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1.
Summary Spot blotch caused by Cochliobolus sativusis considered a major disease problem of wheat(Triticum aestivumL.) in the warm areas of South Asia. This study estimated heritability (h
2) of resistance to spot blotch and its correlation with days to heading DH) and maturity (DM), one-hundred-kernel weight (HKW),
and plant height (PHT) in 14 crosses involving four resistant (‘Attila’, ‘Chirya 7’, ‘G 162’, and ‘SW89.5422’) and two susceptible
(‘Sonalika’ and ‘HD2329’) wheat genotypes. Data were recorded on F5and F6lines in fields under natural epidemics of spot blotch in 2003 and 2004, respectively. Heritability was estimated for area
under disease progress curve (AUDPC), AUDPC/day, and the highest disease score (HDS) using offspring-parent regression (h
op
2) and realized heritability (h
2
R) procedures. Heritability estimates were low to high in terms of AUDPC (0.21 < h
op
2< 0.64; 0.32 < h
R
2< 0.70), AUDPC/day (0.40 < h
op
2< 0.96; 0.42 < h
R
2< 0.99), and HDS (0.29 < h
op
2< 0.92; 0.32 < h
R
2< 0.95). The h
2estimates for AUDPC/day were higher than for AUDPC and HDS. Estimates of h
R
2were by and large higher than h
op
2in the same cross. A weak negative or nonsignificant correlation of spot blotch score with HKW, DH, DM, and PHT indicated
that independent selection for resistance and these agronomic traits is possible. 相似文献
2.
Improvement of the nutritive value of timothy (Phleum pratense L.) through breeding should result in enhanced livestock productivity. This study investigated the extent of genotype × crop
interaction (G × C) between the first and second crops, and the extent of genotype × year interaction (G × Y) and narrow-sense
heritability (h
N2) of the second crop of the nutritive value of timothy. Twenty-six clones were used to evaluate these interactions in 2007
and 2008, and 17 clones and their half-sib progeny were used to evaluate the h
N2 in 2010 in Kunneppu, Japan by analyzing their nutritive value. The content of water-soluble carbohydrate (WSC) was significantly
correlated between the two crops in 12 clones with many internode elongation stems (IES) in the second crop and the 2 years,
with non-significant effects of G × C in these clones and G × Y. However, the low-digestible fiber (Ob) content and the ratio
of Ob to organic cell wall showed weak to medium correlations between the two crops, regardless of IES ratio or the elapsed
time of 2 years, with significant effects shown for the two interactions. The h
N2 of the three traits was medium to high. These results suggest that, in the second crop, selections for WSC content through
the first crop in genotypes with many IES in the second crop, and under multiple environments in other traits are potentially
useful; and that recurrent selection which utilizes an additive genetic variance is likely to be effective for the three traits. 相似文献
3.
H. Walther 《Plant Breeding》1990,105(1):53-61
A yield-based assessment procedure for breeding for resistance to Septoria nodorum (SN) is presented. Artificially infected as well as fungicide-protected plots were analyzed for each genotype. Considerable increase in precision of disease scores was gained by using an assessment matrix for different plant organs and time intervals during disease development. This technique resulted in yield loss: disease attack correlations up to r = 0.85:** and raised coefficients of heritability (h2b= broad sense heritability) with h2b= 0.72 for % yield loss and h2b= 0.86 for SN-attack, calculated for a 3-year replicated field experiment with 105 winter wheat cultivars. 相似文献
4.
A. Elgersma 《Euphytica》1990,51(2):163-171
Summary Seed yield in perennial ryegrass is low and unpredictable. Spaced-plant traits suitable for indirect selection for total seed yield in drilled plots would be very useful. The objectives of this investigation were to evaluate genetic variation for seed yield components and other traits among clones from three perennial ryegrass cultivars differing in seed yield and their open-pollinated progenies. Per cultivar, a random set of 50 genotypes was cloned and on each genotype seed was generated by open pollination. Clonal ramets of the parents were observed for 17 traits in 1986 at two locations. In 1987 and 1988, parents and progenies were observed as single plants in a randomized complete block design with two replications. There was little cultivar-environment interaction for most traits. The parents differed significantly for almost all traits. Half-sib (HS) families differed for only three to five traits. Broad-sense heritabilities (h2
b), based on variance components of the parents, were moderate to high; earliness had the highest hb
2. Narrow-sense heritabilities (h2
n), based on variance components among HS-families, were low to moderate and mostly not significant; for most traits h2
n estimates varied between years and cultivars. Flag leaf width and date of first anthesis showed the highest h2
n. Narrow-sense heritability estimates from parent-offspring regressions (h2
nPO) ranged from non-significant to high, depending on year and cultivar; they were generally higher than the corresponding h2
n estimates. Generally, h2
nPO was highest for earliness, flag leaf width, ear length and the number of spikelets per ear. Breeding methods that capitalize on additive genetic variance, such as mass selection, should result in improvement for these traits. 相似文献
5.
Tef is a staple cereal of Ethiopia in high demand by consumers. In order to cope up with this high consumer demand, productivity
per unit of land must increase through the development and use of high-yielding varieties. To this effect, the National Tef
Research Project has long been striving towards the development of high yielding varieties through direct selection from germplasm
and concentrating favourable alleles through hybridization and selection, despite the tedious crossing technique. The objective
of this study was to assess the degree of genetic variation in F2 populations of tef as a basis for improving grain yield. F2 populations from 12 crosses and their parents were grown at the Debre Zeit Agricultural Research Center, Ethiopia, and assessment
was made on eight traits on individual plant basis. Eleven of the 12 crosses showed substantial genetic variation for grain
yield and its components, indicating the potential for improvement through selection. Moreover, grain yield, plant weight
and yield related traits showed moderate to high heritability values (17–80%). In all the crosses, tiller number, panicle
weight, yield per panicle and panicle length showed significant (P ≤ 0.05) and positive association with grain yield. Considering the degree of genetic variation and heritability values, emphasis
should be given to selected crosses in an effort to developing high-yielding tef varieties. 相似文献
6.
The present investigation was carried out to estimate the interrelationships and repeatabilities of various variability parameters,
i.e., genotypic (σ2g) and phenotypic (σ2p) variances, genotypic (GCV) and phenotypic (PCV) coefficients of variation, broad-sense heritability (hb2), genetic advance (GA), and genetic gain (GG), using data derived from a number of plant characters [seed yield (SY), days
to heading (DH) and maturity (DM), plant height (PH), and thousand kernel weight (TKW)] of 17 spring safflower genotypes grown
in 27 environments in Iran during 2003–2005. The analysis of variance for the five characters revealed significant differences
among the genotypes in most of the environments, indicating a very high variability within the genotype. High genotypic and
phenotypic variances in the quantitative traits, particularly for SY, were markers of increased success. A close correlation
between GCV and PCV was observed for all the traits, indicating that all of the characters were less influenced by the environment
and that the variability which exists in these characters is under genetic influence; however, the relatively higher values
of PCV indicate the predominant role of environment. High expected genetic advances were observed for SY, but this trait showed
large fluctuations in different environments (97.4%). High and low mean values of heritability were observed for DH (74.3%)
and SY (59.7%), respectively, whereas high and low mean values of genetic gain were found for SY (60.3%) and DM (4.2%), respectively.
High heritability coupled with low GA as a percentage of the mean was observed for DH and MD, whereas moderate heritability
with moderate GA as a percentage of the mean was exhibited for SY. Analysis of correlation among the parameters showed that
they were strongly and constantly correlated with each other, but none of them were consistently well correlated with the
heritability parameter (hb2). Based on estimates of the genetic variability parameters within each trial, the ranking of genotypes in the low-performance
subset for all traits differed from that in the high-performance subset. This result indicates poor repeatability for the
genetic variability parameters. The estimates of the parameters in the multi-year trials were almost constant and repeatable,
whereas the responses over years showed poor repeatability. 相似文献
7.
The purpose of the study was to evaluate the relationship between the genetic distances (GD) and phenotypic distances (PD)
of parents and the specific combining ability (SCA) and heterosis effects. The experiment comprised 18 parental genotypes
of wheat (Triticum aestivum L.) and 76 F2 hybrids, obtained after crossing in a line × tester scheme. Parents and hybrids were examined in a field experiment conducted
in a block design with three replications. SCA as well as mid-parent heterosis effects were estimated for selected morphological
and technological traits. PDs and GDs were investigated between pairs of parental genotypes. GD between parental genotypes
was evaluated by using randomly amplified polymorphic DNA markers. Heterosis was observed in all hybrids, and protein content
exhibited the highest heterosis among the seven examined traits. The relationship between PD and GD as well as the SCA and
mid-parent heterosis effects were evaluated using correlation coefficient. The correlation between PD, SCA and heterosis were
low and not significant for the examined traits, whereas the correlation between SCA, heterosis and GDs were significant for
protein content and rheological properties. The results indicate that GDs between parents can be used to predict performance
of hybrids for selected technological traits. 相似文献
8.
Near isogenic lines (NILs) varying for genes for reduced height (Rht) and photoperiod insensitivity (Ppd-D1a) in a cv. Mercia background (rht (tall), Rht-B1b, Rht-D1b, Rht-B1c, Rht8c + Ppd-D1a, Rht-D1c, Rht12) were compared at one field site but within contrasting (‘organic’ vs. ‘conventional’) rotational and agronomic contexts,
in each of 3 years. In the final year, further NILs (rht (tall), Rht-B1b, Rht-D1b, Rht-B1c, Rht-B1b + Rht-D1b, Rht-D1b + Rht-B1c) in both Maris Huntsman and Maris Widgeon backgrounds were added together with 64 lines of a doubled haploid (DH) population
[Savannah (Rht-D1b) × Renesansa (Rht-8c + Ppd-D1a)]. Assessments included laboratory tests of germination and coleoptile length, and various field measurements of crop growth
between emergence and pre jointing [plant population, tillering, leaf length, ground cover (GC), interception of photosynthetically
active radiation (PAR), crop dry matter (DM) and nitrogen accumulation (N), far red: red reflectance ratio (FR:R), crop height,
and weed dry matter]. All of the dwarfing alleles except Rht12 in the Mercia background and Rht8c in the DHs were associated with reduced coleoptile length. Most of the dwarfing alleles (depending on background) reduced
seed viability. Severe dwarfing alleles (Rht-B1c, Rht-D1c and Rht12) were routinely associated with fewer plant numbers and reduced early crop growth (GC, PAR, DM, N, FR:R), and in 1 year,
increased weed DM. In the Mercia background and the DHs the semi-dwarfing allele Rht-D1b was also sometimes associated with reductions in early crop growth; no such negative effects were associated with the marker
for Rht8c. When significant interactions between cropping system and genotype did occur it was because differences between lines were
more exaggerated in the organic system than in the conventional system. Ppd-D1a was associated positively with plant numbers surviving the winter and early crop growth (GC, FR:R, DM, N, PAR, height), and
was the most significant locus in a QTL analysis. We conclude that, within these environmental and system contexts, genes
moderating development are likely to be more important in influencing early resource capture than using Rht8c as an alternative semi-dwarfing gene to Rht-D1b. 相似文献
9.
Light interception and radiation use efficiency in temperate quinoa (Chenopodium quinoa Willd.) cultivars 总被引：1，自引：0，他引：1
Sea level quinoas are grown at low altitudes in Central and Southern Chile. Both sensitivity to photoperiod and response to temperature largely determine quinoa adaptation, but crop biomass production must be quantified to evaluate agronomic performance. The objectives of this work are: (i) to characterize development effects on leaf area evolution for genotypes of sea level quinoa differing in cycle length, (ii) to quantify the extinction coefficient (k) for photosynthetically active radiation (PAR) and radiation use efficiency (RUE) from emergence up to the beginning of grain filling and (iii) to identify which crop attributes related to canopy architecture should be considered to improve biomass production. Four cultivars (NL-6, RU-5, CO-407 and Faro) were cropped in Pergamino (33°56′S, 60°35′W, 65 m a.s.l.), Argentina, at three densities (from 22 to 66 plants m−2) in two consecutive years under field conditions with adequate water and nutrient supply. Thermal time to first anthesis and maximum leaf number on the main stem were linearly correlated (r2 = 0.87; p < 0.0001). Leaf area continued to increase during the flowering phase, notably in NL-6, the earliest genotype. There were significant differences in maximum plant leaf area between cultivars. Increasing density reduced plant leaf area but effects were comparatively small. Estimated k was 0.59 ± 0.02 across genotypes and was higher (p < 0.05) for 66 plants m−2. Values for RUE changed as cumulative intercepted PAR (IPAR) increased; at initial stages of development RUE was 1.25 ± 0.09 g MJ IPAR−1, but if cumulative IPAR was higher than 107.5 ± 10.4 MJ IPAR m−2, RUE was 2.68 ± 0.15 g MJ IPAR−1. That change occurred when leaf area index (LAI) and fraction of PAR intercepted were still low and ranged from 0.61 to 1.38 and from 0.33 to 0.51, respectively. No significant association was found with any developmental stage. Our results agreed to the notion that RUE variation during pre-anthesis phases is largely determined by LAI through its effect on radiation distribution within the canopy. Biomass production could be improved if periods of interception below 50% of incoming PAR were reduced to ensure high RUE. This seems to be possible in temperate areas both by the use of late genotypes with a higher number of leaves on the main stem and by early genotypes provided adequate plant density is chosen. Early increment in LAI and overlapping of the leaf area increase period with the flowering phase are desirable strategies for earliest genotypes to maximize yield. 相似文献
10.
An additive-dominance, additive × additive (ADAA) and genotype × environment interaction mix model was used to study the genetic
control of β-carotene and l-ascorbic acid in six basic generations (P1, P2, F1, F2, BC1P1 and BC1P2) of tomato derived from the cross CDP8779 accession (Solanum lycopersicum L.) × CDP4777 accession (S. lycopersicum var. cerasiforme). The study was performed in two environments: (1) open field; (2) protected environment, consisting of hydroponic cultivation
in a glasshouse. The results indicate that β-carotene accumulation was mainly additive (32.2% of the genetic component), with
a small dominant component (4.2%) and an important additive × environment interaction contribution (63.6%). In target environments
with moderate to high temperatures and no limiting radiation, this the expression additive × environment interaction could
substantially enhance the β-carotene content. This trait showed also a high narrow-sense heritability (h
2 = 0.62). Ascorbic acid accumulation was also mainly additive (61.7% of the genetic component), with a minor additive epistatic
component (21.5%). This epistatic effect caused a negative heterosis that reduced the positive main additive effect. Nevertheless,
in the described target environments, the additive × environment interaction contribution (16.8%) may enhance the ascorbic
acid content and compensate for the negative heterosis effect. The total narrow-sense heritability of this trait can be considered
useful (h
2 = 0.52). In conclusion, the CDP4777 accession is a very interesting donor parent for the joint improvement of β-carotene
(without diminishing lycopene content) and ascorbic acid content in commercial nutraceutical tomato breeding programmes; the
F1 hybrids derived from this accession showed nearly 450% of the commonly reported average β-carotene content and close to 130%
of the ascorbic acid content of the female parent. 相似文献
11.
Sreedhar Alwala Collins A. Kimbeng John C. Veremis Kenneth A. Gravois 《Euphytica》2009,167(1):127-142
The cultivated sugarcane (Saccharum spp. hybrids, 2n = 100–130) is one crop for which interspecific hybridization involving wild germplasm has provided a major breakthrough in
its improvement. Few clones were used in the initial hybridization event leading to a narrow genetic base for continued cultivar
development. Molecular breeding would facilitate the identification and introgression of novel alleles/genes from the wild
germplasm into cultivated sugarcane. We report the identification of molecular markers associated with sugar-related traits
using an F1 population derived from a cross between S. officinarum ‘Louisiana Striped’ × S. spontaneum ‘SES 147B’, the two major progenitor species of cultivated sugarcane. Genetic linkage maps of the S. officinarum and S. spontaneum parents were produced using the AFLP, SRAP and TRAP molecular marker techniques. The mapping population was evaluated for
sugar-related traits namely, Brix (B) and pol (P) at the early (E) and late (L) plant growing season in the plant cane (04)
and first ratoon (05) crops (04EB, 04LB, 04LP, 05EB and 05EP). For S. officinarum, combined across all the traits, a total of 30 putative QTLs was observed with LOD scores ranging from 2.51 to 7.48. The
phenotypic variation (adj. R2) explained by all QTLs per trait ranged from 22.1% (04LP) to 48.4% (04EB). For S. spontaneum, a total of 11 putative QTLs was observed with LOD scores ranging from 2.62 to 4.70 and adj. R2 ranging from 9.3% (04LP) to 43.0% (04LB). Nine digenic interactions (iQTL) were observed in S. officinarum whereas only three were observed in S. spontaneum. About half of the QTLs contributed by both progenitor species were associated with effects on the trait that was contrary
to expectations based on the phenotype of the parent contributing the allele. Quantitative trait loci and their associated
effects were consistent across crop-years and growing seasons with very few QTLs being unique to the early season. When the
data were reanalyzed using the non-parametric discriminant analysis (DA) approach, significant marker-trait associations were
detected for markers that were either identical to or in the vicinity of markers previously identified using the traditional
QTL approach. Discriminant analysis also pointed to previously unidentified markers some of which remained unlinked on the
map. These preliminary results suggest that DA could be used as a complementary approach to traditional QTL analysis in a
crop like sugarcane for which saturated linkage maps are unavailable or difficult to obtain. 相似文献
12.
Heritability of quantitative traits in segregating common bean families using a Bayesian approach 总被引：1，自引：1，他引：0
Maria Celeste Gonçalves-Vidigal Freddy Mora Thaís Souto Bignotto Roxelle Ethienne Ferreira Munhoz Lara Daniela de Souza 《Euphytica》2008,164(2):551-560
Genetic parameters for six quantitative traits in the early generation of segregating populations of common beans (Phaseolus vulgaris L.) were evaluated. A Bayesian approach was used for estimating the variance components, breeding values and broad sense
heritability of the quantitative traits under analysis. The Markov Chain Monte Carlo method was utilized to analyze the contribution
of genes affecting complex traits. Twenty-four F3 families were evaluated in the field during 2005 in Santa Catarina, southern Brazil. With regard to the grain yield and yield
components, the additive variances were relatively similar to the dominance variances. This result is confirmed by the 95%
credible set from the posterior distribution. The mean estimates of broad-sense heritability (H2) varied from 11.5% to 64.2%. The heritability estimates of yield and yield components were higher than the estimates for
the number of days until flowering and reproductive period. However, for grain yield, the 95% heritability credible set included
the heritability estimates from point of crop duration. The predicted genetic gain reached the highest value for the number
of pods per plant (10.95%). Days to flowering and reproductive period had the lowest values of genetic advance. One hundred
seed-weight, grain yield and seeds per pod exhibited a similar predictable level of genetic gain: GA = 5.73%, 5.81% and 4.77%,
respectively. The Bayesian framework provided information that is useful for a breeding program, since it contributes to the
understanding of how quantitative traits are genetically controlled. 相似文献
13.
This study has been conducted to evaluate the usefulness of carbon isotope discrimination (δ) in mature kernels as a criterion for the improvement of water-use efficiency and yield under drought in durum wheat. For this purpose, Triticum durum‘Om Rabi 5’ was crossed with T. polonicum pseudochrysospermum 9 (Tp9) which has been found to be more drought tolerant and to have a lower carbon isotope discrimination value of the grain. The F2 population showed a wide segregation for carbon isotope discrimination. Further, divergent selections (selection of plants most different in carbon isotope discrimination) were made among individual F2 plants, and for carbon isotope discrimination in F3 progenies under field conditions. Selected F3 and F4 progenies were evaluated under field conditions for morphological and agronomical traits. Broad-sense heritability (h2b), response to selection and realized heritability (h2r) were high. The narrow-sense heritability (h2n= 0.37 ± 0.047) indicated that additive and dominance effects were involved in the genetic control of carbon isotope discrimination. Negative correlations were noted between carbon isotope discrimination and grain yield and between carbon isotope discrimination and biomass yield within years and generations. An explanation of this result is attempted by analysing the relationships between carbon isotope discrimination and several phenological and morphological traits influencing the water-use efficiency. The divergent groups selected for low and high carbon isotope discrimination exhibited significant differences for days to heading, plant height, shape of the spike and number of spikelets per spike. Correlations were also found between carbon isotope discrimination and plant height, harvest index, shape of the spike, spike length, and number of spikes per plant. The potential use of carbon isotope discrimination as a criterion for the improvement of water-use efficiency in durum wheat is discussed by considering the genetics of this trait (variability, heritability, response to selection) and also the associations with phenological and morphological traits. 相似文献
14.
Angustias Márquez-Lema José M. Fernández-Martínez Begoña Pérez-Vich Leonardo Velasco 《Euphytica》2008,164(2):365-375
The presence of high levels of sinigrin in the seeds represents a serious constraint for the commercial utilisation of Ethiopian
mustard (Brassica carinata A. Braun) meal. The objective of this research was the introgression of genes for low glucosinolate content from B. juncea into B. carinata. BC1F1 seed from crosses between double zero B. juncea line Heera and B. carinata line N2-142 was produced. Simultaneous selection for B. carinata phenotype and low glucosinolate content was conducted from BC1F2 to BC1F4 plant generations. Forty-three BC1F4 derived lines were selected and subject to a detailed phenotypic and molecular evaluation to identify lines with low glucosinolate
content and genetic proximity to B. carinata. Sixteen phenotypic traits and 80 SSR markers were used. Eight BC1F4 derived lines were very close to N2-142 both at the phenotypic and molecular level. Three of them, with average glucosinolate
contents from 52 to 61 micromoles g−1, compared to 35 micromoles g−1 for Heera and 86 micromoles g−1 for N2-142, were selected and evaluated in two additional environments, resulting in average glucosinolate contents from
43 to 56 micromoles g−1, compared to 29 micromoles g−1 for Heera and 84 micromoles g−1 for N2-142. The best line (BCH-1773), with a glucosinolate profile made up of sinigrin (>95%) and a chromosome number of
2n = 34, was further evaluated in two environments (field and pots in open-air conditions). Average glucosinolate contents over
the four environments included in this research were 42, 31 and 74 micromoles g−1 for BCH-1773, Heera and N2-142, respectively. These are the lowest stable levels of glucosinolates reported so far in B. carinata. 相似文献
15.
This study estimated the heritability (h
2) of early blight (EB) resistance in filial progeny of a cross between a susceptible (`NC84173';mid-season maturity) and a
resistant (`NC39E'; late-season maturity)tomato breeding lines. It addition, it examined the potential of identifying progeny
with mid-season maturity and EB resistance. A total of 162F2 plants were grown under field conditions in 1998 and evaluated for disease symptoms three times during the season, and the
area under the disease progress curve (AUDPC) and final percent defoliation (disease severity) were determined. The F2 plants were self-pollinated and F3 seeds produced. The 162 F3 progeny families, consisting of 20 plants per family, were grown in a replicated field trial in 1999 and evaluated for EB
resistance (final percent defoliation) and plant maturity(days to 50% ripe fruit). The distributions of the final percent
defoliation values in the F2 and F3 generations indicated that resistance from `NC39E' was quantitative in nature. Estimates of h
2 for EB resistance, computed as the correlation coefficients between F3progeny family means and F2 individual plant values, ranged from0.65 to 0.71, indicating that EB resistance of `NC39E' was heritable. Across F3 families, a negative correlation (r = –0.46, p< 0.01) was observed between disease severity and earliness in maturity, indicating that plant maturity affected disease severity.
However, several F3 families were identified with considerable EB resistance and mid-season maturity, indicating that resistance from `NC39E'
might be useful for the development of commercially acceptable EB resistant tomato cultivars.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
16.
Summary To improve jute productivity, locating of sources of suitable quantitative-trait genes in the recently acquired world jute collection was needed. Two hundred sixteen accessions of Corchorus capsularis and 192 accessions of C. olitorius were evaluated at a jute seed research station (87°60\s'E, 23°80\s'N) for four yield and quality linked morpho-physiological traits. The objectives were to estimate the germplasm diversity, phenotypic (PCV) and genetic (GCV) coefficients of variation, broad sense heritability (h2) and genetic advance (GA) with respect to origins and traits. Irrespective of origins all the traits showed more than 60–80% diversity in both species. Trait means of diversity were significant but not the origin means. Generally, only slightly higher PCV values than GCV were obtained for all the traits in both the species. High h2 values ranging from 50% to more than 98% were also found. All the traits can be simultaneously utilized for genetic gain. Most of the C. olitorius accessions with two times higher GA estimates than those of the C. capsularis are likely to be more successful for that matter. Maximum genetic gain is expected from Mutants > China > Brazil > India > Thailand > Nepal > Burma in C. capsularis while from Thailand > Tanzania > Mutants > Kenya > Other countries in C. olitorius. C. capsularis mutants with high heterogenity for most of the traits should be useful for finding many rare alleles. 相似文献
17.
Elite cultivars of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) are high in fruit quality but may not be the highest yielders. The objective of this study was
to estimate the heritability of, and genotypic and phenotypic correlations among, yield traits in two watermelon populations
developed from crosses between obsolete cultivars with high yield and elite modern cultivars. Field trials were conducted
at two locations in North Carolina (Clinton and Kinston). The data were analyzed by regressing S0:1 progeny data on S0 parent data to estimate narrow-sense heritability. Narrow-sense heritability estimates were low for all traits measured [total
fruit weight (0.04–0.12), marketable fruit weight (0.06–0.15), total fruit number (0.04–0.16), fruit size (0.18–0.19), and
percent culls (0.02–0.09) in North Carolina Watermelon 1 (NCWP1) and North Carolina Watermelon 2 (NCWP2) populations, respectively].
Estimates of broad-sense heritability were higher than estimates of narrow-sense heritability. Total fruit weight and marketable
fruit weight were highly correlated (r
g = 0.97–1.00). Marketable fruit weight and fruit size used as single selection criteria in NCWP1 and total fruit number in
NCWP2, were predicted to give the best correlated response for total fruit weight. Narrow-sense heritability was low for fruit
yield; therefore, watermelon breeders should select based on replicated progeny rows in multiple environments to maximize
gain. 相似文献
18.
Twenty-one (near) pentaploid hybrids between sexually incompatible Solanum
commersonii [2x(1EBN)] and cultivated S. tuberosum [4x(4EBN)] were characterized for tuber traits and fertility. A number of genotypes resembled the S. tuberosum type in terms of stolon length and eye depth and produced tubers under long day conditions. Tuber yields were not as high
as expected, probably due to lack of adaptation of the S. commersonii genome to the environmental conditions in southern Italy (on average 325 g·pt−1 and 285 g·pt−1 in 2003 and in 2004, respectively). Compared to 2004, in the summer of 2003, characterized by extremely high temperatures,
hybrids gave a higher tuber yield than the S. tuberosum control, suggesting that in our environmental conditions the wild S. commersonii genome, rather than resulting in heterosis for tuber yield, provides better adaptation to harsh environments. Although aneuploidy
has often been associated with reduced fertility, several hybrids were fertile in crosses with S. tuberosum when used as female parents. In particular, the average berry set and number of seeds per berry were 38.2% and 31.8%, respectively.
Based on significant relationships between ploidy levels and all yield and fertility data measured, the presence of extra
chromosome affected the parameters considered: tuber yield in 2003 and 2004, percentage of fruit set, number of seeds per
berry and number of seeds per pollinated flower. Regression analysis also indicated that “Residuals” were significant for
all parameters measured. Therefore, additional factors (e.g. the genetic makeup of hybrids) may be key to fertility and yield. 相似文献
19.
A factorial crossing scheme of Cofflea canephora (two parents from the Congolese group crossed to 14 parents of the Guinean group) was used to evaluate genetic parameters of several biochemical compounds, bean weight and crop outturn (ration of dry bean weight 10 fresh berry weight). For most characters studied, additive genetic effects were preponderant. Narrow-sense heritability was high for caffeine content (h2ns= 0.80), fat matter content (h2ns, = 0.74), bean weight (h2ns= 0.73) and crop outturn (h2ns= 1). It was intermediate for trigonelline (h2ns= 0.38) and chlorogenic acid (h2ns= 0.36) content. Only sucrose content had a low narrow-sense heritability (h2ns=0.11). There were few genetic and enviromnental correlations, Consequences for breeding, in relation to coffee drinking quality, are discussed. 相似文献
20.
Felipe Oliveira Vilela Antonio Teixeira do Amaral Júnior Silvério de Paiva Freitas Júnior Alexandre Pio Viana Messias Gonzaga Pereira Marcelo Geraldo de Morais Silva 《Euphytica》2009,165(1):21-26
With the objective of selecting superior recombinant lines of snap bean, four segregating F2 populations were selected by early generation testing and advanced by single seed descent. In a randomized complete block
design with two replications within sets 120 F6:7 lines were obtained and evaluated for seven traits of agronomic interest. The mean pod yield of the F6:7 generation was 72% higher than in generation F2, confirming the efficiency of early selection. There was genetic variability in the F6:7 lines within the sets. The selection of superior genotypes was possible by the high estimates of narrow-sense heritability.
Highest gains in simultaneous selection of traits were expressed by the indices proposed by Mulamba & Mock for the genetic
standard deviation and by Williams, based on tentatively attributed arbitrary weights. Line 3 of the F6:7 generation, with a yield of 8,050.0000 kg ha−1 and pod fiber content of 0.3650% is highly promising to be release as new cultivar. 相似文献