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.

Relationships between inbreeding, meiotic irregularity, and fertility in alfalfa

1986 ◽  
Vol 28 (1) ◽  
pp. 130-137 ◽  
Author(s):  
S. E. Smith ◽  
R. P. Murphy
Keyword(s):  
Medicago Sativa ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Pollen Mother Cell ◽  
Mother Cell ◽  
Pollen Parent ◽  
Meiotic Behavior ◽  
Negatively Associated ◽  
Meiotic Irregularity ◽  
Medicago Sativa L

Fertility (seed production) in alfalfa (Medicago sativa L.) is severely depressed by inbreeding; however, little is known of the factors directly responsible for this depression. Irregularities in meiotic behavior could be partially responsible for the inbreeding depression in fertility observed. This study considered relationships between fertility, inbreeding, and irregularity in microsporogenesis. Fertility declined markedly with inbreeding in the materials examined (S0–S3). Irregularity in microsporogenesis, as measured by the percent irregular quartets, (i.e., quartets with micronuclei, supernumerary microspores, or irregular cytokinesis) increased significantly with inbreeding. Increases in quartet irregularity were associated with increases in the number of univalents per pollen mother cell observed at metaphase I. Considering all materials studied, the percentage of irregular quartets was negatively and significantly correlated with fertility as both a seed and a pollen parent. In more detailed analyses, it was observed that the percent irregular quartets was negatively associated with fertility as a pollen parent only when levels of irregularity were relatively high. No association was observed between the percent irregular quartets and fertility when levels of irregularity were relatively low.Key words: Medicago, microsporogenesis, seed production, breeding, fertility.

Productivity and sustainability of four grazed grass – alfalfa mixtures

1999 ◽  
Vol 79 (1) ◽  
pp. 83-89 ◽  
Author(s):  
N. W. Holt ◽  
P. G. Jefferson
Keyword(s):  
Medicago Sativa ◽  
Great Plains ◽  
Ground Cover ◽  
Forage Yield ◽  
Intermediate Wheatgrass ◽  
Bromus Riparius ◽  
Russian Wildrye ◽  
Medicago Sativa L ◽  
Meadow Bromegrass ◽  
Forage Yields

Forage grasses need to be evaluated in pasture trials in the Great Plains region of North America. The objective of this study was to compare four grass–alfalfa (Medicago sativa L.) mixtures for productivity and persistence when grazed during spring and summer. The grasses were Altai wildrye (Leymus angustus [Trin.] Pilger), intermediate wheatgrass (Elytrigia intermedia [Host] Nevski), meadow bromegrass (Bromus riparius Rehm. syn. B. biebersteinii Roem. & Schult.) and Russian wildrye (Psathyrostachys junceus [Fisch.] Nevski), with grass rows seeded perpendicular to the alfalfa rows. Two sites, 4 km apart, were grazed with yearling beef cattle from 1987 to 1993. Forage yield differed among grass treatments in 4 of 5 years, but differences were inconsistent over time. Five-year mean forage yields and total livestock production were not significantly different among the four grasses. Mean annual forage yields ranged from 800 to 8170 kg ha−1 and were related to the amount of growing season (April–August) precipitation. Carrying capacity ranged from 35 steer grazing days per hectare in 1992 to 176 in 1991. Grasses in the mixtures did have a significant effect on the grass–alfalfa ratio and on ground cover. Alfalfa content was highest when grown with Altai wildrye and lowest when grown with Russian wildrye. Percentage of ground cover by the grass plus alfalfa increased from an average of 3.8% in 1987 to 16.1% at one site and 31.9% at the second site by 1993. Russian wildrye contained the least alfalfa and weeds after 7 yr. Intermediate wheatgrass and Altai wildrye did not compete with invading weeds at one site, or with alfalfa at the other, and should not be recommended for spring–summer pastures in semiarid regions. Meadow bromegrass maintained a balance of grass and alfalfa and further research should confirm its persistence in semiarid climates. Key words: Leymus angustus, Elytrigia intermedia, Bromus riparius, Psathyrostachys junceus, Medicago sativa, grazing with cattle

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.

Companion crop, herbicide and weed effects on establishment and yields of alfalfa-bromegrass mixture

1995 ◽  
Vol 75 (1) ◽  
pp. 121-127 ◽  
Author(s):  
J. R. Moyer ◽  
D. E. Cole ◽  
D. C. Maurice ◽  
A. L. Darwent
Keyword(s):  
Medicago Sativa ◽  
Key Words ◽  
Weed Control ◽  
Detrimental Effect ◽  
Wild Oat ◽  
Combined Stress ◽  
Key Words Wheat ◽  
Medicago Sativa L ◽  
Companion Crop ◽  
Forage Yields

Alfalfa (Medicago sativa L.) and bromegrass (Bromus spp.) were seeded with and without a companion crop and with and without herbicides at Westlock and Lethbridge, Alberta, to assess the effect of weed control, companion crop and the herbicide-by-companion crop interaction on forage establishment and subsequent yields. A companion crop reduced both alfalfa and bromegrass yields for at least 2 yr after establishment on a rain fed site at Westlock and for 1 yr after establishment on an irrigated site at Lethbridge. At both sites, weed yields were higher after establishment with a companion crop than after establishment without a companion crop. Unchecked weeds in the establishment year had less effect than a companion crop on subsequent forage yields. At both locations, weed biomass in the establishment year was less than that of the companion crop. The combined stress of a companion crop and 2,4-DB application had a detrimental effect on alfalfa yield for 3 yr after establishment at Lethbridge. Key words: Wheat, barley, wild oat, redroot pigweed, dandelion

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

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

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