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1.
A three-year study was conducted from 1991 through 1993 to evaluate the field performance of potato clones that had been selected for resistance to wilt symptom development and stem colonization byVerticillium dahliae. The total yield, size distribution, and specific-gravity of these highly resistant clones were compared with standard cultivars and two parent clones with high Verticillium resistance and high yield, A66107-51 and A68113-4. Two groups of Verticillium resistant germplasm were selected in 1991. One group was the highly resistant progeny from a cross between A66107-51 and A68113-4. The second group consisted of hybrids between wild species accessions with high Verticillium resistance and cultivated diploid and tetraploid germplasm. Twenty-one out of 125 progeny clones from the A66107-51 × A68113-4 cross were highly resistant to Verticillium infection and were tested in yield trials for two years. Another eight selections had high Verticillium resistance but such low yield of seed tubers that they were tested only one year for yield. Eleven of the original 29 highly resistant selections were significantly lower in total yield than Russet Burbank. Only one clone was significantly higher in yield than RB, and none outyielded either of the resistant parents. Reddale and Century Russet had moderate to high Verticillium resistance, respectively. Both outyielded Russet Burbank and were comparable with the high yielding resistant parents. Of 15 interspecific hybrids tested in 1991, only four had sufficient yield to produce seed for yield trials and good wilt resistance after three successive seasons of evaluation. We concluded from this study that selecting at early stages of variety development strictly for Verticillium resistance is likely to be inefficient. Rather, selection should be for yield and other agronomic criteria in Verticillium infested fields.  相似文献   

2.
Six field trials were carried out in naturally infested soil to identify resistance to powdery scab. Trials were conducted at Anta, Cusco, in southern Peru (3300 m altitude) during six seasons. A scale of 1 (0%) to 9 (>95%) of tuber surface showing infection was used to evaluate resistance. Ratings 1–3 were considered resistant (R), 4 moderately resistant (R) and 5 or more, susceptible (S). Among 467 tested potato accessions (cultivars and advanced clones) of the potato germplasm collection held at the International Potato Center (CIP), 17 were R and 33 MR during two or more seasons. Another 55 were R and 70 MR during only one season. In addition, 251 were S and 41 did not grow for different reasons. Resistant were G-6, LT-6, DGV-103 A, Santiaguina, Alka Pinu, G84270.4, Serrana INTA, Esperanza, Gabriela, Albina, Primicia INTA, Pentland Crown, Ultimus, Katahdin, DTO-28, AL-624, and G81422.6. Cultivars Gabriela and Albina and clone G81422.6 can now be used by Cusco farmers because of their high yield, adaptability, and good resistance to powdery scab.  相似文献   

3.
Phenolic content and discoloration were determined for 13 commercial potato cultivars and 6 potato clones grown at 2 locations over a period of 5 successive years. Tubers from 6 potato cultivars and 5 potato clones resistant to the golden nematode were compared with tubers from 7 potato cultivars and 1 clone known to be susceptible to the golden nematode. Tubers from resistant plants were lower in phenols and discolored less than tubers from susceptible plants.  相似文献   

4.
The genetic diversity of 123 potato clones, consisting of 103 clonal accessions from the International Potato Center (CIP) and 20 Chinese cultivars, was assessed using amplified fragment length polymorphism (AFLP) markers. Ten polymorphic primer combinations were selected to analyse and compare the diversity of the two sources of clones. A total of 521 reproducible bands were amplified, of which 488 were polymorphic. These AFLP markers were analysed to estimate the genetic distance (GD) and genetic similarity (GS) coefficient of all clones. The GD between pairs of clones ranged from 0.03 to 0.48. Nei’s gene diversity index was between 0.236 and 0.387, with an average of 0.330. The index of Shannon’s information varied from 0.361 to 0.567 with an average of 0.498. A high degree of polymorphism was observed with an average of 93.6% loci found to be polymorphic. Cluster analysis showed that the CIP accessions were grouped together at the GS 0.59 clustering line, whereas most Chinese cultivars grouped at the GS 0.82 clustering line. The diversity in CIP potato resources was found to be higher than that of the Chinese cultivars, indicating that the genetic base of Chinese potato cultivars is narrow and may benefit from broadening.  相似文献   

5.
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   

6.
Summary Accessions of tuber-bearingSolanum spp. related toS. tuberosum subsp.tuberosum were obtained from the German-Dutch collection (Braunschweig, Germany) and the Inter-regional potato collection (Sturgeon Bay, USA). They were screened for resistance toG. rostochiensis Rol andG. pallida Pa2/3. Among 1567 clones from 52 accessions, 135 clones (23 accessions) were resistant toG. rostochiensis. They mainly representedS. andigena, gourlayi, spegazzinii andvernei. Among 1689 clones (74 accessions), 105 clones (32 accessions) were resistant toG. pallida. They representedS. gourlayi, spegazzinii, sparsipilum andvernei. About 25 clones were resistant to both species.  相似文献   

7.
In Puerto Rico, bananas (including plantains) are important agricultural commodities; their combined production totaled over 158,000 tons in 2011. Black leaf streak (BLS) and Sigatoka leaf spot diseases, caused by Mycosphaerella fijiensis and Mycosphaerella musicola, respectively, are responsible for significant losses of this crop, due to the high susceptibility of the most important cultivars. Diploid, triploid and tetraploid hybrids were introduced from international breeding programs for evaluation in Isabela, Puerto Rico. Accessions were established in the field in a randomized complete block design and were evaluated over two cropping cycles (2007–2010) for response to BLS and agronomic traits. Significant differences (P = 0.05) in BLS severity were observed among accessions throughout both crop cycles and were most pronounced at harvest. When averaged across production cycles, severity indices at harvest ranged from very resistant (20% of the leaf surface affected) for ‘FHIA 02’ to extremely susceptible (97%) for ‘Grand Nain’. Yield attributes varied widely among the accessions, including mean bunch weights (6.9–41.0 kg), numbers of hands per bunch (6.6–13.4), and the numbers of fruit per bunch (57.0–239.2). Several accessions, mainly from the Fundación Hondureña de Investigación Agrícola (FHIA), were BLS resistant and had short pseudostems, and large bunches. They could potentially replace susceptible cultivars in commercial production or play roles in a nascent organic market.  相似文献   

8.
One hundred accessions of 18 wild diploid potato species were screened for resistance to scab through three cycles of selection, from which a total of 322 clones were selected as resistant. The putative ancestral species of the cultivated potatoes (Solanum bukasovii, S. canasense andS. multidissectum) produced resistant clones with significantly higher rates. Thus, these are primary gene sources for conferring scab resistance to cultivated potatoes.  相似文献   

9.
Fifteen accessions ofSolarium berthaultii Hawkes andS. berthaultii xS. tarijense Hawkes were assessed for resistance to field infestations of the green peach aphid,Myzus persicae (Sulzer), potato leafhopper,Empoasca fabae (Harris), and potato fleabeetle,Epitrix cucumeris (Harris). Accessions bearing both Type A and Type B glandular trichomes were much more resistant to the green peach aphid and potato leafhopper than accessions bearing Type A hairs alone. All accessions had significantly smaller populations of these 3 pests than S.tuberosum cultivars. Total glycoalkaloid (TGA) content of foliage and tubers was not correlated with insect populations. Foliar TGA levels of field-grown plants varied among accessions, ranging from < 2–240 mg/100 g fresh wt. Solasonine and solamargine were the major foliar glycoalkaloids while solamarines predominated in tubers.  相似文献   

10.
Heat therapy and meristem tip propagation were used to develop two or three virus-free clones of 10 cultivars from the following sources: Epicure from British Columbia and Scotland; Katahdin, Kennebec, Keswick, Red Pontiac and Sebago from British Columbia and New Brunswick; Norchip from Alberta, Quebec and Washington; Norland from Alberta, British Columbia and North Dakota; Red La Soda from British Columbia, Nebraska and North Dakota; and White Rose from British Columbia and North Dakota. Tests prior to treatment showed that all but one of the stocks were infected with potato virus X and/or potato virus S but in only five of the ten cultivars were all clones infected with the same virus or viruses. Field trials with the virus-free clones, which extended over four years, showed that one of the Norchip clones produced fewer tubers per plant than two other clones in three years of the four years, but no consistent differences in yield or specific gravity of tubers were found among the clones of any of the 10 cultivars.  相似文献   

11.
Potato was introduced in Montenegro in the middle of the eighteenth century. Since then it has become the most important crop in plant production. During the period between 2008 and 2010 a total of 52 potato accessions was collected across Montenegro and stored in a national gene bank. In the study reported here 23 accessions from the collection were examined using microsatellite (also known as simple sequence repeats or SSRs) molecular markers with the aim to explore genetic diversity and redundancy within the germplasm. The accessions were selected on the basis of preliminary characterization of all 52 accessions for 11 lightsprout traits. Molecular characterization of 23 accessions by 12 SSR markers was carried out at SASA (Science and Advice for Scottish Agriculture) that manages a database of more than 3000 genetic profiles of potato from Europe and abroad. Comparison of SSR genetic profiles of Montenegrin collection against the existing SASA database allowed us to test the authenticity of the Montenegrin accessions. Out of the 23 accessions examined, 13 showed distinct genetic profiles of which seven showed perfect matching with known cultivars, two profiles showed strong similarity to another two cultivars, and four profiles were found unique with regards to the SASA database. Application of microsatellite markers in this study provided valuable information on the extent of genetic diversity residing within Montenegrin potato germplasm; it gave clear indications of the scale of redundancy within the collection; and helped clarify the identity of the accessions. Four accessions within the collection might incorporate unique variation and will be subjected to further agronomical examinations to assess their potential for breeding purposes.  相似文献   

12.
小麦品种在西藏的抗条锈性变异监测分析   总被引：1，自引：0，他引：1  
为了解不同小麦品种在西藏的抗锈性表现,于2009-2011年在西藏林芝西藏农牧学院实习农场,对来自全国小麦条锈病菌变异观察圃的46份已知抗性基因小麦品种、45份生产及后备品种和由西藏农牧学院保存的26份西藏小麦种质资源(包括生产品种、引进抗源品种及区试材料)进行了田间自然诱发抗条锈病鉴定。结果表明,在小麦条锈病菌变异观察圃中,46份已知基因品种中33份表现为抗病,3份表现为感病,10份抗性不稳定;45份生产及后备品种中20份表现为抗病,12份表现为感病,13份抗性不稳定;26份西藏种质中,22份表现为抗病,3份表现为感病,1份抗性不稳定。调查表明,大部分材料表现出较稳定的抗病性,但目前在西藏高原麦作区实际生产中应用却较少。为减轻小麦条锈病的发生危害,应进一步加强抗病品种的选育和推广。  相似文献   

13.
The effects of Potato leafroll virus (PLRV) isolates and inoculation method on the resistance to PLRV in potato clones and cultivars were investigated. In the season of inoculation, aphid inoculation resulted in higher proportions of infected plants and higher virus concentration in infected plants, as compared to graft inoculation. In these respects, grafting showed superiority over aphid inoculation in the tuber progeny of inoculated plants, though distinct dominance of aphid inoculation was observed for some tested clones. This leads to the conclusion that both methods should be applied as complementary tests for the efficient selection of highly resistant potato clones. For inoculations, two isolates of PLRV were applied, and one of them, isolate L7, was routinely used in screening breeding materials for resistance to the virus. The second isolate originated from plants of the highly resistant clone DW84-1457, which were incidentally infected with PLRV. The virus isolated from these plants was able to infect only specific clones, which were resistant to isolate L7. At the same time, potato clones with resistance derived from a source different from that present in DW84-1457, and standard susceptible and resistant cultivars, showed generally lower infection ratings after inoculation with the new isolate. This result suggests that the isolates may be different strains of PLRV. It is possible that under the strong selection pressure of resistance genes present in clone DW84-1457, a new isolate I-1457 could evolve the ability to overcome resistance to infection controlled by these genes.  相似文献   

14.
Bacterial soft rot is a serious disease in potato (Solanum tuberosum L.), causing rapid tuber tissue maceration and, consequently, marketable yield loss. Soft rot bacteria, including Pectobacterium carotovorum subsp. carotovorum (Pbc), are favored by moist conditions, which are prevalent in large potato storage facilities. However, although most potatoes in North America are stored before use, there are no published surveys of soft rot resistance in cultivars exposed to long-term storage conditions. Thus, we tested 65 cultivars and 13 breeding lines for soft rot resistance after 6 months of storage. There was a significant effect of cultivar and production environment on soft rot resistance score. During 6 months of storage, tuber soft rot resistance in resistant clones did not change, while it changed in susceptible clones. The three most resistant cultivars to soft rot were Freedom Russet, Anett, and Alaska Red Eye.  相似文献   

15.
Resistance of 20 F2 Solarium chacoense Bitter clones to the Colorado potato beetle,Leptinotarsa decemlineata (Say), was measured in a field test. Levels of total glycoalkaloids (TGA) and composición of the glycoalkaloid mixtures in foliage of the clones were also determined. Clones with either commersonine or dehydrocommersonine as the major foliar glycoalkaloid were significantly more resistant (lower damage ratings, fewer larvae and adult insects) than clones with solanine and chaconine. Damage ratings were negatively correlated (r = -0.67, p = 0.01) with foliar TGA levels. The results indicate that the types of glycoalkaloids present in the foliage ofS. chacoense may be as important as the level of TGA in limiting damage and numbers of insects.  相似文献   

16.
Nine potato clones/cultivars selected for varying degrees of Verticillium wilt (VW) resistance based on degree of vascular colonization, were intercrossed and outcrossed to 13 uncharacterized clones. Based on growth characteristics of 3,535 seedling transplants and an assay quantifyingV. dahliae in potato vascular tissue, 404 clones were selected for further tests. The average number ofVerticillium dahliae colony forming units (CFU) expressed as Log10(CFU + l)/0.1 ml of plant sap for the 404 clones was 2.3, and 1.3 and 3.7 for resistant Reddale and susceptible Kennebec checks, respectively. Thirty-five clones (8.66%) had CFU values equal to or less than Reddale suggesting that VW resistance is a readily transmitted trait.  相似文献   

17.
Late blight, caused byPhytophthora infestans, is the most important disease of potato worldwide and foliar resistance is an important component of managing late blight in the field. The objective of this research was to identify germplasm for use in breeding cultivars with foliar resistance toP. infestans. More than 500 clones were tested from 1997 to 2002 in inoculated (US8 genotype) field experiments conducted at the Michigan State University Muck Soils Research Farm in Bath, Michigan. All of the current commercial cultivars tested were classified as susceptible toP. infestans. The most resistant clones were A90586-11, AWN86514-2, B0718-3, Jacqueline Lee (MSG274-3), MSI152-A, MSJ307-2, MSJ317-1, MSJ453-4Y, MSJ456-2, MSJ456-4, MSJ461-1, MSK101-2, MSK128-1, NY121, LBR8, LBR9, Tollocan, and Torridon. Some of these resistant selections were from crosses with B0718-3, Jacqueline Lee, and Tollocan suggesting that the resistance toP. infestans was transmissible. These resistant clones will provide the opportunity to breed late-blight-resistant cultivars from a diverse pool of cultivated germplasm. Consistent foliar reaction toP. infestans over years suggested that the Michigan State University Muck Soils Research Farm is a valuable location for North American breeders to assess the reaction of potato germplasm to the US8 genotype of late blight.  相似文献   

18.
The goal of these studies was to evaluate the influence of tuber age on the expression of resistance to Phytophthora infestans in five selected potato genotypes (three cultivars and two clones) varying in tuber resistance and maturity type, and also to select the best time for testing potato tubers for resistance to blight. Resistance was evaluated by inoculating whole tubers at 13 different times as they progressively aged during growth and storage. Tuber age was expressed as weeks after planting. Tubers were rated from week 13 (late July) until week 43 (late February) for tubers planted on 27–28 April, over three consecutive seasons (2001–2003). Analysis of variance performed on tuber resistance data showed significant effects of genotype, year and tuber age. Significant contributions of genotype × year, genotype × tuber age, year × tuber age and year × genotype × tuber age interactions were also detected. A slight increase in tuber resistance with tuber age was observed for cvs Bzura, Sokół and Irga, while the opposite trend was observed for the clones 97-A-63 and DG 92-227. Changes in tuber resistance with age of tested genotypes were not related to their maturity type. The period of most stable expression of tuber resistance was observed when tubers were tested between the 16th and 28th week after planting.  相似文献   

19.
The response to potato late blight of 116 potato cultivars and breeding lines was determined in replicated trials conducted between 1980 and 1988. The index of area under the standardized disease progress curve (ASDPC), based on the cultivar Sebago, was used to rank the cultivars and to identify cultivars that had inconsistent disease responses over years. Most of the cultivars were susceptible to late blight; only 10 cultivars out of 66 currently available (including breeding lines) were judged more resistant than Sebago. Nine cultivars were identified as having inconsistent resistance over years. The index ASDPC was less variable than the relative area under the disease progress curve when the yearly disease conditions differed from the normal.  相似文献   

20.
Dwarf and common cashew (Anacardium occidentale) genotypes were screened separately for resistance against anthracnose (Colletotrichum gloeosporioides). Disease incidence was assessed on emerging leaves over three consecutive crop seasons in Mocuba, Meconta and Pebane districts of northern Mozambique. Evaluation the disease using leaf incidence is presented as a new field method for screening cashew genotypes resistant to anthracnose. It is fast, precise and consistent in ranking cultivars over several tree seasons. Seasonal, cultivar and disease incidence means were compared using Fishers' LSD test. The method enabled the differentiation of highly infected cultivars from those consistently tolerant across seasons and locations. No a single clone with a high level of resistance was identified out of 229 entries. However, hierarchical tables of clonal sensitivity ranked clones 1.12PA, 12.8PA and 1.18PA as tolerant and 11.9PA and 2.3BG as susceptible among the dwarfs. Among the common genotypes, clones NA7, MB77, 1.5R and MCH-2 ranked tolerant and IM1 and MU3 susceptible. Tolerant clones were therefore recommended to be used in the national cashew breeding program for further development of cashew cultivars with durable resistance to anthracnose. Further, clones such as 2.5VM, 1EM, MB75 and others that revealed incidence consistency over seasons can be used as susceptibility or tolerance standards in screening trials.  相似文献   

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