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1.
Summary Lentil is a self-pollinating diploid (2n = 14 chromosomes) annual cool season legume crop that is produced throughout the world and is highly valued as a high protein food. Several abiotic stresses are important to lentil yields world wide and include drought, heat, salt susceptibility and iron deficiency. The biotic stresses are numerous and include: susceptibility to Ascochyta blight, caused by Ascochyta lentis; Anthracnose, caused by Colletotrichum truncatum; Fusarium wilt, caused by Fusarium oxysporum; Sclerotinia white mold, caused by Sclerotinia sclerotiorum; rust, caused by Uromyces fabae; and numerous aphid transmitted viruses. Lentil is also highly susceptible to several species of Orabanche prevalent in the Mediterranean region, for which there does not appear to be much resistance in the germplasm. Plant breeders and geneticists have addressed these stresses by identifying resistant/tolerant germplasm, determining the genetics involved and the genetic map positions of the resistant genes. To this end progress has been made in mapping the lentil genome and several genetic maps are available that eventually will lead to the development of a consensus map for lentil. Marker density has been limited in the published genetic maps and there is a distinct lack of co-dominant markers that would facilitate comparisons of the available genetic maps and efficient identification of markers closely linked to genes of interest. Molecular breeding of lentil for disease resistance genes using marker assisted selection, particularly for resistance to Ascochyta blight and Anthracnose, is underway in Australia and Canada and promising results have been obtained. Comparative genomics and synteny analyses with closely related legumes promises to further advance the knowledge of the lentil genome and provide lentil breeders with additional genes and selectable markers for use in marker assisted selection. Genomic tools such as macro and micro arrays, reverse genetics and genetic transformation are emerging technologies that may eventually be available for use in lentil crop improvement.  相似文献   

2.
Rusts are major biotic constraints of legumes worldwide. Breeding for rust resistance is regarded as the most cost efficient method for rust control. However, in contrast to common bean for which complete monogenic resistance exists and is efficiently used, most of the rust resistance reactions described so far in cool season food legumes are incomplete and of complex inheritance. Incomplete resistance has been described in faba bean, pea, chickpea and lentil and several of their associated QTLs have been mapped. However, the relatively large distance between the QTLs and their associated molecular markers hampers their efficient use for marker assisted selection. Their large genome size drastically hampers the development of genomic resource and limits the saturation of their genetic maps. The use of model plants such as the model legume Medicago truncatula may circumvent this drawback. The important genetic and genomic resources and tools available for this model legume can considerably speed up the discovery and validation of new genes and QTLs in resistance to legume pathogens. Here, the potential of M. truncatula as a model to study rust resistance in legumes, and to transfer rust resistance genes to cool season grain legumes is reviewed.  相似文献   

3.
Overcoming hybridization barriers in potato   总被引：3，自引：0，他引：3  
The cultivated potato is a major crop worldwide. It is a high input crop with complex quality requirements at harvest and during storage. Potato breeders are fortunate to have access to a very diverse and accessible germplasm resource. Wild Solanum relatives provide genetic diversity as well as genes for valuable production and quality traits. In most cases, crossing success can be predicted based on endosperm balance number (EBN), or effective ploidy, of the parents. Crossing barriers between most wild species and the cultivated potato are the consequence of differences in EBN and can be easily overcome using ploidy manipulations and bridge crosses. The most common ploidy manipulations include haploid extraction to reduce EBN and 2n gamete production to increase EBN. Additional methods to produce fertile interspecific hybrids include mentor pollination, embryo rescue, hormone treatments, reciprocal crosses, selection of cross‐compatible genotypes and somatic fusion. Knowledge of crossing barriers and mechanisms to overcome them allows potato breeders access to the rich gene pool in the genus Solanum.  相似文献   

4.
Barley is an economically important cereal crop especially for feed and malt production, but its value as food is increasing due to various health benefits. Wild barley is the progenitor of modern day barley cultivars possessing a rich source of genetic variation for various biotic and abiotic stresses. Species‐specific molecular markers have great potential for efficient introgression of these important traits from wild to cultivated barley. In the present study, 140 microsatellite markers were screened to assess the genetic variation and species‐specific markers between wild and cultivated germplasm. Of these 140, a polymorphic set of 48 genomic (gSSR) and 16 EST‐SSRs amplified a total of 685 alleles. Cluster analysis discriminated all 47 accessions and classified wild and cultivated genotypes into two distinct groups, according to their geographic origin. Our analysis indicated that gSSRs were more informative than EST‐based SSRs. Results from PCoA analysis for species‐specific alleles clearly suggest that wild barley genotypes contain a higher number of unique alleles.  相似文献   

5.
Investigations on interspecific crossability in two species of the genus Citrullus were studied based on their morphology, chromosome pairing and pollen fertility in their hybrids resulting from 12 combinations(including reciprocals). These have been utilized for tracing the phylogenetic relationship between the taxa and factors responsible for their differentiation. A collective evaluation of data on cross compatibility,morphology, chromosome association and pollen fertility indicated a close phylogenetic relationship between the species C. colocynthis (wild2n = 22) and C. vulgaris (cultivated 2n = 22). Significant differences for crossability and pollen fertility were observed between hybrids of C. colocynthis × C. vulgaris and reciprocals. Meiotic analysis of F1 hybrids revealed that these two species are freely crossable and provide normal chromosome association, involving an average of 9 to maximum 11 pairs of chromosomes. This indicated the possibility of high recombination and thereby genetic introgression of desirable traits. As both the species are of economic significance, breeding strategies can be developed for the genetic improvement of these species. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

6.
Wild emmer, Triticum dicoccoides, the progenitor of cultivated wheat, harbors rich genetic resources for wheat improvement. They include many agronomic traits such as abiotic stress tolerances (salt, drought and heat), biotic stress tolerances (powdery mildew, rusts, and Fusarium head blight), grain protein quality and quantity, and micronutrient concentrations (Zn, Fe, and Mn). In this review, we summarize (1) traits and controlling genes identified and mapped in T. dicoccoides; and (2) the genes transferred to cultivated wheat from T. dicoccoides. These genes, controlling important agronomic traits such as disease resistance, high protein and micronutrient content, should contribute to wheat production and food nutrition. However, most of the rich genetic reservoir in wild emmer remains untapped, highlighting the need for further exploration and utilization for long-term wheat breeding programs.  相似文献   

7.
Wild Lens taxa are a reservoir of useful rare genes/alleles for widening the genetic base and synthesis of a new gene pool of lentil. To maximize and sustain lentil production, new gene sources are needed to be identified and incorporated into cultivated background. This needs a comprehensive approach to accumulate favourable alleles from distantly related germplasm for widening of the cultivated gene pool and would be the most appropriate strategy to solve the various problems associated with stressed crop production and plateaued yields. Furthermore, expansion of deeper understanding of lentil genomics along with extensive research undertaken in other crop species can provide suitable guidelines to cover the distribution of Lens genus and component gene pools for further remarkable progress in lentil genetic improvement. This review aims at the genus Lens distribution and gene pools, crop germplasm conserved in ex‐situ and in‐situ collection, wild species characterization and evaluation for useful traits of interest to solve production‐related problems, highlight useful gene sources present in different gene pools and the progress achieved for widening the genetic base of cultivated varieties of lentil through wide hybridization and exploring lentil genomics.  相似文献   

8.
In Brassicaceae crop breeding programs, wild relatives have been evaluated as genetic resources to develop new cultivars with biotic and abiotic stress resistance. This has become necessary because of the diversification of ecotypes of diseases and pests, changing food preferences, advances in production technology, the use of new approaches such as in vitro breeding programs, and the need for economical production of F1 seed. To produce potential new cultivars, interspecific and intergeneric hybridizations have been performed between cultivated species and between cultivated species and their wild relatives. Furthermore, interspecific and intergeneric hybrids have been successfully produced using embryo rescue techniques. In this paper, we review the interspecific and intergeneric incompatibilities between Brassicaceae crops and their wild relatives, and the production, characterization, and improvement of synthetic amphidiploid lines, alien gene introgression lines, alloplasmic lines, monosomic alien chromosome addition lines, and monosomic alien chromosome substitution lines. The goal is to provide useful materials to support practical breeding strategies and to study the genetic effects of individual chromosomes on plant traits, the number of genes that control a trait, their linkage relationships, and genetic improvement in Brassicaceae crops.  相似文献   

9.
Rice is one of the most important crops in the world. The wild species of rice are expected to have novel beneficial alleles that have been lost from cultivated rice during the process of domestication. Therefore, wild species could be the potential source to induce lost genetic diversity in cultivated rice. Serving as an important reservoir of novel genes/QTLs, wild species, in general, are better adapted to different ecologies and can tolerate many biotic and abiotic stresses. Despite that, only a few wild species are studied and extensive characterization both at the molecular and morphological level is yet to be achieved. Several agronomically important genes/QTLs for improving biotic and abiotic stresses, resistance, productivity and grain quality traits were identified from AA genome donor wild species and were tagged with breeder friendly molecular markers for their transfer to elite genetic backgrounds. The present review provides information on the important wild rice species harbouring genes/QTLs for agriculturally important traits and their successful utilization in rice breeding programmes.  相似文献   

10.
Summary Biotic and abiotic stresses cause significant yield losses in legumes and can significantly affect their productivity. Biotechnology tools such as marker-assisted breeding, tissue culture, in vitro mutagenesis and genetic transformation can contribute to solve or reduce some of these constraints. However, only limited success has been achieved so far. The emergence of “omic” technologies and the establishment of model legume plants such as Medicago truncatula and Lotus japonicus are promising strategies for understanding the molecular genetic basis of stress resistance, which is an important bottleneck for molecular breeding. Understanding the mechanisms that regulate the expression of stress-related genes is a fundamental issue in plant biology and will be necessary for the genetic improvement of legumes. In this review, we describe the current status of biotechnology approaches in relation to biotic and abiotic stresses in legumes and how these useful tools could be used to improve resistance to important constraints affecting legume crops.  相似文献   

11.
Summary Necrotrophic pathogens of the cool season food legumes (pea, lentil, chickpea, faba bean and lupin) cause wide spread disease and severe crop losses throughout the world. Environmental conditions play an important role in the development and spread of these diseases. Form of inoculum, inoculum concentration and physiological plant growth stage all affect the degree of infection and the amount of crop loss. Measures to control these diseases have relied on identification of resistant germplasm and development of resistant varieties through screening in the field and in controlled environments. Procedures for screening and scoring germplasm and breeding lines for resistance have lacked uniformity among the various programs worldwide. However, this review highlights the most consistent screening and scoring procedures that are simple to use and provide reliable results. Sources of resistance to the major necrotrophic fungi are summarized for each of the cool season food legumes. Marker-assisted selection is underway for Ascochyta blight of pea, lentil and chickpea, and Phomopsis blight of lupin. Other measures such as fungicidal control and cultural control are also reviewed. The emerging genomic information on the model legume, Medicago truncatula, which has various degrees of genetic synteny with the cool season food legumes, has promise for identification of closely linked markers for resistance genes and possibly for eventual map-based cloning of resistance genes. Durable resistance to the necrotrophic pathogens is a common goal of cool season food legume breeders.  相似文献   

12.
Summary Over 2400 pollinations were made to investigate the crossability relationships between cultivated potatoes, and wild diploid species from Series Tuberosa and Circaeifolia, as well as wild polyploid species in Series Tuberosa and Longipedicellata resistant to potato cyst nematode, Globodera pallida pathotypes P4A and P5A. Wild diploids in Series Tuberosa crossed easily with cultivated diploid species, except with Solanum lignicaule where most pollinations failed, and seed set was extremely low (0.2 seeds per pollination or less). It is suggested that this species is 1EBN. S. capsicibaccatum is clearly isolated from Series Tuberosa, but can form hybrids with S. lignicaule, which can act as a bridging species to S. tuberosum haploids. S. gourlayi and S. oplocense can be crossed with both subspecies of S. tuberosum, but S. papita, Series Longipedicellata is reproductively isolated from the tetraploid cultigens. The crossability data are discussed in the light of germplasm utilisation for breeding potato varieties resistant to potato cyst nematode.  相似文献   

13.
Ground frost resistance is important for the growing of early potatoes and of othervarieties on soils which are prone to suffer from ground frosts. Resistance has beenfound, among others, in the primitive diploid cultivated potato species S. ajanhuiri.The clones of this species which are included in the Wageningen Potato Collection(WAC) were not crossable to ordinary varieties of the species S. tuberosum. However,it was shown to be possible to cross S. ajanhuiri with a dihaploid form of S. tuberosum.Amphidiploid plants were obtained after colchicine treatment. These plants werefertile when crossed with ordinary varieties. Some of the hybrids possess a certainfrost resistance. Backcrosses will be necessary to obtain varieties with good consump-tion qualities.  相似文献   

14.
An effective method of incorporating germplasm of wild 2x Solanum species into the cultivated potato is through hybridization with haploids of 4x S. tuberosum Group Tuberosum. This procedure provides for the introduction of desirable traits and genetic diversity from wild species into potato. Haploid and wild species genotypes can be evaluated for parental value based on the presence of good tuberization, desirable traits, fertility, and 2n gametes in their hybrid progeny. Haploid-wild species hybrids may be intercrossed and evaluated at the 2x level to take advantage of diploid genetic ratios. Selected 2x genotypes may then be brought to the 4x level through sexual polyploidization with 2n gametes.  相似文献   

15.
Introgression of unadapted genes from the wild Cicer species could contribute to the widening of genetic base of important traits such as yield, yield attributes and resistance to major biotic and abiotic stresses. An attempt was made successfully to intercross two wild annual Cicer species with three cultivated chickpea cultivars. Four interspecific cross‐combinations were made, and their true hybridity was ascertained through morphological and molecular markers. These cross‐combinations were also studied for some important quantitative traits under real field conditions. The range, mean and coefficient of variation of agro‐morphological traits were assessed in the parental lines, their F1 and F2 generations to determine the extent of variability generated in cultivated chickpea varieties. A high level of heterosis was recorded for number of pods/plant and seed yield/plant in F1 generation. Three cross‐combinations of ‘Pusa 1103’ × ILWC 46, ‘Pusa 256’ × ILWC 46 and ‘Pusa 256’ × ILWC 239 exhibited substantially higher variability for important yield‐related traits. The present research findings indicate that these wild annual Cicer species can be easily exploited to broaden the genetic base of cultivated gene pool for improving seed yield as well as adaptation.  相似文献   

16.
Summary Random amplified polymorphic DNA (RAPD) markers have been successfully employed to analyse the genetic diversity among cultivated and subspontaneous accessions of Coffea arabica. The narrow genetic base of commercial cultivars was confirmed. On the other hand, a relatively large genetic diversity was observed within the germplasm collection demonstrating the importance of collecting missions. Results suggested an East-West differentiation in Ethiopia, the primary centre of diversification of C. arabica. The large heterosis effect reported in intergroup hybrids could be related to such genetic differentiation. RAPD method appeared to be effective in resolving genetic variations and in grouping germplasm in C. arabica.  相似文献   

17.
J. S. C. Smith 《Euphytica》1989,43(1-2):73-85
Summary Zein chromatographic and isozyme electrophoretic data were used to characterize 61 hybrids of maize (Zea mays L.) that are of current widespread usage in France. A similar study was also carried out for 88 hybrids that are widely available in the central corn belt of the U.S. Objectives were to 1) investigate the degree to which isozyme and chromatographic data could provide unique hybrid identification; 2) to evaluate the wealth of genetic diversity available among hybrids that are currently cultivated in France and in the U.S.; and 3) to compare the patterns and extent of genetic diversity found in both countries with respect to their registration, breeding, and seed production practices.Isozyme data showed that all French hybrids were unique germplasm. However, numerous hybrids had chromatographic profiles that were identical for 11 major peaks and these hybrids could thus have some common germplasm at least among their female parental lines. Although there was a broad base of isozymic diversity among French hybrids, the amount in cultivation was less since the few most widely used hybrids, which were planted on approximately half the cultivated area, were similar for their isozymic and zein chromatographic profiles. Approximately only 50% of the U.S. hybrids were shown to be unique with the remainder classified into groups; at least some of the hybrids within each group could be genetically identical products. Leading U.S. hybrids were unique germplasm but numerous hybrids that collectively covered a large acreage appeared to encompass a relatively narrow genetic base.For the continued success of agriculture, it will be important to improve breeding, registration, and marketing practices in order to ensure the continued supply of genetically different and improved elite hybrids.  相似文献   

18.
Wild relatives are a potential source of genetic diversity to lentil (Lens culinaris Medik). The objective of this research was to obtain viable interspecific hybrids between the domesticated lentil and its wild relatives. The paper details the results of a number of interspecific crosses among L. culinaris, L. orientalis, L. odemensis, L. ervoides and L. nigricans. Viable hybrids were produced between L. culinaris × L. orientalis, L. culinaris × L. nigricans, L. culinaris × L. ervoides and between L. culinaris × L. odemensis. Further viable hybrids were obtained between L. culinaris and L. ervoides, which have the potential to be a ‘bridge’ in hybridization to L. culinaris for specific L. nicrigans lines which proved recalcitrant in L. culinaris × L. nigricans crosses. This is the first time that four wild species of lentils have been used successfully in hybridization with cultivated lentils, and viable hybrids produced. This paper also suggests that the artificial supplement of GA3, hormone is needed after fertilization for the normal growth of the hybrid embryo, possibly as the natural GA3 production is restricted with alien pollinations in cultivated lentils in both F1 and backcross hybrids.  相似文献   

19.
Wild Cicer species are considered to be more resistant for biotic and abiotic stresses than that of the cultivated chickpea (Cicer arietinum L.). Alien genes conferring resistance for biotic and abiotic stresses can be transferred from wild Cicer species to the cultivated chickpea but success in interspecific hybridizations has already been achieved with only two wild Cicer species. The current study was undertaken to compare fruitful heterosis in F2 and F3 for yield and yield criteria and to identify transgressive segregation in F2 and F3 in reciprocal interspecific crosses between C. arietinum and C. reticulatum Ladiz. We define fruitful heterosis as a useful parameter that can be used instead of residual heterosis. Considerable fruitful heterosis in F2 and F3 was found for number of seeds, pods per plant, biological yield, and seed yield. Maximum values of most of the characteristics in F2 and F3 were higher than that of the best parent indicating that superior progeny could be selected for yield from transgressive segregation. Progeny selection should be based on number of seeds, pods per plant, and biological yield since these characteristics had the highest direct effect on seed yield. The narrow sense heritability was found to be the highest for 100-seed weight. It was suggested that the cultivated chickpea could be used as female parent in interspecific hybridization to increase yield and yield criteria since progeny in F2 and F3 had better performance when it was used as female. In conclusion, interspecific hybridization of wild and cultivated chickpea can be used to improve yield and yield components and resistance to biotic and abiotic stresses as well.  相似文献   

20.
Wild Lens species/subspecies are a potential source for increasing genetic diversity in cultivated lentil. Four intraspecific crosses were attempted between cultivated and wild lentils. Viable hybrids were produced between L. culinaris ssp. culinaris × L. culinaris ssp. orientalis and L. culinaris ssp. culinaris × L. culinaris ssp. odomensis. Normal meiosis and pollen fertility were observed in the first set of crosses, whereas chromosomal abnormalities and reduced pollen fertility were observed in the second set of crosses. These crosses were also studied for some quantitative traits. The range, mean and coefficient of variation were calculated in parents, F1, F2 and BC1 generations to determine the extent of variability generated in the cultivated lentil through introgression of genes from wild lentil. The cultivated lentil × L. culinaris ssp. orientalis crosses showed substantially higher variability for all the traits than crosses involving cultivated lentil ×L. culinaris ssp. odomensis. The results of the present study indicated that these wild subspecies can be exploited for breeding purposes and their variation can easily be utilized to widen the genetic base of the cultivated lentil.  相似文献   

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