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1.
Wild potato species possess genetic variability for valuable traits including resistance toPhytophthora infestans, the causal agent for potato late blight disease. Breeding schemes using 2n gametes are a powerful tool for introgressing these traits. Forty-five plant introductions (PIs) across 12Solanum species representing various Endosperm Balance Numbers (EBN) and having resistance toP. infestans (US-8, isolate ND 95-2) were screened for 2n pollen production and male fertility. Species evaluated were 2x(lEBN)S. bulbocastanum, S. cardiophyllum, S. pinnatisectum, andS. trifidum; 2x(2EBN)S. berthaultii, S. megistacrolobum, S. microdontum, andS. verrucosum; 4x(2EBN)S. fendleri andS. stoloniferum; 6x(4EBN)S. guerreroense; and 2x(unknown EBN)S. polyadenium. Acetocarmine staining and cytological analyses were used to determine 2n pollen production and pollen stainability from genotypes grown across three locations. Based on frequency, genotypes were assigned to 2n pollen production categories (0≤1%, Low=1%–10%, Medium=11%–60%, and High≥60%) and pollen stainability categories (0≤1%, 1=196–5%, 2=6%–10%, 3=11%–20%, 4=21%–50%, and 5≥50%). Eleven of the 12 species and 37 of the 45 PIs examined contained genotypes producing ≥1% 2n pollen with ranges of 0%–63.6% and 0%–81.8%, respectively. Dependence was found between location and pollen stainability, EBN and pollen stainability, but not for location and frequency of genotypes with 2n pollen. Stability for 2n pollen production was observed across environments. Among the 1EBN germplasm, dependence was found between 2n pollen and pollen stainability. Resistance toP. infestans was found to be independent of 2n pollen production; therefore, identifying genotypes combining 2n pollen production, fertility, and resistance toP. infestans was possible.  相似文献   

2.
Late blight (Phytophthora infestons (Mont.) de Bary) has re-emerged as an important pathogen of the cultivated potato (Solanum tuberosum subsp.tubero-sum L.) in North America. The purpose of this study was to evaluate the relative susceptibility of potato germplasm in the greenhouse in order to initiate a breeding program for resistance to the US-8/A2 mating type which is the more aggressive and prevalent strain of late blight. Whole plants of 147 cultivars and breeding lines were evaluated. Percent plant area infection was visually assessed. Seven days after inoculation, infection ranged from 0 to 100% and the overall mean was greater than 50%. Two-thirds of the cultivars and breeding lines tested were very susceptible to the US-8 genotype. The highest resistance was identified in the somatic hybrids betweenS. tuberosum andS. bulbocastanum and their backcross derivatives. Pike and Snowden were less susceptible than the other North American cultivars. Zarevo was most resistant among the European cultivars. Seven of the advanced breeding lines were equivalent to Zarevo in infection levels. The host plant resistance identified among the material tested in this study can be used by breeding programs to develop improved cultivars with resistance to US-8 genotypes of late blight.  相似文献   

3.
Wild potato species contain many traits of economic importance. Late blight (LB) resistance and cold chipping are traits desired in potato cultivars. These traits could be co-currently introgressed if they occurred together in wild potato species. Our research objectives were (1) to determine if variation for cold chipping exists between potato species, accessions within species, and plants within accessions all having foliar LB resistance, and (2) to identify wild potato genotypes combining LB resistance and cold chipping. Materials include 665 genotypes from 43 LB-resistant accessions of 12 potato species having Endosperm Balance Numbers (EBN) of 1, 2, and 4, and 59 LB-resistant genotypes retained from these accessions for breeding. Potato chips were made from greenhouse-grown tubers following storage at 4 C for 6 months. Chip color was scored 1–10, ≤ 4 is acceptable by industry standards. Most of the variation for chip color was due to differences between species. Species ranged in the percentage of acceptably chipping genotypes (0% – 67%) with nine of 12 species having cold-chipping genotypes. Appreciable variation was present within accessions as well. The best chipping accessions wereS. verrucosum plant introduction (PI) 161173 – 4.33 / 0.67 (mean / proportion acceptable genotypes),S. stoloniferum PI 250510 -4.36 / 0.64,S. pinnatisectum PI 347766 -4.65 / 0.35 and 275233 -4.73 / 0.44, andS. megistacrolobum PI 195210 -5.14 / 0.29. Eleven 1EBN genotypes fromS. pinnatisectum andS. trifidum and five 2EBN genotypes fromS. verrucosum, S. fendleri,S. stoloniferum, andS. microdontum were identified that combined LB resistance and cold chipping. Co-current introgression would require fewer breeding cycles than other breeding methods to identify hybrid genotypes possessing both traits.  相似文献   

4.
Mexican wild diploid species,Solanum pinnatisectum (S. pnt) (2n=2x=24, 1EBN: endosperm balance number) is a useful germplasm source of late blight and Colorado potato beetle (CPB) resistance in potato improvement. However, it is very difficult to cross this species with other 1EBNSolanum species. Sexual hybrids among three accessions ofS. pnt and two accessions ofS. cardiophyllum (S. cph) (2n=2x=24, 1EBN) were studied. There were large differences in the cross-compatibility among the genotypes and accessions from these two 2x-1EBN species. Interspecific incompatibility existed in the crosses betweenS. pnt andS. cph, in whichS. cph functioned only as the male parent. The crosses with accessions PI 275236 ofS. pnt produced 35 hybrids following the conventional propagation procedures. Seven hybrids were obtained with theS. pnt accession PI 275233 with the aid of embryo rescue, while hybridization involving accession PI 253214 resulted in no fruit. The cytogenetic analysis indicated that all of the hybrids derived from crosses of accession PI 275233 ofS. pnt withS. cph had 2n = 24 chromosomes and were pollen fertile. Crosses involving accession PI 275236 ofS. pnt produced both 2x (2n=24) and 3x (2n=36) hybrids. Meiotic analysis at metaphase I of pollen mother cells (PMCs) showed a fairly high rate of chromosome pairing that averaged between 10.10 and 11.10 bivalents per cell in most of the 2x hybrids, indicatingS. pnt andS. cph have the similar genome. A high frequency of trivalents and quadrivalents were observed in 3x hybrids derived fromS. pnt 2 ×S. cph 1, indicating homology exists among these chromosomes. These results suggest that specific gene(s) and not either differences between genomes or EBN controlled interspecific crossability and embryo development. The disease and insect tests on the 2x and 3x hybrids revealed that all have high levels of resistance to both late blight and CPB. Thus it could appear that selection of genotypes is a key for successful interspecific hybridization when using Mexican wild diploid species as a source of economic important traits.  相似文献   

5.
Tetralobulate (Type A) glandular trichomes are present on foliage of many wild as well as cultivated species of potatoes. These trichomes confer resistance to insect pests if their density, gland size and biochemical products are similar as those ofSolanum berthaultti Hawkes andS. polyadenium Greenm. Hybrids ofS. tuberosum L. ×S. berthaultii have been screened for resistance by measurement of phenolic oxidation activity in their Type A trichomes by use of an enzymic browning assay. However, variability in the procedure has prompted the development of an improved assay.  相似文献   

6.
Successful isolation of haploids (2n=2x=24) from 4x(2EBN) Mexican species was achieved by using Modified Wenzel (MW) and Nitsch and Nitsch (NN) media for anther culture. Both media, MW and NN, gave consistent regeneration of plantlets from 4x(2EBN) Mexican species, and responses to the media were both species and accession (PI) specific. Plantlets regenerated directly from microspores, by-passing the callus cycle, were mostly haploid (2n=2x=24). Haploid plants appeared smaller and weaker than their parents with a drastic reduction in both male and female fertility. Abnormalities observed during meiosis and the lack of success in crossing confirmed the effect of the meiotic irregularities observed in the haploids. A total of 290 seeds was obtained from the 4x × 2x crosses of 4x Mexican species with irradiated pollen of 2xS. cardiophyllum and 2xS. chancayense; however, no haploid (2n=2x=24) plants resulted. Extraction of haploids from colchicinedoubled 4x (2EBN) or natural 6x(4EBN) Mexican species using a Phureja pollinator was examined to provide clues to the potential of using 2x (1EBN) pollinators for haploid induction in 4x(2EBN) × 2x(1EBN) crosses.  相似文献   

7.
Diploid wild potato species, classified as 1EBN (Endosperm Balance Number), do not cross with tetraploid or diploid forms ofS. tuberosum Gp. Tuberosum. The crossing of 2n pollen producing 1EBN clones as well as chromosome-doubled 1EBN clones with Gp. Tuberosum haploids was initiated to overcome this hybridization barrier. The screening of eleven 1EBN species,S. brachistotrichum, S. bulbocastanum, S. cardiophyllum, S. chancayense, S. commersonii, S. etuberosum, S. fernandezianum, S. jamesii, S. mochicense, S. pinnatisectum andS. trifidum, resulted in the identification of 2n pollen producers in eight of the species examined. Direct hybridization with Gp. Tuberosum haploids utilizing the above-mentioned crossing scheme was successful withS. chancayense andS. commersonii. The hybrids obtained, however, were male and female sterile. Abnormal microsporogenesis in the hybrids was postulated to be the result of an interaction between Gp. Tuberosum cytoplasm and nuclear genes contributed by the 1EBN male parent. Analyses of the growth of 1EBN species’ pollen tubes in the stigma/style of Gp. Tuberosum haploids were also conducted. Interspecific incompatibilities were observed with the most severe forms found with the use of species in the Series Etuberosa. The use of the Endosperm Balance Number theory can aid in designing crosses which overcome barriers to successful endosperm development. Sterilities in the hybrids obtained as well as interspecific incompatibilities will also need to be addressed, however, before 1EBN species germplasm can be successfully utilized for the improvement of the cultivated potato.  相似文献   

8.
Phenolic compounds in Type A glandular trichomes of two insectresistant potato species were separated and identified using a combination of high pressure liquid chromatography (HPLC), UV-visible spectrometry, and1H proton nuclear magnetic resonance (NMR) procedures. Type A trichomes ofSolanum berthaultii andS. polyadenium contained a phenolic compound tentatively identified as the glucose ester of p-hydroxyphenylpropionic acid. Its presence in trichomes of both species suggests that this compound may play a major role in formation of the brownish, insect entrapping exudate characteristic of trichome-mediated insect resistance in these species. Chlorogenic acid, a major phenolic constituent of Type A trichomes ofSolanum polyadenium was not detected in trichomes of 5.berthaultii. The exclusive presence of chlorogenic acid in trichome exudates ofS. polyadenium may be responsible, at least in part, for the greater levels of insect entrapment by this species, compared with that ofS. berthaultii.  相似文献   

9.
Wild potatoes are important sources of genes for resistance to disease and insect pests. A collection of wild Mexican and South AmericanSolarium species from the US potato Genebank was evaluated under laboratory and/or field conditions for their reaction to late blight (Phytophthora infestans), Colorado potato beetle (CPB,Leptinotarsa decemlineata Say), and blackleg (Erwinia carotovora subsp.atroseptica (van Hall) Dye) in order to identify individual genotypes with multiple resistance genes. Late blight inoculations using aggressive isolates (US-8/A2 and US-11/A1 mating types) of P.infestans revealed a wide range of variation for resistance between and within the accessions of the wild species tested. For late blight, susceptible as well as moderately to highly resistant genotypes were observed in all the species tested. However, at least one accession from the three Mexican and one South American wild diploid species tested showed a relatively uniform high level of resistance toP. infestans. These includedS. bulbocastanum, S. pinnatisectum, S. cardiophyllum, andS. circaeifolium. Two accessions from South American speciesS. commersonii were highly susceptible to late blight. For the Colorado potato beetle test, only one species,S. pinnatisectum appeared uniformly resistant to CPB under field conditions. Results of screening for blackleg resistance showed that there were major differences between genotypes in the wild species. Accessions ofS. circaeifolium PI 498119 andS. bulbocastanum PI 243504 were identified as having significantly higher blackleg resistance than cultivated potato and the other wild species tested. However, genotypes from these two accessions were more susceptible to late blight and CPB. Characterization of theP. infestans isolate P1801C.16 used for late blight evaluation and multi-locus isolate tests using US-8/A2 and US-11/A1 races revealed that the resistance inS. pinnatisectum genotypes tested corresponded to a race-non-specific genetic system, which was different from any existing R genes.Solanum pin-natisectum genotypes with both high levels of late blight and CPB resistance as well as blackleg resistance genotypes identified in the present study represent a diverse gene pool that may be useful for development of new potato cultivars with multiple disease and insect resistance. The potential utilization of these valuable sources for improvement of cultivated potato is discussed.  相似文献   

10.
The aim of this work is the evaluation of tetraploid potato clones with germplasm fromS. chacoense andS. phureja for chipping and resistance to tuber soft rot (Erwinia carotovora subsp.carotovora). Tetraploid potato clones were obtained via 2n eggs through 2x–4x crosses. Cytological mechanisms were investigated in the diploid hybrid 2n-egg producer used as parent in the unilateral sexual polyploidization scheme; the omission of the second meiotic division and cytokinesis failure at the end of meiosis were identified with a genetic consequence equivalent to second division restitution (SDR). Tuber marketable yield, specific gravity and chip-processing ability evaluated at harvest and after cold storage with and without reconditioning were higher in some clones as compared to theS. tuberosum tetraploid parent. Tuber soft rot resistance, contributed byS. chacoense, was successfully transferred to the4x level. After inoculation withErwinia carotovora subsp.carotovora and estimation of the rotted area, one tetraploid clone proved to be resistant and three partially resistant. The genetic value of exotic germplasm and sexual polyploidization strategy are discussed in relation to potato improvement.  相似文献   

11.
Summary Soluble proteins in seed potato were analyzed by electrophoresis (PAGE). The Index of Variation (IV) was calculated in order to estimate variation within each accession of wild and cultivated potato species andS. chacoense selfed lines. Seeds of 34 accessions representing 14 species from six taxonomic series were analyzed. The IV ofS. chacoense selfed lines decreased from 47.7 in the S2 to 12.9 in the S7 generation. The average IV for the self-incompatible diploid species was 41.2, whereas that of the selfcompatible diploid species,S. polyadenium, was 21.3. TetraploidS. tuberosum ssp.andigena andS. sucrense had an average IV of 62.2, which is much higher than that observed in any other diploid species. The naturally selfing speciesS. acaule (4x), and its colchicine-doubled derivative (8x), showed very low variation (IV=7.5). The IV appears to reflect heterozygosity and is affected by the breeding mode and the genetic constitution of diploid parents for derived polyploids.  相似文献   

12.
Peru has 103 taxa of wild potatoes (species, subspecies, varieties, and forms) according to Hawkes (1990; modified by us by a reduction of species in theSolanum brevicaule complex) and including taxa described by C. Ochoa since 1989. Sixty-nine of these 103 taxa (67% ) were unavailable from any of the world’s genebanks and 85 of them (83%) had less than three germplasm accessions. We conducted a collaborative Peru (INIA), United States (NRSP-6), and International Potato Center (CIP) wild potato (Solanum sect.Petota) collecting expedition in Peru to collect germplasm and gather taxonomic data. This is the first of a series of planned expeditions from 1998–2002. We collected from February 18 to April 18, 1998, in the southern departments of Apurímac, Arequipa, Cusco, Moquegua, Puno, and Tacna. We made 57 germplasm collections, including 14 taxa that are the first available as germplasm for any country (Solanum aymaraesense, S. chillonanum, S. incasicum, S. megistacrolobum subsp.megistacrolobum f. purpureum, S. longiusculus, S. multiflorum,S. pillahuatense, S. sawyeri, S. sandemanii, S. tacnaense, S. tarapatanum, S. urubambae, S. velardei, S. villuspetalum), and two additional taxa that are the first available for Peru but with germplasm from Bolivia (S. megistacrolobum subsp.toralapanum, S. yungasense). Collections also were made for the rare taxaS. acroscopicum, S. buesii, S. limbaniense, andS. santolallae. Our collections suggest the following minimum synonymy may be needed for Peruvian potatoes:S. sawyeri as a synonym ofS. tuberosum;S. hawkesii andS. incasicum as synonyms ofS. raphanifolium;S. multiflorum andS. villuspetalum as synonyms ofS. urubambae.  相似文献   

13.
Blue light fluorescence microscopy was found to be a quick and easy procedure for assessing pollen tube development in interspecific pollinations ofSolanum. Based on penetration of pollen tubes to the base of the style, several combinations of green-peach-aphid-resistant species and potential bridging species to S.tuberosum ssp.tuberosum should be considered for embryo culture. Sterile or highly infertile hybrids were obtained between green-peach-aphid-resistantS. tuquerrense andS. tuberosum ssp.tuberosum and are described. Slightly fertile hybrids were obtained betweenS. tuquerrense andS. polytrichon, a species compatible withS. tuberosum ssp.tuberosum.  相似文献   

14.
Protoplasts were fused to produce somatic hybrids between a triploid (2n=3x=32-34) interspecific somatohaploid betweenSolanum brevidens Phil. andS. tuberosum L., and a dihaploid (2n=2x=24) anther-derived line ofS. tuberosum cv. Van Gogh. A total of 265 plants were regenerated from protoplast fusion derived calli and their hybridity was verified using fusion partner specific RAPD markers. These “second generation” somatic hybrids were aneuploid pentaploids (2n=5x=51-65) with a 2C DNA content ranging from 3.36 to 4.43 pg, which corresponded to the sum of the 2C values of each of the fusion partners (somatohaploid: 2.22 pg; and the dihaploid line of cv. Van Gogh: 1.87 pg). Most of the “second generation” somatic hybrids were vigorous, but variable in morphology. They were extremely resistant to PLRV and they had tolerance to PVY infection derived from the somatohaploid fusion partner. Even though most of the “second generation” hybrids tuberized, the tuber morphology was variable and most were poorly shaped. InErwinia soft rot resistance tests, the tubers showed higher level of resistance than the tetraploidS. tuberosum cultivars, the dihaploidS. tuberosum fusion partners and the hexaploid somatic hybrids betweenS. brevidens andS. tuberosum. The “second generation” somatic hybrids were all male sterile and failed to produce berries or seeds.  相似文献   

15.
Seeds of three progenies segregating for resistance to two pathotypes ofGlobodera rostochiensis (Rol and Ro2) and two pathotypes ofG. pallida (Pa2 and Pa3) are being released by the Cornell University Experiment Station and the USDA/ARS. This resistance is in a form suitable for North American production and was developed for use in the event that pathotypes ofG. pallida, which are prevalent in many other potato production areas of the world, are ever introduced into North America. The source of the resistance is germplasm obtained in 1984 from the International Potato Center in LaMolina, Peru. The combined resistance in this germplasm is fromS. tuberosum sspandigena andS. vernei. Resistance to PVY is also segregating in two of these progenies.  相似文献   

16.
The basis of low seed set was investigated in a diploid hybrid population with germplasm from the cultivated speciesSolanum tuberosum spp.tuberosum andS. tuberosum ssp.phureja and the wild speciesS. chacoense. Controlled crosses were performed following an incomplete diallel mating design which included the hybrid population and the parental species. Pollen grain germination and pollen tube growth were observed with fluorescence microscopy in 174 intrapopulation and interspecific combinations of genotypes. Fifty percent of the combinations of genotypes within the hybrid population and 46% of those between this population and the parental species were incompatible; overall, 71% of the interspecific combinations of genotypes were compatible when plants of the hybrid population were used as females, vs. 5% when used as males. Although the site of reaction could vary in a given intrapopulation or interspecific cross with the combinations of genotypes, pollen tube inhibition occurred in the first third of the style in 42% of them. Since the gene pool of the hybrid population had been widened with germplasm from other geographic areas and the genotypes ofS. tuberosum ssp.tuberosum, S. chacoense andS. tuberosum ssp.phureja used in this study were not the ones involved in the original crosses, it is concluded that the S-locus is not controlling the incompatibility reaction but rather that a cross-incompatibility system, possibly governed by more than one locus, is acting.  相似文献   

17.
Development of potato cultivars resistant to Erwinia species (Erwinia carotovora subspeciesatroseptica, E. carotovora subspeciescarotovora, andErwinia chrysanthemi) causing soft rot of stems and tubers involves identification and transfer of the resistance to breeding lines possessing desirable agronomic traits. In total, 363 accessions of six wildSolanum species, three somatic hybrids and nine sexual progeny of somatic hybrids were screened for stem soft rot resistance. Thirty-one, 50, and 67 percent of accessions ofSolanum boliviense, Solanum chacoense, and Solanumsanctarosae, respectively, were resistant or highly resistant, whereas, 100, 97, and 95 percent of accessions ofSolanum canasense, Solanum tarijense, andSolanum spegazzinii were susceptible or highly susceptible, respectively. Two tuber soft-rot resistant somatic hybrids, A937 and T355-11 produced earlier by the fusion ofSolanum brevidens (PI 218228) andSolanum tuberosum (PI203900) orS. tuberosum cv. Russet Burbank, respectively, and the sexual progeny of A937 andS. tuberosum cv. Katahdin were also highly resistant. Transfer of resistance fromS. brevidens to somatic hybrid (A937) and subsequently to the progeny suggests that the resistance is simply inherited. In addition to the identification of 65 resistant or highly resistant clones of wildSolanum species, this study has identified three tuber soft rot-resistant clones that are also resistant to stem soft rot. Potato cultivars showed a range of responses to the pathogen.  相似文献   

18.
Forty-one clones of 34 accessions belonging to 25 tuber-bearingSolanum species were tested for their reaction to root knot nematode,Meloidogyne incognita. A high degree of resistance was found inS. bulbocastanum, S. gandarillasii, S. lignicaule, S. ajanhuiri andS. tuberosum groupandigena. S. vernei andS. spegazzinii were the most resistant species.  相似文献   

19.
Diploid potato clones, interspecific hybrids ofSolanum species, having in their originS. tuberosum,S. chacoense, S. yungasense, S. phureja, S. gourlayi, andS. demissum, with resistance to soft rot, were crossed to tetraploid potato clones in 4x-2x crosses. The 24 tetraploid families obtained in a North Carolina II design were examined for tuber resistance to soft rot in a laboratory test and for basic agronomic traits in field trials conducted for two consecutive years. In addition, one family originating from a 4x-2x cross of two susceptible parents was tested. Statistical analysis of the data revealed significant general (GCA) and specific combining ability (SCA) effects, year, GCA (female) × year, GCA (male) × year, and SCA × year upon the inheritance of resistance to soft rot. About 35% of the progeny was selected as resistant to tuber soft rot, and of these 11% showed high resistance combined with good tuber yield, tuber weight, and tuber appearance. The relationships between resistance to soft rot and chosen agronomic traits were not noted or were weakly significant and sporadic. The resistance to tuber soft rot found in diploid potato hybrids can be transferred to the cultivated tetraploid pool through 4x-2x crosses, and a high frequency of offspring posses resistance.  相似文献   

20.
Several species ofFusarium cause both dry rot in storage and seedpiece decay in the field, which results in severe losses in all major potato-growing regions. In temperate climates twoFusarium species are the principle causes of tuber dry rot-F.sambucinum andF. coeruleum. Resistance toF. sambucinum was identified in cultivated and wildSolanum species. Relatively high levels of resistance exist in the following 2EBN species:S. boliviense (PI#’s 265860, 310975, 310974, 545853, 545889, 545964),S. gourlayi ssp.gourlayi (PI#’s 473344, 545865),S. microdontum (PI#’s 310979, 473171),S. sancta-rosae (PI# 498392),S. kurtzianum (PI# 472930),S. fendleri ssp.fendleri (PI# 262895),S. gandarillasii (PI#’s 265866, 283076),S. oplocense (PI# 498281) andS. vidaurrei (PI# 498332). The resistance is highly heritable but appears, at least in some of the species, to be associated with recessive alleles.  相似文献   

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