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1.
The nutritional value of cucumber (Cucumis sativus L.) can be improved by the introgression of β-carotene (i.e., provitamin A and/or orange flesh) genes from “Xishuangbanna
gourd” (XIS; Cucumis sativus var. xishuangbannanesis Qi et Yuan) into US pickling cucumber. However, the genetics of β-carotene content has not been clearly defined in this US
market type. Thus, three previous populations derived from a US pickling cucumber (‘Addis’) × XIS mating were evaluated for
β-carotene content, from which the high β-carotene inbred line (S4), ‘EOM 402-10’, was developed. A cross was then made between the US pickling cucumber inbred line ‘Gy7’ [gynoecious, no β-carotene,
white flesh; P1] and ‘EOM 402-10’ [monoecious, possessing β-carotene, orange flesh; P2] to determine the inheritance of β-carotene in fruit mesocarp and endocarp tissue. Parents and derived cross-progenies (F1, F2, BC1P1, and BC1P2) were evaluated for β-carotene content in a greenhouse in Madison, Wisconsin. While F1 and BC1P1 progeny produced mature fruits possessing white, light-green, and green (0.01–0.02 μg g−1 β-carotene) mesocarp, the F2 and BC1P2 progeny mesocarp segregated in various hues of white, green, yellow (0.01–0.34 μg g−1 β-carotene), and orange (1.90–2.72 μg g−1 β-carotene). Mesocarp and endocarp F2 segregation adequately fit a 15:1 [low-β-carotene (0.01–0.34 μg g−1): high-β-carotene (1.90–2.72 μg g−1)] and 3:1 (low-β-carotene: high-β-carotene) ratio, respectively. Likewise, segregation of carotene concentration in mesocarp
and endocarp tissues in BC1P2 progeny adequately fit a 3:1 (low-β-carotene: high-β-carotene) and 1:1 (low-β-carotene: high-β-carotene) ratio, respectively.
Progeny segregations indicate that two recessive genes control the β-carotene content in the mesocarp, while one recessive
gene controls β-carotene content in the endocarp. Single marker analysis of F2 progeny using the carotenoid biosynthesis gene Phytoene synthase determined that there was no association between this gene and the observed β-carotene variation in either fruit mesocarp
or endocarp. 相似文献
2.
S. H. Jalikop 《Euphytica》2007,158(1-2):201-207
Summary Inheritance of fruit acidity in pomegranate (Punica granatum L.) was studied in 3 sweet or low acid (‘Ganesh’, ‘Ruby’ and ‘Kabul Yellow’) and 3 sour or high acid (‘Nana’, ‘Daru’ and
‘Double Flower’) varieties and their progenies. The F1 and F2 data of ‘Ganesh’ × ‘Nana’ showed that fruit acidity is monogenically controlled and the sour nature is dominant over sweet.
Further, whether a genotype produces sweet or sour fruit is determined by a major gene (SS) while a few modifiers with small effects cause fluctuations in the acidity levels within sour and sweet types. All the trees
of 3 crosses involving ‘Daru’ produced acidic fruits but those of (‘Ganesh’ × ‘Nana’) × ‘Daru’ reached acidity as high as
71.2 g/l which could be because of cumulative influence of modifying genes derived from the two acidic varieties ‘Nana’ and
‘Daru’. Pollination of functionally sterile ‘Double Flower’ variety with single (normal) flower types revealed that ‘Double
Flower’ is a dominant mutant from an acidic fruited genotype (Ss). The segregation pattern in F1 indicated the possible linkage between genes governing total acidity and flower type. All the F1 hybrids between ‘Kabul Yellow’ and ‘Ganesh’ (sweet × sweet) were sour fruited with almost 8-fold jump in fruit acidity over
the mid-parental value. The steep increase in acidity cannot be convincingly attributed to overdominance which is certainly
rare at major gene level. Alternatively, linked dominant alleles or epistatic effect of neighboring loci which readily simulate
overdominance (pseudo-overdominance) could have caused a major shift in F1 fruit acidity. 相似文献
3.
Inheritance and Correlation of Self-Compatibility and other Yield Components in the Apricot Hybrid F1 Populations 总被引：2，自引：0，他引：2
Xuesen Chen Yan Wu Meixia Chen Tianming He Jianrong Feng Qing Liang Wen Liu Honghua Yang Lijie Zhang 《Euphytica》2006,150(1-2):69-74
Summary To provide genetic basis for apricot (Prunus armeniaca Lam.) breeding, inheritance and correlation of yield components including self-compatibility, self-pollinated fruiting rate, fertile flower rate, average fruit weight and fruit number per plant were studied with 5-year-old seedlings of apricot F1 hybrids from ‘Katy’ × (‘Xinshiji’, ‘Katy’ × (‘Hongfeng’ and ‘Katy’ × (‘Taianshuixing’, respectively. Using the criteria that cultivars with self-pollinated fruiting rate ≥6% were self-compatible(SC), we found that the ratios of self-compatible (SC) to self-incompatible (SI) individuals were 27:25, 9:12 and 15:19 in the above three families, respectively, and conformed to the ratio of 1:1 segregation by χ2 test, indicating that the S-locus of ‘Katy’ was heterozygous and self-compatibility was dominant to self-incompatibility. Twenty-seven seedlings from the F1 population of ‘Katy’ × ‘Xinshiji’ were chosen for S-allele-specific PCR. As a result, four S-genotypes with the ratio of 10:6:4:7 were obtained, which was linear to the 1:1:1:1 ratio by χ2 test. Great differences in self-compatibility degree were observed among seedlings even with the same S-genotype. In the F1 populations, a very extensive segregation in self-pollinated fruiting rate, fertile flower rate and average fruit weight was observed, and average values of these traits were lower than that of mid-parent. Therefore, these traits were confirmed to be quantitative. However, significant differences were found in broad heritability (H
b
2) of following three characters: the H
b
2 of self-pollinated fruiting rate (87.1% – 91.4%) was the greatest, with the variation mainly resulted from inheritance; fertile flower rate (36.8% – 49.1%) was the least and its variation was mainly caused by environmental factors. In addition, self-pollinated fruiting rate and fertile flower rate had very significantly positive correlations with single plant yield, so both may play important roles in the determination of single plant yield. In contrast, correlation between yield and average fruit weight was not significant. 相似文献
4.
Pomegranate cultivation is one of the most attractive farming enterprises in the Indian arid tropics. However, the quality
of the fruit is often severely affected by a physiological disorder called ‘aril browning’ in which a part or all the arils
show discolouration (browning) and such fruits are unfit for consumption. This has become a serious concern to consumers,
growers and researchers in the recent times. In order to understand the genotypic variation for aril browning and its association
with other fruit traits, 158 progenies obtained by selfing two pomegranate multiple hybrids viz., {(‘Ganesh’ × ‘Kabul’) × ‘Yercaud’} × {(‘Ganesh’ × ‘Gulsha
Rose Pink’)-F2} and {(‘Yercaud’ × ‘Jyothi’) × (‘Ganesh’ × ‘Gulsha Rose Pink’)-F2} × {(‘Ganesh’ × ‘Kabul’) × ‘Yercaud’} were studied. Because of heterozygous nature of the crop and diverse genetic base of
parents, a wide array of recombinants were produced which were scored for aril browning, fruit skin colour, aril colour, total
soluble solids (TSS) and seed mellowness. Results of Spearman’s correlation analysis revealed that aril browning is inversely
related with aril colour (r = −0.41). A statistical model constructed to study the reasons for the observed variation in aril browning showed that about
82.9% of it was accounted collectively by skin colour, aril colour, TSS and seed mellowness. Further, a refined model represented
by Y (aril browning severity) = 0.78 − 0.52 X1 (aril colour) + 0.23 X2 (TSS) was found to contribute to 73.5% of the observed variability in aril browning with least error in prediction. Analysis
of data further showed that every unit increase in intensity of aril colour amounted to decrease in severity of aril browning
by 0.52 units. However, for every unit increase in TSS there was an increase of 0.23 units in severity of aril browning. Thus,
with the increase in intensity of aril colour there was a reduction in severity of aril browning while with raise in TSS,
aril browning incidence was higher, an association often not favourable in selection of desirable genotypes. The results of
the present study suggested that while developing varieties free from aril browning it is important to strike a balance between
aril colour and TSS level. 相似文献
5.
Summary The effect of self-pollination of cucumber (Cucumis sativus L.) for 6 generations in lines developed from the North Carolina Medium Base Pickle population was determined by regression of trait expression for each generation on Wright's coefficient of inbreeding. Two yield traits (total and marketable), earliness and 3 fruit quality traits (shape, color and seedcell size) were evaluated in 2 environments (spring and summer, 1983). The regression did not result in significant negative slopes, indicating that inbreeding depression was not important in the population for the traits studied. Midparent heterosis was found for most traits in many hybrids obtained from crossing S6 lines with the gynoecious inbred line, Gy 14A. 相似文献
6.
The development of triploid cultivars from crosses between the tetraploid landrace ‘Morado de Huetor’ and diploid commercial
cultivars was studied in this work. Fertility of both 4x × 2x and 2x × 4x crosses, as measured by fruit set and number of
seeds per fruit, and germination rate of triploid seeds, were studied in order to assess the viability of producing commercial
seeds. Seven triploid hybrid progenies were included in a progeny test together with thirteen experimental tetraploid hybrids
and four cultivars (‘Grande’, ‘UC157-F2’, ‘Purple Passion’ and ‘Morado de Huetor’). Marketable spear production and mean diameter
of spears were evaluated in both 2007 and 2008. Crosses 4x × 2x were more successful than 2x × 4x, and a wide variation from
high to very low fertility within tetraploid females was found. Germination rate of triploid seeds was similar to diploid
ones. After 2 years of evaluation experimental hybrid triploids were more productive than tetraploids with values similar
to the highest yielding diploid cultivar (‘Grande’). Spear diameter of triploid hybrids was in general thicker than the tetraploid
hybrids and significantly thinner than the standard cultivars ‘Grande’ and ‘Purple Passion’ (tertraploid). These results suggest
that the development of new triploid cultivars (4x × 2x) employing a tetraploid landrace from a different genetic background
of current diplods could be interesting in asparagus breeding, broadening the spectrum of cultivated asparagus cultivars. 相似文献
7.
Mohamed F. Mohamed 《Euphytica》1998,103(2):211-217
‘Nadja’ tomato (Lycopersicon esculentum Mill.) set both seedless and seeded fruits under the fluctuating temperatures prevailing
during late-March and early-April in Assiut district, Egypt. Entirely seedless fruits developed under the low temperatures
prevailing during Dec. Seedless fruits seemed to develop vegetatively , i.e. with no need for stimulus pollination. All seedless
fruits were normally jelled and appeared similar in shape and size to the seeded fruits. Study of F1, F2, and backcross generations for the crosses ‘Cal Ace’ × ‘Nadja’ and ‘Peto-86’ × ‘Nadja’ suggested that the expression of the
trait was due to single homozygous recessive gene. Yield produced by ‘Nadja’ was higher than the F1, F2, and backcross generations in both the early- summer and the late-winter plantings. Potentially useful parthenocarpic segregates
were found in F2 of the two crosses for increased fruit weight of normally shaped and jelled fruits.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
Salvador Becerra-Rodríguez Víctor Manuel Medina-Urrutia Marciano Manuel Robles-González Timothy Williams 《Euphytica》2008,164(1):27-36
Grapefruit growers in the tropics require information about existing and new citrus cultivars with high productivity potential.
The objective of this study was to determine the growth, yield, and fruit quality performance of seven pigmented and four
white grapefruit cultivars under the dry tropic conditions of Colima, Mexico. The trees were budded on sour orange (Citrus aurantium L.) rootstock and planted at a distance of 8 × 4 m. ‘Oroblanco’ and ‘Marsh Gardner’ white-fleshed grapefruit cultivars and
‘Chandler’, a pink-fleshed pummelo, were the largest trees with the greatest height (5.0–5.6 m), canopy diameter (6.2–6.3 m),
trunk diameter (21.9–23.3 cm), and canopy volume (109–123 m3). Lower height (4.3–4.8 m) and canopy volume (73–96 m3), but with similar canopy diameter to the previously mentioned cultivars, were recorded for the remaining pigmented cultivars.
‘Chandler’ pummelo and four pigmented grapefruit cultivars (‘Shambar’, ‘Río Red’, ‘Ray Ruby’, and ‘Redblush #3’) had yearly
productions of 34.8, 34.9, 34.1, 32.7, and 30.6 ton ha−1, respectively. The most productive white grapefruit cultivar was ‘Marsh Gardner’ (30.5 ton ha−1). Grapefruit cultivars having the largest fruit size showed a higher inverse relationship between fruit weight and yield
than those with small fruit. Most genotypes had higher values of fruit weight, juice content, and maturity index than those
required by the local market. The most promising grapefruit cultivars based on their acceptable growth, yield superior to
30 ton ha−1, and acceptable fruit color were ‘Río Red’, ‘Shambar’, ‘Ray Ruby’, and ‘Redblush #3’. 相似文献
9.
There is a need to identify genetic markers that can assist coconut (Cocos nucifera L.) breeding programs. With that objective,
electrophoretic patterns of leaf peroxidases, endopeptidases and coomassie blue stained proteins were analysed in four cultivars
(‘West African Tall’, ‘Rennell Tall’, ‘Malayan Yellow Dwarf’, ‘Cameroon Red Dwarf’), and in the hybrids PB121 (‘Malayan Yellow
Dwarf’ × ‘West African Tall’) and PB111 (‘Cameroon Red Dwarf’ × ‘West African Tall’). The polymorphisms detected fit the expression
of two alleles of a dimeric peroxidase, two alleles of a monomeric endopeptidase, and a pair of active and null alleles of
a coomassie blue stained protein. Four distinctive genotypes were identified. One for each of the tall cultivars, another
for both of the dwarf cultivars, and the last for both of the hybrids. Applications of the markers in breeding programs, and
in research concerning reproductive biology and phylogeny, are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
European flint maize (Zea mays L.)cannot be considered an uniform group of germplasm based on its origin and area of adaptation. However, maize breeders
have not taken full advantage of the variability within the European flint germplasm. The objective of this work was to study
the heterotic relationships among European maize inbreds from different origins. Nine European flint inbreds were crossed
in a diallel that was evaluated in three environments in northwestern Spain. The variability within the European flint germplasm
and the agronomic value of some inbreds could be utilized for maize breeding programs as an alternative to the systematic
introduction of U.S. dent germplasm that is narrowing the germplasm base of breeding programs even in places where it is poorly
adapted. Some European flint inbreds may also be valuable sources of earliness (F7 and EP42), resistance to root lodging (EA1070),
and yield (EP42).These results suggest that, within the European flint germplasm, there could be some heterotic patterns,
such as ‘north-central Europe × southern Europe’, which could provide an alternative to the heterotic pattern ‘European flint
× U.S. dent’.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
Cardamom is an important high value spice crop. Hybrid breeding is discussed for some time, but there is no information for
cardamom. Eight genetically diverse cardamom lines were crossed in a diallel to evaluate the performance of hybrids and determine
heterosis over mid-parent, better-parent and standard control for yield and yield components. The study was undertaken for
a period of 3 years from 1988 to 2001 (Experiment I). Hybrids generally showed good overall performance for most of the characteristics
compared with parents. Ten of the 56 hybrids significantly out-yielded the standard control (RR 1). Substantial mid-parent
(MPH), better-parent (BPH) and standard (SH) heterosis were observed for the majority of the characteristics studied. Further
evaluation of selected hybrids for yield and disease resistance during 2002–2007 (Experiment II) led to the identification
of two cross combinations (CCS 1 × NKE 19 and RR 1 × NKE 12) with high yield and mosaic resistance. The study revealed that
cardamom hybrids with high yield potential, desirable quality characteristics and mosaic resistance can be developed from
appropriate parents through heterosis breeding. This is the first report of heterosis in cardamom for yield and yield contributing
characteristics. 相似文献
12.
Summary To determine the levels of heterosis in F1 hybrids, four current pea (Pisum sativum L.) cultivars from southern Australia were used as female parents and crossed with 18 introduced genotypes. The 22 parents, 72 F1 hybrids and, depending on the environment, either 54 or all 72 F2 families were grown in replicated plots in four environments. Grain yield, total dry matter, harvest index, branches per plant, pods per plant, seeds per pod, hundred seed weight, plant height, onset of flowering and flowering periods were evaluated. For both the F1 and F2 generation, heterosis was determined as the superiority over the mid-parent and also over the better parent. In addition, the superiority over the best commercial cultivar was calculated. Most hybrids were higher yielding than their mid-parent but were less stable in yield across environments. Four F1 hybrids were significantly higher yielding than the best parent, by up to 26%. There were significant correlations between F1 hybrid and mid-parent value for plant height, pods per plant and hundred seed weight but not for yield. Overall, grain yield heterosis was mainly due to more pods per plant in the hybrids. The level of heterosis for yield in a poor yielding environment was higher than that in a high yielding one. Both additive and non-additive gene effects were important in the expression of all studied traits. The average level of heterosis for grain yield and total dry matter in the F2 population was half of that in F1 hybrids. The low level of inbreeding depression from the F1 to the F2 generation suggested that epistatic gene action also contributed to the expression of grain yield. Some F2 populations maintained the high yield levels of the corresponding F1 hybrids. 相似文献
13.
Summary Single and 3-way cross hybrids derived from 13 parental lines of pickling cucumber were used to estimate general and specific combining ability for femaleness and yield. Parental lines 551F, 368G, 581H, and 5802A exhibited the highest general combining ability effects in both single and 3-way crosses for total yield and marketable yield. Additive effects of genes were found to be relatively more important than nonadditive effects for both femaleness and yield. Cucumber breeders might develop high yielding cultivars based on high general combining ability for yield in parental arrays; moreover, the general performance of the parental lines in single crosses could be used to predict high yielding 3-way hybrid crosses. 相似文献
14.
Relationship between hybrid performance and AFLP based genetic distance in highland maize inbred lines 总被引：1，自引：0，他引：1
B. W. Legesse A. A. Myburg K. V. Pixley S. Twumasi-Afriyie A. M. Botha 《Euphytica》2008,162(3):313-323
The objectives of this study were to determine the crossing performance of highland maize inbred lines for grain yield, days
to silk and plant height; estimate genetic distance (GD) among the inbred lines and in association with tester parents, and
to investigate the relationship of GD with hybrid performance and midparent heterosis (MPH). A total of 26 inbred lines were
crossed with six (population and line) testers in a factorial-mating scheme. The F1’s and the parents were evaluated at five locations in Ethiopia. Nine amplified fragment length polymorphism (AFLP) primer
pairs were used to genotype all the parents. The F1’s were found to vary widely for grain yield and other traits measured. Yield superiority of more than 30% over the best hybrid
check was obtained for some testcross hybrids. Midparent heterosis on average was moderate for grain yield and, plant height.
And for days to silking, MPH values were mostly negative. Mean GD values determined from the inbred lines by population tester
(0.680) and line tester (0.661) combinations were not significantly different. Cluster analysis separated the tester parents
from the corresponding inbred lines. AFLP grouping of the inbred lines was in agreement with their pedigree records. Genetic
distances derived from the inbred lines × all testers and from the population testers’ sub-group were not positively correlated
with hybrid performance and MPH for most traits. In contrast, correlations of GDs involving the line testers’ sub-group with
F1’s and MPH were significantly positive but with low magnitude to be of predictive value. 相似文献
15.
黄瓜早熟及丰产性与主要农艺性状的相关性分析 总被引：6，自引：0，他引：6
通过对黄瓜杂种一代苗期及成株33个性状的性状值、超中优势、超亲优势进行了全面系统地研究,分析了黄瓜丰产及早熟两个性状的主要构成因素及与其他性状间的相关性。结果表明,总瓜条数、单瓜重、主枝瓜重量、主枝单瓜重、主枝瓜条数、侧枝瓜条数、侧枝单瓜重、侧枝瓜重量、茎粗和生育天数等性状是决定总产量最为重要的因素并具有较强的杂种优势,无论在性状值、超亲还是超中优势中均达到极显著相关。前期产量主要决定于第一雌花节位和雌花节率及主侧枝瓜条数和瓜重、株高、叶面积等性状,达到显著水平,其中第一雌花节位和雌花节率在性状值、超亲和超中优势中都呈极显著相关性,说明这两个性状是决定黄瓜早熟性的决定性的因素并具有较强的杂种优势。根据试验结果分析了在黄瓜育种和生产过程中为达到早熟高产目的应当注意的几个主要问题。 相似文献
16.
A unique flower initiation of the wild Junebearing strawberry strain ‘CHI-24-1’ in Fragaria chiloensis occurs under 24 h DL and high temperature conditions. To introduce the floral initiation characteristics of ‘CHI-24-1’ into
cultivated strawberries of F. × ananassa, a cross pollination was conducted between ‘CHI-24-1’ and the Japanese short-day type strawberry cultivar ‘Nyoho’. The floral
initiation of ‘CHI-24-1’ was induced in both parent and daughter plants linked with runners under a 24 h DL and 23/20 ∘C, but not 8 and 16 h DLs at the same temperatures. Of the 21 F1 hybrids grown under the 24 h DL, 12 showed flower truss production
in the parent and/or daughter plants linked with runners. Among 64 F1 hybrids, 26 exposed to 8, 16 and 24 h DLs for 30 days
produced no flower trusses. However, 32, one and five F1 hybrids produced flower trusses under the 24 h DL alone, 8 h DL alone
and both the 8 and 24 h DLs, respectively. The results of the experiments indicated that none of the F1 hybrids were day-neutral
plants, but approximately 60% had the characteristics of floral initiation under 24 h DL, which was inherited from the pollen
parent of ‘CHI-24-1’. The importance of the unique floral initiation characteristics under 24 h DL with high temperature for
strawberry breeding was discussed. 相似文献
17.
Self and cross-incompatibility determination by means of fruit and seed set experiments or pollen tube growth observations
in the style has been frequently reported to be unclear in pear (Pyrus communis L.). Thus,in order to develop a reliable in vivo method to test pollen-pistil incompatibility in pear, pollen tube performance has been studied along the pistil following
self and cross-pollinations. Results show that, while pollen tube growth in the style may be an unclear test, ovule observation
at the microscope for the presence of pollen tube in the nucellus is a proper method to test incompatibility in this crop.
With this analysis we could identify S-alleles of ‘Williams’ (S1S2) and ‘Coscia’(S3S4), and three of the four possible S-genotypes resulting from the ‘Williams’ × ‘Coscia’ cross, as represented by ‘Butirra Precoz
Morettini’ (S1S3), ‘Santa Maria Morettini’ (S2S3)and ‘Tosca’ (S1S4). This result demonstrates that ‘Williams’ and ‘Coscia’ cultivars do not share any allele in common. We also established
two new inter-incompatibility groups in pear. Furthermore, the presence of a common allele between ‘Williams’ and ‘Agua de
Aranjuez’,and ‘Coscia’ and ‘Agua de Aranjuez’, three apparently unrelated old cultivars, may indicate a narrower genetic base
than expected for European pear. This finding together with the fact that 40% of new released cultivars have direct or indirect
parental relationship with the cultivars ‘Coscia’ and/or ‘Williams’, anticipates the possibility of new cases of cross-incompatibility
for this crop in the future. Both the method described and the determination of the S-genotypes will facilitate the characterisation
of self and cross-incompatibility relationships in this species.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
Characterization of segregation distortion on chromosome 3 induced in wide hybridization between indica and japonica type rice varieties 总被引：6，自引：0，他引：6
S. Matsushita T. Iseki Y. Fukuta E. Araki S. Kobayashi M. Osaki M. Yamagishi 《Euphytica》2003,134(1):27-32
We previously surveyed chromosomal regions showing segregation distortion of RFLP markers in the F2 population from the cross between a japonica type variety ‘Nipponbare’ and an indica type variety ‘Milyang23’, and showed
that the most skewed segregation appeared on the short arm of chromosome 3. By comparison with the marker loci where distortion
factors were previously identified, this region was assumed to be a gametophytic selection-2 (ga2) gene region. To evaluate this region, two near isogenic lines (NILs) were developed. One NIL had the ‘Nipponbare’ segment
of this region on the genetic background of ‘Milyang23’ (NIL9-23), and the other NIL had the ‘Milyang23’ segment on the genetic
background of ‘Nipponbare’ (NIL33-18). NIL9-23 and ‘Milyang23’, NIL33-18 and
‘Nipponbare’, and ‘Nipponbare’ and ‘Milyang23’ were respectively crossed to produce F1 and F2 populations. The F1 plants of NIL9-23 × ‘Milyang23’ and NIL33-18 × ‘Nipponbare’ showed high seed fertility and the same pollen fertility as their
parental cultivars, indicating that ga2 does not reduce seed and pollen fertility. Segregation ratio of a molecular marker on the ga2 region in the three F2 populations was investigated to clarify whether segregation distortion occurred on the different genetic backgrounds. Segregation
distortion of the ga2 region appeared in the both F2 populations from the NIL9-23 and ‘Milyang23’ cross (background was
‘Milyang23’ homozygote) and the ‘Nipponbare’ and ‘Milyang23’ cross (background was heterozygote), but did notin the F2 population from the NIL33-18 and ‘Nipponbare’ cross (background was ‘Nipponbare’ homozygote). This result indicates that
ga2 interacts with a ‘Milyang23’ allele(s) on the different chromosomal region(s) to cause skewed segregation of the ga2 region. In addition, segregation ratio was the same between the F2 populations from NIL9-23 × ‘Milyang23’ and ‘Nipponbare’ × ‘Milyang23’ crosses, suggesting that the both genotypes, ‘Milyang23’
homozygote and heterozygote, of gene(s) located on the different chromosomal region(s) have the same effect on the segregation
distortion.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
20.
Summary Sixty-six chrysanthemum (Dendranthema grandiflora) inbred selections, noninbred cultivars and hybrids, and D. makinoi were the base populations from which up to three generations of inbreds were obtained using multiple plant descent. Each parent possessed pseudo-self compatibility (PSC), which allowed seed set following self pollination. Rapid-generation cycling (laboratory seed ripening to heart stage and subsequent embryo rescue) reduced generation time and minimized confounding maternal with zygotic inbreeding depression during post heart-stage seed development. Selection criteria were male/female fertility and PSC. Two stages of the life cycle were chosen to evaluate inbreeding depression: germination (seed development to germination) and survivorship (fertile individuals at anthesis). PSC was environmentally interactive and genotype dependent, causing variable levels of self seed set between and within populations and generations. By the end of the second generation, families from all noninbred cultivars, D. makinoi, and one F1 hybrid were eliminated from the experiment due to self incompatibility and/or inbreeding depression. Post-germination inbreeding depression was severe in several advanced inbreds. Inbred progeny of most F1 or F2 hybrids expressed less or equal amounts of inbreeding depression compared to advanced inbreds. Linear regression coefficients for either germination or survivorship on percent homozygosity were negative. Correlation coefficients between percent germination and survivorship (as a percent of seed set) were highly significant for Minnesota inbreds (r=0.67, P0.002) and hybrids (r=0.67, P0.006). The correlation coefficient was higher when percent germination and survivorship (as a percent of germinated seedlings) were compared (r=0.95, P0.001).Abbreviations F
Fisher's Coefficient of Inbreeding
- IBD
Inbreeding Depression
- PSC
Pseudo-self Compatibility
- RGC
Rapid Generation Cycle
- SI
Self Incompatibility 相似文献