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1.
Berseem clover Trifolium alexandrinum L. is an annual forage legume commonly grown in pure stands and in grass mixtures in the Medi-terranean basin. Six populations were naturally cross-pollinated in 1990 and 1991 by a half-sib breeding method. In 1992 and 1993. 54 half-sib maternal plants, six original populations, and six advanced populations were field evaluated for forage (short cycle, harvest made at seven or eight inlernodes: long cycle, harvested at flowering) and seed yield (no forage harvest) in experiments at the Forage Crop Institute at Foggia, Italy (typical Mediterranean location). Genetic variability, narrow-sense herilability, genetic and phenotypic correlations among forage and seed yield component trails were investigated. The genetic variance in dry matter among maternal half-sib populations in short cycle was 51% greater than in long cycle. Narrow-sense heritabilily was 35% higher in short cycle than long cycle for dry matter and 26% higher for seed weight than seed yield. The magnitude of the genetic variance components and genetic correlations suggested that selection among plants of maternal half-sib populations would be more effective for improving dry matter in short than in long cycle harvests. The selection applied in the study was not effective for increasing seed yield per se however, the trait may be increased by selecting indirectly for seed weight. 相似文献
2.
L. Pecetti P. Annicchiarico A. Abdelguerfi R. Kallida M. Mefti C. Porqueddu N. M. Simões F. Volaire F. Lelièvre 《Journal of Agronomy and Crop Science》2011,197(1):12-20
Extensive livestock is a basic socio‐economic feature of the Mediterranean region whose environmental and economic sustainability depends on the ability of forage resources to withstand climatically stressful conditions. Perennial forages such as tall fescue can be a valuable alternative to annuals, if they can survive across successive summer droughts. Three‐year dry matter yield and plant survival of five cultivars of Mediterranean‐type tall fescue were evaluated in six sites of Algeria, France, Italy, Morocco and Portugal, with the following objectives: (i) modelling adaptive responses and targeting cultivars as a function of environmental factors associated with genotype × location interaction; and (ii) defining plant ideotypes, adaptation strategies and opportunities for international co‐operation for regional breeding programmes. Site mean yield and winter temperatures were positively correlated, whereas sward persistence was positively correlated to lower site heat and drought stress. Cultivar adaptation was adequately modelled by factorial regression as a function of site spring–summer (April–September) drought stress (long‐term potential evapotranspiration minus actual water available) for yield, and annual drought stress for final persistence. Specific‐adaptation responses to high‐ or low‐stress environments emerged which were consistent with drought‐stress levels of cultivar selection environments. However, the wide‐adaptation response of cultivar Flecha suggested that breeding for wide adaptation can be feasible. 相似文献
3.
To study the genetic variation, heritability and genetic correlations of some agro-morphological traits in tall fescue, 25
parents from a genetically broad-base germplasm were polycrossed and their respective half-sib families were generated. Clonally
propagated parents and their half-sib families were grown as spaced single plants using a randomized complete-block design
with three replications, and observed for seven traits in 2006 and 2007. The estimates of broad-sense heritability were moderate to high for the traits studied. Narrow-sense heritability estimates from analyses of progenies and from regression of half-sib (HS) progenies on parents suggested that genetic variation for these traits was largely controlled by additive gene action. Association of dry matter
yield (DMY) with plant height, number of fertile shoot, curbs width and spring growth was positive and significant. With the
exception of number of days to pollination, correlation coefficients of the traits between the parents and offspring were
not significant. Based on parent-offspring regression, genetic gain from selection for DMY was high, demonstrating genetic
potential for improving this trait. Overall, there was high genetic variation and moderate heritability for most traits in
the tall fescue populations evaluated. In conclusion, to improve herbage yield, selection would be more effective based on
forage yield components. 相似文献
4.
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
5.
Experiments were undertaken to identify an efficient method of selection for yield in early segregating generations of narrow-leaf lupin crosses. A first series of experiments involved simulation of F2 populations with mixtures of ten cultivars and advanced breeding lines. The performance of genotypes in mixtures sown at different densities was compared with their monoculture [commercial density) yields m the same and the following year. These comparisons provided a basis for assessing the value of different planting designs and different selection criteria in early generation selection for yield. Correlated monoculture yield responses to simulated selection for single plant yield were similar for the honeycomb design and standard selection procedures at both low and commercial densities. These responses were much higher than that for grid selection in a low density population. Correlated monoculture yield responses to selection for other plant characters were substantial only for flowering time and number of pod bearing branches under certain conditions. These responses were greatest for selection in a low density mixture and in the year following selection. A procedure involving selection of the earliest flowering plants and selection within this group of plants with the highest number of pod bearing branches should be an effective approach to early generation yield selection in the narrow-leaf lupin. 相似文献
6.
Endophyte Infection May Affect the Competitive Ability of Tall Fescue Grown with Red Clover 总被引：4，自引：0，他引：4
D. P. Malinowski D. P. Belesky J. M. Fedders 《Journal of Agronomy and Crop Science》1999,183(2):91-101
Cool-season grasses infected with Neotyphodium endophytes may be more persistent and competitive than non-infected plants. In a greenhouse experiment, two tall fescue ( Festuca arundinacea Schreb.) cloned genotypes (DN2 and DN11) with different growth characteristics and endophyte status (E−, non-infected; E+, infected) were grown in monocultures and in full competition with red clover ( Trifolium pratense L.) cv. Reddy Red for 20 weeks. When grown in monoculture, endophyte infection reduced the root dry matter (DM) of DN2 (16 %) and DN11 (5 %) when compared to E− plants, while shoot DM was not affected. In full competition with red clover, root and shoot DM of tall fescue were not influenced by endophytes, but cumulative herbage DM yield was less in E+ than in E− plants. Root growth of red clover was significantly depressed (22 %) in competition with E+ plants of DN2 compared to E− plants, but was not affected when plants were grown in competition with DN11. The relative yield total (RYT) did not differ from 1.0 in red clover mixtures with E− plants of DN2 and DN11, and with E+ plants of DN11, indicating competition between the competitors for the same resources. In contrast, RYT was less than 1.0 in the red clover/DN2 E+ mixture, suggesting a negative interaction between the competitors. Endophyte infection increased the competitive ability of DN2 but reduced that of DN11 when compared to E− plants. Because the concentration of pyrrolizidine alkaloids in roots of E+ plants of DN2 was twice that found in roots of DN11 (1083 and 536 μg g−1 , respectively), we suggest that pyrrolizidine alkaloids might influence the competitive ability of some endophyte–tall fescue associations through a possible allelopathic effect on companion species. 相似文献
7.
Herrick Sydney Easton 《Euphytica》2007,154(3):295-306
Neotyphodium endophytes profoundly affect the biology of their host grasses, including the important forage species perennial ryegrass,
tall fescue and meadow fescue. The endophytic association is finely balanced, involving adaptation in each associate. The
evidence for co-adaptation is discussed. The presence of endophyte, and the difference between endophyte strains, can affect
some plant properties more than genetic variation intrinsic to the host. Conversely, host genotype exerts significant influence
on the activity of the endophyte. Control of endophyte status is essential in any grass breeding programme, and developing
knowledge of endophyte and its role in a herbage association offers new opportunities to grass breeders. 相似文献
8.
Tall fescue is an important outcrossing forage and turf grass species that requires vernalization to flower. A reproducible protocol was developed for vernalization of regenerated, transgenic and seed‐derived tall fescue plants. Following the vernalization scheme that involved gradual changes of temperature and daylength, seeds were routinely produced from vernalized plants under greenhouse conditions. Molecular analyses of progenies obtained from crosses between transgenic and seed‐derived plants revealed stable meiotic transmission of transgenes following Mendelian inheritance in transgenic tall fescue. 相似文献
9.
首次在河南省对5种优良牧草和花生进行间作套种的研究,并且在牧草与花生“5+6”套作模式的情况下,对比与分析了两者的相互影响、综合生产水平以及可行性。研究表明,套种后紫花苜蓿、白三叶以及苇状羊茅影响花生果实产量,花生果实产量分别下降14.2%、12.6%和7.6%,达到了极显著(前两者)和显著水平。苜蓿和白三叶还对花生的百果重、饱果数有抑制作用,而对总果数影响不大。和紫花苜蓿套作,花生秧产量下降7.3%(p<0.05),与其他牧草套作花生秧的产量无显著影响。与花生的套作能够极显著地促进多年生黑麦草、鸡脚草和苇状羊茅3种禾草的分蘖(11.01%~14.26%)(p<0.01),显著增加其叶面积指数(4.62%~6.37%)和叶绿素含量(5.04%~5.50%)(p<0.05),3种禾草的青干草产量分别提高了8.2%、8.1%、9.3%。花生秧与禾草混合调制成青干草后,饲草中的粗蛋白、粗脂肪和钙的含量得到了显著和极显著的提高,而粗纤维含量却明显降低。与花生套作能够提高紫苜蓿产草量5.8%(p<0.01)和,但豆科牧草与花生秧混合调制以后,粗蛋白、粗纤维以及钙和磷的含量明显下降,粗脂肪得到了极显著的提高。 相似文献
10.
Fitness in tall fescue could be determined as the relative seed production by overcoming self-incompatibility barriers. This study was an attempt to investigate the effects of plant genotype and symbiotic fungal endophyte on seed production and associated traits in tall fescue. Fifteen clones of tall fescue free from endophyte and two clones with both endophyte-infected (E+) and non-infected (E?) counterparts were evaluated under two pollination systems of natural open-pollination and obligate self-pollination. Although seed yield was depressed by self-pollination in all E? genotypes, some genotypes exhibited reasonable selfing ratio. However, endophyte infection was much more effective to increase selfing ratio and seed yield through self-pollination particularly in the genotype 75B. Endophyte infection almost removed self-incompatibilty in the host plants and on average resulted in 3.0 times more number of seeds per self-pollinated seedheads than the non-counterpart E? tall fescue genotypes. Although it may need more elaborated studies, incorporating Epichloë fungal endophyte in plant genotypes not only may make the inbreeding in tall fescue possible but also may improve forage yield and seed production, simultaneously. 相似文献
11.
Breeding programmes in common bean (Phaseolus vulgaris L.) have mainly focused on performance under monoculture conditions. Interactions among cultivars and cropping systems do
occur and genotypes bred for pure cropping may not be suitable for intercropping. This study was undertaken to obtain estimates
of genetic parameters of quality traits for bush bean landraces grown in two cropping systems, and the interrelationships
of these traits between pure cropping and intercropping with maize (Zea mays L.). Field experiments were conducted at two locations for two years. Expression of most traits was not strongly influenced
by genotype × environment interactions. Heritability estimates were similar in both cropping systems for most pod and seed
quality traits. Positive correlations were observed between pure cropping and intercropping for pod characters (weight, length,
width and texture) and seed characters (dry and imbided weight, length, hardness, coat proportion, water absorption and crude
protein). Use of a selection index is suggested for breeding for seed size, water absorption,coat proportion and crude protein
for both cropping systems. However, larger gains would be expected in pure cropping for most traits. Bean accessions PHA-0267,
PHA-0285, PHA-0286 and PHA-0299 should be used for developing acceptable culinary and high protein breeding lines for either
cropping system.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
M. D. Casler 《Plant Breeding》1998,117(3):243-249
Information on both mean performance and genetic variation is important in determining the value of germplasm for breeding via recurrent selection. The objectives of this experiment were to evaluate different methods of controlling spatial variation for forage yield, and to estimate genetic variances and heritability in eight perennial forage grass populations. Polycross families of two populations of smooth bromegrass (Bromus inermis Leyss.), two populations of hybrid wheatgrass (Elytrigia×muctonata (Opiz ex. Bercht.) Prokud.), and four populations of orchardgrass (Dactylis glomerata L.) were field tested for 2 years. Spatial variation was present in all three progeny tests, but was well accounted for by either the incomplete block design or a nearest neighbour analysis (NNA) of yield potentials. Low rank correlations between adjusted family means for the incomplete block design vs. the NNA created the unanswered question of which would provide a more appropriate estimate of family mean performance. Genetic variation was detected in six out of eight populations for forage yield, four out of six populations for ground cover, all four orchardgrass populations for maturity and one of four orchardgrass populations for leafspot reaction (caused by Drechslera spp.). Excessive year-family interactions prevented detection of genetic variation for leafspot reaction in the other populations. Heritability estimates ranged from 0.30 to 0.42 for forage yield. In all three species, there was a trend toward a negative relationship between population mean and genetic variance, suggesting that less elite populations may need to contribute other traits to be useful in the short term. 相似文献
13.
To develop efficient breeding strategies for the improvement of oil content and onset of flowering in Dimorphotheca pluvialis, narrow-sense heritabilities of these characters were estimated. Forty plant progenies were tested in 2 years and heritabilities were estimated from parent-offspring regression as well as from half-sib family variance components analyses. For oil content, the heritabilities estimated by means of parent-offspring regression were 0.36 and 0.33 for 1993 and 1994, respectively. The heritabilities obtained from the variance components analyses were 0.41 and 0.23 for the two years. Heritability estimates for onset of flowering showed more variation. From parent-offspring regression, the heritabilities were 0.72 and 0.37, and from variance component analysis the estimates were 0.53 and 0.19 for 1993 and 1994, respectively. The obtained heritability values and realized responses suggest that particularly in early selection generations, even with mass selection, considerable progress can be expected. Since correlation studies revealed neither phenotypic nor genotypic correlation between oil content and onset of flowering, selection for both characters can be undertaken independently. 相似文献
14.
José Marcelo Soriano Viana Ísis Fernanda de Almeida Marcos Deon Vilela de Resende Vinícius Ribeiro Faria Fabyano Fonseca e Silva 《Euphytica》2010,174(1):31-39
Best Linear Unbiased Prediction (BLUP) has become the most widely used method for genetic assessment of animal and perennial species, and it is potentially relevant for annual crops. The objective of this study was to assess this method for selection within non-inbred families in recurrent breeding programs. The ‘animal model’ was fitted. The data were expansion volume (EV) and grain yield of plants in recombination plots of two to three selection cycles in the popcorn population Viçosa, with half- and full-sib progenies. The ASReml program was used to perform the analyses. For both EV and yield the breeding values predicted from the additive and additive-dominant models were highly correlated. Multi-generation BLUP was, in general, more accurate than single-generation analysis. These two methods resulted in highly correlated predicted breeding values. The dominance genetic values predicted from the single- and multi-generation analysis were also highly correlated. The pedigree information reduced the percentage of coincidences among the selected individuals relative to phenotypic selection mainly in the population structured in half-sib families. Based on breeding values predicted by BLUP analysis, the most efficient selection procedure was mass selection. 相似文献
15.
Summary Heritabilities of the pungency and single center traits were estimated in onion breeding populations using selection response and half-sib family analyses. Pungency was determined indirectly by measuring enzymatically produced pyruvic acid in individual bulbs. After one generation of selection, pungency was lowered by 8.1% and 8.9% in the populations 90-61-1 and 89-69-8, respectively, and realized heritabilities of 0.21 and 0.51 were estimated.Selection had no effect in lowering the pungency of population 90–62. Heritability estimates calculated through half-sib progeny analysis were 0.53, 0.48, and 0.25 for pungency in the populations 90-61-1, 90–62 and 89-69-8, respectively. The number of single centered onions was increased by 19% and 22% in populations 90–62 and 89-69-8, respectively, after one generation of selection, and the realized heritability estimates were 0.37 and 0.34, respectively. 相似文献
16.
箭筈豌豆与燕麦不同间作混播模式对产量和品质的影响 总被引：8，自引：0，他引：8
豆科牧草与禾本科牧草混播是提高饲草产量和品质的重要措施。在低氮条件下比较分析12种燕麦与箭筈豌豆不同间作与混播模式对饲草产量和品质的影响。研究结果表明,燕麦蜡熟期与箭筈豌豆枯黄期混合饲草产量和粗蛋白产量最高。所有处理中H7（燕麦与箭筈豌豆3∶1间作）干物质产量和粗蛋白产量最高,土地利用率提高了76%。其中干物质产量在灌浆期比单播燕麦增产47%,蜡熟期增产40%;粗蛋白产量在灌浆期分别比单播燕麦和箭筈豌豆增产52.6%和2.6%;在蜡熟期增产97.2%和103.2%,均显著高于单播燕麦和单播箭筈豌豆（P<0.05）。同行混播各处理干物质产量均显著高于单播燕麦和单播箭筈豌豆（P<0.05）,且同行混播各处理之间并无显著差异;粗蛋白产量在2次刈割期H9（燕麦与箭筈豌豆1∶2混播）较高,土地利用率与单作相比提高了51%。间作混播处理有利于提高混合草的RFV值,与单播燕麦相比间混作提高饲草RFV值的幅度为0.3%~22.7%。综合全年牧草的产量、品质以及土地当量比分析,燕麦与箭筈豌豆3∶1的间作种植模式最好,能更好地发挥燕麦和箭豆的种间互补优势,获得较高的干物质产量,说明间作增产可能与燕麦和箭筈豌豆田间带距和行比的合理搭配有关。 相似文献
17.
Intensively managed sown temperate grasslands are generally of low species diversity, although swards based on grass-legume mixtures may have superior productivity and herbage quality than grass-only swards. We conducted a cutting experiment over two years to test the effect of species composition and diversity on herbage yield, contents of N, neutral detergent fibre (NDF) and in vitro organic matter digestibility (IVOMD). Perennial ryegrass (PR, Lolium perenne) was sown alone and with each of four forage legumes: red clover (RC, Trifolium pratense), lucerne (LU, Medicago sativa), birdsfoot trefoil (BT, Lotus corniculatus) and white clover (WC, Trifolium repens); WC was also sown with hybrid ryegrass (HR, Lolium × boucheanum), meadow fescue (MF, Festuca pratensis) and timothy (TI, Phleum pratense). Herbage productivity was lowest in pure PR followed by PR/BT, and highest in PR/RC; this mixture had the highest legume proportion, N content and N yield. There was less WC in swards with HR and MF than with PR and TI. These differences were reflected in N contents of herbage of the mixtures. Legumes had higher N and lignin and lower NDF contents and IVOMD than grasses. Among legumes, NDF content was highest and IVOMD lowest in LU, followed by BT and the clovers. The highest N content was in WC. Among grasses, PR and HR had lower NDF contents and a higher IVOMD than MF; the highest N content was in PR. The grass component of mixtures had less effect than the legume component on herbage yield and quality. Results are discussed in terms of their potential to contribute to forage resources in farming practice and enhance resource use efficiency and ecosystem services. 相似文献
18.
M. Ghesquière J.-C. Emile J. Jadas-Hécart C. Mousset R. Traineau C. Poisson 《Plant Breeding》1996,115(4):238-244
This paper reports on the first results of feeding value experiments, assessed with sheep, of hybrids between tetraploid Italian ryegrass (Lolium multiflorum, 2n = 4×= 28) and a progenitor of tall fescue, Festuca arundinacea var. glaucescens (2n = 4×= 28). Three hybrid populations resulting from either high, low or no selection for palatability were compared with a variety of Italian ryegrass as control and two varieties of the cultivated hexaploid (2n = 6×= 42) tall fescue, one of which had been selected for high palatability. On average, the hybrid populations were found to be as palatable as the improved tall fescue with voluntary intake (VI), in vivo digestibility of organic matter (DOM), and net energy expressed in fodder units for milk, similar to the best palatable tall fescue and to Italian ryegrass. However, selection for improved palatability among hybrids did not result in any further improvement of other traits, except VI in the hybrid selected for high palatability which significantly exceeded VI of Italian ryegrass. In conclusion, intergeneric hybridization between L. multiflorum and F. arundinacea var. glaucescens led to an immediate increase of feeding value compared with selection for palatability in tall fescue. However, to improve feeding value of hybrids further, similar selection for high palatability appeared questionable and possibly detrimental for other agronomic traits because of complicated inheritance in tetraploid L. multiflorum×F. glaucescens hybrids. 相似文献
19.
Heritability and Correlation Studies on Some Vegetative Traits in Nigerian Local White Onion, Allium cepa L. 总被引：1，自引：0，他引：1
Heritability estimates for soluble solids, bulb firmness and bulb weight were carried out in two ways, namely, parent-offspring regression and half-sib family intra-class correlation. Leaf characters were estimated only by half-sib intra-class correlations. For soluble solids the values were high (72% and 58% respectively), while the values for bulb weight And bulb firmness were low (20% and 39%, and 32%, and 33% respectively) using the two methods. Some high additive genetic correlations were observed between bulb firmness and length of longest leaf (rA= 0.830), bulb weight and leaf area of longest leaf (rA= 0.704). 相似文献
20.
Maryam Ebrahimiyan Mohammad Mahdi Majidi Aghafakhr Mirlohi Abbas Noroozi 《Euphytica》2013,190(3):401-414
The physiological basis of genetic variation in drought response and its association with yield and related indices is not clear in tall fescue. In this study thirty genotypes of tall fescue (Festuca arundinacea Schreb.) were sampled from a polycross population and evaluated under two levels of irrigation in 2010 (normal and intense stress) and 2011 (normal and mild stress). Physiological traits including relative water content (RWC), total chlorophyll (TChl), chlorophyll a (Chla), chlorophyll b (Chlb), Chla/Chlb, carotenoids (Car), TChl/Car and proline content along with forage yield, agro-morpholgical traits and selection indices (stress tolerance index, STI and drought susceptibility index, DSI) were studied. Large variation and moderate to high heritability was estimated for most of the studied traits. Intense drought condition decreased chlorophyll content while mild stress significantly increased it. In the other hand intense drought stress increased Chla/b while mild stress didn’t change it. Under mild drought stress condition STI was positively correlated with RWC while under intense drought stress condition STI was positively correlated with chlorophyll content. Although proline content was significantly increased in both intense and mild drought stress conditions, no relationship was found between proline accumulation with forage yield and STI. Applications of principle component analysis for screening suitable genotypes are also discussed. 相似文献