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1.
The genetic base of sunflower elite lines is very narrow, due to many years of selection and breeding. To broaden the genetic diversity of the cultivated sunflower, in 1995 73 wild sunflower populations were crossed with 3 cultivated lines (Testers), and 219 hybrid offspring’s were evaluated in the field. GCA and SCA effects were computed suggesting for all traits a genetic potential for improvement through selection. Study of the hybrids revealed that the wild accessions bear different genetic abilities to combine with the testers for traits of morphological architecture, phenology and yield (seed weight and seed oil). The variance due to GCA and SCA showed that gene action was additive for days to flowering, branching and plant height. Genotypes derived from the same geographic origin may have either good or poor general combing ability. The correlation between GCA and per se genotype performance was positive for all traits except for seed oil content. This was the first attempt to evaluate wild-cultivated hybrids in sunflower on a large scale and will be the starting point for the management of hybrid Helianthus annuus populations for breeding. GCA and SCA estimations will facilitate the definition of strategies to manage and exploit the natural diversity for this crop.  相似文献   

2.
Seedling traits are important for development, flower bud differentiation, fruit production and fruit quality of cucumber (Cucumis sativus L.). In this study, 160 recombinant inbred lines (RILs), derived from crossing wild cucumber inbred line PI 183967 (C. sativus var. hardwickii) with ‘931’ northern China cultivated cucumber inbred line 931, were employed to identify quantitative trait loci (QTLs) of cotyledon length (Cl), cotyledon width (Cw), hypocotyl length (Hl), first true leaf length (Fll), first true leaf width (Flw), aboveground fresh biomass (Afb) and aboveground dry biomass (Adb) at seedling stage. A genetic map including 307 SSR markers was developed which spanned 993.3 cM, with an average genetic distance of 3.23 cM between adjacent markers. 36 QTLs associated with the seven traits were detected on chromosomes 1, 2, 3, 5 and 6 in four environments (spring and autumn of 2012 and 2013), explaining 6.1 to 23.6% of the observed phenotypic variations. Among the 36 QTLs, 21 were responsible for more than 10% of observed phenotypic variations. We obtained 2, 2, 1 and 3 QTL loci for the traits of Fll, Flw, Afw and Adw, respectively. In addition, genes in the genetic region spanned by SSR15321‐SSR07711 on chr. 5 may contribute to Flw, Afw and Adw.  相似文献   

3.
Understanding the genetic basis underlying domestication-related traits (DRTs) of cowpea (Vigna unguiculata (L.) Walp.) is important since the genome has experienced divergent domestication and in addition it is also useful to utilize the wild germplasm efficiently for improving different traits of the cultivated cowpea. Quantitative trait loci (QTLs) for DRTs were identified in a population of 159 F7 recombinant inbred lines derived from a cross between a domesticated cowpea (V. unguiculata (L.) Walp.) variety, 524B, and a wild accession, 219. Using the constructed linkage map, QTLs for 10 DRTs were analysed and mapped. QTLs for seed, pod and flower related traits were detected. Subsequently, QTL for ovule number was also identified. To our knowledge, this is the first time a QTL for this trait has been observed. QTLs for DRTs show co-localization on three linkage groups and pleiotropy or close linkage of genes for the traits is suggested in these chromosome regions. The information gained in this study can be used for marker-assisted selection of domestication-related QTLs in cowpea and enhance understanding of domestication in the genus Vigna.  相似文献   

4.
Chickpea shows a distinct domestication trajectory vis‐a‐vis pod dehiscence and growth cycle mediated by vernalization insensitivity compared with its companion Near Eastern legumes. Our objectives were: (i) to map the quantitative trait loci (QTLs) associated with vernalization response and seed free tryptophan in domesticated × wild chickpea progeny and (ii) estimate the genetic correlation between vernalization response and free tryptophan content. A domesticated × wild chickpea cross was used to document phenotypic segregation in both traits and to construct a skeletal genetic map for QTL detection. A number of vernalization response and seed free tryptophan content QTLs were documented in both F2 and F3 generations. No significant genetic correlation between these two traits was observed. Epistatic relationship between two free tryptophan loci was documented. It is evident that selection for high seed tryptophan is easier to accomplish relative to selection for vernalization insensitivity. This suggests that the two traits were selected independently in antiquity, thereby corroborating earlier claims for conscious selection processes associated with chickpea domestication.  相似文献   

5.
A doubled haploid population of Brassica juncea, developed from a cross between two parental lines differing for days to maturity, was used to study the efficiency of indirect selection for a primary trait through selection of secondary trait(s) over direct selection for the primary trait when quantitative trait loci information is available for both primary and secondary traits, and applied. Days to maturity was considered as primary trait, while days to first flowering, days to end of flowering, flowering period and plant height were considered as secondary traits. An RFLP linkage map was employed for QTL analysis of maturity and maturity-determinant traits, and a stable QTL B6 simultaneously affecting these two types of traits was identified. This linked QTL explained 11.7% phenotypic variation for days to maturity, 20.7% variation for days to first flowering, 24.3% variation for days to end of flowering and 14.4% variation for plant height. Phenotypic evaluation of maturity and/or maturity-determinant traits, viz. days to first flowering, days to end of flowering and plant height revealed that limited genetic advance for early maturity can be achieved through phenotypic selection of the primary and/or the secondary trait(s). However, the estimates of genetic advance for early maturity based on combined phenotypic evaluation and linked QTL data was found to be, at least, three times higher compared to genetic advance based on phenotypic evaluation only, demonstrating the potential of marker-assisted selection in breeding for early maturity in B. juncea.  相似文献   

6.
We investigated the variability and inheritance of flowering in a seedling population of diploid Actinidia chinensis Planch. We found considerable variation in time to reach 50% flowering (D50) and flowering duration (FD). D50 was highly heritable (h 2 > 0.85) suggesting that this trait would respond well to selection in this population, whereas FD was greatly affected by the environment (h 2 < 0.20). The results also showed that the flowering times of male vines were more sensitive to the environment than those of female vines. However, significant specific combining ability (SCA) effects could be achieved by targeting specific bi-parental combinations for breeding and selection of flowering time. The diversity in flowering traits among males will facilitate the selection of male pollinizers that coincide in flowering time with present or future female cultivars. The possibility of breeding female cultivars with a short flowering period to improve the consistency of fruit maturity at harvest is discussed.  相似文献   

7.
The inheritance of earliness and fruit Weight in tomato was studied in tour interspecific crosses. Two cultivated varieties, i.e.‘HS 101’ and “HS 102′, were hybridized with two wild species. L. birsutum f. glabratum‘B 6013’ and L. pimpinellifolium‘A 1921′. Six generations of these crosses were evaluated for these traits and the estimates of gene effects were derived from the generation mean using an epistatic (six parameters) model. There were very wide differences between cultivated and wild species for earliness and fruit weight and in the segregating populations, plants with delayed maturity and smaller fruit size were recorded with high frequency. It was found that the inheritance pattern was mainly governed by additive gene action. Epistatic effects also contributed towards the inheritance of both traits.  相似文献   

8.
Z. Sun    J. E. Staub    S. M. Chung    R. L. Lower 《Plant Breeding》2006,125(3):281-287
Parthenocarpy (seedless fruit) is an economically important yield‐related trait in cucumber (Cucumis sativus L.; 2n = 2x = 14). However, the genomic locations of factors controlling parthenocarpic fruit development in this species are not known. Therefore, an F2 : 3 mating design was utilized to map quantitative trait loci (QTL) for parthenocarpy using a narrow cross employing two gynoecious, indeterminate and normal leaf lines [2A (parthenocarpic) and Gy8 (non‐parthenocarpic)]. QTL detection was performed employing 2A‐ and Gy8‐coupling phase data using the parthenocarpic yield of 126 F3 families grown at two locations at Hancock, WI in 2000. The QTLs detected in this study were compared with the map locations of QTLs conditioning first‐harvest yield of seeded cucumber characterized in a previous study. There were 10 QTLs for parthenocarpy detected defining four genomic regions, in which three QTLs also mapped to the same genomic regions as QTLs detected for fruit yield at first‐harvest as reported in a previous study. The eight fluorescence amplified fragment length polymorphism (AFLP) markers linked to parthenocarpy through QTL mapping defined herein (four each in linkage groups 1 and 4) are candidates for use in marker‐assisted selection programmes where breeding for increased levels of parthenocarpy is an objective in the elite‐processing cucumber populations.  相似文献   

9.
Heterosis, or hybrid vigour, has been used to improve seed yield in several important crops for decades and it has potential applications in soybean. The discovery of over‐dominant quantitative trait loci (QTL) underlying yield‐related traits, such as seed weight, will facilitate hybrid soybean breeding via marker‐assisted selection. In this study, F2 and F2 : 3 populations derived from the crosses of ‘Jidou 12’ (Glycine max) × ‘ZYD2738’ (Glycine soja) and ‘Jidou 9’ (G. max) × ‘ZYD2738’ were used to identify over‐dominant QTL associated with seed weight. A total of seven QTL were identified. Among them, qSWT_13_1, mapped on chromosome 13 and linked with Satt114, showed an over‐dominant effect in two populations for two successive generations. This over‐dominant effect was further examined by six subpopulations derived from ‘Jidou12’ × ‘ZYD2738’. The seed weight for heterozygous individuals was 1.1‐ to 1.6‐fold higher than that of homozygous individuals among the six validation populations examined in different locations and years. Therefore, qSWT_13_1 may be a useful locus to improve the yield of hybrid soybean and to understand the molecular mechanism of heterosis in soybean.  相似文献   

10.
The objective of this study was to identify molecular markers linked to fruit-related traits in the tomato subjected to high temperatures. In total, 160 F2 plants derived from a cross between a heat-tolerant breeding line, CL5915-93D4-1-0-3 (Solanum esculentum), and a heat-sensitive wild accession, L4422 (S. pimpinellifolium), were grown in a greenhouse. Six traits including fruit number, fruit weight, brix, seed number, fruit setting, and flower number were scored. The distributions of fruit number, fruit set, flower number, and seed number were skewed towards heat susceptibility which is known to be characteristic of L4422. Polymorphic bands were generated by PCR-derived methods of RAPD, ISSR and AFLP Polymorphism, the segregation ratio, and distribution over the genome of the above 3 markers were compared. Ten linkage groups, ranging 20.6–151.6 cM in size, were constructed with 62 informative markers spanning a total of 776.3 cM. Fruit-related quantitative trait loci (QTLs) were non-randomly distributed in the tomato genome. For the 6 traits investigated, 21 QTLs were dispersed on linkage groups 2–5. The genetic effects of the various QTLs were differently exhibited, in our study we have respectively found from 10.5% to 30.2% of the variation explained by the QTL for flower number (FRN4) and brix (BX2). Thirteen QTL-mapped markers were unique to 1 trait, and 4 markers were linked to more than 1 trait. Among them, QTLs linked to the I868-470 marker had effects on fruit weight and brix, and a significant positive correlation between these 2 traits was noted (r = 0.35, P < 0.05). Thus, the I868-470 marker may have the potential for simultaneous selection of high fruit weight and brix. These markers also allowed us to align genome linkage maps across distantly related species and to reveal the co-localization between these QTLs and major genes.  相似文献   

11.
Plant breeding of lingonberry (Vaccinium vitis-idaea L.) is still in its infancy. In order to optimize sampling strategy to broaden the genetic base and to improve horticulturally important traits, we need more information about the genetic structure of wild populations. In a field study, seeds were collected from thirteen widely spaced lingonberry populations in Sweden, from one in Estonia and from one in Japan. The resulting seedlings were subsequently transferred into a field with a randomized design and were investigated regarding horticulturally important traits (growth, flowering, phenology and cropping performance). Common for all traits was that the amount of variation (mean for 17 traits: 21.8% ± 11.2) was smaller among populations than within populations. In spite of this low variation, the study revealed significant genetic variation (p<0.05) among populations in nearly all traits investigated. Significant correlations were found between several traits: between plant width and plant height (r=0.516, p<0.001),between plant height and total fruit yield (r=0.253, p<0.001),between number of rhizome-derived daughter plants and total fruit yield (r=–0.189, p<0.001) and between the beginning of spring flowering and the duration of repeat flowering (r=–0.354, p<0.001). Many traits were associated with the latitude of the sample location, e.g. duration of flowering (r=–0.620, p<0.05) and total fruit yield (r=–0.580, p<0.05). Populations collected from southern latitudes (56°–60°N) in general showed better values than the northern populations for horticulturally important traits. The Japanese population, which belongs to the subspecies minus, differed in many traits from all the other populations which belong to the subspecies vitis-idaea. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
As an important fruit vegetable, fruit-related traits have become one of the breeding hotspots of wax gourd (Benincasa hispida). The fruit traits have an important role on the quality and yield of wax gourd, and QTL mapping of these traits will provide solid basis for fruit character improvement as well as high-yield breeding. In this study, the inheritance of four fruit-related traits, including fruit weight (FW), fruit length (FL), fruit diameter (FD) and flesh thickness (FT), was analyzed. All the frequency distribution of the four traits in an F2 population showed a single peak skewed distribution, which proved them to be quantitative. Subsequently, based on the high-density genetic map using 140 F2 individuals, nine QTLs associated with the four traits were detected on chromosome 3, 4, 5, 6, 9, 10 and 11. Four of the nine QTLs had major effect, which were responsible for more than 10.0% of phenotypic variance. Furthermore, the major QTLs of FW, FD and FT shared similar location intervals, which implied that this location might contain some pleiotropic genes. This is the first report on QTL mapping of quantitative trait in wax gourd, which plays an important role for fine mapping of these important fruit traits.  相似文献   

13.
Firmness is an indicator of fruit freshness and a main component of tomato (Solanum lycopersicum) fruit texture. In this work, the genetic variability in fruit firmness and stiffness was analyzed in pre- and postharvest periods and underlying anatomical and biochemical traits were identified. Three tomato contrasted parental lines and six derived quantitative trait loci (QTL)-NILs harboring texture QTL on chromosome 4 (QTL4) and 9 (QTL9) were analyzed; the seasonal variability was assessed on two distant trusses. Firmness and stiffness were measured by compression and puncture tests at harvest and after 7-day storage at 20 °C. QTL4 poorly influenced the textural variables, on the contrary to QTL9 which increased firmness measured by puncture test and had similar effects in the two genetic backgrounds. According to this test, firmness increased along the season, but ranks among genotypes and QTL effects were hardly affected. Only some of the QTL effects were still significant after storage and firmness losses were not predicted by firmness at harvest. Fruit firmness and stiffness measured by puncture tests correlated with both morphological (locular number, R = −0.89), histological (cell size, R < −0.80) and biochemical (dry matter (R > 0.82) and soluble sugar content (R < −0.74)) fruit traits. In contrast, compression test values hardly correlated with any of the measured traits. This work provided an original comprehensive approach to analyse fleshy fruit firmness and paves the way for a future predictive model.  相似文献   

14.
Controlled crosses in bambara groundnut were attempted between a range of thirty-six bambara groundnut landraces (thirty domesticated (V. subterranea var. subterranea) and six wild (V. subterranea var. spontanea)). Ten F1 seed were produced. Of these, eight germinated producing F2 populations. On seed set, four populations could be unambiguously confirmed as true crosses by F3 seed coat colour. A single F2 population, derived from a domesticated landrace from Botswana (DipC; female parent) crossed with a wild accession collected in Cameroon (VSSP11; male parent) was used to study a range of agronomic and domestication traits. These included; days to emergence, days to flowering, internode (fourth) length at harvest, number of stems per plant, leaf area, Specific Leaf Area (SLA), Carbon Isotope Discrimination (CID), 100 seed weight, testa colour and eye pattern around the hilum. On the basis of variation for internode length and stems per plant, 14 small F3 families were selected and grown under field conditions to further investigate the genetic basis of the ‘spreading’ versus ‘bunched’ plant character, a major difference between wild and cultivated bambara groundnut. Results presented suggest that traits including leaf area, SLA, CID and 100 seed weight are controlled by several genes. In contrast, the variation for traits such as internode length, stems per plant, days to emergence and seed eye pattern around the hilum are likely to be under largely monogenic control. The results of this work are discussed in relation to the domestication of bambara groundnut.  相似文献   

15.
A set of 224 recombinant inbred lines (RILs) derived from a narrow cross between two fresh eaten types (S94 (Northern China type) × S06 (Northern European type)) (Cucumis sativus L.) was used to construct a genetic linkage map. With the RILs a 257-point genetic map was constructed including 206 SRAPs, 22 SSRs, 25 SCARs, 1 STS, and three economically important morphological markers (small spines (ss), uniform immature fruit color (u), dull fruit skin (D)). The seven linkage groups covered 1005.9 cM with a mean marker interval of 3.9 cM. The ss locus was linked to D and u, and they were all on Linkage group 6. The RIL map contained a total of 51 sequence-specific markers, which made possible the comparison of molecular linkage maps developed in different laboratories. Using the F6:7 derived families, a total of 78 QTLs were detected with relatively high LOD scores (2.9–84.4) for nine fruit-related traits (fruit weight, length, and diameter, fruit flesh thickness, seed-cavity diameter, fruit-stalk length, fruit pedicel length, length/diameter and length/stalk ratio) and three flower-related traits (first flower node, first female flower node and female flower ratios). Several sequence-anchor markers (CSWCT25, CS30, CMBR41, CS08 etc.) were closely linked with some QTLs for fruit weight, fruit length, fruit flesh thickness and sex expression, which can be used for the future marker-assisted selection to improve the fruit traits in cucumber breeding. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. X. J. Yuan and J. S. Pan contributed equally to this investigation.  相似文献   

16.
Helianthus argophyllus is a wild species known as “silver sunflower”, which possesses several traits, including morphological traits that increase drought tolerance. Therefore, introgressions between chosen cultivated lines and two H. argophyllus accessions were made, and segregating generations were established. Important agronomic traits including single heading, high pollen fertility, silver canopy (indicating more cuticular wax), and content of cuticular waxes and oil were selected over six segregating generations. The resulting F6 lines showed introgression of water saving traits, as they had lower excise leaf water loss, with comparable yield to standard checks. However, these F6 lines were late maturing and showed poor flowering synchronization between the cultivated and introgressed lines. Introgressed line “D‐22” was particularly promising as a breeding line, with superior agronomic and drought resistance traits. This line had the potential to be used as an inbred parental line for introgression of drought resistance traits into elite sunflower germplasm. Combining ability analysis of the introgressed lines further showed their potential for heterosis breeding or to be used as parental lines in breeding programme.  相似文献   

17.
Fifty-eight F2 individuals derived from an interspecific cross between cultivated eggplant, Solanum melongena, and its wild relative, S. linnaeanum, were phenotyped for 42 plant, leaf, flower, and fruit traits. Composite interval mapping analysis using genotypic data from 736 molecular markers revealed the positions of 71 statistically significant (P ≤ 0.05) quantitative trait loci (QTL) influencing 32 of the morphological traits. Although most QTL were location-specific, QTL governing three traits (leaf lobing, leaf prickles and prickle anthocyanin) were detected in both experimental locations. Analysis of three additional traits (stem prickles, fruit calyx prickles and fruit length) in both locations yielded QTL in similar but non-overlapping map positions. The majority (69 %) of the QTL corresponded closely with those detected in previous analyses of this data set. However the increased resolution of the linkage map combined with advances in QTL mapping permitted more precise localization, such that the average interval length of these QTL was reduced by 93 %. Thirty-one percent of the QTL were novel, suggesting that simple linear regression with a low density linkage map (the method used in previous studies of this population) missed a substantial portion of significant QTL. Hotspots of QTL affecting plant hairiness, prickliness, and pigmentation were identified on chromosomes 3, 6, and 10, respectively, and may reflect the pleiotropic activity of single structural or regulatory genes at these positions. Based on synteny between the eggplant, tomato, potato and pepper genomes, putative orthologs were identified for 35 % of the QTL suggesting strong conservation of gene function within the Solanaceae. These results should make it easier to target particular loci for map-based cloning and marker-assisted selection studies.  相似文献   

18.
Akebia trifoliata belongs to the Lardizabalaceae family of flowering plants, has tremendous potential as a new fruit crop for further domestication and commercialization in China. However, the selection of A. trifoliata is extremely limited due to lack of information about basic inheritance of fruit traits. In this study, 11 key fruit characters, including single fruit weight (SFW), fruit length (FL), fruit width (FW), peel thickness (PT), peel weight (PW), soluble solids content (SSC), seed weight (SW), pulp weight (PuW), edible ratio (ER), hundred-grain weight (HGW) and seed number (SN) were evaluated, and genetic parameters were analyzed. The results showed that the 11 tested traits have high repeatability range from 0.87 to 0.95. Correlation analysis showed that SFW was positively correlated with FL, FW, PT, PW and PuW, but negatively correlated with ER. The Smith–Hazel-index based multitrait selection was used to select superior lines. The SH selection index identified superior lines with high SFW and ER, and low SN. Taken together, our results provide important information for domestication and breeding program of Akebia trifoliate.  相似文献   

19.
Wild radish (Raphanus raphanistrum) has developed introgressed populations after hybridization with its cultivated counterpart (R. sativus) in California. Hybridization with various Brassica and Sinapis species is also possible. To determine if hybridization is responsible of the genetic diversity of European populations, six wild radish populations with distinct morphological traits were sampled from geographically distant regions in Europe. Plants were cultivated in an oilseed rape field and in insect‐proof cages. Silique and flower morphology, growth, and reproductive traits were measured. The wild radish populations could be discriminated by the morphological traits, but not related to geographic regions. In particular, populations of one region showed wide variability in terms of silique shape and growth behaviour, and small‐sized flowers. Although the origin of morphological diversity in wild radish is unclear, i.e. native or due to gene flow from the cultivated radish or other Brassicaceae, significant morphological divergence was found that could have relevant effects on plant ecology and adaptation.  相似文献   

20.
Despite the well-recognized importance of grain yield in high-oil maize (Zea mays L.) breeding and production, few studies have reported the application of QTL mapping of such traits. An inbred line of high-oil maize designated ‘GY220’ was crossed with two dent maize inbred lines to generate two connected F2:3 populations with 284 and 265 F2:3 families. Our main objective was to evaluate the influence of genetic background on QTL detection of grain yield traits through comparisons between the F2:3 populations. The field experiments were conducted during the spring in Luoyang and summer in Xuchang, Henan, China. Two genetic linkage maps were constructed with a genetic distance of 2111.7 and 2298.5 cM using 185 and 173 polymorphic SSR markers, respectively. In total, 18 and 15 QTL were detected for six grain yield traits in the two populations. Only one common QTL marker was shared between the two populations. A QTL cluster associated with five traits was identified at bin 1.05–1.06, including the shared QTL for 100GW, which demonstrated the largest effect (16.7%). Among the detected QTL, 12 digenic interactions were identified. Our results reflect the substantial influence of dent maize genetic background on QTL detection of grain yield traits.  相似文献   

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