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1.
Inheritance of resistance to late blight in foliage and tubers of progenies from parents differing in resistance 总被引：5，自引：0，他引：5
Summary TenSolanum tuberosum genotypes differing in resistance to late blight (Phytophthora infestans (Mont.) de Bary) in foliage and tubers were intercrossed to determine the inheritance of disease resistance in their progenies.
Plots of 10–15 clones per progeny were established in each of 2 years and resistance assessed by field or laboratory tests.
The parental genotypes were similarly tested each year.
The parents differed in general combining ability (GCA) for both foliage blight (FB) and tuber blight (TB). The parental and
GCA scores were significantly correlated for both aspects of the disease, but the correlations between foliage and tuber scores
for parents and for GCAs were not significant.
Three parental genotypes were highly resistant in both foliage and tubers, and the genotype with the highest GCA for resistance
to both FB and TB (cv. stirling) is recommended as the best parent. There was no evidence of strong genetic correlation between
both aspects of resistance, and it is suggested that both be selected for in a breeding programme. 相似文献
2.
Summary The resistance to common scab of nine cultivars and eight advanced breeding lines of potatoes, fiveSolanum andigenum Juz. et Buk. clones, and three potato breeding lines selected for resistance to common scab, was investigated in a field
and a pot trial. In the pot trial potaroes were planted in inoculated coarse river sand in plastic pots (150 mm in diameter)
placed on irrigated subsoil in a glassfibre house. In a field trial potatoes were planted in an artificially infested field.
The harvested tubers were scored individually for scab incidence according to two scales, viz. a 1–5 point scale for percentage
surface covered with scab and a 1–3 point scale for lesion type. A scab index value was calculated for each tuber. A significant
correlation coefficient of 0.82 was obtained for the results of the two tests. 相似文献
3.
In order to optimize potato crop management in organic farming systems, knowledge of crop growth processes in relation to
limitations and reductions by nitrogen (N) and disease is necessary. This paper examines the effect of different prevention
measures (seed tuber pre-sprouting, choice of cultivars: resistance to Phytophthora infestans; earliness of tuber initiation) against disease-related constraints on yields, depending on the N-mediated growing conditions
of organic potato crops. Under conditions of a relatively high N supply, accelerating the early development and tuber initiation
of potato crops by seed tuber pre-sprouting (yield increase of c. 18–23%) or the selective choice of cultivars with an earlier
tuber initiation (yield increase of c. 0–21%) are the most effective strategies in combating late blight. They bring forward
the crop development c. 7–10 days, escaping the negative impact of the fungus on tuber growth. Under conditions of a relatively
low N supply, these strategies do not affect final tuber yield. The reason for the differences of the effect depending on
N supply of the crops is, that the lower the N supply, the shorter the period of time over which tuber growth takes place,
independent of whether P. infestans becomes severe or not. Tuber growth of organic crops low in N has mostly ceased by the time late blight becomes potentially
important for limiting yield, with the consequence that preventative measures against P. infestans are meaningless. Surprisingly, the level of cultivar haulm resistance to late blight did not affect tuber yields in years
with an early and strong late blight development. Probably, the positive effect of a longer resistance to the fungus (c. 1 week)
was counterbalanced by a later tuber initiation (also c. 1 week). In years with a moderate late blight incidence, less susceptible
cultivars were able to produce higher tuber yields on fields with a lower N availability (c. 17–20%), probably due to higher
N use efficiency and a better match of N mineralization and N uptake. Under conditions of a relatively high N supply, the
tested cultivars with a higher haulm resistance to late blight were not able to improve tuber yields. 相似文献
4.
An investigation of the level of reducing sugars in diploid potatoes before and after cold storage 总被引：1，自引：0，他引：1
Summary The reducing sugar content and chip colour were studied in diploid potatoes bred for superior table and chipping quality.
The reducing sugar content in the tubers of 119 diploid clones was estimated before and after cold storage (4–6°C) in the
years 1987–1991, and reducing sugar and chip colour were determined in 1990 and 1991 for 36 clones. Thirty two clones had
a significantly lower reducing sugar content after cold storage than cv. Mila. The year of evaluation, storage temperature
and genotype significantly affected the reducing sugar content. 相似文献
5.
J. Hagman 《Potato Research》2012,55(2):185-195
Earlier harvest of potatoes (Solanum tuberosum L.) can be achieved by different pretreatments of the seed tubers. In factorial field trials in 2008–2010, two different
pre-sprouting methods were evaluated: conventional pre-sprouting of tubers and pre-sprouting of tubers with stimulation of
adventitious root formation (PR). The results were compared with those for untreated seed tubers stored at 4 °C until planting
(control). One variety was included in three trials, and two varieties were included in one trial. The new PR method was intended
to give faster development and tuber initiation than conventional pre-sprouting, which can be of value when the growing season
is restricted or when early harvest is important. Plant emergence, leaf necrosis (as a measure of maturity) and incidence
of late blight were assessed during the growing season. After harvest, tuber fresh weight, size and density were assessed.
It was found that pre-sprouting treatments gave on average 7 days earlier emergence compared with the control. Necrosis began
earlier in pre-sprouted treatments in all cases except for the late variety Sarpo Mira. In 2008 and 2009 potato late blight
struck late, after onset of senescence, but in 2010 it struck earlier and the pre-sprouted treatments proved more susceptible
than the control. Total tuber yield was 7–24% higher on average in all pre-sprouted treatments in the different field trials.
Tests on time of harvest showed that the advantage for the pre-sprouting treatments was maintained during the season, but
the difference with the control decreased with time. When the different pre-sprouted treatments were compared, the new PR
method proved to be not better than conventional pre-sprouting. 相似文献
6.
Summary This paper reports results of a 3-year evaluation of CIP advanced potato clones in a bacterial wilt-infested field (race 3)
in Peru. Clones resistant or moderately resistant to wilt were selected and all tubers harvested from each clone were tested
for latent infection byRalstonia solanacearum using a sensitive serological technique developed at CIP. A sampling strategy to estimate accurately the frequency of infected
tubers in the clones has been evaluated. This method will allow consideration of tuber latent infection as a new selection
criterion in breeding for resistance to bacterial wilt. Thirteen clones were found resistant to wilt in all three evaluations
(i.e.≤6% wilt), from which five had no wilt in all trials. However, all clones harboured latent infection in tubers averaging
30%. Analysing 30 tubers/clone provides an accurate estimation of the proportion of infected tubers with a high precision
level. 相似文献
7.
Summary A comparative study of nine Indian potato varieties showed a good correlation between their total carotenoid content and the
tuber flesh colour. Regardless of varietal differences, carotenoid level showed an increase during storage at ambient temperature
(25–30°C) and to a lesser extent at 2–4°C and 15°C. Tubers exposed to an irradiation dose of 10 krad for sprout inhibition
showed decreased levels of carotenoids during storage, particularly at 15°C where 50% loss was observed after 6 months of
storage. Irradiated tubers stored for seven months at 15°C, on reconditioning at 34–35°C for 6 to 12 days showed a 2- to 6-fold
increase in their carotenoid content. 相似文献
8.
The plasmodiophorid pathogen Spongospora subterranea f. sp. subterranea causes powdery scab disease of potatoes (Solanum tuberosum L.), which severely affects tuber quality. Adequate chemical control of the disease is lacking, so breeding resistant potato
cultivars is important. Little is known about the mechanisms or genetics of host resistance, as the epidemiology of the pathogen
makes research on the disease difficult. An environmentally controlled disease screen that allows the accurate and repeatable
assessment of diseased tubers (rather than a ranking system) is required to study host resistance in more detail. A high-throughput
greenhouse disease assay is described that has been used to assess varying levels of tuber disease resistance of potato genotypes
for three consecutive Southern Hemisphere growing seasons (2001–2002, 2002–2003, 2003–2004). This assay allows the evaluation
of symptoms on tubers to verify resistance, rather than inferring the tuber infection on the basis of root galling or zoosporangial
root infection. The assay was used to determine the level of resistance of genotypes of both known and unknown resistance
status. The assay clearly distinguished the susceptible and resistant standards, and the results were highly correlated over
the three seasons. The most efficient ways of assessing tuber disease susceptibility of genotypes are discussed. The consistency
of the results and the ability to screen many genotypes confirms the value of the assay as a tool for early-generation selection
in a plant breeding programme. 相似文献
9.
Summary About 13,000 somaclones of 17 cultivars and clones of potato were obtained from in vitro callus cultures and individually
planted in a greenhouse, followed by tuber generations grown in the field. These plants were subjected to the multistage selection
procedure commonly used in potato breeding. Over a period of five years and three field generations the tuber number, size,
shape, eye depth, starch content, starch yield and tuber appearance of these somaclones were assessed and compared with that
of the controls. These characters varied depending on donor genotype and trait. The frequency of variants was assessed and
there were acceptable proportions of desirable abberrants and invariants among the somaclones. Depending on trait the average
gain rate for all donor genotypes ranged between 0.2 and 2.3% for-deviants, between 12.2 and 15.5% for invariants and between
0.1–1.4% for +deviants.
It is concluded that this technique should be used into potato breeding programmes to improve commercially important characteristics
of specific cultivars and breeding clones. 相似文献
10.
Summary Plants of early potato cultivars were sampled at successive harvests during tuber development and individual tubers were analysed
for α-solanine and α-chaconine using high-performance liquid chromatography. Mean tuber total glycoalkaloid concentration
(α-solanine plus α-chaconine) per plant decreased with time and statistically significant differences between cultivars were
observed in the patterns of decline during tuber growth. The mean tuber ratio of α-chaconine to α-solanine increased during
tuber development and was also affected by genotype. Total glycoalkaloid concentration for individual tubers of marketable
sizes (up to 50 g fresh weight) exceeded the safety limit of 20 mg per 100 g fresh weight for cultivars Home Guard and British
Queen but not for Rocket. These differences were attributable to differences in both rates and patterns of glycoalkaloid accumulation
during tuber development, although in all cultivars results were consistent with glycoalkaloid accumulation occurring in the
expanding peripheral cell layers of tubers for a considerable period after tuber initiation. 相似文献
11.
Summary Tuber samples taken at 2-week intervals from plots of cvs King Edward, Majestic and Pentland Crown in 1964–75 showed that
the maximum bulking rates ranged from 1 to 5 tonnes/hectare/week. Maximum tuber numbers were usually produced by 11 weeks
after planting and thereafter numbers declined. In September, about 70% of the tubers initiated were recovered, and between
24 and 52% of the tubers had reached marketable size (>4 cm).
Tuber size distributions developed similarly in all years with all cultivars. During tuber initiation the distributions appeared
as one population, and usually between 9 and 11 weeks after planting a second population of larger tubers developed. The population
of small tubers later declined although in most years it was still present in September. This development fitted a model based
on a mixture of two normal distributions and was determined by five parameters; the proportion of tubers in the small population
and the means and standard errors of both populations. 相似文献
12.
Jane Muthoni Hussein Shimelis Rob Melis Z. M. Kinyua 《American Journal of Potato Research》2014,91(2):215-232
Potato varietal resistance to bacterial wilt disease caused by Ralstonia solanacearum Yabuuchi et al., (Microbiology and Immunology 39:897–904, 1995) is the best management of the disease. Because the causal pathogen exhibits strong host-pathogen-environment interaction, screening the potential parents for resistance under the target growing environmental conditions is the first important step for effective resistance breeding. The objective of this study was to determine the response to bacterial wilt of selected potato genotypes currently grown by farmers in Kenya and candidate clones from the International Potato Center to identify parents that can be used in the local breeding program to develop resistant cultivars. A study was carried out at Kabete, Kenya for three consecutive seasons between November 2011 and February 2013. Thirty six potato genotypes were planted on an inoculated field at the Kenya Agricultural Research Institute (KARI), Kabete using alpha lattice experimental design with three replications. Data collected were days from planting to onset of wilting (DTOW), bacterial wilt incidence (BWI), total tuber weight (ton ha?1) (TTW), total tuber numbers/hectare (TTN), proportion of ware sized tubers (PWTTW), proportion of symptomatic tubers based on weight (PSTTW), proportion of symptomatic tubers based on tuber numbers (PSTTN) and latent infection (LI) of the tubers. Almost, all the potato genotypes evaluated in this study were susceptible to bacerial wilt. Ranking of genotypes based on resistance differed among the three seasons. On average, the three most resistant genotypes were Kenya Karibu, Kenya Sifa and Ingabire. The study identified eight potato genotypes (Meru, Ingabire, Kenya Karibu, Sherekea, Kihoro, Tigoni, Bishop Gitonga and Cangi) to be used as promising parents for subsequent crosses. The chosen genotypes are prolific in pollen production and popularly grown by Kenyan farmers. 相似文献
13.
Summary In the Mediterranean area the potato is a very important crop and can be cultivated throughout the year. However, tuber yields
are generally much lower than those in Northern European countries. This is because the environmental and agro-economic conditions
are different from those of Northern countries where most cultivars were developed. We feel that the objective for the “new
Mediterranean potato” must be the availability of potato cultivars for each environment and for each planting season. Breeding
programmes should focus on improving potato production within a specific agro-ecological Mediterranean area rather than improving
crop production across areas. This paper reports aspects of potato breeding and physiology related to resistance to stress
conditions in the Mediterranean area, with particular emphasis given to resistance to abiotic (heat, drought and frost) as
well as biotic stresses. We also discuss the potential to produce seed tubers suitable for potato cultivation in the Mediterranean
area. 相似文献
14.
Summary A potato crop can be grown from true potato seed (TPS) either by transplanting seedlings to the field (seedling transplants)
or by planting tubers derived from seedlings (seedling tubers). The effect of the planting method on performance of TPS families
was evaluated for three types of families, 4x×2x hybrid, open pollinated, and self pollinated. Families from seedling transplants
and seedling tubers and their 4x parental clones were compared for tuber yield and specific gravity. Families from tubers
had substantially higher yields and significantly more uniform specific gravity than families from transplants. Hybrid seedling
tuber families had a higher mean yield than the parental clones and did not differ from them in specific gravity. Selection
in the seedling generation could further improve both OP and hybrid families from transplants and from seedling tubers.
Paper no. 3163 from the Department of Genetics, University of Madison. 相似文献
15.
J. Marinus 《Potato Research》1993,36(1):55-61
Summary The formation of above-ground tubers on stem cuttings of eight potato cultivars was studied over three seasons. To promote
tuber formation in the leaf axils, stems grown from single node cuttings were exposed to short day conditions. Tuber formation
underground was reduced by covering the soil with a plastic sheet and by using single node cuttings planted with the leaf
axils several centimetres above the soil surface. With all cultivars except Alpha, which produced mis-shapen tubers in all
experiments, an average of 11 (maximum 40) tubers per cutting were harvested. Significant cultivar × year interactions were
observed. 相似文献
16.
M. K. Van Ittersum 《Potato Research》1992,35(4):355-364
Summary The duration of dormancy of seed potatoes varies between years and between origins. Therefore, the effects of conditions during
crop growth on dormancy of progeny tubers were studied. The effect of nitrogen during tuber bulking on the duration of dormancy
was investigated in three field experiments with two cultivars. In addition to an application of 125 kg N/ha at planting,
top dressings of 0–150 kg N/ha were given about 2 weeks after tuber initiation. Haulm was pulled about 4 weeks later. The
effect of nitrogen rate at planting was also examined in one experiment.
Nitrogen top dressings shortened dormancy in all experiments by 5–8 days. An increased nitrogen rate at planting resulted
in a shorter dormancy when the duration of dormancy was expressed in days after tuber initiation, but not when it was expressed
in days after haulm pulling, probably because extra nitrogen also delayed tuber initiation. 相似文献
17.
Soft rot of potato tubers, caused byErwinia (Pectobacterium), is a serious disease affecting potato crops during storage. Studies on the inheritance of resistance to tuber soft rot were undertaken on diploid potato hybrids. A total of 480 clones, derived from 12 families, were examined for resistance to soft rot in laboratory tests over 3 years and for basic agronomic traits in field experiments over 2 years. General (GCA) and specific (SCA) combining abilities were significant in the inheritance of resistance to soft rot; however, GCA for female parents were significant in 1 or 2 years during 3 years of evaluation and SCA was significant for eight, two, and six families out of 10 tested in 1994, 1995, and 1996, respectively. There were also significant differences between years. Moreover, marked interactions for GCAfemales × year and SCA × year in the variation of soft rot resistance were found. Broad-sense and narrowsense heritability of resistance, measured as diameter of rotten tissue, was estimated as 0.92 and 0.89, respectively. The maternal effect, evaluated in two sets of reciprocal crosses, was not significant for the genetic determination of resistance to soft rot. No significant relationships were found between resistance to soft rot and the main agronomic traits in the tested diploid families. These results suggest that diploid potato clones with resistance to soft rot can be selected after being evaluated over a few seasons. It is also possible to select clones combining good resistance to soft rot with high yield, superior tuber characteristics, and acceptable starch content. These resistant diploids can be used as male parents in 4x-2x crosses in breeding tetraploid potato resistant to soft rot. 相似文献
18.
Summary The influence of a short tuber dormancy and the subsequent sprout growth of the seed tubers during storage at 4 °C on the
processes related to plant development and tuber formation was investigated in a diploid population with 238 genotypes, its
crossing parents and seven tetraploid varieties. Sprout growth during storage at 4 °C was positively correlated to the duration
of the dormancy period at 18–22 °C, the low temperature prolonging the dormancy period. Results show that the duration of
the dormancy period and the sprouting of seed tubers during storage at low temperature did not have a determinant influence
on plant development, tuber formation or the duration of the plant cycle in this large and highly diverse population of potato. 相似文献
19.
Summary To determine calcium fertility and high temperature effects on internal brown spot development in potato, cv. Russet Burbank
plants were fertilised with Hoagland's nutrient solution with or without calcium. Prevalence and severity of internal brown
spot were greatest in tubers receiving no calcium fertilisation during growth. Internal brown spot was evident as early as
tuber initiation. A high growth medium temperature (32°C) at tuber maturity with a lack of calcium increased internal brown
spot incidence and severity. No tubers subjected to the high temperature and fertilised with calcium developed internal brown
spot. Peel calcium concentration of tubers receiving no calcium fertilisation was lower (0.5–0.8 g/kg) than tubers receiving
calcium (1.2–1.9 g/kg). Medullary tissue calcium concentration was similar under both calcium regimes. Calcium availability
during early tuber growth was an influential factor in internal brown spot development, however high temperature effects may
not be discounted in exacerbating the disorder.
H/LA Paper No. 95-7. Project No. 1984, College of Agriculture and Home Economics Research Center, Pullman WA 99164, USA 相似文献
20.
Summary Using potato parental lines homozygous at a locus or loci controlling resistance to potato leafroll virus (PLRV) can give
advantages in the selection of resistant forms. In order to identify homozygous diploid clones their test-cross families were
evaluated. All the clones that were test-crossed expressed resistance in primarily- and secondarily-infected plants and etiolated
sprouts, and were derived from mating genotypes highly resistant to PLRV. Genotypes from test-cross families varied in resistance
to PLRV, and one family was found which had only resistant genotypes, suggesting that the resistant parent of this progeny
was homozygous at resistance loci. Evidence was gathered that resistance in some diploid clones may result from resistance
to virus multiplication as well as restricted virus transport from leaves to tubers. 相似文献