Effects of stand age on agronomic, morphological and chemical characteristics of alfalfa

1991 ◽  
Vol 71 (2) ◽  
pp. 445-452 ◽  
Author(s):  
Michio Suzuki
Keyword(s):  
Medicago Sativa ◽  
Cold Hardiness ◽  
Plant Density ◽  
Age Groups ◽  
Stand Age ◽  
Chemical Characteristics ◽  
Total Nonstructural Carbohydrates ◽  
Vertical Extension ◽  
Shoot Number ◽  
Medicago Sativa L

Iroquois alfalfa (Medicago sativa L.) was seeded every spring from 1978 to 1988, and the established stands were maintained until the fall of 1988. Agronomic, morphological and chemical characteristics of the stands were compared among different age groups. A drastic reduction of alfalfa population occurred in the seeding year and during the first winter. There were about 40 plants m−2 in the 2nd yr which gradually decreased to 25 plants m−2 in the 8th yr, and between 12 and 24 plants m−2 in the 10th yr. There were more grass weeds in older stands. Total dry matter yield of forage, including weeds, did not decrease significantly with age of alfalfa stand Alfalfa yield, however, decreased with age, and the reduction in older stands was more evident in cut 1 than cut 2. There was little or no difference in cold hardiness among different stand ages in postseeding years. Root development pattern changed from vertical extension in the seeding year to lateral development of branched roots in postseeding years. Shoot number, crown diameter, crown decay taproot diameter, root depth, and number and spread of branched roots were associated with aging. Concentrations of total nonstructural carbohydrates (TNC) in the crown and roots decreased slightly with age. In the root, concentrations of K, Ca, B, and Fe increased, and Ca was most closely associated with age. No significant association of P, Mg, S, Mn, Cu, or Zn with age was found. Concentrations of minerals in the crown did not change with age, except B which increased slightly. Key words: Medicago sativa L., persistence, longevity, plant density, yield, minerals

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 Importance of progeny testing in alfalfa breeding (Medicago sativa L.)

Genetika ◽  
2010 ◽  
Vol 42 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Dragan Milic ◽  
Slobodan Katic ◽  
Jan Bocanski ◽  
Djura Karagic ◽  
Aleksandar Mikic ◽  
...  
Keyword(s):  
Medicago Sativa ◽  
Inbreeding Depression ◽  
Breeding Program ◽  
Progeny Testing ◽  
Shoot Number ◽  
Genetic Origins ◽  
Medicago Sativa L ◽  
Progeny Tests ◽  
Progeny Analysis ◽  
Forage Yields

The objective of this paper was to assess the importance and effectiveness of progeny tests that can be used in alfalfa breeding for increased green forage yields and shoot number per plant. A total of 35 alfalfa genotypes of different geographic and genetic origins were analyzed. The results of the study have shown that crossing full-sib or half-sib parents leads to a significant increase in yield and shoot number per plant. Significant inbreeding depression was observed in the S1 progenies of all the genotypes involved. The choice of alfalfa parents must be based on progeny analysis. Which particular method will be used will depend on the objective of the breeding program.

Further studies on the determination of cold hardiness in Trifolium repens L. and Medicago sativa L.

1960 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
CG Greenham ◽  
H Daday
Keyword(s):  
Medicago Sativa ◽  
Trifolium Repens ◽  
Cold Hardiness ◽  
Cold Treatment ◽  
Low Frequency ◽  
Resistance Index ◽  
Medicago Sativa L ◽  
Trifolium Repens L ◽  
Probe Measurements

This paper deals with probe measurements of low frequency resistance (RLF), high frequency resistance (RHF), and resistance index (= 100 x RLF/RHF), for the determination of cold hardiness or the injury caused by cold treatments. Populations of white clover (Trifolium repens L.) were subjected to different periods of freezing. Discrimination between treatments could be made in terms of RLF, RHF, and resistance index, though discrimination in terms of RHF is poor. The rest of the paper deals with lucerne (Medicago sativa L.). Measurements were made after a cold treatment on field plants consisting of four commercial strains and their F1 crosses, and also on F2 seedlings. RLF and the resistance index appear to be equally good predictors for the recovery of strains or of individual plants from such populations. The Appendix deals with measurements on commercial (tetraploid) plants, diploids, and colchicine-produced tetraploids.

Root and crown characteristics of alfalfas varying in fall dormancy

1994 ◽  
Vol 74 (1) ◽  
pp. 125-127 ◽  
Author(s):  
N. A. Juan ◽  
C. C. Sheaffer ◽  
D. K. Barnes
Keyword(s):  
Medicago Sativa ◽  
Key Words ◽  
Dry Weight ◽  
Nonstructural Carbohydrate ◽  
Shoot Number ◽  
Fall Dormancy ◽  
Crown Morphology ◽  
Medicago Sativa L ◽  
Crown Characteristics ◽  
Alfalfa Root

We compared root and crown characteristics of five alfalfa (Medicago sativa L.) entries which differed in fall dormancy. Alfalfas were subjected to bud or mid-bloom harvests. The most consistent entry effect occurred for root and crown dry weight and root total nonstructural carbohydrate (TNC) concentrations. Root TNC concentration was highest and root and crown weight were greatest for the nondormant and least in the most dormant entries. Entries did not consistently differ in crown bud numbers, shoot number, or shoot origin. In October, the number of elongated crown buds were greater for a non-fall dormant alfalfa Nitro than for the most fall dormant alfalfa. Key words: Alfalfa, root and crown morphology, fall dormancy, root carbohydrates

EVALUATION OF FACTORS AFFECTING YIELD REDUCTION IN MATURE ALFALFA (Medicago sativa L.)

1984 ◽  
Vol 64 (4) ◽  
pp. 901-907 ◽  
Author(s):  
E. R. JONES ◽  
R. H. SWAIN ◽  
K. W. BELL ◽  
R. B. CARROLL
Keyword(s):  
Medicago Sativa ◽  
Stand Density ◽  
Yield Reduction ◽  
Root Weight ◽  
Nonstructural Carbohydrates ◽  
Forage Production ◽  
Foliar Diseases ◽  
Total Nonstructural Carbohydrates ◽  
Crown Tissue ◽  
Medicago Sativa L

Alfalfa (Medicago sativa L.) stand longevity continues to be a problem even though progressive management practices are followed. The following parameters were evaluated on mature alfalfa stands to determine what factors were responsible for stand thinning: forage production, stand density, foliar and crown-root diseases, root and crown tissue weights, and total nonstructural carbohydrate levels. Foliar diseases did not affect stand density; however, three of five anthracnose-resistant cultivars had denser stands than susceptible parents. Fusarium infection was quite high but did not appear to be related to stand density. Individual root weight, root mass, and total nonstructural carbohydrates were not good indicators of stand density.Key words: Alfalfa stand longevity, foliar diseases, crown and root rot, root and crown tissue weight, total nonstructural carbohydrates, forage production

FALL GROWTH AND WINTER SURVIVAL OF ALFALFA IN INTERIOR BRITISH COLUMBIA

1989 ◽  
Vol 69 (2) ◽  
pp. 491-499 ◽  
Author(s):  
DARRYL G. STOUT ◽  
JOHN W. HALL
Keyword(s):  
British Columbia ◽  
Low Temperature ◽  
Medicago Sativa ◽  
Cold Hardiness ◽  
Winter Survival ◽  
Temperature Growth ◽  
Usual Procedure ◽  
Medicago Sativa L ◽  
Selection Of ◽  
Fall Growth

Extensive winter injury, likely caused by cold damage, occurred in alfalfa (Medicago sativa L.) cultivar yield tests underway at Kamloops, British Columbia during the 1985–1986 winter. Fall yield of cultivars during the year of seeding was negatively correlated with their winter survival (r = − 0.92 in one trial with 20 cultivars or strains, and r = − 0.74 in a second study with 34 cultivars or strains). Use of fall yield to predict winter survival has the advantage over the usual procedure of measuring plant height in space-planted plots, in that both total annual yield and fall growth can be evaluated in a single study. This results in a major saving of costs. Six cultivar studies all revealed that in the interior of British Columbia spring-summer yield is positively correlated to fall yield (r = 0.24 to 0.72). For this reason, selection of a cultivar with low fall growth to obtain high winter survival is likely to result in selection of a cultivar with reduced spring-summer yield.Key words: Medicago sativa, alfalfa, low temperature growth, winter injury, cold hardiness

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