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1.
Downy mildew (Pseudoperonospora
cubensis) is the most devastating disease in muskmelon (Cucumis
melo). A generation mean analysis study was designed to determine the types of gene action and estimate the heritability for resistance
to downy mildew in four selected crosses of muskmelon. Generation mean analysis revealed that genetic dominance may be of
greater importance for expression of resistance to downy mildew in both greenhouse and field experiments and in all the crosses.
The F1 mean was significantly lesser than the mid-parent value and skewed towards resistant parent in all the crosses. Negative
sign associated with gene effects indicated, in those crosses, that disease level could be decreased in relation to midparent.
All the crosses expressed significant and positive additive (d) gene effects. Dominance (h) and dominance × dominance (l)
gene effects had opposite sign in all crosses and both experiments, which implied duplicate type of gene action. High mid-parent
heterosis in all the crosses indicated strong dominance effects (as combination of parental alleles) for resistance to downy
mildew. In all the crosses, both resistant and susceptible parent contributed one or more dominant/partially dominant factors
for resistance. Estimates of broad-sense heritability were high and relatively consistent in both experiments. The two different
screening experiments showed that fixable gene effects (d + i) were lower than the non-fixable gene effects (h + l) in all
the crosses indicating greater role of non-additive effects in the inheritance of resistance to downy mildew. Resistance to
downy appeared to be controlled mainly by dominance effects, therefore the inbred lines IIHR 121 and IIHR 122 could be used
strategically to exploit heterotic effects. 相似文献
2.
Genetic Analysis of Developmental Traits in Chickpea 总被引：1，自引：0，他引：1
Chickpea (Cicer arietinum L.) is an important legume crop in India. The present study was conducted to investigate the inheritance of several developmental traits in three crosses of chickpea, viz., WFWG III’בT20’, ‘T88’בBold Seeded’, and ‘NP34’בP1528-1-1’, each having seven generations. The seven generations were P1, P2, F1, B1, B2, F2, and F3. The experimental lay-out was randomized complete block design with three replications. Data were acquired on days to flowering (DF), days to maturity (DM), plant height in cm (PH), number of primary branches (PB), and number of secondary branches (SB). Generation mean analysis was used to estimate the genetic components; narrow sense heritability was estimated using variance components; and correlation analysis to estimate correlation coefficients among different traits. Genetic differences were found in all three crosses for all traits studied. Additive, dominance, and epistatic effects were found for many traits'. Duplicate epistasis was observed for all traits except number of PB. Higher order interactions and/or linkage were detected for DM and SB. For many traits the relative magnitudes of the genetic effects differed among crosses, thus the extrapolation to other crosses may be difficult. The inheritance becomes more complex as the fate of the character is decided at a later stage in the life cycle. Positive heterosis was observed for some traits, but the exploitation of this component may not Feasible since stable male sterile lines are not available. Early maturity and high yield ‘may be selected independently because of the absence of any significant correlation between these two traits. 相似文献
3.
Recurrent selection programs can use several crossing arrangements to synthesize basic populations for breeding purposes.
This study evaluated heritability and correlations among traits in forty-five populations of F2[4] and F2:3[4] generations obtained throughout four-way crosses [4] between two dialells among ten semi-late and ten late maturity soybean
(Glycine max L. Merrill) genotypes. The generation advance was made by the TSHD (Thinned Single Hill Descent) method and all individual
plants were evaluated for the following traits: number of days to flowering (NDF) and maturity (NDM), plant height at flowering
(PHF) and maturity (PHM), agronomic value (AV) and seed yield (YLD). Four-way crosses associated with TSHD method provided
high genetic variability in the populations with little or no reduction from F2[4] to F2:3[4]. The ‘narrow sense’ heritability estimated using correlations between F2[4] and F2:3[4] plants was lower than but closely related to broad-sense estimates. The populations 21(IAC-4 × IAC-9) × (GO79-1039 × Paranagoiana)
and 23 (IAC-4 × Santa Rosa) × (GO79-1039 × Tropical) were the most productive with high variability in F2[4] and/or F2:3[4] generations. Genotypic correlations measured were generally high, positive and consistent for the two generations except
for those related to AV and YLD. These results indicate that the use of four-way crosses can be an efficient method to increase
the genetic base of populations for recurrent selection or cultivar development. Significant AV × YLD correlations indicated
visual selection can be used as additional selection criteria for improving populations.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Binaissa U. Levene Castiano Paul K. Kimurto Pascal P. Okwiri Ojwang 《Plant Breeding》2023,142(1):74-85
Root system architecture is important for common bean (Phaseolus vulgaris) adaptability to diverse environments. Beans employ complex adaptive root mechanisms for coping with multiple stresses in production environments. Understanding genetic control of root traits is central to improvement of common bean for adaptation to marginal environments. The objectives of this study were to (i) determine combining ability of root and agronomic traits and (ii) estimate the heritability and genetic correlation of root and agronomic traits in common bean. Four bean lines with superior root traits were crossed with four locally adapted varieties in a North Carolina II mating scheme to generate 16 crosses. The 16 F1s were selfed and advanced to F2 generation. Eight parents and their F2 progenies were evaluated in an alpha-Lattice design with two replications. General and specific combing ability mean squares were significant (p ≤ .05) for all traits measured. General predictability ratios ranged from .47 to .68 across locations suggesting that both additive and non-additive gene action modulate root traits and seed yield. Positive and significant (p ≤ .05) phenotypic and genetic correlations revealed significant association between root traits and yield. Moderate to high heritability estimates of between .43 and .67 were realized. Such estimates point to possible deployment of a successful selection programme. Genotype AFR398 displayed significant positive GCA effects among its crosses for both root and agronomic traits hence a potential candidate genotype for inclusion in a bean genetic improvement programme for marginal environments. 相似文献
5.
Wild Lens species/subspecies are a potential source for increasing genetic diversity in cultivated lentil. Four intraspecific crosses were attempted between cultivated and wild lentils. Viable hybrids were produced between L. culinaris ssp. culinaris × L. culinaris ssp. orientalis and L. culinaris ssp. culinaris × L. culinaris ssp. odomensis. Normal meiosis and pollen fertility were observed in the first set of crosses, whereas chromosomal abnormalities and reduced pollen fertility were observed in the second set of crosses. These crosses were also studied for some quantitative traits. The range, mean and coefficient of variation were calculated in parents, F1, F2 and BC1 generations to determine the extent of variability generated in the cultivated lentil through introgression of genes from wild lentil. The cultivated lentil × L. culinaris ssp. orientalis crosses showed substantially higher variability for all the traits than crosses involving cultivated lentil ×L. culinaris ssp. odomensis. The results of the present study indicated that these wild subspecies can be exploited for breeding purposes and their variation can easily be utilized to widen the genetic base of the cultivated lentil. 相似文献
6.
Fusarium root rot (FRR) is a major disease of common bean worldwide. Knowledge of the inheritance of resistance to FRR would be important
in devising strategies to breed resistant varieties. Therefore, a 12 × 12 full diallel mating scheme with reciprocal crosses
was performed to generate 132 F1 progenies, which were then advanced to the F3. The progenies were evaluated for resistance to FRR under green house conditions in Uganda. General combining ability (GCA)
effects were highly significant (P ≤ 0.01) for disease scores. Specific combining ability effects were not significant (P > 0.05) in the F1, but were highly significant (P < 0.01) in the F3 generation. These results indicate that resistance to FRR was governed by genes with additive effects in combination with
genes with non-additive effects. Reciprocal differences were also significant (P = 0.01) at F1 and F3, primarily reflecting a large influence of maternal effects in both these generations. In fact, susceptible parents did not
differ significantly (P > 0.05) for disease scores when used as paternal parents in the F3, but differed strongly as maternal parents (P = 0.0002). Generally, the progenies were distinctly more resistant when the resistant parent was used as the female in crosses,
especially as observed in the F3. The maternal effects were strong in the F3 generation, suggesting a complex form of cytoplasmic–genetic interaction. The non-maternal reciprocal effects in the F3 were significant (P < 0.05) in both the resistant × resistant diallel, and in the resistant × susceptible crosses. Mid-parent heterosis (MPH)
occurred in most crosses, with average heterosis approximately equal in each of the three generations, indicating that epistasis
was probably more influential than dominance of individual genes. Gene-number formulas indicated that several genes were involved
in resistant × susceptible crosses. Among resistant × resistant crosses, many produced continuous distributions of F1 progeny scores, suggesting polygenic inheritance, while bi-modal distributions were characteristic of the F3 distributions, and fit expected ratios for two or three loci segregating in each cross. Dominant forms of epistasis favoring
resistance were strongly indicated. Parent–offspring heritability estimates were moderate. Overall, the results indicate that
resistant parents contain a number of different resistance genes that can be combined with the expectation of producing strong
and durable resistance. The lines MLB-49-89A, MLB-48-89, RWR719 and Vuninkingi, with large and negative GCA effects, contributed
high levels of resistance in crosses and would be recommended for use in breeding programs. 相似文献
7.
The heritability of tolerance of wheat F3 lines to competition from annual ryegrass (Lolium rigidum), and its relationship to morphological traits, were determined using crosses between wheat cultivars with good and poor
competitive ability. Forty F2-derived F3 lines from a cross between two late flowering varieties (Machete × Spear) and 40 from a cross between early flowering varieties
(Wilgoyne × Gutha) were grown in the field with and without annual ryegrass. There was significant genetic variation between
lines within each of the two populations in a number of aspects of plant growth and development, including yield in monoculture.
The estimates of heritability for % yield loss due to competition were 0.25 and 0.57 in the two crosses respectively, indicating
that selection for high tolerance to competition in the F3 generation or later should be effective. Fairly strong relationships between height and % yield loss and between leaf length
and % yield loss suggest that these may be useful auxiliary traits when selecting for low % yield loss. However, differences
between crosses in the magnitude and sign of genetic and phenotypic correlation between traits indicate that competitive ability
is a complex character influenced by many factors.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
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
9.
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
10.
B. C. Ajay B. N. Gnanesh K. N. Ganapathy M. Byre Gowda P. S. Prasad G. N. Veerakumar S. C. Venkatesha R. Abdul Fiyaz K. T. Ramya 《Euphytica》2012,186(3):705-714
Basic information on genetics and inheritance of quantitative characters, which is necessary to develop future breeding programme, is not widely studied in pigeonpea. Hence, present study was conducted among 5 generations in four pigeonpea crosses to know significance of additive-dominance model, gene action involved in inheritance of quantitative characters, heritability and genetic advance. “Scaling” and “joint scaling test” was significant for most characters indicating that additive-dominance model alone is not enough to explain the inheritance of a character. Though additive variance was more, dominance variance also played important role for most of the traits. Positive and negative alleles were found to be distributed between parents. Additive gene effect (d) was significant for pods per plant and seeds per pod whereas dominance gene effect (h) was more predominant among pod yield and seed yield. Dominance × Dominance inter-allelic interactions (l) was more important than Additive × Additive type (i) for most of the traits studied which could be exploited by selecting individuals based on their performance in recurrent selection. Complementary gene action was observed among many traits with few exhibiting duplicate gene action. Heritability and genetic advance was high indicating the effectiveness of selection. Since dominance effects is also present along with additive effects selection could be practised in later generations to identify high yielding genotypes. 相似文献
11.
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
12.
The genetics of disease resistance, winter hardiness, spring bloom date, fruit set, ovule set, fruit size, and photoperiod
sensitivity was investigated in crosses between sets of elite selections of F. virginiana and F. chiloensis in Minnesota and Ontario. In Minnesota, family means varied considerably for all traits except ovule set. For all other traits,
general combining ability was significant for at least one species, while specific combining ability was significant for only
spring bloom date. In Ontario, general combining ability was significant for all traits in at least one species except flower
number. Just as they were in previous crosses with F. × ananassa cultivars, the F. virginiana parents High Falls 22 and Montreal River 10 were notable for producing offspring with large fruit and high fertility. Fragaria chiloensis parents exhibited strong combining ability effects for short day-induced flowering and suppressed the expression of day-neutral
flowering in these progeny compared to progeny of these F. virginiana in previous crosses with F. × ananassa. These results indicate that substantial breeding progress can be made by reconstructing F. × ananassa if care is taken to select elite, complementary genotypes of F. virginiana and F. chiloensis. 相似文献
13.
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
14.
Indica-japonica hybridization is an important approach for developing superior performing hybrids in rice (Oryza sativa L.). In view of the scanty information available on cooking quality characters in indica-japonica crosses, an investigation was undertaken to estimate genetic and genotype × environment variance and covariance components
of amylose content, gel consistency and alkali digestion value, and to determine the relative importance of direct genetic
effects, maternal genetic effects and cytoplasmic effects in the genetic variations of the three quality characters. Two indica photo-sensitive genic male sterile (PGMS) lines and four japonica varieties were used as parents to make crosses. Genetic model with genotype × environment interactions for triploid endosperm
was used for genetic studies of the three cooking quality characters. Variance component analysis revealed that genetic variations
of the three characters were mainly attributable to direct additive and maternal additive effects, and the three traits had
significant direct and maternal heritabilities. Genotype × environment interactions were mainly dominance × environment (including
direct dominance × environment and maternal dominance × environment) and cytoplasm × environment interactions. Environment
factors could only affect the expression extent of dominant genes, without changing their directions. Predicted values of
genetic effects indicated that the parental lines, ‘VI-70’ and ‘H9304-1’, appeared to be best for amylose content, ‘T 1950’
and ‘Suxuan’ appeared to be best for gel consistency and alkali digestion value.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Eight cross combinations of Zinnia elegans were made using two recessive nuclear male sterile lines crossed with four restorers using the North Carolina Design II statistical
method. Heterosis, combining ability and heritability was analysed using 12 horticultural traits and these demonstrated the
advantage of heterosis in hybrid breeding of Zinnia elegans. Heterosis served to increase the number of whorls of ray florets across capitulum and the number of branches, and also decreased
plant height, crown size, pedicel length and length of node. Thus, six horticultural traits were improved over mid parent
and best parent status to fulfill major breeding goals of this herbaceous flower. The traits of plant height, number of whorls
of ray florets across capitulum and pedicel length were primarily controlled by paternal additive effects, whereas crown size
was mainly controlled by non-additive effects. Number of branches and length of node were affected both by paternal additive
effects and non-additive effects. The ratio of general combining ability to specific combining ability indicated the importance
of additive genes in the expression of these traits. Among the parental lines, AH003A and restorer A3 were chosen as primary
female and male combiners, respectively. AH001A and restorer S5 were chosen as secondary combiners. The cross AH003A × A3
was determined as the most promising combination for producing potted plant characteristics, and AH001A × S5 was the best
hybrid obtained in this study for cut flower traits. The analysis of combining ability for the parental lines showed that
there was no causal relationship between general combining ability and specific combining ability effects. 相似文献
16.
Hamid Khazaei Damian Wach Alicja Pecio Albert Vandenberg Frederick L. Stoddard 《Plant Breeding》2019,138(6):761-769
Increasing productivity through improvement of photosynthesis in faba bean breeding programmes requires understanding of the genetic control of photosynthesis‐related traits. Hence, we investigated the gene action of leaf area, gas exchange traits, canopy temperature, chlorophyll content, chlorophyll fluorescence parameters and biomass. We chose inbred lines derived from cultivars 'Aurora' (Sweden) and 'Mélodie' (France) along with an Andean accession, ILB 938, crossed them (Aurora/2 × Mélodie/2, ILB 938/2 × Aurora/2 and Mélodie/2 × ILB 938/2), and prepared the six standard generations for quantitative analysis (P1, P2, F1, F2, B1, and B2). Gene action was complex for each trait, involving additive and dominance gene actions and interactions. Additive gene action was important for SPAD, photosynthetic rate, stomatal conductance and Fv/Fm. Dominance effect was important for biomass production. It is suggested that breeders selecting for productivity can maximize genetic gain by selecting early generations for canopy temperature, SPAD and Fv/Fm, then later generations for biomass. The information on genetics of various contributing traits of photosynthesis will assist plant breeders in choosing an appropriate breeding strategy for enhancing productivity in faba bean. 相似文献
17.
G. A. Owusu D. Nyadanu K. Obeng-Antwi R. Adu Amoah F. C. Danso S. Amissah 《Euphytica》2017,213(12):287
Maize (Zea mays L.) is the most important cereal crop produced in Ghana. However, yield of the crop is generally low, producing just about 1.7 t/ha. The low yield is attributed to continuous use of local/unimproved varieties. Generally, hybrid varieties have proven to out-yield the local/unimproved varieties due to improved vigour. Development of hybrid varieties depend on good understanding of combining ability and inheritance of important quantitative traits such as grain yield (GY). 45 half-diallel crosses generated from 10 extra-early maturing yellow inbred lines were evaluated in 2015 under rain-fed conditions. The objectives were to determine the genetic control, breeding value and estimate heritability for GY and agronomic traits of the inbred lines under contrasting growing environments in Ghana. General combining ability (GCA) and specific combining ability (SCA) were important in the inheritance of GY and agronomic traits of the inbred lines. However, GCA was more important than SCA across environments to suggest that additive gene action was more important than non-additive gene action in the inheritance of GY and agronomic traits in the inbred lines. High broad-sense heritability, for GY and other agronomic traits indicated preponderance of additive gene action in trait expression, thus, selection based on phenotypic expression could be feasible. Inbred lines P1, P4 and P8 were good combiners for high GY. The genotype, P4 × P8, was identified as the ideal and most yielding single-cross hybrid across research environments and should be further tested on-farm before commercialization. 相似文献
18.
Devastating maize grain yield and quality losses are caused by Aspergillus flavus, Fusarium verticillioides and Stenocarpella maydis ear rots especially in tropical countries. Therefore, combining ability of tropical maize populations for ear rot severity
and ear rot-related traits was investigated. Ten full-sib progenies, comprising one resistant and one susceptible from each
of the five populations, were selected for mating in a 10 × 10 full diallel. The full-sib progeny crosses were evaluated across
two environments with two replications in Zambia. To determine resistance across three ear rots that occur together in Zambia,
the crosses were artificially inoculated with a mixture of Aspergillus flavus, Fusarium verticillioides and Stenocarpella maydis isolates. There were marked differences between environment main effects and their interaction with GCA and SCA effects were
highly significant, suggesting observation of genotype × environment interaction effects. Both additive and non-additive gene
effects were significant for ear rot severity. Highly significant reciprocal differences were also revealed, suggesting that
cytoplasmic gene effects and their interaction with nuclear genes were responsible in modifying resistance across the three
ear rot diseases in the full-sib progenies that were derived from the five tropical maize populations. 相似文献
19.
Jing wen Jin-xing Tu Zai-yun Li Ting-dong Fu Chao-zhi Ma Jin-xiong Shen 《Euphytica》2008,162(1):81-89
The primary aim of this study was to optimize in vitro culture protocols to establish an efficient reproducible culture system
for different Brassica interspecific crosses, and to synthesize yellow-seeded Brassica napus (AACC) for breeding and genetical studies. Reciprocal crosses were carried out between three B. rapa L. ssp. oleifera varieties (AA) and five accessions of B. oleracea var. acephala (CC). All the parental lines were yellow-seeded except one accession of B. oleracea. Hybrids were obtained through either ovary culture from crosses B. rapa × B. oleracea, or embryo culture from crosses B. oleracea × B. rapa. A higher rate of hybrid production was recorded when ovaries were cultured at 4–7 days after pollination (DAP). Of different
culture media, medium E (MS with half strength macronutrients) showed good response for ovaries from all the crosses, the
highest rate of hybrid production reaching 45% in B. rapa (1151) × B. oleracea (T2). In embryo culture, the hybrid rate was significantly enhanced at 16–18 DAP, up to 48.1% in B. oleracea (T3) × B. rapa (JB2). The combinations of optimal DAP for excision and media components increased recovery of hybrids for ovary and embryo culture,
and constituted an improved technique for B. rapa × B. oleracea crosses. In addition, yellow seeds were obtained from progenies of two crosses, indicating the feasibility of developing yellow-seeded
B. napus through the hybridization between yellow-seeded diploids B. rapa and B. oleracea var. acephala. 相似文献
20.
Combining ability analysis and association of yield and yield components among selected cowpea lines 总被引：1，自引：0，他引：1
The study was carried out to determine combining ability and association of yield and yield components among crosses derived
from seven selected cowpea (Vigna unguiculata (L.) Walp) parents. Twenty-one hybrids were generated from diallel crosses excluding reciprocals. Hybrids along with seven
parents were studied for combining ability and phenotypic correlations for seed yield and eight yield components. The result
indicated that the general combining ability (gca) and specific combining ability (sca) were significant for most characters indicating the importance of both additive and non-additive genetic components. Additive
gene action was important for eight characters except pod number, whereas non-additive gene action was not important for nodule
number and grain yield. Parental lines IT86D-716 and IT81D-985 were found to be good general combiners for grain yield and
other traits. The most promising specific combiners for yield and yield components were from crosses including IT87D-697-2 × IT86D-716,
IT88D-867-11 × IT86D-716, IT93K-624 × IT87D-697-2, and IT87D-697-2 × IT92KD-405-1. Significant positive phenotypic correlations
were observed between seed yield with pod length (POL), number of pods per plant (PON), and number of seeds per pod (SPD).
POL, pod number per plant, SPD, and grain yield were identified as the best selection criteria that could be used in cowpea
breeding programs. 相似文献