共查询到20条相似文献，搜索用时 15 毫秒
1.
T. Visser 《Euphytica》1976,25(1):339-342
Summary Analysis of two incomplete half-diallel schemes of crosses, involving 22 apple and 33 pear progenies with 2500 and 5400 seedlings respectively, showed a highly significant GCA and an insignificant SCA variance for the juvenile period (J.P.). This indicates that the inheritance of the J.P. is of an additive nature, a mode of inheritance which is a function of the inheritance of a complex of factors governing growth. The mean J.P. of apple progenies varied between 3.4 and 5.0 years, that of pear progenies between 4.7 and 7.0 years. The implications for breeding are discussed.Also presented at the Juvenility Symposium held at West-Berlin, November 1976. 相似文献
2.
T. Visser 《Euphytica》1967,16(3):319-320
The existence of a genetical relation between the precocity of the parents and the length of the juvenile period of their progeny suggested a similar relation between precocity in the juvenile and in the adult phase of a seedling. This was confirmed in a trial with adult apple and pear seedlings budded on a rootstock. The percentage of trees which flowered in the third year following budding was higher when the juvenile period had been shorter. This relation should be taken into consideration in breeding. 相似文献
3.
Precocity and productivity of propagated apple and pear seedlings as dependent on the juvenile period 总被引：1，自引：0，他引：1
Summary Adult apple and pear seedlings varying in juvenile period were propagated on rootstocks. They were subsequently found to be more precocious and more productive when the juvenile period had been shorter. In view of the significant relation between vigour measured by stem diameter) and precocity of both seedlings and propagated trees, it is possible to pre-select for the potentially more precocious seedlings on the basis of vigour.Samenvatting
De vruchtbaarheid van vegetatief vermeerderde appel- en peerzaailingen in verband met hun jeugdperiode
Reeds vruchtdragende appel- en perezaailingen, waarvan de voormalige jeugdperiode sterk varieerde, werden op onderstam geoculeerd. Het bleek dat de bomen gemiddeld vroeger vruchtbaar en productiever waren naarmate de voormalige jeugdperiode korter was geweest.De al eerder geconstateerde relatie tussen groeikracht en jeugdperiode (kortere jeugdperiode naarmate de bommen dikker zijn), bleek ook na vermeerdering te bestaan, d.w.z. de dikkere bomen bloeiden eerder dan de dunnere. Daar deze samenhang erfelijk bepaald is, biedt dit de mogelijkheid om de potentieel vroeg-vruchtbare zaailingen reeds in het kwekerijstadium op basis van groeikracht te selecteren. 相似文献
4.
S. H. Hjeltnes 《Euphytica》1994,77(1-2):55-58
Summary In the Norwegian pear breeding programme selection is based on evaluation of 20 fruit samples together with field observations
of precocity, productivity and resistance to biotic and abiotic factors. Fruit weight is recorded in grams, and then transformed
to a scale of 20 gram classes. Appearance, shelf life and flavour are recorded on a 0 to 9 scale, and observations of shelf
life and flavour are made at 4 defined intervals following ripening at 20 °C. The final index is made by summarizing the scores
of fruit size and appearance, mean score of internal breakdown, mean score of flavour, maximum score of flavour and scores
of precocity, productivity and resistance. All parameters, except mean flavour, are given a weighting of one, mean fruit flavour
is given a weighting of 2. Data for 160 seedlings evaluated in 1992 is presented. 相似文献
5.
Summary Eight controlled crosses were made between seven different sweet-kerneled almond cultivars (Prunus dulcis [Mill.] D. A. Webb), and five crosses were made between sweet x highly floriferous bitter almond clones. Sweet x bitter progenies out-yielded the sweet x sweet matings by more than three to one in the first year of production. This was attributable to greater cropping efficiency rather than to tree size or precocity. There was no pleiotropic association or association due to linkage between bitterness and yield. The selected Alnem (bitter) clones appear to be potentially useful progenitors for increasing almond yield capacity by conventional breeding methodology. 相似文献
6.
Summary The production of self-seed was investigated in apple and pear with the aid of viable and compatible mentor/ pioneer pollen in relation to the proportion of self-imcompatible pollen present in the pollen cloud.Treatments consisted of mixtures of compatible and self-incompatible pollen at ratios of 1:1, 1:2 and 1:9 applied once or twice or followed by self-pollination. Selfing only, whether once or twice, produced virtually no fruits or seeds, while mixed pollinations did. Generally, fruit set tended to decrease and the self-seed to increase with increasing amounts of self pollen in the pollinations.The pioncer-pollen method (compatible in advance of self pollen) appeared more effective than the mentor pollen method (compatible and self pollen mixed). The use of viable instead of dead mentor/pioneer pollen causes competition for the ovules with the self pollen, but has the advantage that, in addition to some self-seed, other seeds are formed which, e.g. in apple, are necessary to keep the fruits on the tree until harvest.Fruit set was moderately reduced at ratios of compatible pollen to self pollen not exceeding 1:9 with pear and 1:5 with apple which constitute maximal ratios in practice as regards pollinator trees: trees of the main cultivar. In fruit orchards and probably in nature with other species, the interaction between compatible and self pollen may result in more self-seed, and so suggests that inbreeding played a greater part in the evolution of self-incompatible species, than the meager results of articial self-pollination imply. 相似文献
7.
Acidity and sweetness in apple and pear 总被引：2，自引：0，他引：2
Summary Sweetness and acidity in apple and pear inherit independently and can be organoleptically evaluated separately, but less accurately in pear than in apple. For breeding purposes an analysis of fruits for acidity and sweetness with pH indicator paper and a hand refractometer is to be prefered to the organoleptic method.In apple, the acidity-decreasing with time-of the unripe fruit was already strongly indicative of that of the eating-ripe fruit; sugar-increasing with time-not before the fruit was picking ripe. Sugar content in apple and pear, and the pH in pear, appeared to be normally distributed; the pH in apple showed a segregation into an acid and a low-acid group, which occurred in both the unripe and ripe stage. The segregation ratio between these groups was found to be highly variable. On the whole, the mean acidity and sugar content of apple and pear progenies is significantly determined by that of the parents. Most of the observations made did not support the theory that low acidity in apple is determined by one recessive gene. The relationship between the pH of leaf juice and fruit juice in apple may offer a possibility for pre-selection. 相似文献
8.
A. E. F. Neele 《Euphytica》1990,48(2):159-166
Summary The inheritance of potato tuber yield was studied considering the seasonal course of harvest index. Harvests of several progenies and their parents were performed at intervals and fresh weight of foliage, underground stems, tubers and stolons was assessed.Tuber yield depends on the time of tuber initiation and the proportion of the assimilates allocated to the tubers, as reflected in the increase rate of harvest index. The time of tuber initiation of the progenies was associated with the time of tuber initiation of the earliest tuberizing parent. The mean increase rate of the harvest index of the progenies was in most cases equal to the mean values of parents, however in crosses combining early with late maturing parents the rate equaled the value of the maternal parent. Using these relations, differences in harvest index between progenies can be predicted with a high degree of precision by using the harvest index parameters of the parents. This estimated harvest index showed a fairly good correlation to tuber yield at mid-September and can be used in the prediction of the yield of the progeny. The use of the mid-parent value for this purpose is not suitable. 相似文献
9.
Summary The wide diversity of old fruit-tree cultivars originating or introduced into Belgium during the 18
th
and 19
th
centuries was collected as far as feasible over the last fifteen years at the State Plant Pathology Station in Gembloux.
Out of the 2400 accessions now collected, one quarter was recovered from old public collections, and three quarters came from
farms or gardens. The initial intention was to screen the material for disease resistance and other characters of agronomic
interest with a view to using the best cultivars as breeding parents. However, as the collection developed, genetic resources
conservation also became an objectiveper se. The collection presently contains 1150 apple, 850 pear and 300 plum accessions, and smaller numbers of other fruit species.
Each accession is evaluated in an experimental orchard for at least ten years. In view of the growing public interest in old
fruit-tree cultivars, the Plant Pathology Station has for several years been releasing to the nursery trade the better cultivars
emerging from the evaluation, namely nine apple and four plum cultivars, and one peach cultivar. The principal features of
the apple cultivars are presented in this paper. Since 1988, old apple and plum cultivars have been being used at the Station
as parents in a breeding programme, with both controlled and open pollination. In some instances, old apple cultivars have
also been crossed with a modern parent carrying the Vf gene for scab resistance. The preliminary observations on some of these
seedlings are presented. 相似文献
10.
Summary Six pear and five apple trials were carried out to ascertain the outcome of combinations of compatible pollen (C) with self (S) or incongruous pollen (I) as to the pollination index (PI=seeds/pollinated flower). The PI of the mixture C+I (1:5) was consistently depressed as compared to that of the control C. The results of the double pollinations S/C and I/C were affected by the temperature at pollination; their PI's at <15°C were twice as high as those at >15°C, being well above and below the PI of C in the former and latter case respectively. The opposite was true for the C/S combination, the PI of which increased with the pollination temperature; the PI of C/I did not differ much from the PI of C, irrespective of temperature. The conclusion was reached that the interaction previously and presently found between compatible and self-incompatible pollen also exists to a fair extent between compatible and incongruous pollen. However, in pear neither the mentor nor the pioneer pollen technique proved to aid its hybridization with apple, the formation of self seed was not observed either. In apple the production of apple × pear hybrids was likewise doubtful, but the double pollinations S/C and C/S formed 4–10% self seed. 相似文献
11.
G. Lockwood 《Euphytica》1976,25(1):647-658
Summary Progeny trials were planted at Tafo in 1952 and 1954 to compare 3 selfed local-Trinitarios, 1 outcrossed and 3 sibbed Upper Amazon progenies and 13 hybrids between Amelonado or local-Trinitarios and Upper Amazons; 1 trial included West African Amelonado. The Amazon hybrids and the outcrossed Amazon were particularly vigorous and precocious and maintained a yield advantage for 20 years. The 13 hybrids were similar in yield potential, but varied in net yield following differential losses from pod diseases, mainly caused by Phytophthora palmivora. Disease losses were lowest on one of the sibbed Amazons and the outcrossed Amazon and lower on Amelonado than on any of the 7 hybrids tested with it; in both trials losses were lower on Amelonado hybrids than on Trinitario hybrids.There was wide variation in both size and growth rates of mature trees and no consistent relationship between continued growth and crop. It seemed that later yields were not prejudiced by the precocity of Amazon hybrids, the yields from all types fluctuated together. Because the differences in disease losses are likely to be accentuated under farmer's conditions. Amelonado hybrids are preferable to local-Trinitario hybrids. The results also suggest that commercially acceptable pure Upper Amazon varieties could be developed.On secondment on technical assistance from the United Kingdom Ministry of Overseas Development. 相似文献
12.
H. Tan 《Euphytica》1978,27(2):521-528
Summary A study using yield data from seedlings from controlled pollinations and clones derived from them, revealed that, for clones, promising parents can be selected in the first year of tapping and, for seedlings, in the second year. It should be noted that secondary characters (e.g. vigour on tapping, resistance to wind, diseases and dryness) will assume importance for parental assessment only when information on these become available, after several years of tapping. Correlation studies between GCA estimates for seedling and clonal yields support an earlier finding that the former can be used as a criterion for selection of parents. 相似文献
13.
It was investigated whether and to what extent the duration of the juvenile phase of pear and apple seedlings is related to their vegetative growth. The juvenile phase was defined as the period in years that the seedling remains vegetative; the trunk diameter served as a measure of vegetative vigour. The following observations were made:
-
1)
A significant negative correlation exists between the duration of the juvenile phase and the vigour of the seedling (as measured by trunk diameter).
-
2)
Environmental conditions with respect to weather, soil and cultural practices which promote or restrict growth, tend to shorten or lengthen the juvenile phase accordingly by their influence on the time required for the attainment of a certain minimum size which at least partly determines the attainment of the flowering condition.
-
3)
The weak rootstock M. IX significantly accelerated the onset of flowering of apple seedlings by about 1 1/2 years; this rootstock appears to combine a retarding effect on growth with a specific influence on flowering.
14.
Early determination of genotypes for apple scab resistance by forced flowering of test cross progenies 总被引：1，自引：0，他引：1
Summary Apple selections with different major genes for resistance to apple scab (Venturia inaequalis) derived from Malus floribunda and M. pumila were crossed with each other. The progenies were screened as young seedlings for their reaction to V. inaequalis race 1. A gene for resistance from M. pumila, causing stellate necrotic (SN) lesions, was epistatic to a second gene for resistance from M. floribunda, causing irregular chlorotic (Chl) lesions. Although in most cases SN, Chl and susceptible phenotypes were clearly distinct, occasionally reactions were difficult to characterize or varied from one inoculation to another. Selected seedlings showing resistant or susceptible reactions were forced to flower in 16–20 months in the greenhouse and test crossed with susceptible cultivars. Test cross seedlings were screened for scab reaction. The presence of both genes for resistance in a resistant plant was indicated by presence of both Chl and SN resistant phenotypes in the test cross progeny. Chi-square analysis of four large progenies produced a good fit to the expected ratio. The use of the forced flowering technique to determine scab resistance genotypes in 28 months demonstrated its value in breeding apples with multiple disease resistance. 相似文献
15.
T. Visser 《Euphytica》1970,19(3):293-302
Summary The stem diameter of apple seedlings, either measured in the nursery or later, is associated with both the duration of the juvenile period (the thicker, the shorter) and initial productivity (the thicker, the higher) of the seedlings. The relation between vigour and juvenile period, or precocity in general, is probably largely inherent, and thus remains valid for the propagated clone.No significant relation existed between stem diameter and size or season of ripening of the fruits, nor between the latter two characteristics and the duration of the juvenile period. The stem diameter is therefore an effective parameter of selection for fertility alone during the nursery stage. Provided growth conditions are uniform, selection for vigour may enhance breeding efficiency in three ways:- it shortens the first screening period of seedlings on their own roots in the orchard;- it shortens the second screening period of the seedlings selected and propagated after the first period;- it improves the chances of finding precocious varieties.Samenvatting
Het verband tussen groei, jeugdperiode en vruchtdracht van appelzaailingen en zijn gebruik om de veredelingsefficiëntie te verbeteren
De lange duur van de jeugdperiode (tijd in jaren tussen zaadkieming en eerste bloei) bij fruitgewassen, zoals appel, vormt een belangrijke hinderpaal voor de veredeling. Verkorting van deze periode verhoogt de doelmatigheid. Eén van de middelen hiertoe is het toepassen van voorselectie in de kwekerij op basis van groeikracht. Het is nl. gebleken, dat de stamdiameter, gemeten na twee of meer groeiseizoenen, in sterke mate gecorreleerd is met de duur van de jeugdperiode; d.w.z. de dikkere zaailingen blijken gemiddeld eerder te bloeien en beter te dragen dan de dunnere. De relatie is goeddeels erfelijk bepaald en handhaaft zich na vermeerdering op onderstam. Selectie van de dikste zaailingen verkort dus de omlooptijd van een nakomelingschap. Een zodanige selectie blijkt geen nadelige invloed te hebben op de grootte of rijptijd van de vruchten, maar biedt wel het extra voordeel dat de kansen op het vinden van vruchtbare rassen worden vergroot. 相似文献
16.
Summary Pollen of dry apple, pear, lily and rose pollen was heated up to 48 h at a range of temperatures. About half or more than half of the pollen grains survived 48 h at 40 C, 24 h at 50 C, 8 16 h at 60 C. 4 8 h at 70 C, more than one hour at 80 C. and between 10 and 20 min at 90 C. Presumably, pollen able to withstand low humidity is also heat resistant, a property which may be usable to make pollen virus free through heat treatment and perhaps to overcome incompatibility. 相似文献
17.
Graham J. King F. H. Alston I. Battle E. Chevreau C. Gessler J. Janse P. Lindhout A. G. Manganaris S. Sansavini H. Schmidt K. Tobutt 《Euphytica》1991,56(1):89-94
Summary A recently initiated collaborative project involving apple breeders in seven European countries is described. The objective is to improve the European apple crop by molecular-aided breeding to increase efficency and reduce the time-scale in breeding for resistance, tree habit and fruit quality. The strategy adopted provides a model for similar studies in fruit, forest and other woody species. The project is based on progenies from a small number of crosses involving many important agronomic genes. Replication of these reference progenies by vegetative propagation will enable studies to be carried out simultaneously in each country. By developing a range of molecular markers, including isozymes, RFLPs and sequence-tagged DNA probes, an integrated molecular map is being constructed for use in a wide range of breeding and genetic studies. Construction of a database recording many mapped molecular markers will enable efficient exploitation of data in future genetic, breeding and physiological studies of apple. Aspects of the adopted strategy, techniques and management are discussed in the context of mapping genes in perennial crop genomes. 相似文献
18.
Summary Commercially grown fruit trees in the U.S. are almost invariably compound genetic systems with the top or scion cultivar budded or grafted to root systems derived from genetically unique zygotic seedlings. Although variation in tree size, yield, and cropping efficiency (CE) exists among trees within individual orchards, there have been no attempts to partition this variation in individual tree performance between the heterogeneity of zygotic seedling genotypes utilized as rootstocks and site-specific environmental variables such as soil type, fertility, and soil moisture, etc. We compared Field Blocking (FB), Moving Average (MA), and State Space (SS) procedures to infer environmental trends. Deviations from the estimated environmental effects that compose such trends were used to develop mass selection alternatives. FB was seen as a discrete approximation to an environmental response surface that varied regularly along tree rows. Regular trends within blocks for FB will result in a confounding of genetic and environmental effects and will decrease the precision of estimates of genetic potentiality based on block mean deviations. Trends estimated using the MA and SS procedures were very similar and appeared to minimize the confounding of genetic potentiality with the environmental response surface. Deviations from environmental trends estimated using the MA and SS procedures demonstrate that genetic variation of J. hindsii seedling rootstokes accounted for about 20% of the total variance in tree yield. Evidence for genotypic variation in CE was less clear. 相似文献
19.
Simple sequence repeats for genetic analysis in pear 总被引：26，自引：0，他引：26
T. Yamamoto T. Kimura Y. Sawamura T. Manabe K. Kotobuki T. Hayashi Y. Ban N. Matsuta 《Euphytica》2002,124(1):129-137
The development of highly informative DNA markers, such as simple sequence repeats (SSRs), is essential for breeding to select
agronomically important traits and for genetic studies in pear. We developed SSR markers by using two approaches, RAHM (random
amplified hybridization microsatellites) and 5' anchored PCR methods. Segregation analysis of the SSRs revealed that amplified
fragments were derived from the same loci, using 3 sets of progenies from crosses between pear varieties. Genetic diversity
was characterized using 32 varieties, including 10 from Japanese pear (Pyrus pyrifolia), 9 from Chinese pear (P. bretschneideri, P. ussuriensis), 10 from European pear (P. communis) as well as 3 wild relatives (P. calleryana). Diversity of SSR genotypes was observed among species as well as within species and 65 putative alleles were detected.
The use of seven SSR markers was sufficient to differentiate between all of the 32 varieties.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
梨杂交后代童期和童程的研究 总被引：1，自引：0，他引：1
以八个梨杂交组合后代492株实生树为试材,调查了其童程、始花节位数、节间长度和树干直径,探讨了童期和童程以及二者的关系。结果表明：在调查所有杂交组合中,有68.7%的杂种实生后代童期为3-5年,平均童程为214.26cm;节间长度与童程存在正相关性,始花节位数和干径都与童程存在极显著的正相关;童期与童程存在极显著的正相关,表明矮化的植株具有早结果的潜力。 相似文献