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1.
Information on the genetic variability of seed yield and yield components is limited and no information is available on correlations
among seed yield and yield components and direct and indirect effects of the yield components on seed yield in switchgrass,
Panicum
virgatum L. Accordingly, we conducted replicated experiments at Chickasha and Perkins, OK, in 1998 involving 11 lowland type switchgrass
populations to assess genetic variation for seed yield and yield components, quantify interrelationships among them, and determine
direct and indirect effects of yield components on seed yield through path coefficient analysis to identify traits for indirect
selection of seed yield. Significant (P ≤ 0.01) variation existed among the 11 populations over locations for percent seed set and 100-seed weight. Seed yield/plant
and the seed yield components panicle number/plant, spikelet number/panicle, and seed number/panicle had significant (P ≤ 0.05) population × location interactions, indicating substantial environmental influence on these traits for these populations.
Accordingly, data for these traits were analyzed separately for each location revealing significant (P ≤ 0.01) differences among populations at both locations for each of these traits. Phenotypic correlation between seed yield/plant
and seed number/panicle was positive (r = 0.76** at Chickasha and r = 0.72** at Perkins). Path coefficient analyses revealed that seed number/panicle had the highest positive direct effect
on seed yield at both locations. Ample genetic variability was present among the switchgrass populations studied to allow
breeding improvement of seed yield. Selection for increased seed number/panicle would be the most effective means of indirectly
selecting for higher seed yield within this germplasm. Correlation and path coefficient analyses among biomass yield, seed
yield, and harvest index indicated that, at least within the switchgrass germplasm studied, it would be possible to breed
switchgrass cultivars with enhanced biomass yielding ability and sufficient seed production capability for their commercial
propagation. 相似文献
2.
Moderate to high heterosis for yield and ten related characters was studied in 45 crosses involving six indica (I) and four
tropical japonica (J) varieties of rice under three (E1-optimum sowing and high fertility, E2-both optimum sowing and fertility and E3- late sowing and high fertility) environments. Trends of magnitude of heterosis for grain yield and plant height were I/J
> I/I > J/J and for days to 50% flowering I/J > J/J > I/I hybrids. Estimates of standard heterosis (%) for grain yield were
–64.5 to 146.1 in E1, –70.4 to 82.2 in E2 and –67.2 to 63.8 in E3. Environment E1 seemed to be more favorable for higher heterosis expression than others. Higher heterosis in yield also accompanied heterosis
in panicle number, dry matter and spikelet and grain number per panicle. Most estimates for days to flower were negative.
Heterotic I/J hybrids also recorded maximum heterosis for earliness. Moderate to low standard heterosis for plant height across
environments (2.0 to 13.7%) was recorded. Hybrids were identified in specific environments for direct exploitation
in hybrid breeding. Hybrids B4116 / Sarjoo 52, B4122 / Pant Dhan 4 and B4122 / Narendera 359 were more stable than others
over three environments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
The F
1 and F
2 generations of a twenty parent fractional diallel cross of opium poppy (P. somniferum L.) were analyzed for combining ability for ten quantitative and five quality (alkaloids) traits. The results indicated significant
differences among the parents for combining ability for all the traits. The GCA and SCA components of variances were significant
for all the characters. However, the SCA component of variance (δ
2s) was predominant indicating the preponderance of non-additive gene effect for all the traits except for leaves/plant and
papaverine in F1 hybrids. The average degree of dominance (δ
2s/δ
2g) was more than unity indicating over dominance and also confirming non-additive mode of gene action. Among the parents IS-16,
IS-13 and NBRI-1 for early flowering, BR226 and BR241 for branches/plant, capsule weight/plant, seed yield/plant and husk
yield/plant, BR227 for leaves/plant, UO1285 for capsule size and opium yield/plant, NBRI-5 for husk yield/plant, morphine,
codeine, and thebaine and ‘Papline’ for plant height and papaverine content were found good general combiners. Parent ND1001
was good combiner for codeine and narcotine content. Inclusion of good general combiners in a multiple crossing program or
an intermating population involving all the possible crosses among them subjected to bi-parental mating may be expected to
offer maximum promise in breeding for higher opium, seed yield and alkaloid contents. 相似文献
4.
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
5.
Two cucumber recombinant inbred lines (RILs) differing in plant habit were crossed and progeny self-pollinated to produce
F3 individuals upon which phenotypic selection was practiced to identify a base population which in turn underwent either two
cycles of MAS or random mating without selection (RAN). MAS and RAN were practiced to produce F4 and F5 progeny sets. RIL, crossing parents, and F3–F5 progeny sets were then evaluated under replicated field conditions for fruit yield and quality (L:D and E:T) to evaluate
gain from selection (ΔG). The broad-sense heritability (h
2
B) over cycles (C) of selection ranged 0.22–0.45, 0.09–0.20, and 0.11–0.15 for yield, L:D, and E:T, respectively. Although
one cycle of PHE selection followed by MAS was effective in conserving the performance of the traits examined during inbreeding,
progeny performance during RAN fluctuated (F4–F5 generation; C2). Lack of ΔG during advanced generations (F4–F5) of MAS was likely due to allelic fixation and/or optimized epistatic complementation. 相似文献
6.
Using three selected overlapping RILs to fine-map the yield component QTL on Chro.D8 in Upland cotton 总被引:1,自引:0,他引:1
Hong Chen Neng Qian Wangzhen Guo Qingping Song Baocheng Li Fujun Deng Cunguang Dong Tianzhen Zhang 《Euphytica》2010,176(3):321-329
Cotton yield improvement is vital to fulfill rising global demands. The identification of major quantitative trait loci (QTL)
for yield components was helpful in molecular marker-assisted selection (MAS) to improve cotton yield. We previously identified
a densely populated QTL region for fiber qualities and yield components on chromosome D8 (Chro.D8) of Upland cotton from a
(7235 × TM-1)RIL. In the present study, to fine-map yield component QTLs, we chose three overlapped recombinant inbred lines
(RILs) with different intervals included the yield component QTLs, and backcrossed each line with TM-1 to develop three large
sized mapping populations. Phenotypic data for yield components were collected in Nanjing (JES/NAU) and Xinjiang (BES/XJ)
in 2006 and 2007. Three simple sequence repeat (SSR) genetic linkage maps on chro.D8 were constructed using 907 individuals
in (7TR-133 × TM-1)F2 (Pop A), 670 in (7TR-132 × TM-1)F2 (Pop B), and 940 in (7TR-214 × TM-1)F2 (Pop C). Three stable QTLs for boll size, two for lint percentage and one for boll number per plant,were detected on chro.D8
following analysis of three RIL backcrossed F2/F2:3 progeny at JES/NAU and BES/XJ although their cultivation practices differ greatly between these two cotton-growing regions.
One QTL for boll number per plant exhibited a phenotypic variance (PV) of 5.6–10.1%, three QTLs for boll size exhibited 15.0–35.5%
PV and two lint percentage QTLs exhibited 10.9–19.3% PV. Negative correlation between lint yield and fiber strength was confirmed. 相似文献
7.
Long Yan Ying‐Hui Li Chun‐Yan Yang Shu‐Xin Ren Ru‐Zhen Chang Meng‐Chen Zhang Li‐Juan Qiu 《Plant Breeding》2014,133(5):632-637
Heterosis, or hybrid vigour, has been used to improve seed yield in several important crops for decades and it has potential applications in soybean. The discovery of over‐dominant quantitative trait loci (QTL) underlying yield‐related traits, such as seed weight, will facilitate hybrid soybean breeding via marker‐assisted selection. In this study, F2 and F2 : 3 populations derived from the crosses of ‘Jidou 12’ (Glycine max) × ‘ZYD2738’ (Glycine soja) and ‘Jidou 9’ (G. max) × ‘ZYD2738’ were used to identify over‐dominant QTL associated with seed weight. A total of seven QTL were identified. Among them, qSWT_13_1, mapped on chromosome 13 and linked with Satt114, showed an over‐dominant effect in two populations for two successive generations. This over‐dominant effect was further examined by six subpopulations derived from ‘Jidou12’ × ‘ZYD2738’. The seed weight for heterozygous individuals was 1.1‐ to 1.6‐fold higher than that of homozygous individuals among the six validation populations examined in different locations and years. Therefore, qSWT_13_1 may be a useful locus to improve the yield of hybrid soybean and to understand the molecular mechanism of heterosis in soybean. 相似文献
8.
M. Sincik B. N. Candogan C. Demirtas H. Büyükcangaz S. Yazgan & A. T. Göksoy 《Journal of Agronomy and Crop Science》2008,194(3):200-205
An experiment was conducted to investigate the influence of different levels of water deficit on yield and crop water requirement of soya beans in a sub‐humid environment (Southern Marmara region, Bursa, Turkey) in 2005 and 2006. One full‐irrigated treatment (T1), one non‐irrigated treatment (T5) and three different deficit irrigation (T2 = 25 % water deficit, T3 = 50 % water deficit, T4 = 75 % water deficit) treatments were applied to ‘Nova’ soya bean planted on a clay soil. Non‐irrigated and all deficit irrigation treatments significantly reduced biomass and seed yield and yield components. The full‐irrigated (T1) treatment had the highest yield (3760 kg ha?1), while the non‐irrigated (T5) treatment had the lowest yield (2069 kg ha?1), a 45.0 % seed yield reduction. T2, T3 and T4 deficit irrigation treatments produced 11.7–27.4 % less seed yield than the T1 treatment. Harvest index showed less and irregular variation among irrigation treatments. Both leaf area per plant and leaf area index were significantly reduced at all growth stages as amount of irrigation water was decreased. Evapotranspiration increased with increased amounts of irrigation water supplied. Our results indicate that higher amounts of irrigation resulted in higher seed yield, whereas water use efficiency and irrigation water use efficiency values decreased when irrigation amount increased. 相似文献
9.
The objective of this work was to check the possible allelism between two sources of resistance to the root-knot nematode
Meloidogyne incognita race 1 in lettuce (‘Grand Rapids’ and ‘Salinas-88’). The experiments were carried out in greenhouses, in expanded 128-cell
polystyrene trays filled with commercial substrate. Lettuce cultivars ‘Salinas 88’ and ‘Grand Rapids’ were tested along with
the populations F1 (‘Grand Rapids’ × ‘Salinas-88’), F2 (‘Grand Rapids’ × ‘Salinas-88’), F3 (‘Grand Rapids’ × ‘Salinas-88’), and with F4 families derived from the latter population. Seedlings were inoculated 15 days after sowing with a nematode egg suspension
equivalent to 30 eggs ml−1 of substrate. Plants were evaluated for apparent gall incidence, gall scores, egg mass scores and extracted egg numbers 45 days
after the inoculation date. There was evidence that two different genes are involved in control of resistance to M. incognita race 1 in lettuce cultivars Grand Rapids and Salinas-88. Lines with higher levels of nematode resistance than either Grand
Rapids or Salinas-88 could be selected in the F4 generation of the cross between these resistant parental lines. 相似文献
10.
Path and correlation analysis of perennial ryegrass (Lolium perenne L.) seed yield components 下载免费PDF全文
Maximum perennial ryegrass seed production potential is substantially greater than harvested yields with harvested yields representing only 20% of calculated potential. Similar to wheat, maize and other agriculturally important crops, seed yield is highly dependent on a number of interacting seed yield components. This research was performed to apply and describe path analysis of perennial ryegrass seed yield components in relation to harvested seed yields. Utilising extensive yield components which included subdividing reproductive inflorescences into five size categories, path analysis was undertaken assuming a unidirectional causal‐admissible relationship between seed yield components and harvested seed yield in six commercial seed production fields. Both spikelets per inflorescence and florets per spikelet had a significant (p < .05) direct effect on the overall seed yield; however, total path correlation coefficients showed that inflorescence size had the largest positive influence on seed yield via its indirect effects on other seed yield components. Our results will allow seed producers, seed production researchers and plant breeders alike to more efficiently increase harvested seed yield. 相似文献
11.
Common bean (Phaseolus vulgaris L.) and tepary bean (P. acutifolius Gray) are grown for their edible seed and production is
limited by insufficient soil moisture in many parts of the world. Carbon isotope discrimination (Δ) against 13CO_2 during
photosynthesis has been suggested as a useful selection criterion to improve crop productivity in water-limited environments,
however, there is a need to first understand relationships between productivity and Δ in common bean. The objectives of this
study were to: 1) evaluate relationships between productivity (as measured by seed yield and biomass) and Δ among diverse
dry bean lines and F2 progeny, 2) evaluate associations for Δ, seed yield and biomass among lines grown in different field
environments and 3) estimate narrow sense heritability for Δ, seed yield and yield components. One hundred dry bean lines
were evaluated at Yellow Jacket, CO in irrigated and non-irrigated field plots during 1988 and 1989. All significant relationships
between seed yield or biomass and Δ were positive. In general, relationship between seed yield and Δ among lines were weak
and R2 ranged from near zero to 0.29 across years and environments. The correlations for Δ, seed yield and biomass production
among lines grown in different environments were all significant and positive (0.76 > r > 0.36). Narrow-sense heritability
estimates for Δ and seed yield were 0.78 and 0.75, respectively. These results support the positive relationship between productivity
and Δ in bean, however, the weak relationships between Δ and seed yield do not suggest that Δ would be a useful sole selection
criterion to improve productivity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Inheritance and Correlation of Self-Compatibility and other Yield Components in the Apricot Hybrid F1 Populations 总被引:2,自引:0,他引:2
Xuesen Chen Yan Wu Meixia Chen Tianming He Jianrong Feng Qing Liang Wen Liu Honghua Yang Lijie Zhang 《Euphytica》2006,150(1-2):69-74
Summary To provide genetic basis for apricot (Prunus armeniaca Lam.) breeding, inheritance and correlation of yield components including self-compatibility, self-pollinated fruiting rate, fertile flower rate, average fruit weight and fruit number per plant were studied with 5-year-old seedlings of apricot F1 hybrids from ‘Katy’ × (‘Xinshiji’, ‘Katy’ × (‘Hongfeng’ and ‘Katy’ × (‘Taianshuixing’, respectively. Using the criteria that cultivars with self-pollinated fruiting rate ≥6% were self-compatible(SC), we found that the ratios of self-compatible (SC) to self-incompatible (SI) individuals were 27:25, 9:12 and 15:19 in the above three families, respectively, and conformed to the ratio of 1:1 segregation by χ2 test, indicating that the S-locus of ‘Katy’ was heterozygous and self-compatibility was dominant to self-incompatibility. Twenty-seven seedlings from the F1 population of ‘Katy’ × ‘Xinshiji’ were chosen for S-allele-specific PCR. As a result, four S-genotypes with the ratio of 10:6:4:7 were obtained, which was linear to the 1:1:1:1 ratio by χ2 test. Great differences in self-compatibility degree were observed among seedlings even with the same S-genotype. In the F1 populations, a very extensive segregation in self-pollinated fruiting rate, fertile flower rate and average fruit weight was observed, and average values of these traits were lower than that of mid-parent. Therefore, these traits were confirmed to be quantitative. However, significant differences were found in broad heritability (H
b
2) of following three characters: the H
b
2 of self-pollinated fruiting rate (87.1% – 91.4%) was the greatest, with the variation mainly resulted from inheritance; fertile flower rate (36.8% – 49.1%) was the least and its variation was mainly caused by environmental factors. In addition, self-pollinated fruiting rate and fertile flower rate had very significantly positive correlations with single plant yield, so both may play important roles in the determination of single plant yield. In contrast, correlation between yield and average fruit weight was not significant. 相似文献
13.
Reciprocal recurrent selection (RRS) exploits the genetic complementarity of dura populations of palms with a small number of large bunches and tenera/pisifera group of palms with large number of small bunches. An extra phase was introduced to RRS just after the second cycle of selection
where outstanding dura derived from (DA3D × DA5D) combinations of the second cycle were self-pollinated for seed production. Best palms based on
the phenotype were selected and crossed with pisifera of second cycle offspring of LM2T. [(DA3D × DA5D) self-pollinated × LM2T self-pollinated] progenies were field tested at
La Dibamba (Cameroun) from 1987 to 1997. They were precocious with regard to the three-first years’ bunch yields (13.16–15.77 t/ha).
Homogeneity for all bunch yield components and homogeneity for vertical growth were illustrated by low values of the variation
coefficient (5.75–7.75%). The oil yield was 107% of the control against 115% from [(DA3D × DA5D) × LM2T self-pollinated] progenies
of the second cycle of RRS, mostly due to poor mesocarp to fruit and poor oil to mesocarp ratios which led to a low oil extraction
rate. The extra selection phase led mainly to homogenisation of progenies but also reduced the fruit quality. However, three
progenies whose average oil yield represented 115% of the control (4.87 t/ha) in addition to their precocity can be released
to oil palm growers. The extension of RRS did not fully meet expectations and poses the problem of its reliability. 相似文献
14.
The fungal disease cercospora leaf spot CLS (Cercospora zonata) has affected major faba bean (Vicia faba) production regions in southern Australian in the last several years. This study offers the first report of sources of resistance
to CLS in faba bean and describes techniques to evaluate resistance to C. zonata in faba bean genotypes within a controlled environment. The method was rapid (43 days), repeatable (R
2 > 0.74) and demonstrated positive correlations (R
2 > 0.45–0.80) to data collected from field disease nurseries under naturally established CLS epiphytotics. All faba bean cultivars
currently adopted by the Australian industry were found to be susceptible to CLS and defoliation was found to be an important
component of disease expression. Genetic analysis of segregation patterns in F
2 derived F
3 families of 1322/2*Farah (resistant*susceptible) showed the mode of inheritance of resistance to C. zonata was monogenic dominant. F
3 families were shown to segregate in the ratio of 1:2:1 for homozygous resistant: heterozygous: homozygous susceptible (χ22 = 2.78; P > 0.05) and individual plants within heterozygous F
3 families segregated in the ratio of 3:1 for resistant: susceptible responses (χ12 = 2.93; P > 0.05). Monogenic dominant inheritance also explained the change in frequency of resistant and susceptible plants within
a population of cv. Cairo following one generation of self-pollination (χ2 = 0.88, 0.3 < P < 0.5). The sources of resistance identified in this study are being used to transfer CLS resistance to adapted faba bean
genotypes for future cultivar releases to the southern Australian industry. 相似文献
15.
1‐Methylcyclopropene (1‐MCP)‐Induced Alteration in Leaf Photosynthetic Rate,Chlorophyll Fluorescence,Respiration and Membrane Damage in Rice (Oryza sativa L.) Under High Night Temperature 下载免费PDF全文
A. R. Mohammed J. T. Cothren M.‐H. Chen L. Tarpley 《Journal of Agronomy and Crop Science》2015,201(2):105-116
High night temperature (HNT) can induce ethylene‐triggered reactive oxygen species production, which can cause premature leaf senescence and membrane damage, thereby affecting production, consumption and transfer of photosyn‐thates, and yield. The 1‐methylcyclopropene (1‐MCP) can competitively bind with ethylene receptors and decrease ethylene effects. The objective was to determine the effects of HNT and 1‐MCP on leaf photosynthetic rate (PN), chlorophyll fluorescence, total chlorophyll (TC), respiration, membrane damage, pollen germination, spikelet fertility (SF) and yield of rice hybrid ‘XL723’. Plants were grown under ambient night temperature (ANT) (25 °C) or HNT (30 °C) with or without 1‐MCP treatment. Application of 1‐MCP was at the boot stage. The decrease in yield (11 %) under HNT was associated with decreased PN (4 %), stomatal conductance (8 %), quantum yield (11 %) TC (23 %) and SF (5 %) and increased respiration (74 %), Fo/Fm (increase in thylakoid membrane damage; 11 %) and membrane damage (leaf electrolytic leakage; 57 %). The 1‐MCP‐treated plants grown under HNT showed increased yield (17 %), which was associated with increased PN (10 %), stomatal conductance (30 %), quantum yield (9 %), TC (37 %) and SF (11 %) and decreased respiration (39 %), Fo/Fm (5 %) and membrane damage (18 %). Plants grown under HNT showed increased grain chalkiness (154 %) compared with plants grown under ANT. 相似文献
16.
Three CMS lines, Ogu1A, Ogu2A and Ogu3A were selected among ten lines after BC7 based on superior commercial, floral and seed setting traits. Introgression of sterile Ogura cytoplasm in cauliflower nuclear
background reduced the flower size but did not affect commercial and seed setting traits drastically. Line × Tester analysis
was done by taking these three CMS lines free from floral deformities as female parent with nine diverse lines of snowball
cauliflower as tester. The parent Ogu2A exhibited highest GCA effect for curd yield (4.51) and harvest index (1.97) while
Ogu1A exhibited highest GCA for earliness (−2.73). The parent, Ogu2A exhibited significant GCA for curd length (0.39) while,
none of the CMS lines showed significant GCA for curd diameter and depth. Heterosis for curd yield was highest in the hybrid,
Ogu2A × Kt-22 (63.5%) followed by Ogu1A × WF (36.9%) and Ogu1A × Kt-15 was the best hybrid for earliness followed by Ogu3A × Kt-22
with heterosis of −14.4% and −11.7%. However, the number of heterotic hybrids for yield and earliness was low indicating narrow
genetic base of the snowball cauliflower. 相似文献
17.
M. A. Cheema M. A. Malik A. Hussain S. H. Shah & S. M. A. Basra 《Journal of Agronomy and Crop Science》2001,186(2):103-110
A field study was conducted to investigate the influence of variable rates of application of N and P fertilizers in splits at various times on the growth and the seed and oil yields of canola (Brassica napus L.) during 1995–97. Rates of fertilizer application were 0 and 0 (F0), 60 and 0 (F1), 0 and 30 (F2), 60 and 30 (F3), 90 and 60 (F4) and 120 and 90 (F5) kg N ha?1 and kg P2O5 ha?1. All the P was applied at sowing while N was applied in splits, i.e. all at sowing, half at sowing and half with first irrigation, or half at sowing and half at flowering. The responses of growth, seed yield and components of yield were consistent in both years. Increasing the rate of fertilizer application from F4 (90/60 kg N/P2O5 ha?1) to F5 (120/90 kg N/P2O5 ha?1) increased the leaf area index (LAI) relative to the control and to lower rates of fertilizer application. For both crops, application of 90/60 kg N/P2O5 ha?1 significantly enhanced total dry matter (TDM) and seed yield. Seed yield increased mainly due to a greater number of pods per plant and seeds per seed‐pod. The time of fertilizer application did not significantly affect seed yield or components of yield in either season. Oil yield generally followed seed yield, increasing with increasing rate of fertilizer application up to 90/60 kg N/P2O5 ha?1. The maximum oil contents were obtained from the control. The results show that seed and oil yields of canola were maximized at the F4 (90/60 kg N/P2O5 ha?1) rate of application under the agro‐ecological conditions of Faisalabad, Pakistan. 相似文献
18.
Modified mass and family selection for seed yield production of berseem clover (Trifolium alexandrinum L.) c.v. ‘Fahl’ were applied for two generations. Two hundred plants (5 % intensity of selection) were selected for seed yield in the first season, 1985/86. In the second season, 1986/87, selection between and within half-sib families was practiced. In addition, equal parts of seeds from each of the 200 selected plants were bulked to form the C1 modified mass selection; after establishing, the same procedure was adopted to form the C2 generation. The cycles 1 and 2 of half-sib families and modified mass selection along with the base population family were evaluated for forage and seed yields. The realized gains from modified mass selection were 6.03 and 9.51 % for fresh forage yield, 5.57 and 10.86 % for protein yield and 13.23 and 16.19 % for seed yield in cycles 1 and 2, respectively, over the base population. The realized gain from family selection in cycle 2 as a percentage of the base population mean amounted to 11.32, 13.35, 17.47 and 3.15% for forage, protein, and seed yield and seed index, respectively. The broad sense heritability, as estimated from the variance components was 89.63, 63.03, and 76.67 % for dry forage, seed yield and seed index, respectively. Although, all these five traits (fresh, dry, protein, and seed yield and seed index) had positive correlation with each other, weak correlations were found between seed yield and forage yields. Furthermore, close associations were found among forage yield traits. 相似文献
19.
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
20.
Genetic male sterility (GMS) genes in wheat (Triticum aestivum L.) can be used for commercial hybrid seed production. A new wheat GMS mutant, LZ, was successfully used in the 4E-ms system
for producing hybrid wheat, a new approach of producing hybrid seed based on GMS. Our objective was to analyse the genetic
mechanism of male sterility and locate the GMS gene in mutant LZ to a chromosome. We firstly crossed male sterile line 257A
(2n = 42) derived from mutant LZ to Chinese Spring and several other cultivars for determining the self-fertility of the F1 hybrids and the segregation ratios of male-sterile and fertile plants in the F2 and BC1 generations. Secondly, we conducted nullisomic analysis by crossing male sterile plants of line 257A to 21 self-fertile nullisomic
lines as male to test the F1 fertilities and to locate the GMS gene in mutant LZ to a chromosome. Thirdly, we conducted an allelism test with Cornerstone,
which has ms1c located on chromosome 4BS. All F1s were male fertile and the segregation ratio of male-sterile: fertile plants in all BC1 and F2 populations fitted 1:1 and 1:3 ratios, respectively. The male sterility was stably inherited, and was not affected by environmental
factors in two different locations or by the cytoplasm of wheat cultivars in four reciprocal cross combinations. The results
of nullisomic analysis indicated the gene was on chromosome 4B. The allelism test showed that the mutant LZ was allelic to
ms1c. We concluded that the mutant LZ has common wheat cytoplasm and carries a stably inherited monogenic recessive gene named
ms1g. 相似文献