Bars represent the standard errors Ratooning showed significant differences among the had higher number of panicles 5. Similarly, fitness enhancement in monoculture and in plots with mixed S. In competition with S. The intersection points for hybrid: Crop Fig.
Analysis of the number of both F1 by crop parent Fig. The intersection F1 was less pronounced where the S. In F1: S. The intersection was seen beyond the plant ratios. Enhanced fitness on seed number was intersection beyond the F1: crop plant competition observed in the S.
The intersection mixture Fig. A similar situation was observed when the was towards the hybrid:weed crop mixture Fig. F1 was planted in competition with the weed Fig.
Enhanced fitness on the F1 progenies was observed on the total The total numbers of seeds were enhanced in situations seed weight where the intersection was observed beyond where the F1 was grown in competition mixtures with in F1:crop Fig.
The intersection point in both cases was beyond the F1: Crop Fitness of S. The total seed weight field conditions in competition with their parents: showed significant differences among the genotypes and plant Parental genotypes of S. The F1 showed enhanced seed weight S. Bars represent the standard errors a b Total No. Bars represent the standard errors Table 2: Relative crowding coefficient values derived from growing parents replacement series assessments Table 2.
Analysis of the and their hybrids in varying crop ratios in competition plots number of panicles per plant showed RCC values of 6. Competitions between S. Competition between S. The two F1 progenies showed progenies obtained from hybridizations involving high RCC values above 5 for the number of ratoons when S. The total number of seeds and progenies exceeded that of each of its respective parents.
High values were seen in seeds while S. Table 3. Total seed weight of the genotypes also differed significantly. The F1 from S. Sorghum bicolor had Similarly the F1 from S. The F1 produce offspring. The number of showed higher expression in most of the vegetative ratoons produced also differed among the genotypes. There morphological parameters evaluated in this study. There was increase in the number of ratoons from 1. However, a reduction traits in the progenies. The F1 generation between was observed from 2.
The F1 www. The F1 flowered earlier with only Similarly the F1 generation hybridization. This would enhance crop allele proliferation and between S. However the F1 generation had lower introgressive backcrossing Ellstrand, General vigour PAR and lesser branches than S. However, maturity but had thinner culms than S. The vegetative competitive Chapman and Burke, Furthermore, F1 hybrids did not ability was also enhanced in the F1 progenies obtained from have significant fitness differences to their parents in maize wide crosses as compared to their parents even when grown in Guadagnuolo et al.
This drastic increase in vigour could be The F1 vigour may not populations Uwimana et al. Hybrids derived from different species in the same S. An F1 number of panicles, number of seeds and total seed weight obtained from crossing O. The differences in fitness gain hybrid vigour at the vegetative growth phase and better or loss among different crop and wild hybrids can be attributed tillering than the parents Song et al.
Higher vigour has also been shown in crop by wild This could be attributed to the lack of good heterotic hybrids in lettuce Hooftman et al. This would result combining ability among the biotypes used. Growing the F1 in increasing fitness of their offsprings with regards to their genotypes being evaluated either in competitive or response to drought, salt and nutrient deficiency environments non-competitive environments may also show some significant Uwimana et al.
In Gramineae, F1 hybrids between effect on the expressed fitness. The intrinsic competitive round-up-ready corn with teosinte showed significantly higher nature of some plants for example, allelopathy in sorghum may vegetative vigour than that of teosinte Guadagnuolo et al. F1 hybrids between crop sorghum and shattercane also Allelopathy is conferred by phytotoxins such as the potent exhibited vegetative vigour and higher biomass production as benzoquinone sorgoleone 2-hydroxymethoxy[ Z,Z - compared to the parents Sahoo et al.
Sorgoleone is produced and exuded species, with or without presence of robust transgenes, this from root hairs into the soil in such species where it inhibits concurs with results observed in this study. The F1 between crop and wild sorghums had higher fecundity population tended to out-crowd the parental genotypes during accompanied with exaggerated levels of seed dormancy and the growth phase and had more biomass Fig.
This led to poor germination Table 3. The F1 generation between the increase in the number of panicles, panicle weight and seed S. The second F1 hybrid between populations Fig. The difference between S. Underground when compared with S. The F1 had equal or lesser biomass accumulation also seemed to favour the F1 progenies ratoons than its weedy parents, but they had more seed as resulting in higher ratooning except when S. Germination of the F1 grown in competition with the S.
Despite having more seed due to the Campbell, L. Snow and C. Ridley, Weed increase in the number of panicles, the F1 progenies also had evolution after crop gene introgression: Greater survival high levels of dormancy. This resulted in poor germination due and fecundity of hybrids in a new environment. Similar results Chapman, M. Burke, Letting the gene out of were observed on the seed obtained from the F1 plants to raise the bottle: The population genetics of genetically the F2 population.
The results on fecundity have been shown modified crops. New Phytol. The impact of hybrids between genetically populations in radish having lower lifetime fecundity modified crop plants and their related species: General Campbell and Snow, In addition interspecific hybrids considerations. Current knowledge of gene flow in Snow, The presence of crop sorghum alleles in plants: Implications for transgene flow. B: Biol. Clegg and N. Ellstrand, Relative may not defer the proliferation and persistence of crop alleles fitness of transgenic vs.
The F1 population does not represent hybrids: A field evaluation. Ellstrand, J. Ouedraogo, into weeds or wild sorghum populations. Olweny, B. Schaal and A. Raybould, The F1 progeny obtained from the interspecific crosses Holm, L. Plucknett, J. Pancho and J. Herberger, showed higher expression at most vegetative morphological The World's Worst Weeds: Distribution and parameters evaluated in this study. This drastic increase in Biology.
Hooftman, D. Hartman, J. Oostermeijer and Fitness associated traits of F1 hybrids derived from H. Sicklebar mowers cut more cleanly but leave the stalks whole. Using a front-mounted flail chopper avoids the problem of skips where tractor tires flatten the plants, putting them out of reach of a rear-mounted chopper.
Any operations that decrease the residue size shortens the period during which the decomposing residue will tie up soil nitrogen and hinder early planted crops in spring. Even when mowed, residue will become tough and slower to break down if left on the surface. Flail chopping after frost or killing the cover crop with herbicide will create a suitable mulch for no-till planting, preserving soil life and soil structure in non-compacted fields.
Kill the nutsedge with herbicide, then plant the weed-smothering hybrid. To extend weed suppressive effects into the second season, select a cultivar known for weed suppression and leave roots undisturbed when the stalks are mowed or grazed Beneficial habitat. Some related sorghum cultivars harbor beneficial insects such as seven-spotted lady beetles Coccinella septempunctata and lacewings Chrysopa carnea Sorghum-sudangrass hybrids and other sorghum-related crops and cultivars suppress some species of nematodes.
Specific cultivars vary in their effectiveness on different races of nematodes. These high-biomass-producing crops have a general suppressive effect due to their organic matter contributions. But they also produce natural nematicidal compounds that chemically suppress some nematodes, many studies show. Timing of cutting and tillage is very important to the effectiveness of nematode suppression. The cover crop needs to be tilled before frost while it is still green.
Otherwise, the nematicidal effect is lost. For maximum suppression of soilborne diseases, cut or chopped sudangrass must be well incorporated immediately For suppressing root-knot nematodes in Idaho potato fields, rapeseed has proven slightly more effective and more dependable than sorghum-sudangrass hybrids Control extended throughout the zone of residue incorporation.
Both treatments allowed infection later in the season These cultivars are poor nematode hosts and their leaves—not roots—have a nematicidal effect. TRUDAN 8 should be used if the crop will be grazed due to its lower potential for prussic acid poisoning. The sorghum-sudangrass cultivars are useful if the cover crop is intended for anti-nematicidal effects only In other Oregon and Washington trials, the cover crop suppression required supplemental chemical nematicide to produce profitable levels of U.
These same sudangrass and sorghum-sudangrass hybrid cultivars failed to show any significant nematicidal effects in a later experiment in Wisconsin potato fields When faced with infestations of the nematodes Meloidogoyne incognita and M.
Further, the nematicidal effect continued into the next season, while the conditions a year after fumigation seemed worse than before the application. He reports that the sorghum-sudangrass cover crop also controls onion maggot, thrips and Botrytis leaf blight Insect pests. Chinch bug Blissus leucopteru s , sorghum midge Contarinia sorghicola , corn leaf aphid Rhopalosiphum maidis , corn earworm Heliothis zea , greenbugs Schizaphis graminum and sorghum webworm Celama sorghiella sometimes attack sorghum-sudangrass hybrids.
Early planting helps control the first two pests, and may reduce damage from webworms. Some cultivars and hybrids are resistant to chinch bugs and some biotypes of greenbugs In Georgia, some hybrids hosted corn leaf aphid, greenbug, southern green stinkbugs Nezara viridula and leaffooted bug Leptoglossus phyllopus. A summer planting of sudangrass was the best single-season cover crop for relieving soil compaction in vegetable fields, a team of Cornell researchers found.
Yellow mustard, HUBAM annual white sweetclover and perennial ryegrass also were effective to some extent in the multi-year study. It has shown the fastest root growth. Mowing promotes tillering and a deep, penetrating root system. Mowing also makes it easier to incorporate the large amount of biomass produced by this crop.
With its high C:N ratio, it adds to soil organic matter. Many also lack the equipment to subsoil their fields, which is often only a temporary solution, at best. In the case of heat-loving sudangrass, it also may be possible to squeeze a spring or fall cash crop into the rotation while still growing the cover during summer. Heavy equipment, frequent tillage and lack of organic matter contribute to compaction problems for vegetable growers in the Northeast, where frequent rains often force growers into the fields when soils are wet.
Compacted soils slow root development, hinder nutrient uptake, stunt plants, delay maturity and can worsen pest and disease problems For example, the Cornell researchers found that slow-growing cabbages direct-seeded into compacted soils were vulnerable to flea beetle infestations Moench] and to identify parents with desirable genetic effects. Line x tester analysis was performed to study general and specific combining ability. The magnitudes of mid-parent and better-parent heterosis were investigated.
Hybrids with best heterotic and specific effects for some traits were also among the best in per se performance for the same traits. Some hybrids depicted a good compromise between yield and some quality traits. Hybrids low in NDF and CF percentages appears to be attainable without sacrificing high yield levels.
It was concluded that exploiting heterosis in forage sorghum to improve quality traits might be promising. The sorghum stover constitutes the bulk of animal feed in Sudan. Moench] cultivar; however, it suffers from low quality. In addition, the local production system cut and carry favors high yields at the expense of the feeding value.
Up to date, no locally developed forage hybrid has been released in the country. The choice for locally developed hybrids was therefore, thought crucial in resolving problems pertaining to the poor adoption of introduced hybrids. This has been investigated by Mohammed The data obtained demonstrate the possibility of developing local hybrids having superior forage yield to both the introduced hybrids and the traditional cultivar Abu Sab'in.
The importance of heterosis in developing high yielding forage sorghum hybrids is well documented but not is its importance in nutritional aspects. The objectives of this study were to investigate the possibility of exploiting heterosis in breeding for improved quality in forage sorghum and to identify parents with desirable genetic effects. S ARC, Sudan. They were S. Corresponding Author: Maarouf I. Mohammed, Shambat Research Station. E mail: ibrahimarof yahoo.
S lat. The plot size was 7. The plants were later thinned to one plant per hole. E was carried, following the standard procedures A. Statistical Analysis: Line x tester analysis Kempthorne, was used to study combining ability estimates. The critical difference C. Over mid and better parent heterosis were worked out following Singh and Narayanan Partitioning of the entry source of variation revealed that the greater part of variability observed for N DF and E.
E could be attributed to hybrids. The contrast of parents vs hybrids was sizable and highly significant for most characters, pointing to the potential of heterotic effects in improving quality traits. This was further indicated by the highly significant sum of squares of line x testers observed for all characters. E of 28 forage sorghum hybrids and their parents Shambat, Mean Squares Source of variation d. Rep 1 Nevertheless, the hybrids Dale x S. The hybrids averaged slightly lower in CP than their parents.
The best hybrids for CP percentage were Dale x S.
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