Inheritance of somatic embryogenesis in alfalfa (Medicago sativa L.)

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 318-321 ◽  
Author(s):  
M. M. Hernández-Fernández ◽  
B. R. Christie

To study the inheritance of somatic embryogenesis in alfalfa (Medicago sativa L.), three alfalfa genotypes were self-pollinated and intercrossed. A70-34 is a highly embryogenic genotype; R3 produced callus but not embryos; and MK does not produce callus. Callus production was controlled by one locus with complete dominance. In a survey of 107 alfalfa genotypes, the dominant and recessive alleles were present in equal frequencies. Embryogenesis among those plants producing callus was controlled by two complementary loci with additivity within each locus. The suggested designations for the two genes are Rna and Rnb.Key words: alfalfa, Medicago sativa L., tissue culture, somatic embryogenesis, inheritance.

1992 ◽  
Vol 72 (2) ◽  
pp. 483-485 ◽  
Author(s):  
A. R. McElroy ◽  
D. C. W. Brown

A transplant plug technique was developed that uses in vitro somatic embryogenesis techniques to mass-multiply alfalfa plants in a form suitable for direct transplanting. The plug contains potting media covered with an agar nutrient cap. Plants develop from embryos placed on the cap and then establish in the potting media.Key words: Hybrid alfalfa, Medicago sativa L., tissue culture, transplant plug, somatic embryogenesis


Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 474-477 ◽  
Author(s):  
G. A. Kielly ◽  
S. R. Bowley

The genetic control of somatic embryogenesis in alfalfa (Medicago sativa L.) was studied using one nonembryogenic and three embryogenic genotypes: A70-34, a selection from 'Rangelander'; RA3, a selection from 'Regen-S'; and C2-4, a selection from a breeding population that had A70-34 in its pedigree. Crosses of embryogenic × embryogenic and embryogenic × nonembryogenic and S1 and BC1 testcrosses were evaluated for in vitro regeneration. Selfing reduced the expression of the trait. Somatic embryogenesis was dominant and explained by two loci. All three regenerating genotypes shared a common genetic system.Key words: alfalfa, Medicago sativa, somatic embryogenesis, tissue culture.


1998 ◽  
Vol 78 (4) ◽  
pp. 719-722
Author(s):  
A. D. Iwaasa ◽  
K. A. Beauchemin ◽  
S. N. Acharya ◽  
J. G. Buchanan-Smith

Shearing force of alfalfa (Medicago sativa L.) stems was measured to evaluate genotype-by-year interactions. Based on mean shearing force for each stem segment and genotype clustering criteria, several genotypes had similarly shearing forces among years. Therefore, selecting genotypes with desirable shearing force characteristics to improve digestibility or intake potential of forages may be possible. Key words: Genotype, environment, shearing force, cell wall chemical constituents


Author(s):  
Bo Xu ◽  
Rina Wu ◽  
Fang Tang ◽  
Cuiping Gao ◽  
Xia Gao ◽  
...  

Background: Alfalfa (Medicago Sativa), a perennial cross-pollinated plant, is one of the most important forage crops in the world with commercial value and ecological significance. However, due to the complexity of its genome, varietal improvement is difficult. Therefore, generating genetically homozygous materials have greater significance for breeding. In the current study, we aimed to identify the best tissue culture conditions to obtain haploid plants and double haploid plants.Methods: In this study, the haploid plants of alfalfa were obtained by combining tissue culture regeneration system with Flow cytometry. Different concentrations of colchicine were applied to the haploid plants using solid and liquid cultivation methods to determine the optimum conditions to obtain double haploid plants of Medicago Sativa L. cv. ‘XinJiangDaYe’. Result: Among the two colchicine cultivation methods tested, the doubling rate of regenerated plants obtained by liquid cultivation method was higher and the leaves developed under this system have the best doubling effect among the three explants tested. Optimal doubling conditions for alfalfa haploid (Medicago Sativa L. cv. ‘XinJiangDaYe’) were identified. The double haploid plant material generated from the current study could serve as a genetic resource for developing the hybrid combinations and for analyzing genetic linkage in alfalfa improvement programs.


1999 ◽  
Vol 79 (4) ◽  
pp. 509-517 ◽  
Author(s):  
Suwarno Suwarno ◽  
K. M. Wittenberg ◽  
W. P. McCaughey

A study was conducted to monitor nutrient and microbial count changes during wilting of alfalfa (Medicago sativa L.) in response to varying degrees of maceration at mowing. Early bloom alfalfa was mowed with either a roller-conditioner (CONV) or a macerator set to deliver four degrees of maceration during alfalfa mowing: LIGHT, LIGHT+, SEVERE, and SEVERE+. Macerated alfalfa reached 80% dry matter in 9–11 h compared with alfalfa mowed by roller-conditioner, which required 54 h. The most rapid wilting rates were associated with LIGHT+, SEVERE, and SEVERE+ maceration treatments when alfalfa was not exposed to precipitation. The wilting coefficient in the first 24 h was increased by more than 100% for the SEVERE treatment compared with alfalfa mowed using a conventional roller-conditioner in alfalfa that was not exposed to precipitation. Precipitation at 1.5 h post-mowing increased wilting time by 8.3 h to achieve 45% DM, and by 17.5 to achieve 80% DM in the SEVERE+ maceration treatment relative to alfalfa from the same conditioning treatment that was not exposed to precipitation. Precipitation at 24 h post-mowing increased wilting time to reach 80% DM by 11 h and 21 h for the LIGHT and LIGHT+ maceration treatments relative to alfalfa of the same mowing treatments not exposed to precipitation. Maceration of alfalfa resulted in a 24.2 to 26.8 h shorter wilting time relative to the conventional roller-conditioner treatment when alfalfa was exposed to precipitation at 24 h post-mowing. SEVERE and SEVERE+ maceration treatments at mowing resulted in higher (P < 0.05) neutral detergent fibre and acid detergent fibre levels post-wilting. Lactic acid bacteria populations on alfalfa tended to be higher with maceration within 1 h post-mowing (P < 0.10) and post-wilting (P < 0.08). Key words: Alfalfa, maceration, precipitation, wilting time, bacteria, nutrient profile, compressibility


1993 ◽  
Vol 73 (1) ◽  
pp. 131-137 ◽  
Author(s):  
S. R. Bowley ◽  
G. A. Kielly ◽  
K. Anandarajah ◽  
B. D. McKersie ◽  
T. Senaratna

For successful application of artificial seed technology to alfalfa (Medicago sativa L.), parental plants must possess the necessary genes for somatic embryogenesis and produce progeny having high commercial value. A backcross procedure was initiated to transfer the ability to form somatic embryos from genotype A70-34, a selection from the cultivar Rangelander, to multiple-pest-resistant alfalfa germplasm. The objectives of this study were to evaluate the growth characteristics and seed yield of the F1; BC1 and BC2 generations to determine if introgression with commercial germplasm had improved the agronomic features of the embryogenic germplasm. This study consisted of two field experiments, each conducted at two locations. One experiment evaluated herbage growth characteristics and herbage production at Elora and Woodstock, Ontario, and the other evaluated seed yield at Elora and Delhi, Ontario. Significant increases in fall regrowth height, leaflet length:width ratio, and seed yield were detected over the cycles of crossing. By the BC2, fall dormancy and leaflet length:width ratio were similar to those in commercial populations. Although improvements in seed yield were detected, the BC2 was inferior in seed yield compared with commercial germplasm, and further introgression and (or) conscious selection for improved seed yield will be required. Through a population backcross procedure, it appears possible to develop commercial alfalfa germplasm capable of in vitro manipulation. Key words: Alfalfa, Medicago sativa L., somatic embryogenesis, artificial seed, backcross


1994 ◽  
Vol 74 (3) ◽  
pp. 451-456 ◽  
Author(s):  
J. W. Hall ◽  
W. Majak ◽  
D. G. Stout ◽  
K.-J. Cheng ◽  
B. P. Goplen ◽  
...  

Investigations of legume species which do and do not cause bloat suggested that a bloat-safe alfalfa (Medicago sativa L.) might be produced by reducing its initial rate of digestion. This study compared a third cycle alfalfa synthetic selected for a low initial rate of digestion (LIRD) with a control cultivar (Beaver). The occurrence of bloat was not significantly lower when cattle were fed cycle 3 LIRD than when fed Beaver in three grazing trials or in two of three feedlot trials. The deviation of the results in the third trial could not be explained by differences in dry matter or protein content. When grown under irrigation, the 4 h dry matter disappearance (DMD) of cycle 3 LIRD was 89% to 96% of that for Beaver. This reduction was much less than has been hypothesized to prevent bloat. Without irrigation the 4 h DMD of both cultivars were reduced by 1–3% while cycle 3 LIRD continued to have a lower DMD than Beaver. LIRD may provide some protection against bloat on dry rangelands though the response may be variable in years when moisture is well supplied. Studies with a fourth cycle LIRD selection will investigate this further. Key words: Legumes, Medicago sativa L., nylon bag, digestion


2001 ◽  
Vol 81 (2) ◽  
pp. 281-283 ◽  
Author(s):  
J. W. Hall ◽  
W. Majak ◽  
T. A. McAllister ◽  
J. K. Merrill

Rumensin controlled release capsule (CRC) was evaluated in grazing trials and in confinement with fistulated steers fed alfalfa at the vegetative to early bud stage of growth. These stages promoted a high incidence of bloat, both in animal days of bloat and in daily frequency of distension. The bolus reduced the incidence of bloat by an average of 50% in five trials, the difference being statistically significant in four of them. The cultivars AC Grazeland and Alfagraze did not differ significantly in daily bloat incidence when evaluated at early stages of growth. Key words: Cattle, bloat, legumes, Medicago sativa L.


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