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961.
Dilson A. Bisognin David S. Douches Kazimierz Jastrzebski William W. Kirk 《Euphytica》2002,125(1):129-138
The objectives of this study were to evaluate the use of potato (Solanum tuberosum L.) late blight (Phytophthora infestans (Mont.) de Bary) resistant parents in cultivar development and identify superior clones possessing moderate to high late
blight resistance combined with acceptable maturity and tuber quality. Ninety-five crosses were made between eight unadapted
parents with reported late blight resistance (B0718-3, Bertita, Bzura, Greta, Libertas, Stobrawa, Tollocan and Zarevo) and
susceptible parents (cultivars or advanced breeding clones) adapted to North American growing conditions. A total of 408 field
selected clones were assessed for late blight resistance in the greenhouse and in the field using a mixture of US8 P. infestans isolates (A2 mating type, metalaxyl resistant) that overcame all known R-genes except R8 and R9. Clones with ≤ 10% infected
foliar area in the greenhouse test or ≤ 0.30 RAUDPC (relative area under the disease progress curve) value in the field in
1998 were re-tested in 1999. A total of 118 (29% of 408) putative late blight resistant clones were selected. The eight late
blight resistant parents differed in both the ability to transmit late blight resistance and in the level of resistance transmitted
to the progeny. The Tollocan and B0718-3 families (half-sib progeny) had the greatest degree of resistance and frequency of
resistant clones. Scott-Knott cluster analysis ranked 79 clones (67% of 118) in the high and moderate late blight resistant
groups. Among these 79 clones, 19 clones had vine maturity equal to or earlier than mid-season combined with acceptable tuber
quality. Further selection in 2000 resulted in eight advanced selected clones (six from Tollocan and two from B0718-3 families)
with the same level of resistance as the parent combined with vine maturity and tuber quality equivalent to Atlantic, a standard
cultivar for chip processing in North America. The results indicate that this breeding approach can be used to select parents
for late blight resistance breeding and to identify superior clones with high levels of late blight resistance and marketable
vine maturity and tuber quality.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
962.
963.
Red clover (Trifolium pratense L.) is one of the main forage species of temperate regions. Cultivars of red clover are heterogeneous which makes their genetic
analysis difficult. We applied RAPDs (Random Amplifed Polymorphic DNA) in order to assess the genetic relationship and levels
of genetic variability existing among a group of 16 elite red clover parents organised in four subsets of 4 parents each.
Out of 55 primers 21 provided reproducible results. A total of 135 reliable and polymorphic RAPD bands were detected which
were used to estimate genetic distances among pair-wise combinations of elite parents. Nei and Li's similarity values ranged
from 0.60 to 0.77, with a mean of 0.66, which reflects a rather high genetic variability among the genotypes evaluated. Lower
levels of genetic variability, as detected by polymorphic loci and mean heterogeneity values, were detected in a subset of
parents selected for resistance to the stem nematode. Cluster analyses resolved the different sets of parents in a manner
consistent with what is known from their breeding origins. An Analysis of Molecular Variance detected substantial levels of
variation within subsets of parents. RAPDs represent a valuable source of genetic information for red clover breeding programmes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
964.
Summary A knowledge of the biological and functional relationships among traits would be of benefit to plant breeders in the choice of traits to use for increasing efficiency of selection in a breeding program. Principal factor analysis was used to identify biological and functional relationships among dry bean (Phaseolus vulgaris L.) traits in segregating populations of a phenotypic recurrent selection program designed to introduce upright architecture into medium-sized dry bean.Two biological interpretations were assigned to factors extracted in the analysis of four seed/pod traits. The first was a size factor, loaded with seed weight and pod width, and the second a number factor, which was loaded with number of seeds per pod and pod length. Similarly, three factors were extracted from the analysis of fifteen architectural traits. The first factor was interpreted as an elongation factor, and was loaded with internode length measurements, while the second factor was interpreted as a structural factor, and was further divided into two subclasses namely, sturdiness factor and profile factor. The sturdiness factor comprised hypocotyl diameter and hypocotyl length, while the profile factor comprised branch angle and number of basal branches. The third factor which was called a reproductive factor was loaded with pod distribution traits and the number and location of nodes on which pods were borne. 相似文献
965.
Induced parthenogenesis as a possible method of haploidization in sunflower (H. annuus L.) was tested in previous investigations
(Todorova et al., 1994) and conditions for reproducible regeneration of gynogenic doubled haploids were established by the
present work. Forty eight treatments were studied, involving four pollen donors and four recipient hybrids. Pollen was irradiated
with doses of 300 Gy, 600 Gy and 900 Gy. In total, 2279 embryos were cultivated in vitro of which 1107 plants were obtained
and 582 of them produced seeds after selfing. The ploidy level of the regenerants was evaluated at the two – three leaf stage
and 296 of the plantlets obtained were haploids. Some of them underwent spontaneous diploidization, the others were treated
with colchicine solution for chromosome doubling. The diploid plantlets were checked for their gynogenic origin by genetical
and biochemical methods. The effectiveness of the method expressed as the number of agronomically useful DH lines to the number
obtained that were fertile and resistant to downy mildew, branched and unbranched plants was 8,6% on average.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
966.
J. Hill 《Euphytica》1996,92(1-2):135-138
Summary The problems posed by breeding components for use in binary mixtures are discussed. Breeding and selection strategies designed to overcome some of these problems are outlined. 相似文献
967.
968.
The effect of anther orientation on microspore-derived plant production in barley (Hordeum vulgare L.) 总被引:1,自引:0,他引:1
Summary The effect of anther orientation on culture response has been examined in a range of barley cultivars of agronomic importance. Anther orientation did not significantly affect the percentage of anthers responding. However, orientation of the anthers in the up position with one lobe in contact with the medium significantly increased the number of green plants produced when compared to anthers cultured in the flat position. Green plantlet production was observed directly from embryoids i.e. without an intermediate callus phase. Cytological examination of the regenerants indicated that the majority of the plantlets possessed the normal barley karyotype. The implications of these results for Barley breeding are discussed. 相似文献
969.
Summary Three Cucumis sativus L. (CS) lines adapted to USA growing conditions were used as female parents in crosses to one line each of seven Cucumis sativus var. hardwickii (R.) Alef. (CH) accessions used as male parents to determine the relative combining ability of the CH accessions for six horticultural characters. The 21 F1 progenies were grown in a randomized complete block design in two locations and evaluated for fruit number, lateral branch number, fruit length, fruit length/diameter ratio, number of female flowering nodes, and days to anthesis. General combining ability (GCA) was significant for all characters in each location. Specific combining ability (SCA) was significant for all characters except days to anthesis in one location and lateral branch number in both locations. Significant location × combining ability interactions were also evident for several characters. Results suggest that CH may be useful for improving fruit yield in commercial cucumber, but that limitations may lie in the attainment of acceptable fruit.Research supported by the College of Agric. and Life Sci., Univ. of Wisconsin, Madison; USDA, ARS, and by funds from Pickle Packers Intl., Inc. Mention of a trademark, proprietary product, or vendor does not constitute a guarantee of warranty of the product by the USDA and does not imply its improval to the exclusion of the other products or vendors that may also be suitable. 相似文献
970.
E. Ebmeyer 《Plant Breeding》1988,101(3):200-207
Handcrosses were made in a factorial manner with 24 Vicia faba inbred lines m three sets, each between four male and four female parents. The resulting 48 hybrids, their parental inbreds and three commercial varieties were grown in performance trials during the years 1985—87 with three replications at one location. Yield and yield components were recorded on single plant basis. The average superiority of the hybrids above the control varieties was 26 % in plant yield. The best crosses outyielded the controls by more than 50 %. However, a few inbred lines also reached, the yield level of the controls. The average heterosis was significant for all characters except for maturity date. In plant yield the average heterosis was 75%, ranging between 34% and 148% in the various cross combinations. The highest average heterosis of 110 % was observed in yield at the lateral stems. In all characters the best inbreds were superior to the lower hybrids and in some characters even equal to the average of the hybrids. A strong positive relationship was found for all characters between hybrid performance and mid-parent value and between the per se performance of the inbreds and their general combining ability. Genotypic differences between the hybrids as well as between the inbreds were highly significant. Most of the variability between the hybrids in all characters were attributed to general combining, ability with only little evidence for specific combining ability. In the discussion the results are evaluated according to the choice of the breeding category of the partial allogamous faba bean species. 相似文献