SELECTION IN ALFALFA FOR TOLERANCE TO TOXIC LEVELS OF ALUMINUM

1988 ◽  
Vol 68 (3) ◽  
pp. 743-753 ◽  
Author(s):  
T. A. CAMPBELL ◽  
J. H. ELGIN JR. ◽  
C. D. FOY ◽  
J. E. McMURTREY III
Keyword(s):  
Honey Bees ◽  
Shoot Growth ◽  
Recurrent Selection ◽  
Selection Procedure ◽  
Phenotypic Selection ◽  
Al Tolerance ◽  
Medicago Sativa L ◽  
Selection For ◽  
Nutrient Solutions ◽  
Made In

The alfalfa (Medicago sativa L.) population ’B13’ was screened through four cycles of recurrent phenotypic selection for tolerance to toxic levels of Al in growth chambers; germplasm from cycles 1 through 4 was designated B13-A11, B13-A12, B13-A13, and B13-A14, respectively. Cycles 1 and 2 were screened in Tatum clay-loam subsoil (36% Al saturation for cycle 1 and 61% Al saturation for cycle 2), and cycles 3 and 4 were screened in a modified Steinberg solution (111 μmol Al, pH 4.5). Selection was based on root growth in the first two cycles and shoot growth in the latter two cycles. Selections were intercrossed with honey bees (Apis mellifera L.) at the end of each cycle. Efficacy of the selection procedure was evaluated in pH 4.5 Steinberg solutions (Al concentration of 0 or 111 μmol), and in Tatum soil (0 or 68% Al saturation). Regression analysis indicated that significant but minimal progress was made in developing synthetics with improved vigor under Al toxic conditions. B13-A14 was among the least impaired of the entries in the ability to take up nutrients whereas AS-4 and Williamsburg (susceptible checks) were among the most impaired. It was concluded that tolerance to Al in nutrient solutions and soil could involve different mechanisms and that the screening procedure used here was much more effective in selecting for vigor than for Al tolerance. Alternative breeding approaches were proposed.Key words: Alfalfa, plant breeding, germplasm, recurrent selection, hydroponic, nutrient solution

Identification and selection for salt tolerance in lucerne (Medicago sativa L.)

1984 ◽  
Vol 35 (2) ◽  
pp. 239 ◽  
Author(s):  
CL Noble ◽  
GM Halloran ◽  
DW West
Keyword(s):  
Salt Tolerance ◽  
Medicago Sativa ◽  
Recurrent Selection ◽  
Leaf Damage ◽  
Shoot Number ◽  
Two Generations ◽  
Medicago Sativa L ◽  
Selection For ◽  
Efficiency Of Selection ◽  
Chloride Concentrations

Variation existed between plants of the lucerne (Medicago sativa L.) cultivar CUF 101 for dry matter production, shoot number and length, and leaf damage when grown for 70 days under 250 mM NaCl (15 h photoperiod, 20�C day, 10�C night). Salt tolerance evaluation using the criteria percentage leaf damage (percentage of total number of leaves with complete or partial necrosis) and length of the main shoot, isolated plants which showed salt tolerance of reasonably high heritability (h2=0.41). Two generations of recurrent selection for tolerance significantly increased the mean population tolerance without decreasing production under non-saline conditions. While both sodium and chloride concentrations of the shoot were lower in the tolerant than in less tolerant plants, chloride was more closely associated with salt tolerance than sodium. Sodium and chloride concentrations in the roots did not vary with the level of salt tolerance. No association of shoot and root potassium concentration with tolerance was evident. Selection for salt tolerance in lucerne plants using percentage leaf damage of less than 10% as the main criterion should give a rapid response to selection. The efficiency of selection may be increased if selection is based on the efficiency of chloride exclusion from the shoots and/or the level of chloride tolerated by the shoots prior to leaf damage becoming evident.

scholarly journals Recurrent Selection for Improved Germination under Water Stress in Russian Dandelion

2017 ◽  
Vol 142 (2) ◽  
pp. 85-91 ◽  
Author(s):  
Katrina J.M. Hodgson-Kratky ◽  
Olivier M. Stoffyn ◽  
David J. Wolyn
Keyword(s):  
Polyethylene Glycol ◽  
Water Stress ◽  
Recurrent Selection ◽  
Field Experiments ◽  
Phenotypic Selection ◽  
Bare Soil ◽  
Promising Candidate ◽  
Breeding Programs ◽  
Selection For

Russian dandelion [Taraxacum kok-saghyz (TKS)] is a promising candidate for introducing natural rubber production into North America. Seeds normally germinate in a humid microenvironment, such as the thatch layer of a lawn or under a canopy of grass; however, 5% to 15% establishment is often observed on bare soil, presumably due to water stress. Phenotypic selection and half-sib family recurrent selection were conducted for three cycles to improve germination in vitro, under low osmotic potential (Ψs), using a polyethylene glycol (PEG) solution. Populations were then tested for establishment on bare soil in the greenhouse and field. Germination under water stress in vitro increased from 5.8% for the cycle 0 (C0) population to 40.8% and 47.8% for the C3-phenotypic and C3-half-sib family populations, respectively. Soil establishment in the greenhouse and field was improved up to two- and 4-fold, respectively, compared with the C0, in two of four greenhouse experiments and three of eight field experiments. Overall, recurrent selection for germination under water stress in vitro has potential to improve establishment in the field and can be incorporated into current breeding programs to support the overall goal of creating cultivars with high-rubber yield.

scholarly journals Recurrent restricted phenotypic selection for forage yield in timothy and orchardgrass

1995 ◽  
Vol 75 (4) ◽  
pp. 871-875 ◽  
Author(s):  
D. Shateryan ◽  
B. E. Coulman ◽  
D. E. Mather
Keyword(s):  
Recurrent Selection ◽  
Dactylis Glomerata ◽  
Phenotypic Selection ◽  
Phleum Pratense ◽  
Forage Yield ◽  
Correlated Responses ◽  
Plant Persistence ◽  
Selection For ◽  
Dactylis Glomerata L ◽  
Phleum Pratense L

Three cycles of recurrent restricted phenotypic selection for forage yield were carried out in orchardgrass (Dactylis glomerata L. 'Avon' and 'Pennlate') and timothy (Phleum pratense L. 'Salvo' and 'Drummond'). The objectives of this study were to measure the effectiveness of this selection and to assess whether the selection produced any correlated responses on other characters. The three selected cycles and the original populations (cycle 0) were evaluated in both sward and space-planted experiments over a period of 4 yr. For the majority of the years of evaluation, there were no significant (P < 0.05) differences in forage yield among the different selection cycles. Under space-planted evaluation, cycle 3 of Drummond timothy was lower in both forage and seed yield than the other populations. In general, there was a trend to taller plants with greater circumferences in orchardgrass, and shorter, smaller plants in timothy over selection cycles. Selection had little effect on plant persistence and maturity. In conclusion, three cycles of recurrent restricted phenotypic selection were not effective in improving the forage yield of timothy or orchardgrass. Key words: Timothy, Phleum pratense, orchardgrass, Dactylis glomerata, recurrent selection

scholarly journals Marker-assisted selection for quantitative traits

2011 ◽  
Vol 11 (spe) ◽  
pp. 50-55 ◽  
Author(s):  
Ivan Schuster
Keyword(s):  
Molecular Markers ◽  
Cost Reduction ◽  
Marker Assisted Selection ◽  
Quantitative Traits ◽  
Large Scale ◽  
Recurrent Selection ◽  
Phenotypic Selection ◽  
Breeding Programs ◽  
The Subject ◽  
Selection For

Although thousands of scientific articles have been published on the subject of marker-assisted selection (MAS) and quantitative trait loci (QTL), the application of MAS for QTL in plant breeding has been restricted. Among the main causes for this limited use are the low accuracy of QTL mapping and the high costs of genotyping thousands of plants with tens or hundreds of molecular markers in routine breeding programs. Recently, new large-scale genotyping technologies have resulted in a cost reduction. Nevertheless, the MAS for QTL has so far been limited to selection programs using several generations per year, where phenotypic selection cannot be performed in all generations, mainly in recurrent selection programs. Methods of MAS for QTL in breeding programs using self-pollination have been developed.

Selection for resistance to the root-lesion nematode in alfalfa

1992 ◽  
Vol 72 (2) ◽  
pp. 593-598
Author(s):  
B. R. Christie ◽  
J. L. Townshend
Keyword(s):  
Medicago Sativa ◽  
Pratylenchus Penetrans ◽  
Root Lesion Nematode ◽  
Lesion Nematodes ◽  
Growth Room ◽  
Medicago Sativa L ◽  
Lesion Nematode ◽  
Selection For ◽  
Root Lesion Nematodes ◽  
Made In

A study was conducted to evaluate response of alfalfa (Medicago sativa L.) to selection for resistance to the root-lesion nematode (Pratylenchus penetrans (Cobb) Filipjev and Sch.-Stek.) under growth-room facilities. Six hundred plants of the cultivar Vernal were inoculated with root-lesion nematodes. Counts were made 13–14 wk later of the number of nematodes g−1 root. Selections were made for relatively low counts (resistant) and high counts (susceptible). Selections were self-pollinated, and the S1 progeny of nine plants (five resistant and four susceptible) were evaluated. The S1 progenies from both types of selections had similar counts. The S2 progenies of resistant S1 parents, however, had lower counts than those of susceptible parents. The F1 crosses generally reacted as expected on the basis of the S2 parents. Results of this study suggest that progress can be made in breeding for resistance to the root-lesion nematode in alfalfa.Key words: Nematode, Pratylenchus penetrans, alfalfa, selection

Divergent phenotypic selection for alfalfa cell wall fractions and indirect response in digestibility

2008 ◽  
Vol 88 (5) ◽  
pp. 891-898 ◽  
Author(s):  
I. Y. Tecle ◽  
J. L. Hansen ◽  
A. N. Pell ◽  
D. R. Viands
Keyword(s):  
Cell Wall ◽  
Phenotypic Selection ◽  
Breeding Strategy ◽  
Fiber Concentration ◽  
Indirect Response ◽  
Forage Digestibility ◽  
Acid Detergent Lignin ◽  
Medicago Sativa L ◽  
Selection For

An alfalfa (Medicago sativa L.) breeding strategy to decrease slowly digestible or indigestible fiber and simultaneously increase digestible fiber could improve forage quality without reducing total fiber. The objectives were: (1) to estimate selection responses from divergent and opposite direction selections of (i) hemicellulose (HEM) and acid detergent fiber (ADF), (ii) acid detergent lignin (LIG) and HEM + cellulose (CEL) and (iii) CEL and HEM + LIG, and (2) to determine correlated responses in in vitro true digestibility (IVTD). Selection progress was evaluated in replicated plot trials at two locations, sampled for 2 or 3 yr. Selection for divergent HEM and ADF resulted in change only for ADF [10.9 g kg-1 dry matter (DM)]. Selection for divergent LIG and HEM + CEL, resulted in same direction change in LIG (3.3 g kg-1 DM). Selection for divergent CEL and HEM + LIG resulted in change only in CEL (5.1 g kg-1 DM). Low LIG and high HEM + CEL, and low ADF and high HEM populations had 9.7 and 8.3 g kg-1 DM higher IVTD than their counterparts, respectively. The first cycle of selection for the fiber components simultaneously in the opposite directions was not successful. However, reduced LIG or ADF concentration appears to increase alfalfa forage digestibility and decrease total fiber concentration. Key words: Alfalfa, cell wall, hemicellulose, cellulose, lignin, digestibility

INHERITANCE OF DRY MATTER YIELD IN A HETEROZYGOUS POPULATION OF ALFALFA

1981 ◽  
Vol 61 (2) ◽  
pp. 313-318 ◽  
Author(s):  
STEVE R. BOWLEY ◽  
B. R. CHRISTIE
Keyword(s):  
Dry Matter ◽  
Genetic Variance ◽  
Total Yield ◽  
Dry Matter Yield ◽  
Response To Selection ◽  
Additive Variance ◽  
Growth Room ◽  
Medicago Sativa L ◽  
Selection For ◽  
Made In

Additive and digenic variances for dry matter yield were estimated from a population of F1 lines of alfalfa (Medicago sativa L.). The F1 lines and their polycross (PX) progenies were both evaluated over three harvests in a simulated sward in a growth room. From the analyses of variance, the genetic variances of the F1 and PX lines were estimated and the covariance between the F1 and PX performance calculated for dry matter yield. Correlations between relatives were used to partition these variances into additive and digenic effects. Narrow-sense heritabilities and the expected response to selection were estimated for the F1 population and broad-sense heritabilities were calculated from the F1 and PX trials. The pooled estimates of additive variance were significantly greater than zero for the second harvest and total yield while all estimates of digenic variance were nonsignificant. This indicated that the genetic variance for dry matter yield was mainly additive. The expected response to selection for total dry matter yield, if the top 10% of the F1 lines were recombined, was 23% of the F1 population mean. Based on these results, it was concluded that selection gains for yield could be made in this population of alfalfa.

INDIRECT SELECTION FOR RESISTANCE TO SCLEROTINIA CROWN AND STEM ROT ON ALFALFA

1984 ◽  
Vol 64 (1) ◽  
pp. 145-150 ◽  
Author(s):  
D. E. ROWE ◽  
R. E. WELTY
Keyword(s):  
Medicago Sativa ◽  
Sampling Error ◽  
Selection Procedure ◽  
Selection Response ◽  
Sclerotinia Trifoliorum ◽  
Seedling Resistance ◽  
Medicago Sativa L ◽  
Selection For ◽  
Significant Regression ◽  
Relationship Of

The possibility of improving seedling resistance to Sclerotinia trifoliorum (Eriks) by selecting seedlings of alfalfa (Medicago sativa L.) for resistance to sprays of oxalate solutions was investigated using four populations of alfalfa. Seedlings with two or three trifoliate leaves were sprayed with 0.16 or 0.125 molar solutions of oxalate. The selections from each oxalate treatment in each population were polycrossed. Seedlings from remnant seed of screened populations and seed from respective polycrosses of selections for oxalate resistance were evaluated for resistance to oxalate and S. trifoliorum in the greenhouse. The selection for oxalate resistance at 0.16 molar treatment was effective in doubling the frequency of resistant seedlings. The realized heritabilities averaged 17.4 with [Formula: see text] of 1.83. The resistance to S. trifoliorum was regressed on resistance to oxalate. Only one of the four populations had a significant regression. Thus, a physiological relationship of resistance to oxalate and resistance to S. trifoliorum was not demonstrated and it was concluded that this selection procedure was unsatisfactory. Linkage and sampling error are discussed as possible causes for the single significant regression.Key words: Medicago sativa, Sclerotinia trifoliorum, selection response, heritability, disease resistance

Sign in / Sign up

Export Citation Format

Share Document