those cultivars with poor to medium tillering and high ear weight are very well adapted to the reduced nutrient flow in low external input systems of farming. –In low external input systems, a satisfactory wheat crop need be established before tillering. 相似文献
11.
Maize participatory breeding in Portugal: Comparison of farmer's and breeder's on‐farm selection 
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下载免费PDF全文 Pedro Mendes‐Moreira Zlatko Satovic João Mendes‐Moreira João Pedro Santos João Pedro Nina Santos Silas Pêgo Maria Carlota Vaz Patto 《Plant Breeding》2017,136(6):861-871
“VASO” is a Portuguese participatory maize breeding project (1984), where several maize landraces such as “Pigarro” have been selected both by a farmer's (phenotypic recurrent selection) and a breeder's approach (S2 lines recurrent selection). The objectives of this study were to determine the phenotypic and genotypic responses to participatory selection using these two different approaches, to clarify to which extent both selection methods preserve genetic diversity, and conclude what is the preferred method to apply in sustainable farming systems. The results, obtained via ANOVA, regression analyses and molecular markers, indicate that for both selection methods, genetic diversity was not significantly reduced, even with the most intensive breeder's selection. Although there were some common outputs, such as the determinated versus indeterminated ears, cob and ear weight ratio per ear and rachis 2, specific phenotypic traits evolved in opposite directions between the two selection approaches. Yield increase was only detected during farmer selection, indicating its interest on PPB. Candidate genes were identified for a few of the traits under selection as potential functional markers in participatory plant breeding. 相似文献
12.
Progress from plant breeding has been slow in some marginal environments. Conventional or formal plant breeding (FPB) programs
conducted by international agricultural research centres or national programs in developing countries have been criticized
for ignoring indigenous germplasm, failing to breed for conditions facing poor farmers, and emphasizing selection for broad
versus local adaptation. A suite of techniques, referred to as participatory plant breeding (PPB) and including farmer-participatory
or farmer-led selection, on-farm evaluation, and use of local landraces, has been advocated in response to this critique.
PPB programs are diverse in scope and approach, but often rely heavily on farmer visual evaluation or phenotypic mass selection
to select for simply-inherited traits, with limited replicated yield testing in multiple-environment trials (MET), one of
the main tools of FPB. Prediction equations derived from selection theory can be used to examine the conditions under which
idealized versions of FPB and PPB may be expected to achieve genetic progress for traits such as yield. The effectiveness
of any selection environment is determined by both the genetic correlation between genotype performance in it and the target
environment (r
G) and the heritability of genotypic differences in the selection environment (H
s). r is a measure of the accuracy with which performance of genotypes in the selection environment predicts performance in the
target environment; H
s is a measure of the precision with which performance differences among genotypes can be measured in the selection environment.
We compare FPB and PPB with respect to these determinants of selection response, using examples from self-pollinated species.
Particular areas examined include: (i) selection for broad versus specific adaptation; (ii) on-station versus on-farm selection;
and (iii) selection under high-yield versus low-yield conditions. In general, PPB systems attempt to maximize gains through
the use of on-farm evaluation and the skills of farmer-selectors to maximize r
G. FPB exploits METs to maximize H
s. PPB is most likely to develop cultivars that out-perform the products of FPB when it is applied in low-yield cropping systems,
because it is in such situations that r
G between high-yield breeding nurseries and low-yield target environments is likely to be low or negative. To make continued
gains, and to compete with internationally-supported FPB programs, PPB systems will need to counter the obscuring effects
of uncontrollable within-field, site-to-site, and year-to-year heterogeneity. Simple and robust designs for on-farm METs are
needed for this purpose.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Xuekun Zhang Guangyuan Lu Weihua Long Xiling Zou Feng Li Takeshi Nishio 《Breeding Science》2014,64(1):60-73
Water deficit imposed by either drought or salinity brings about severe growth retardation and yield loss of crops. Since Brassica crops are important contributors to total oilseed production, it is urgently needed to develop tolerant cultivars to ensure yields under such adverse conditions. There are various physiochemical mechanisms for dealing with drought and salinity in plants at different developmental stages. Accordingly, different indicators of tolerance to drought or salinity at the germination, seedling, flowering and mature stages have been developed and used for germplasm screening and selection in breeding practices. Classical genetic and modern genomic approaches coupled with precise phenotyping have boosted the unravelling of genes and metabolic pathways conferring drought or salt tolerance in crops. QTL mapping of drought and salt tolerance has provided several dozen target QTLs in Brassica and the closely related Arabidopsis. Many drought- or salt-tolerant genes have also been isolated, some of which have been confirmed to have great potential for genetic improvement of plant tolerance. It has been suggested that molecular breeding approaches, such as marker-assisted selection and gene transformation, that will enhance oil product security under a changing climate be integrated in the development of drought- and salt-tolerant Brassica crops. 相似文献
14.
Knowledge of genetic relationships in crop breeding programs provides valuable information that can be used by plant breeders
as a parental line selection tool. In Upland cotton (Gossypium hirsutum L.), the Pee Dee germplasm program represents one of the most historically significant Upland cotton breeding programs and
is known as a key source of fiber quality genes for commercial cultivars. The foundation of the Pee Dee germplasm is known
to represent an array of genetic diversity involving the hybridization of G. hirsutum L., G. barbadense L., and triple hybrid strains (G. arboreum L. × G. thurberi Todaro × G. hirsutum L.). In this study, we characterized genetic relationships within the Pee Dee germplasm collection using molecular marker
and field performance data. Molecular marker and field performance data showed the Pee Dee germplasm collection still maintains
useful amounts of genetic diversity. The methods described provide plant breeders of cotton and other crops a strategy to
develop a parental line selection tool based on genotypic and phenotypic information. Cotton breeders can directly use the
information provided to select specific Pee Dee germplasm parental line combinations based on genotypic (molecular marker)
and phenotypic (field performance) information rather than relying on pedigree and phenotypic information alone. 相似文献
15.
Black spot disease, incited by the fungus Diplocarpon rosae Wolf, is the most important disease of roses (Rosa hybrida L.) in the outdoor landscape. Though partial resistance exists in cultivated germplasm, the genetic basis of this trait has
not yet been elucidated. Six diploid and six tetraploid rose cultivars were crossed in two factorial combining ability arrays.
Whole plant and detached leaf inoculation methods were used to assess partial resistance under two different disease pressures
using a characterized single-spore isolate. Parents from both arrays had significant general combining ability effects across
multiple inoculation methods and environments. Specific combining ability was not significant for either array. Parent per
se performance was highly correlated with progeny performance on a family mean basis. High positive correlations among whole
plant and detached leaf inoculation methods indicate that detached leaf assays can substitute for whole plant assays. Based
on these results, a breeding strategy including parental selection and early, among-family selection is proposed. To our knowledge,
this is the first investigation of combining ability for disease resistance in rose. 相似文献
16.
甘蔗野生种蔗茅的形态多样性分析 总被引：1，自引：0，他引：1
蔗茅(Erianthusfulvus)是甘蔗育种中极为重要的野生种质资源,研究其形态性状的遗传多样性对选育抗旱、抗寒、耐贫瘠、高蔗糖分含量的甘蔗新品种极为重要。为深入研究利用蔗茅野生资源,以保育在云南农业大学甘蔗研究所甘蔗种质资源圃的48份蔗茅无性系为试验材料,进行包括株高、叶宽、节间长度、茎径、锤度的田间调查和统计分析。结果表明,48份蔗茅材料在所调查性状上具有显著差异,变异系数介于9.37%~33.52%之间;基于5个性状的聚类分析将所分析材料分为了3类以及很多小类群,表明所研究蔗茅资源具有丰富的遗传多样性。研究结果对蔗茅资源在甘蔗育种中的利用具有重要参考价值。 相似文献
17.
冬小麦种质材料主要农艺性状研究 总被引：9，自引：5，他引：4
小麦种质资源是小麦育种的重要基础,小麦遗传多样性评价不仅有助于种质资源的搜集、管理和利用,也有利于核心种质的研究。为了合理利用小麦种质资源,降低组配小麦杂交组合的盲目性,选取73份国内外种质材料,在旱地条件种植,以株高、穗粒数、千粒重、有效穗数和产量为指标对其进行了聚类分析。结果表明,在雨养条件下各性状的变异系数大小为：产量>有效穗数>穗粒数>千粒重>株高;产量构成因素与产量的相关程度为：有效穗数>穗粒数>千粒重;供试材料可以分为六类,并对各类种质材料的特点及在育种中的应用作了评述。试验中综合表现较好的4个亲本材料为第Ⅵ组的18th FAWWON-IR-023、18th FAWWON-IR-111、18th FAWWON-IR-027和18th FAWWON-IR-169,可为选育抗旱优质丰产小麦新品种提供优异基因。 相似文献
18.
植物育种的株选技术方法研究 总被引：7，自引：0，他引：7
结合豇豆育种实践阐述了植物育种中株选的重要性和目的、株选的策略和株选方法等。笔者新提出了改良加权评分法和同工酶辅助株选法。认为（1）通过对易观察、遗传力高且与育种目标相关性大的性状选择可尽快实现育种目标。（2）把各性状看作灰选性状，单株级别则视为灰选等级，根据灰选等级进行株选，以各经济性状与产量的灰色关联度作为各性状的权重，计算得到各单株综合评价值，确定等级标准值，并划分等级结果，变权重主观赋值为客观求值，有利于提高株选的准确性和效率（3）利用同工酶生化标记辅助株选，可克服株选中仅从表现型出发而导致的偏差，也有利于改变过去只有在品种选育成功后，才研究其生化或遗传基础，藉此可大大缩短育种年限。本研究可资豇豆育种利用和其他植物育种借鉴。 相似文献
19.
Summary Plant growth habit (type) plays a major determining role in the acceptance of a dry bean cultivar by commercial growers. Under the threat of wet fall conditions in the midwestern U.S., growers show a preference for upright plant types-I and II over the more prostrate type-III growth habit of commercial pinto cultivars. The prostrate habit creates considerably more risk of harvest losses and potential of white mold (Sclerotinia sclerotiorum) development during a wet growing season.The breeding strategy being utilized to develop better adapted pinto bean cultivars for the humid midwest is based on the concept of ideotype breeding which has been successfully applied to small seeded navy and black beans. A system of phenotypic recurrent selection using S1 selection is being followed in order to recombine desirable traits from two diverse germplasm pools. One germplasm pool possesses the desirable architectural plant form and disease resistance traits of the small-seeded types while the medium-seeded germplasm source possesses the desirable seed size, shape and color characteristics of the pinto class. Since a repulsion phase linkage appears to exist between type-II architecture (architype) and medium seed size (40 g/100 seeds), recurrent selection is shown to be the most effective procedure for breaking up undesirable linkage groups and for increasing the frequency of desirable genes, thus enhancing the chance for the desirable genetic recombinations to occur.Journal Article No. 11667 of the Michigan Agricultural Experiment Station. 相似文献
20.
分子标记技术在甜菜育种中的应用 总被引：3，自引：3，他引：0
分子标记技术与常规育种技术相互紧密结合能显著提高育种效率。为了更好地阐明分子标记在甜菜育种中的作用,总结了国内外分子标记在甜菜亲缘关系及遗传多样性研究、遗传连锁图谱构建、数量性状基因定位（QTL）、分子标记辅助选择育种、杂种优势及种质鉴定中的研究现状和存在的问题。指出建立相应的高效分子标记辅助选育体系,创造出高产、优质、多抗或具广谱抗性的甜菜种质或品种是甜菜分子育种的研究方向。当前甜菜种质资源鉴定的关键任务是大力开发新型的分子标记进行甜菜种质资源遗传分析,绘制指纹图谱、进一步构建甜菜种质分子身份证。今后应加强对甜菜重要农艺性状基因进行精细定位,充分发掘QTL的信息,构建更为饱和的分子标记连锁图谱。 相似文献