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1.
The quantity of N2 fixed in common bean (Phaseolus vulgaris L.) is a quantitatively inherited trait that shows sufficient genetic variability for improvement through breeding, but there is little information on gain from selection for 15N-determined N2 fixation ability. The objective was to determine whether intrapopulation recombination and selection could be used to improve N2 fixation. Four agronomically acceptable lines were selected, based on their acetylene reduction-determined N2 fixation ability, from an inbred backcross (IB) line population created from a cross between the high N2-fixing donor parent ‘Puebla 152’ and a commercial, low N2-fixing recurrent parent ‘Sanilac’. These four IB lines were intercrossed, advanced to the F3, and the six resulting F3 populations with 25 F3 families per population were evaluated for N2 fixation in a low-N field using 15N-depleted (NH4)2SO4. The six F3 population means differed significantly and were superior to ‘Sanilac’ for N2 fixation ability and yield, indicating significant improvement over ‘Sanilac’. Four F3 population means were similar to ‘Puebla 152’, indicating selection advance towards high N2 fixation while retaining favorable agronomic characteristics. Fifty percent of the F3 families were superior to ‘Sanilac’ for N2 fixation and one family exceeded ‘Puebla 152’, indicating that intrapopulation recombination produced improvement of 15N-determined N2 fixation. 相似文献
2.
Breeding for high symbiotic nitrogen (N) fixation (SNF) in common bean (Phaseolus vulgaris L.) is expected to contribute to reduced application of chemical fertilizers in cropping systems involving common bean. The magnitude of variation and the genetic and phenotypic correlation among seed yield, SNF, estimated as the percentage of nitrogen derived from atmosphere, and related traits were studied in a population of 140 F4-derived F5 recombinant inbred lines, developed from a cross between low- and high-SNF bean genotypes ‘Sanilac’ and ‘Mist’, respectively. The experiment was conducted in a total of five location-years in Ontario, Canada, from 2011 to 2013. These location-years were grouped into stress- and optimum moisture test sites, based on the total precipitation during the growing season. In each test site two nitrogen supply management strategies, SNF-dependent and N fertilizer-dependent, were simulated separately in the field by inoculating the seed with a commercial Rhizobium leguminosarum bv. phaseoli and by application of N fertilizers at 100 kg ha?1, respectively. The genetic variation was significant for seed yield, SNF and related traits. The heritability of the traits ranged from 14 to 71% and 4 to 25% in optimum moisture and in stress environments, respectively. No significant correlation between SNF and seed yield indicated that selection for high SNF does not necessarily lead to greater seed yield and that selection for both traits should be performed simultaneously. 相似文献
3.
Genetic variance, heritability, and expected response from selection arc useful in devising alternative methods and criteria of: selection. The objectives of this study were to estimate these for seed yield and its components from 200 F2: populations involving 80 cultivars and lines of mostly small-seeded dry bush bean (Phaseolus vulgaris L.) of habits growth I, II, and III of Middle-American origin. All cultivars and lines were crossed in eight sets of ten parents each in a Design II mating system. The F2 populations, without parents, were evaluated in the field in a replicates-in-sets design at two locations in Colombia in 1983. Estimates of additive genetic variance were significant for yield, pods/m2, seeds/pod, and seed weight. Interaction with environments was also significant. Values for nonadditive genetic variance were not significant for either yield or yield components. The estimates of narrow sense heritability, based on the F2 population mean and unbiased by genotype x environment interaction, were 0.21 ± 0.13 for yield. 20 ± 0.13 for pods/m2, 0.57 ± 0.13 for seeds/pod, and 0.74 ± 0.15 for seed weight. The expected direct response from selection of the top 20 % of F2 populations for yield per se would result in a 4.30 % increase in yield with a correlated response of 0.21 % in seed weight. In contrast, the expected gain from direct selection for seed weight would result in a 11.76 % increase in seed weight with a, correlated gain of 0.28 % for yield. Direct selection for pods/m2 would decrease yield, seeds/pod and seed weight, while direct selection for seeds/pod would reduce pods/m2 and seed weight but increase seed yield by 0.37 %. Data on yield from replicated trials in the early segregating generations could be utilized for identification and selection of promising crosses and families or lines with crosses for dry bean yield improvement. 相似文献
4.
Heritability analysis for cold tolerance in lentil was conducted using parental, F2 and F3 populations at two locations in Balochistan, Pakistan and one controlled environment in Fort Collins, Colorado, USA. Populations of parental and F2 families were grown over 2 years (1991‐92 and 1992‐93) at Quetta, Balochistan, Pakistan. In 1992‐93, parental and F3 families were studied at Quetta, and Kalat, Balochistan, Pakistan. Evaluation for normality using non‐transformed and log‐transformed data failed. Attempts to use analysis of variance were then abandoned in favour of parent‐offspring regression for narrow‐sense heritability. Estimates of narrow‐sense heritability ranged from 0.31±0.06 to 0.71 ± 0.06 under field conditions. Under controlled conditions, the estimated heritability was maximized at 1.00 ± 0.17 using 6‐ to 8‐week‐old lentils. Significant transgressive segregants were found in five of the six populations in the F3 generation. Transgressive segregants appeared in the controlled F3 generation but were not observed in field environments. This indicates that cold tolerance is under additive gene control and is environmentally sensitive in gene expression. 相似文献
5.
大豆籽粒大小与形状性状的QTL定位 总被引：2，自引：0，他引：2
大豆籽粒大小和粒形性状不仅与产量和外观品量紧密相关,还对机械化播种有着一定的影响。本研究采用大粒栽培品种冀豆12与小粒半野生地方品种黑豆(ZDD03651)杂交衍生的包含188个重组自交系的F6:8和F6:9群体为材料,对粒长、粒宽、粒厚、长宽比、长厚比和宽厚比的遗传结构进行分析,并分别以WinQTLCart 2.5、QTLNetwork 2.1和IciMapping 4.1 3种模型对以上性状的加性效应QTL,QE互作效应及上位性互作效应进行检测。6个性状的广义遗传率介于64.01%~79.57%,遗传力较高,且除粒厚外的其他性状受环境影响显著。共定位到加性效应QTL38个,单个QTL的贡献率介于2.21%~10.71%之间,分布在12条染色体的17个标记区间内,且12个染色体区段至少与两种性状相关。两种及以上模型同时检测到的QTL有24个,3种模型均能检测到的QTL共8个,分别为qSL-17-1、qSL-18-1、qSW-6-1、qST-2-1、qST-6-1、qSLT-2-2、qSWT-2-1和qSWT-20-1。检测到7对上位性互作QTL,分别涉及粒长、粒宽、长宽比、长厚比和宽厚比,互作效应贡献率介于0.78%~6.20%之间。QE互作效应贡献率均较低,介于0.0005%~0.3900%之间。以多种模型同时检测结果准确性较高,可为分子标记辅助育种工作提供可靠理论基础。 相似文献
6.
Summary To satisfy farmer and consumer preferences, breeding efforts to increase yield potential in common bean must take into account the interrelated effects of growth habit, seed size, maturity, and gene pool on yield expression in segregating populations. To examine the relationships among these traits, a genetic study was conducted to determine the effect of growth habit on yield and seed size in crosses among five bean lines from diverse gene pools. Two parental bean lines had determinate, type I growth habits and large seed size typical of the Neuva Granada-Andean gene pool. Two other lines were tropical Mesoamerican types with type II growth habits and small seed size; and the fifth line, G13625, a landrace of the Jalisco gene pool from the Mexican highlands, had a type IV climbing growth habit and medium seed size. Individual F2 plants from each cross and parental lines were evaluated for growth habit and yield component traits under high input field conditions. The following season, the evaluations were repeated on random F3 plants. Of the five parental lines, only G13625 showed significant GCA effects for yield in both the F2 and F3 generations. Improved yielding ability of G13625 progeny was associated with an increased expression of climbing bean growth habit traits: guide length, climbing ability, node number on main stem, and plant height. Crosses between Andean x Mesoamerican and Andean x Jalisco genotypes, as well between growth habit type I (Andean x Andean) and between type II (Mesoamerican x Mesoamerican) had very low parent-offspring heritability values for yield. Yield heritability was only significant for crosses between Mesomerican x Jalisco gene pools. An apparent simple genetic control of growth habit modification towards semi-climbing and climbing types is proposed as the major reason for increased yields in these crosses. No genetic linkage between genes controlling growth habit and seed size was detected which might restrict the development of high yielding large-seeded type II lines. 相似文献
7.
The consumption of products made from Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) has increased in recent years in Japan. Increased consumer demand has led to recognition of the need for early varieties of this crop with high and stable yields. In order to accomplish this, more information is needed on the genetic mechanisms affecting earliness and yield. We conducted genetic analysis of 3 agronomic traits (days to flowering, plant height and total seed weight per plant) to segregate F2 and F3 populations derived from a cross between Tartary buckwheat cultivars ‘Hokuriku No. 4’ and ‘Ishisoba’. Broad-sense heritability estimates for days to flowering, plant height and total seed weight were 0.70, 0.62 and 0.75, respectively, in F3 population. Narrow-sense heritability for total seed weight (0.51) was highest, followed by heritability for days to flowering (0.37), with heritability for plant height (0.26) lowest. Later flowering was associated with increased plant height and higher yields. From the F4 generation, we identified twelve candidate plants with earlier maturity and reduced plant height compared to ‘Hokuriku No. 4’, but almost the same total seed weight. These results suggest that hybridization breeding using the single seed descent (SSD) method is an effective approach for improving agronomic characteristics of Tartary buckwheat. 相似文献
8.
Jiwen Yu Shuxun Yu Michael Gore Man Wu Honghong Zhai Xingli Li Shuli Fan Meizhen Song Jinfa Zhang 《Euphytica》2013,191(3):375-389
The most widely grown tetraploid Gossypium hirsutum and G. barbadense differ greatly in yield potential and fiber quality and numerous quantitative trait loci (QTLs) have been reported. However, correspondence of QTLs between experiments and populations is poor due to limited number of markers, small population size and inaccurate phenotyping. The purpose of the present study was to map QTLs for yield, yield components and fiber quality traits using testcross progenies between a large interspecific F2 population and a commercial cotton cultivar as the tester. The results were compared to these from its F2 and F2:3 progenies. Of the 177 QTLs identified from the three populations, 65 fiber QTLs and 51 yield QTLs were unique with an average of 8–12 QTLs per traits. All the 26 chromosomes carried QTLs, but differed in the number of QTLs and the number of QTLs between fiber and yield QTLs. The congruence of QTLs identified across populations was higher (20–60 %) for traits with higher heritabilities including fiber quality, seed index and lint percentage, but lower (10–25 %) for lower heritability traits-seedcotton and lint yields. Major QTLs, QTL clusters for the same traits and QTL ‘hotspots’ for different traits were also identified. This research represents the first report using a testcross population in QTL mapping in interspecific cotton crosses and provides useful information for further comparative analysis and marker-assisted selection. 相似文献
9.
Summary Microspore embryogenesis technology allows plant breeders to efficiently generate homozygous micros-pore-derived breeding populations of oilseed rape (Brassica napus L.) without traditional generations of inbreeding. This study was conducted to compare the frequency distribution of microspore-derived population and single seed descent populations with respect to fatty acids of seed oil. Both microspore-derived populations and single seed descent populations were produced from each of three crosses made between selected parents containing contrasting amount of erucic, oleic, linoleic and linolenic acids. The fatty acid content of F3 plants derived lines (F5 seed) developed by single seed descent was compared to that of microspore-derived populations. The means, ranges and distribution pattern of seed fatty acid contents were similar in both populations for each fatty acid studied, although a few heterozygous lines were observed in the single seed descent populations. The results indicated that microspore-derived population form random, homozygous F1 plant derived gametic arrays for all fatty acids evaluated. Selection for altered fatty acid composition in microspore-derived and single seed descent homozygous populations should be equally efficient, in the absence of linkage of traits investigated. 相似文献
10.
Genetic variability in response to anther culture was investigated in 49 winter hexaploid wheats, comprising 33 pure lines (F10) derived from a composite cross programme and their 16 parental genotypes. All genotypes were grown in a randomized block design with three replications in a controlled greenhouse. The number of embryoids and total plant regeneration per 100 anthers, as well as the numbers of green and albino plants regenerated per 100 embryoids, were measured. Significant genetic variability was observed among the 49 genotypes for all the traits studied. All traits showed high heritability. Among the genotypes compared, DC230N and 1BPT-40 gave the best results for the production of embryoids and IBPT-78 had the highest value for the production of green plants. The genotype IBPT-34 developed a large number of albino plants, and it should be useful as a parent in studies to determine the genetic control of albino plants in wheat. 相似文献
11.
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
12.
This study was undertaken to estimate heritability of pod length and seed weight in guar, Cyamopsis tetragonoloba (L.) Taub., and to determine genetic relationships between the two traits. Narrow-sense heritability (h2) estimates ranged from 0.63 to 0.68 for pod length and from 0.54 to 0.57 for seed weight. An additive-dominance model was adequate to explain gene action involved in the inheritance of both traits. Estimates indicate a minimum of 5 loci or chromosome segments control pod length and 2 control seed weight. Phenotypic correlations between pod length and seed weight were highly significant and positive. Genotypic correlations between the two traits were low and positive. Moderate to high heritability values for the two traits indicate that selection for improvement in either trait should be fairly rapid. Low genotypic correlations between the traits should not pose a significant barrier in developing large seed, grain-type cultivars. 相似文献
13.
Genetics and mapping of quantitative traits for nodule number, weight, and size in soybean (Glycine max L.[Merr.]) 总被引：1，自引：0，他引：1
Sadal Hwang Jeffery D. Ray Perry B. Cregan C. Andy King Marilynn K. Davies Larry C. Purcell 《Euphytica》2014,195(3):419-434
Soybean research has found that nodule traits, especially nodule biomass, are associated with N2 fixation ability. Two genotypes, differing in nodule number per plant and individual nodule weight, KS4895 and Jackson, were mated to create 17 F3- and 80 F5-derived RILs. The population was mapped with 664 informative markers with an average distance of less than 20 cM between adjacent markers. Nodule traits were evaluated in 3-year field trials. Broad-sense heritability for nodule number (no. plant?1), individual nodule dry weight (mg nodule?1), individual nodule size (mm nodule?1), and total nodule dry weight (g plant?1) was 0.41, 0.42, 0.45, and 0.27, respectively. Nodule number was negatively correlated with individual nodule weight and size. Nodule number, individual nodule weight, and size are major components which likely contributed to increased total nodule weight per plant. Composite interval mapping (CIM) identified eight QTLs for nodule number with R2 values ranging from 0.14 to 0.20. Multiple interval mapping (MIM) identified two QTLs for nodule number, one of which was located close to the QTL identified with CIM. Six QTLs for individual nodule weight were detected with CIM, and one QTL was identified with MIM. For nodule size, CIM identified seven QTLs with R2 values ranging from 0.14 to 0.27. Five QTLs for total nodule weight were detected with CIM, one of which was located close to a QTL identified with MIM. These results document the first QTL information on nodule traits in soybean from field experiments utilizing a dense, complete linkage map. 相似文献
14.
Selection of superior host genotypes in symbiosis with native Bradyrhizobium has been suggested as a means of increasing nitrogen fixation m peanut (Arachis hypogaea L.). In this study progeny from a cross of cultivars ‘Florigiant’ and ‘Florunner’ inter-mated twice and selected for yield formed the base population. The 44 selected S2,1 families, ‘Florigiant’ and ‘Florunner’ were evaluated at two sampling dates at each of two locations for traits indicative of nitrogen fixation. Five families were selected in each of four selection groups — high and low acetylene reduction and high and low plant weight. Selected families were retested in a second year and inter-mated. S2,1 progeny within each selection group were bulked and evaluated for nitrogen-if using characteristics at two ‘sampling dates at two locations. After intermating, the mean of the high acetylene reduction group, 62.9 μ/moles C2H4/plant hr, was Significantly greater than the mean of the low acetylene reduction group, 52.5 μmoles C2H4/plant/hr, and of the mid-parent, 55.8 μ/moles C2H4/plant/hr. The associated estimate of realised heritability was 55 ± 08 indicating the response to selection was approximately halt the selection differential and that the distinction between families selected for high and low acetylene redaction was maintained after intermating. However, the realized heritability estimate obtained from the means of the base population and the selected families inbred one generation was .14 ± .06 indicating a failure to maintain distinct groups after one generation of inbreeding. The utility of early generation selection for enhanced N: fixation is, therefore, doubtful in this population. Selection based on plant weight was not effective. A significant difference in the plant weight means of the high and low plant weight groups was not detected when selections were retested or after inter-mating. Plant weight was not a useful indirect selection criterion for enhanced N2 fixation. 相似文献
15.
Yields of large-seeded Andean (A) common bean (Phaseolus vulgaris L.) cultivars of Chile and Nueva Granada races are 40 to 60% lower compared to their Middle American (M) counterparts of small-seeded Mesoamerica and medium-seeded Durango races. Our objective was to use the concept of congruity backcrossing between Andean x Middle American inter-gene pool [AM 11833 = A 483 (A)///// A 686 (M) //// PVA 800A(A)/// ‘Carioca’ (M)// Carioca (M)/ G 19833 (A)] and between races within Andean gene pool [i.e., intra-gene pool Andean, AA 11834 = A483 (A)//// ‘Cardinal’(A) /// ‘Blanco Español’(A) // BlancoEspañol (A) / ‘Taylor’ (A)] to compare selection for seed yield improvement of large-seeded Andean beans. Seven hundred sixty seven F2-derived F3 (F2:3) families were produced for each population. Visual appraisal for total plant performance, combined with seed yield from non-replicated plots was used for selection of 551 families in F2:3, 182 families in F2:4, and 91 families in F2:5 in each population. Eight hundred twenty three F5:6 lines were developed from the 91 F2:5 families in each population. Visual selection, combined with seed yield in non-replicated plots was again used to select 294 lines in F5:6 in each population. Similarly, 44 highest yielding F5:7 lines were selected in AM 11833 and 39 F5:7 lines in AA 11834. Thus, single plant selections were made in the F2 and F5, and plants within each plot were harvested in bulk in F3, F4, F6, and F7. Thirty nine F5:8 lines from AA 11834 and 44 lines from AM 11833, parents, and checks were evaluated at Popayán and Quilichao, Colombia in 1998 and 1999. Selected lines in both populations, on average, out-yielded the mean of their large-seeded Andean parents. Mean yield of the lines selected from AM 11833 was 50% higher than AA 11834 lines. Twelve F5:8 lines out-yielded the highest yielding Andean parents G 19833 and A 483 in AM 11833, whereas only one line yielded significantly higher (p < 0.05) than the highest yielding parent A 483 in AA 11834. However, none of selected lines out-yielded small-seeded Middle American parents used in AM 11833 (A 686 and ‘Carioca’). The mean 100 seed-weight of AA 11834 was 36 g compared to 28 G for AM 11833 F5:8 lines. Selected lines had similar days to maturity as parents in AM 11833, and matured 3 d later in AA11834. Correlation coefficients between yield and 100 seed-weight were negative in both populations. Yield and days to maturity were positively correlated in AA 11834. 相似文献
16.
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
17.
M. Santalla M. Lema A. P. Rodiño A. M. González A. B. Monteagudo A. M. De Ron 《Euphytica》2005,142(1-2):85-95
Approaches are needed to broaden the genetic base and improve earliness and yield potential of large-seeded beans under sustainable cropping systems. The objective of this research was to develop adapted dwarf bean populations having a commercial seed quality and yield suitable for the production in the South of Europe. The original base populations were produced from crosses between genotypes within each Mesoamerica, Nueva Granada and Peru races, and between Peru and Nueva Granada, and Mesoamerica and Nueva Granada races. Visual mass selection for plant performance was practised in the F2 and F3 generations. In the F4 and F5, single plants were harvested under two cropping systems (sole cropping and intercropping with maize). From F4, selection was based on precocity, combined with seed yield and seed commercial type. The F4:7 selected lines from each original population were compared with their parents and five checks at four environments and two cropping systems. Differences among environments, populations, parents and checks were observed for all traits. Under intercropping with maize, there was a 50% reduction in seed yield. Yield of parents and checks belonging to Andean South American races, intraracial (Nueva Granada × Nueva Granada) and interracial (Nueva Granada × Peru) populations, was higher than that of those of Middle American origin. Intraracial crosses within large-seeded Andean South American (Peru race) and Middle American gene pools (Mesoamerica race) did not produce lines yielding more than the highest yielding parent. Only two large-seeded lines selected from crosses between small- and large-seeded gene pools out-yielded the best parent and check cultivar. 相似文献
18.
定位棉花种子性状的基因对揭示棉花种子性状的遗传规律,以及明确棉花种子、产量、纤维品质等性状间的遗传关系具有重要意义。以(渝棉1号×T586) F2:7重组近交系群体构建的遗传连锁图谱,在鉴定270个家系3个环境种子物理性状的基础上,利用MQM作图方法,共检测到34个种子物理性状QTL,包括9个种子重(qSW)、5个短绒重(qFW)、3个短绒率(qFP)、8个种仁重(qKW)、6个种子壳重(qHW)和3个种仁率(qKP)QTL,它们可解释4.6%~80.1%的性状表型变异。9个QTL在2个或3个环境中被检测到,其中包括第12染色体显性光子位点的短绒重与短绒率QTL,以及另外7个微效应QTL。34个QTL分布于15条染色体,其中A染色体组20个,D染色体组14个。有12个染色体区段分布有2个或2个以上的QTL,而且同一染色体区域同一亲本所具有的不同性状QTL的方向大多数与性状表型相关系数的正负一致。 相似文献
19.
Summary Parent-offspring regression was used to estimate heritability for three traits (-glucan content, groat percentage, and resistance to crown rust (Puccinia coronata Cda. f. sp. avenae Eriks.) in oat (Avena sativa L.). The populations used were derived from two crosses, Nova x Marion QC and Sylva x Marion QC. Marion QC was used as a parent because other research had shown that it is relatively high in -glucan, a trait for which heritability had not previously been estimated. Nova and Sylva are similar in adaptation to Marion QC, and Sylva may be a source of general resistance to crown rust. Random F5 plants were grown in a greenhouse, and their F6 and F7 progeny were grown in replicated field trials. Heritability estimates for the two grain quality traits were based on regression of F6 values on F5 values, F7 values on F6 values, and F7 values on F5 values. Heritability estimates for -glucan content were between 0.27 and 0.45. The highest estimate was the one based on the F6 and F7 generations of Sylva x Marion QC: 0.45, compared to estimates of 0.32 or less for earlier generations of the same cross, and to estimates of 0.35 or less for all generations of Nova x Marion QC. Heritability estimates for groat percentage were all between 0.23 and 0.32. The F6 and F7 generations were evaluated for resistance to crown rust resistance. The Sylva x Marion QC cross seemed to segregate for heritable resistance (h
2=0.31) but the Nova x Marion QC cross did not (h
2=0.07). Several lines from the Sylva x Marion QC cross had low symptoms in both the F6 and F7 generations. There were no strong genetic correlations among the traits. 相似文献
20.
Heritability of, and genetic correlations among, forage and seed yield traits in Ladino white clover 总被引：1，自引：0，他引：1
Sixteen white clover genotypes and their half-sib progenies were grown in pure stand. Each clover progeny was also grown in a mixed stand that also included three grass varieties of different species. Dry matter (DM) yield was measured over 2 years and seed yield at the second year. Competitive ability of clover families was defined as the ratio between mixed stand and pure stand for clover DM yield. Narrow-sense heritability from parent-offspring regression of pure stand data was high to moderate (h20.50) for DM yield, seed yield and most of their components. Persistence as predicted by stolon density showed negative genetic correlations with seed yield (rg= -0.70) and DM yield (r2= -0.60), whereas seed yield and DM yield tended towards a negative correlation (r2=0.45). Sizes of different vegetative or reproductive organs were generally correlated positively. Evidence was provided that the set of parent genotypes represents well the genetic variation available within the Ladino gene pool. The results highlighted the difficulty of combining relatively short-term DM yield, persistence and seed yield into a unique plant type. Differences in competitive ability emerged only in the second year, better ability being related mainly to petiole length among the traits assessed in pure stand. 相似文献