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1.
Lilium are Fritillaria-type plants. Triploid lilies, regardless of their male sterility, can be used as female parents to cross
with appropriate males, in contrast to other triploid Polygonum-type plants, which are usually seedless. Up to now, however,
little attention has been paid to the reason. Here we made allotriploid × diploid/tetraploid crosses in Lilium. Endosperm and progenies of LAA × AA/AAAA crosses were analyzed for ploidy level and genome composition. The endosperm of
some LAA × AA/AAAA ovules developed well but there was little or no development of LAA × LL/OO endosperm. The endosperm genome
composition of LAA × AA, LAA × AAAA, LAA × LL, LAA × OO are theoretically derived as 5A + 2L, 6A + 2L, 4A + 3L, 4A + 2L + O,
respectively. Genomic in situ hybridization showed that the progenies of LAA × AA/AAAA were aneuploid. Based on the experimental
results and analyses, our hypothesis is that five same genomes of endosperms are essential for its development in triploid × diploid/tetraploid
crosses of Lilium. The hypothesis can explain the success or failure of 3x × 2x/4x crosses in Lilium and is of importance for lily breeders who need to know the likelihood of success when producing new cultivars of this economically
important horticultural crop. 相似文献
2.
About 19 cultivars, which had originated from backcrosses between F1 LA (Longiflorum × Asiatic) hybrids (2n = 2x = 24) as
female parents and Asiatic cultivars as male parents (2n = 2x = 24), were analyzed with genomic in situ hybridization. 17
of them were triploid (2n = 3x = 36), and two aneuploid (2n = 3x + 1 = 37). The triploid cultivars had resulted from the functional
2n eggs produced by the female parents (F1 hybrids) because first division restitution (FDR) occurred in their meiosis during
megasporogenesis. Similarly, the aneuploid cultivars had originated from viable 2n + 1 eggs. The extra chromosome in cultivar
041555 or 041572 resulted from one univalent or one half-bivalent which might have lagged behind when the sister chromatids
of the other univalents and half-bivalents were segregating during the FDR process in their LA hybrid parents, respectively.
That the majority of cultivars possessed recombinant chromosomes showed that intergenomic recombination might play an important
role during the selection of the cultivars directly from BC1 progenies. That five cultivars of the 15 recombinant cultivars
only had reciprocal recombinant chromosomes and 10 cultivars had non-reciprocal recombinant chromosomes indicates that the
latter are more important. Because 9 of the 10 non-reciprocal recombinant cultivars possessed substitutions for recombinant
segments, it also indicated that such substitutions could be an important source for the genetic variation in the sexual triploid
BC1 progenies. In such cases there was a potential for the expression of the recessive genes of the backcross parent in a
nulliplex (aaa) condition in the substituted segments. Genetic variation resulting from such nulliplex loci might have played
a role in the selection of some of the cultivars. 相似文献
3.
T. Dennis Thomas 《Euphytica》2008,164(2):317-323
Bitter melon (Momordica
Charantia L.) is an important vegetable crop with nutritional and medicinal qualities. As a member of cucurbitaceae it is monoecious
with varying proportions of staminate and pistillate flowers. This study was undertaken to determine the effects of various
applications of ethrel and gibberellic acid (GA3) on sex modification in M. charantia. In the first set of experiments, various concentrations of hormones were added to the seed germination medium, in the second,
adult plants growing in the field were sprayed with aqueous solutions of ethrel or GA3 three times at three-day intervals. The number and sex of open flowers was recorded daily for 60 days after the first flower
opened and total number of staminate and pistillate flowers was calculated at the end of the experiment. The highest frequency
(29.5%) of pistillate flowers was observed in plants treated with 500 ppm ethrel at germination. Similarly, spraying of adult
plants with 100 ppm GA3 increased the proportion of pistillate flowers to 26% relative to 15% in untreated controls. Both ethrel and GA3 induced significantly higher number of pistillate flowers than control. In vitro hormone application during seed germination
was much more successful than spraying of field grown plants. 相似文献
4.
The possibility to induce embryo development after pollination of F1 interspecific cotton hybrids (Gossypium barbadense × Gossypium. hirsutum) with pollen from Abelmoschus esculentus was investigated to determine if wide-cross hybrid, haploid or other types of progeny might result. Small numbers of progeny
(Pa) were indeed recovered after numerous alien pollinations and in-planta development or in-vitro culture. The Pa plants
were characterized phenotypically and studied cytogenetically and microscopically to help establish their origin documenting
their reproductive basis. Root-tip chromosome counts and meiotic Metaphase-I analyses revealed that chromosome numbers among
cells of the Pa plants ranged from 33 to 44 and that the differences in chromosome number among cells of the same plant ranged
from 1 to 3, indicating somatic instability. Flow cytometric analysis also indicated the aneuploid nature of Pa plants. Although
the reproductive mechanisms need to be characterized more extensively by cytological and molecular means, the observations
suggest that alien pollinations may have resulted in parthenogenetic (Pa) egg cell development, or some other unusual reproductive
events. The production of wide-crosses and high degrees of aneuploidy could be of use for several types of genomic studies,
e.g., functional genomic characterization of genome shock, deletion mapping, and germplasm introgression. 相似文献
5.
Nigel A. R. Urwin 《Euphytica》2014,196(3):331-339
Double podding in cultivated chickpeas (Cicer arietinum L.) can increase yield and yield stability. In the present study, we performed reciprocal crosses of ‘kabuli’ (double podded) and ‘desi’ (single podded) chickpeas to determine (i) the expressivity and penetrance of double podding, (ii) the correlations of yield and yield components, and (iii) the heritability of double podding, flower color, and stem pigmentation in F2 plants. Reciprocal crosses were performed with two genotypes, AC 2969 (kabuli) and ICC 4969 (desi), to generate F1 and F2 plants. The results indicated hybrid vigor (heterosis) for yield in F1 plants and better performance of F2 plants. Yield and yield components of some lines in F2 were superior to the best parent, indicative of transgressive segregation. In particular, the presence of double podding (‘s’ allele) significantly increased yield in some of the transgressive segregants. Expressivity and penetrance of the ‘s’ allele depends on the background of the female parent. Some of the double podding progeny had greater seed yields than those of the single podding progeny and greater seed yields than the best parents. Double podding, stem pigmentation, and pink flowers each appears to be governed by a single recessive gene. Stem pigmentation and pink flowers appear to be linked traits that depend on the genetic background of the crossed chickpeas. Taken together, our studies of reciprocal crosses of kabuli and desi chickpeas clearly showed that yield could be improved by selection for transgressive phenotypes that have double podding. 相似文献
6.
Marinês Bastianel Mariângela Cristofani-Yaly Antonio Carlos de Oliveira Juliana Freitas-Astúa Antonio Augusto Franco Garcia Marcos Deon Vilela de Resende Vandeclei Rodrigues Marcos Antônio Machado 《Euphytica》2009,169(1):101-111
Leprosis, caused by citrus leprosis virus (CiLV) and transmitted by the tenuipalpid mite Brevipalpus phoenicis, is one of the most important viruses of citrus in the Americas. Sweet oranges (Citrus sinensis L. Osb.) are highly susceptible to CiLV, while mandarins (C. reticulata Blanco) and some of their hybrids have higher tolerance or resistance to this disease. The mechanisms involved in the resistance
and its inheritance are still largely unknown. To study the quantitative trait loci (QTL; quantitative trait loci) associated
with the resistance to CiLV, progeny analyses were established with 143 hybrid individuals of ‘Pêra’ sweet orange (C. sinensis L. Osb.) and ‘Murcott’ tangor (C. reticulata Blanco × C. sinensis L. Osb.) from controlled crossings. Disease assessment of the hybrid individuals was conducted by infesting the plants with
viruliferous mites in the field. The experiment consisted of a randomized completely block design with ten replicates. The
evaluated phenotypic traits were incidence and severity of the disease on leaves and branches, for a period of 3 years. The
MapQTL™ v.4.0 software was used for the identification and location of possible QTL associated with resistance to CiLV on
a genetic map obtained from 260 AFLP and 5 RAPD markers. Only consistent QTLs from different phenotypic traits and years of
evaluation, with the critical LOD scores to determine the presence or absence of each QTL calculated through the random permutation
test, were considered. A QTL was observed and had a significant effect on the phenotypic variation, ranging from 79.4 to 84%
depending on which trait (incidence or severity) was assessed. This suggests that few genes are involved in the genetic resistance
of citrus to CiLV. 相似文献
7.
Lee T. Hickey Mark J. Dieters Ian H. DeLacy Mandy J. Christopher Olena Y. Kravchuk Phillip M. Banks 《Euphytica》2010,172(2):183-195
Pre-harvest sprouting (PHS) in wheat (Triticum aestivum L.) is a significant problem. Introgression of genes controlling grain dormancy into white-grained bread wheat is one means
of improving resistance to PHS. In this study seven dormant (containing the SW95-50213 and AUS1408 sources) × non-dormant
crosses were produced to investigate the effectiveness of selection for grain dormancy in early segregating generations. Each
generation (F1–F4) was grown in a temperature controlled glasshouse with an extended photoperiod (i.e. continuous light). F2 and F3 generations were subject to selection. Five hundred harvest-ripe grains were tested for germination over a 14 day period,
and the 100 most dormant grains were retained and grown-on to produce the next generation within each cross. The response
to selection was assessed through analysis of the time to 50% germination (G50) in the F2, F3 and F4 generations. In addition, changes in marker class frequencies for two SSR markers (barc170 and gpw2279) flanking a known
quantitative trait locus (QTL) for grain dormancy on chromosome 4A were assessed in DNA from F2 plants selected from early germinating (non-dormant) and late germinating (dormant) phenotypic extremes within each cross.
Selection for grain dormancy in the F2 and F3 generations effectively recovered the dormant phenotype in all seven crosses, i.e. the F4 generation was not significantly different from the dormant parent. Further, selection based on individual F2 grains changed marker class frequencies for the 4A dormancy QTL; in most cases eliminating the marker class homozygous for
the non-dormant alleles. Application of this screening method will enable breeders to better select for grain dormancy and
may lead to development of new cultivars offering effective resistance to PHS in the near future. 相似文献
8.
Alexsander Luís Moreto Magno Antonio Patto Ramalho Adriano Teodoro Bruzi 《Euphytica》2012,186(3):755-760
The objective of this investigation was to check if epistasis is present in Andean × Mesoamerican beans crosses using triple test cross (TTC) method. The parents of the segregating population were Carioca–MG (Mesoamerican) and BRS Radiante (Andean). In July 2005, F2 progenies (backcrossed with the parents and F1 generation) were evaluated at two locations for three characters: number of pods plant−1, number of grains plant−1 and grain weight plant−1. The presence of epistasis was detected for all yield components. In the partitioning of epistasis in additive x additive (i) and dominant x dominant (j) and dominant × additive (l) it was observed that, for the traits number of pods/plant and number of grains/plant, only epistasis of the type (j) + (l) were significant. For the trait grain mass/plant, all types of epistasis were significant. 相似文献
9.
Zhenchang Liang Min Sang Benhong Wu Aihong Ma Shengjian Zhao Gan-Yuan Zhong Shaohua Li 《Euphytica》2012,186(2):343-356
Variation patterns and inheritance of anthocyanin content in the ripe berries of a tetraploid × diploid table grape cross population were investigated in two successive years. The population segregated for three different ploid levels: dipolids, triploids, and tetraploids. A total of 28 different anthocyanins were detected and quantified in the progeny population. Transgressive segregation for the total anthocyanin content was observed in all the three ploid progeny populations. The total anthocyanin content increased as the ploid level increased. The broad sense heritabilities (H2) of the total anthocyanin content were all relatively high, ranging from 0.53 to 0.98, 0.57 to 0.97 and 0.43 to 0.94 in the diploid, triploid and tetraploid population, respectively. Our results suggested that the total anthocyanin content followed an additive inheritance model in this polyploid segregation population. We also observed that the relative contribution of individual anthocyanins to the total anthocyanin content varied significantly among different ploid populations, suggesting that genetic background has important impact on the accumulation of the individual anthocyanin compounds. These results will help develop better breeding strategies in a polyploid table grape breeding program for improving the content of anthocyanins, an important class of polyphenolics possessing antioxidant activities and many other health-related benefits. 相似文献
10.
11.
Maize grey leaf spot (GLS) disease remains an important foliar disease in sub-Saharan Africa accounting for more than 25% yield losses in maize. Information on inheritance of GLS resistance of germplasm adapted to African environments is required in new sources being identified. Therefore, hybrids generated from a 10 × 10 half-diallel mating of tropical advanced maize inbred lines were evaluated in six environments to determine combining ability, genotype × environment interaction (G × E) and the impact of GLS disease on grain yield. General combining ability effects were highly significant and accounted for 72 and 68% of the variation for GLS resistance and grain yield, respectively. Significant specific combining ability effects associated with reduced disease levels were observed in some hybrids when one parent was resistant, and these may be exploited in developing single cross maize hybrids. Regression analysis showed a 260–320 kg ha?1 decrease in maize grain yield per each increase in GLS disease severity score, and significant associations (r = ?0.31 to ?0.60) were observed between grain yield and GLS severity scores. This showed the potential of GLS disease to reduce yield in susceptible varieties grown under favourable disease conditions, without control measures. Genotype and genotype × environment biplots and correlation analysis indicated that the significant G × E observed was not due to changes in hybrid ranking, implying absence of a significant crossover interaction. Therefore, predominance of additive gene effects imply that breeding progress for GLS disease resistance would be made through selection and this could be achieved at a few hot-spot sites, such as Baynesfield and Cedara locations in South Africa, and still deploy the resistant germplasm to other environments in which they are adapted. 相似文献
12.
Isatis tinctoria L. (woad) is a dye plant whose cultivation is increasing because of its adaptability to marginal conditions and increasing
demand for natural products. Suitable breeding schemes need to be set up in order to obtain woad varieties for each proposed
environment. Presently, no data about the reproductive system are available. The effects of selfing and crossing on setting
and progeny vigour were assessed. Results showed the existence of an outcrossing system in I. tinctoria. Obligate self-pollinated plants produced fewer siliques (7.1 g per plant) with lower weight (6.0 mg) and lower seed germinability
(8.2%) than outcrossing plants (44.1 g, 8.0 mg and 46.0% for each character, respectively). Self-pollinated progenies also
generally showed lower vigour than outcrossing progenies. 相似文献
13.
Anthracnose is a serious disease affecting dry bean production especially in the cool highland areas worldwide. The objective
of this research was to study the inheritance of anthracnose resistance in market-class dry beans. A complete diallel set
of crosses was generated from nine diverse parents comprising six resistant and three susceptible to anthracnose. The F1 and F2 crosses and parents were artificially inoculated with Colletotriclum lindenumthianum Race-767 in a growth room. There was significant variation for anthracnose resistance among genotypes. General combining
ability (GCA) and specific combining ability effects were significant for resistance, indicating importance of both additive
and non-additive effects, respectively. Preponderance of GCA effects (66%) suggested that additive effects were more important
than non-additive effects (24%), which were also reflected by high heritability estimates (70%), and suggested that simple
selection or backcrossing would be useful for improving the resistance in market class varieties. The study was not conclusive
on whether epistatic gene action played a major role, but if available it might have biased the dominance gene effects. Reciprocal
effects (10%) were not significant (P > 0.05), suggesting that cytoplasmic genes did not play a major role in modifying anthracnose resistance. Parental lines
G2333, AB136, NAT002, and NAT003 showed highly negative GCA effects qualifying them as suitable parents for transferring resistance
genes to their progenies. A few major genes, 1–3, displaying partial dominance conditioned anthracnose resistance, suggesting
a possibility of using marker-assisted selection to improve anthracnose resistance in market-class dry beans. 相似文献
14.
15.
Frego (fg) bract is an important agronomic trait in tetraploid cotton, which has been widely introduced into several cotton varities
or lines in the past several years. In order to help us further understand the underlying molecular mechanism of frego bract
development, a map-base cloning strategy was used to localize the fg locus. An F2 population which comprised of 290 fg individuals derived from a cross of the multiple-marker line T582 (G. hirsutum, carrying the fg gene) with Hai7124 (G. barbadense) was constructed. Genetic linkage analysis was carried out to map of the fg locus with SSR and EST-SSR markers in tetraploid cotton. Genetic linkage analysis showed that the fg locus was flanked by the marker NAU3016 and NAU3172 on the long arm of chromosome 3, with the genetic distance of 0.3 cM
and 4.7 cM, respectively. The information of fg locus provided the basic information for the final isolation of this important gene in tetraploid cotton, these marker information
could be used in marker-assisted selection in cotton. 相似文献
16.
Uttam Kumar Arun K. Joshi Maya Kumari Rajneesh Paliwal Sundeep Kumar Marion S. Röder 《Euphytica》2010,174(3):437-445
Stay green or delayed senescence is considered to play a crucial role in grain development in wheat when assimilates are limited.
We identified three QTLs for stay green on the chromosomes 1AS, 3BS and 7DS using a recombinant inbred (RI) population developed
by making crosses between the stay green parent ‘Chirya 3’ and non-stay green ‘Sonalika’. The RI lines were evaluated in natural
field conditions for 2 years in replicated trial. The QTL on chromosome 1A was identified in both the years, while the QTLs
on 3BS and 7DS were identified only in 1st and 2nd year, respectively. The QTLs explained up to 38.7% of phenotypic variation
in a final simultaneous fit. The alleles for higher stay green values derived from the stay green parent ‘Chirya 3’. The QTLs
were named as QSg.bhu-1A, QSg.bhu-3B and QSg.bhu-7D. The QTL QSg.bhu-3B and QSg.bhu-7D were placed in the 3BS9-0.57-0.78 and 7DS5-0.36-0.61 deletion bins, respectively. 相似文献
17.
18.
Zhenchang Liang Min Sang Aihong Ma Shengjian Zhao Gan-yuan Zhong Shaohua Li 《Euphytica》2011,180(2):251-259
Pearl millet [Pennisetum glaucum (L.) R. Br.] is a major warm-season cereal, grown primarily for grain production in the arid and semi-arid tropical regions
of Asia and Africa. Iron (Fe) and zinc (Zn) deficiencies have been reported to be a food-related primary health problem affecting
nearly two billion people worldwide. Improving Fe and Zn densities of staple crops by breeding offers a cost-effective and
sustainable solution to reducing micronutrient malnutrition in resource poor communities. An understanding of the genetics
of these micronutrients can help to accelerate the breeding process, but little is known about the genetics and heterosis
pattern of Fe and Zn densities in pearl millet. In the present study, ten inbred lines and their full diallel crosses were
used to study the nature of gene action and heterosis for these micronutrients. The general combining ability (GCA) effects
of parents and specific combining ability (SCA) effects of hybrids showed significant differences for both of the micronutrients.
However, the predictability ratio (2σ2gca/(2σ2gca + σ2sca)) was around unity both for Fe and Zn densities, implying preponderance of additive gene action. Further, highly significant
positive correlation between mid-parent values and hybrid performance, and no correlation between mid-parent values and mid-parent
heterosis confirmed again the predominant role of additive gene action for these micronutrients. Barring a few exceptions
with one parent, hybrids did not outperform the parents having high Fe and Zn levels. This showed that there would be little
opportunity, if any, to exploit heterosis for these mineral micronutrients in pearl millet. In general, high Fe and Zn levels
in both of the parental lines would be required to increase the probability of breeding high Fe and Zn hybrids. 相似文献
19.
Introduced maize (Zea mays L.) germplasm can serve as sources of favorable alleles to enhance performance in new maize varieties and hybrids under drought stress conditions. In the present study, the combining abilities of 12 exotic maize inbred lines from CIMMYT and 12 adapted maize inbred lines from IITA were studied for grain yield and other traits under controlled drought stress. The inbred lines from each institution were separated into groups using SSR-based genetic diversity and were intercrossed using a factorial mating scheme to generate 96 hybrids. These hybrids were evaluated under both controlled drought stress and well-watered conditions at Ikenne in Nigeria in 2010 and 2011. Average mean yields of hybrids under drought stress represented 23 % of the average yield of hybrids under full irrigation. General combining ability (GCA) effects accounted for 49–85 % of the observed variation for several traits recorded under both well-watered and drought stress conditions. Specific combining ability effects for grain yield, though positive in most hybrids, were not significant under drought stress conditions. All the twelve exotic and nine adapted lines had positive GCA effects (female, male, or both) for grain yield under either drought stress or full irrigation, or both environments. EXL03 and EXL15 that had positive and significant female and male GCA effects for grain yield under both environments can be used to improve their adapted counterparts for grain yield and drought tolerance. Normalized difference vegetation index had weak but significant correlation with grain yield. 相似文献
20.
Shelley Jansky 《Euphytica》2011,178(2):273-281
Valuable genetic diversity in diploid wild Solanum species can be accessed through crosses to haploids (2n = 2×) of the tetraploid cultivated potato, Solanum tuberosum. Haploid-wild species hybrids segregate for the ability to tuberize in the field. In addition, they vary in male fertility,
vine size, stolon length, and tuber size. In this study, three haploids were crossed with nine diploid wild Solanum species and 27 hybrid families were evaluated in the field for two years. The proportion of male fertile hybrid clones varied
depending on the wild species parent. A large effect of the female parent was detected for vine size, stolon length, tuber
size, percent tuberization, and percent plants selected for agronomic quality. An exceptional haploid (US-W4) was identified
for the production of agronomically desirable haploid-wild species hybrids. In hybrids derived from US-W4, differences among
wild species parents were observed for agronomic quality. Superior hybrids were produced by S. berthaultii and S. microdontum. Reciprocal crosses were evaluated for a subset of families. When the wild species was used as the female parent, male fertility
was restored, but tuberization and tuber size were reduced. Careful selection of both haploid and wild species parents can
result in a large proportion of fertile, agronomically desirable hybrid offspring. 相似文献