SELECTION FOR SEED SET IN NONINBRED AND PARTLY INBRED POPULATIONS OF ALFALFA

1977 ◽  
Vol 57 (3) ◽  
pp. 873-881 ◽  
Author(s):  
R. MICHAUD ◽  
T. H. BUSBICE
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Exponential Model ◽  
Seed Setting ◽  
Medicago Sativa L ◽  
Selection For ◽  
Inbred Populations ◽  
The Relationship ◽  
Advanced Generation ◽  
Coefficient Of Inbreeding

Alfalfa (Medicago sativa L.) is a highly heterozygous cross-pollinating species, and most breeding efforts have been conducted on noninbred populations. The purpose of this study was to determine whether greater breeding progress could be made by selecting within partly inbred populations rather than within noninbred ones. One hundred and twenty F1 (noninbred) and 120 S1 (partly inbred) plants that were issued from crossing and selfing four alfalfa clones were evaluated for self-fertility. The most self-fertile 10% of the plants from each family were selected in each population. The selected plants within each level of inbreeding were intercrossed to produce an advanced generation in which the effectiveness of the selection was evaluated. Selection increased both self- and cross-fertility in the advanced generation. Selection was more effective at the F1 level than at the S1 level. Fertility was reduced drastically by inbreeding. The average self-fertility of the S1’s was only about 7% of the cross-fertility of their parental clones. An exponential model was proposed to describe the relationship between seed setting and the coefficient of inbreeding in the developing zygote. This model explained 95% of the variation among 11 unselected populations having differing levels of inbreeding.

CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

1979 ◽  
Vol 21 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Nicholi Vorsa ◽  
E. T. Bingham
Keyword(s):  
Medicago Sativa ◽  
Seed Set ◽  
Pollen Grains ◽  
Genetic Constitution ◽  
2N Pollen ◽  
Diploid Parent ◽  
2N Gamete ◽  
Medicago Sativa L ◽  
Pollen Formation ◽  
Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

RAPD polymorphism in the prebreeding material for cultivation of synthetic variations of lucerne (Medicago sativa L.)

2013 ◽  
Vol 8 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Lidia Skuza ◽  
Stanisława Rogalska ◽  
Stanisław Dyba ◽  
Jan Bocianowski
Keyword(s):  
Medicago Sativa ◽  
Genetic Similarity ◽  
Seed Set ◽  
Inbred Lines ◽  
Specific Yield ◽  
Group Method ◽  
Green Mass ◽  
Molecular Image ◽  
Synthetic Population ◽  
Medicago Sativa L

AbstractGenetic diversity between synthetic cultivars (Syn5, Syn7), inbred lines (D3, D5, E1/2, G1/1, G1/2) and ecotypes (E16, E51, E182, E231) of lucerne (Medicago sativa L.) was studied using the RAPD-PCR method. The plants differed in the efficiency of seed set and in the yield of green mass. The ecotypes E182 and E231 and the synthetic population Syn5 showed the highest fertility. Additionally, Syn5 also showed the highest efficiency of seed set and the yield of green mass. Among the inbred lines, D3 was characterised by the highest yield of green mass and E1/2 by the highest fertility. An optimal combination of yield and biomass was observed for the synthetic population Syn5, obtained by crossing the lines D3, D5 and G1/1, as demonstrated using comparative analysis. A total of 338 polymorphic products were generated using 20 arbitrary primers. Cluster analysis using the Unweighted-Pair Group Method with Arithmetic Mean (UPGMA) in the Molecular image Gel Doc™ XR (Bio-Rad) software based on the Dice’s coefficient of genetic similarity showed a division of the studied forms into two groups based on genetic similarity. The ecotype E16 formed one of the groups whereas all of the other ecotypes observed in this study clustered into the second group. A high level of polymorphism among the studied lucerne forms was detected indicating an interesting gene pool awaiting future exploration. Analysis of variance also supported a high diversity among the studied forms. This study provides insightful information into the heterosis effect of synthetic populations or hybrids of F1 lucerine by providing correlations between the genetic background of the inbred lines and their ability to produce a specific yield.

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 Studia embriologiczne u pięciu odmian Medicago saliva L. Cz. II [Embriological studies in five varieties of Medicago sativa L. Part II.]

2015 ◽  
Vol 26 (1) ◽  
pp. 31-51
Author(s):  
K. Bijok ◽  
E. Adamkiewicz ◽  
L. Grygorczyk
Keyword(s):  
Medicago Sativa ◽  
Embryo Sac ◽  
Endosperm Development ◽  
Climatic Conditions ◽  
Low Fertility ◽  
Seed Setting ◽  
Medicago Saliva ◽  
Poor Seed ◽  
Medicago Sativa L ◽  
Pollination And Fertilization

The objective of this study was to elucidate the problem of low seedy yields of five varieties of <i>Medicago sativa</i> L. (Australijska, Grimma, Kleszczewska, Miechowska, and Warmińska) under climatic conditions of northern Poland. The study included pollination and fertilization processes, embryo sac, embryo and endosperm development. These factors in case of lack of the proper amount of pollen, and insufficient number of pollinators, may under certain environmental conditions results in poor seed setting and low fertility of the varieties studied.

Determination of degradation in the rumen for dry matter, organic matter and crude protein of alfalfa (Medicago sativa L.) harvested at differentmaturity stages using the in situ nylon bag method

2016 ◽  
Author(s):  
Elif Karayilanli ◽  
Veysel Ayhan
Keyword(s):  
Organic Matter ◽  
Medicago Sativa ◽  
Crude Protein ◽  
Dry Matter ◽  
Seed Setting ◽  
Maturity Stages ◽  
Mature Period ◽  
Medicago Sativa L

The aim of this study was to determine the degradation in the rumen for the dry matter (DM), organic matter (OM) and crude protein (CP) of alfalfa (Medicago sativa L.) harvested at different maturity stages by using an in situ nylon bag method. Maturity and harvesting effects were observed in ruminally degradable DM, OM and CP. High correlations between in situ degradability and maturity were determined. Alfalfa harvested in the bud period exhibited more extensive ruminal DM, OM and CP degradation than that harvested at other maturity stages. The alfalfa hay’s DM, OM and CP degradability were lowest (62.18%, 59.52% and 76.31%, respectively) in its most mature period of seed setting; its degradability decreased with maturity (17%, 14% and 13%, respectively).

COMPARISON OF YIELD COMPONENTS OF RED CLOVER AND ALFALFA

1988 ◽  
Vol 68 (1) ◽  
pp. 103-114 ◽  
Author(s):  
S. R. BOWLEY ◽  
C. T. DOUGHERTY ◽  
N. L. TAYLOR ◽  
P. L. CORNELIUS
Keyword(s):  
Medicago Sativa ◽  
Yield Components ◽  
Trifolium Pratense ◽  
Total Yield ◽  
Red Clover ◽  
Herbage Yield ◽  
Trifolium Pratense L ◽  
Medicago Sativa L ◽  
Stem Development ◽  
Selection For

Yield components of five regrowth cycles, two in 1981 and three in 1982, of three red clover (Trifolium pratense L.) populations and three alfalfa (Medicago sativa L.) cultivars were compared in swards. Red clover left more stubble but produced less herbage and accumulated total yield (herbage, stubble and 10 cm depth root) at a slower rate than alfalfa during most regrowths. The percent leaf at flowering of red clover was similar to that of alfalfa. Maximum LAI declined during successive regrowths each year. Maximum crop growth rates were 30 and 34 g m−2 d−1 for red clover and alfalfa, respectively. Stem development (canopy height) followed patterns of accumulation of herbage yield. The initiation of stems was slower in red clover and stem populations were less than that of alfalfa. Selection for faster stem initiation rates, higher stem populations, and reduced partitioning of dry matter towards stem bases which would be left as stubble were suggested as ways of increasing the herbage yield of red clover.Key words: Trifolium pratense L., Medicago sativa L., yield components, growth analysis clover (red), alfalfa

Effect of divergent selection for root size in field-grown alfalfa

1999 ◽  
Vol 79 (1) ◽  
pp. 93-95 ◽  
Author(s):  
O. Chloupek ◽  
M. Skácel ◽  
J. Ehrenbergerova
Keyword(s):  
Medicago Sativa ◽  
Root System ◽  
Selection Criterion ◽  
System Size ◽  
Forage Yield ◽  
Electrical Capacitance ◽  
Root System Size ◽  
Medicago Sativa L ◽  
Selection For ◽  
Root Size

The size of the root system as measured by its electrical capacitance was evaluated on two alfalfa (Medicago sativa L.) cultivars (Zuzana, Palava) for 3 yr. Plants with root system size (RSS) significantly larger or smaller than the cultivar mean were selected and their open-pollinated progenies were evaluated in the following 3 yr. Progenies of plants with large RSS tended to have larger RSS and higher forage yield than progenies of plants with small RSS. The differences for both parameters were significant (P < 0.05) in the case of Zuzana. It is concluded that RSS is a useful selection criterion in alfalfa breeding. Key words: Medicago sativa L., root system size, selection, yield, survival

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