scholarly journals Morpho-anatomical characterization of root in recurrent selection cycles for flood tolerance of maize (Zea mays L.)

2009 ◽  
Vol 55 (No. 11) ◽  
pp. 504-510 ◽  
Author(s):  
T.C. De Souza ◽  
E.M. De Castro ◽  
F.J. Pereira ◽  
S.N. Parentoni ◽  
P.C. Magalhăes
Keyword(s):  
Zea Mays ◽  
Recurrent Selection ◽  
Gradual Increase ◽  
Flood Tolerance ◽  
Flooded Soils ◽  
Anatomical Structures ◽  
Phenotypic Recurrent Selection ◽  
Root Sample ◽  
Selection For

Changes in root anatomical structures at successive cycles of selection (cycle 1 to cycle 18, alternating) were observed in the study of maize (<i>Zea mays</i> L. cv. Saracura-BRS 4154) capable to survive and produce in temporarily flooded soils; this cultivars was developed by the Maize and Sorghum National Research Center through stratified phenotypic recurrent selection for cultivation wetland soils. Field trial was carried out and flooding of the soil was initiated at the six-leaf stage; the soil was flooded with water (20-cm deep) three times per week. Root sample was collected, fixed, and selected for observation in photon microscope. A gradual increase in the number of aerenchyma, the proportion of vascular cylinder, smaller metaxylem, and phloem and epidermis width, and a decrease in exodermis and cortex were observed in successive selection cycles. Such phenotypic changes impart the flood tolerance ability to this maize cultivar.

scholarly journals Ear Quality in Three Sweet Corn Populations Selected for Resistance to Common Rust

1999 ◽  
Vol 124 (6) ◽  
pp. 641-643
Author(s):  
Bruce G. Abedon ◽  
William F. Tracy
Keyword(s):  
Zea Mays ◽  
Rust Resistance ◽  
Recurrent Selection ◽  
Sweet Corn ◽  
Environment Interaction ◽  
Quality Traits ◽  
Kernel Size ◽  
Puccinia Sorghi ◽  
Phenotypic Recurrent Selection ◽  
Selection For

Research was conducted to evaluate correlated effects of full-sib phenotypic recurrent selection for resistance to common rust (Puccinia sorghi Schw.) on ear quality traits in three sugary1 (su1) sweet corn (Zea mays L.) populations: Minn11, Minn14, and NECDR. Cycles 0, 1, 2, and 3 of each population were evaluated in both rust infested and nonrust infested environments. Generally, selection for rust resistance resulted in significant, but minor, decreases in ear and kernel size. Changes in specific traits varied with population. The nonsignificant cycle × environment interaction indicates similar responses occurred in all environments evaluated. Based on these results, selection for ear quality traits need not accompany selection for resistance to common rust if maintenance of ear quality is desired.

RECURRENT SELECTION FOR FORAGE AND SEED YIELD IN ZIGZAG CLOVER

1984 ◽  
Vol 64 (1) ◽  
pp. 119-130 ◽  
Author(s):  
NORMAN L. TAYLOR ◽  
PAUL L. CORNELIUS ◽  
ROY E. SIGAFUS
Keyword(s):  
Recurrent Selection ◽  
Selection Process ◽  
Linear Increase ◽  
Rate Of Change ◽  
Forage Yield ◽  
Annual Basis ◽  
Phenotypic Recurrent Selection ◽  
Winter Temperatures ◽  
Selection For ◽  
Efficiency Of Selection

Phenotypic recurrent selection on an annual basis was conducted with zigzag clover (Trifolium medium L.) to determine the efficiency of selection for improved seed and forage yield and the relationships among these characters. Seedlings were exposed to winter temperatures in a cold frame before they were transplanted in a field in the spring. The undesirable types were mowed prior to flowering and the selected plants were allowed to cross. Heads and seeds were harvested from each plant, and after seed threshing and counting, plants were further selected on the basis of numbers of seeds and heads. The effectiveness of four cycles of selection was evaluated over a 2-yr period in an experiment initiated with remnant seed and with management similar to that imposed during the selection process. Recurrent selection was effective in increasing vigor, seeds per head, heads per plant, and seeds per plant. A significant linear increase over cycles was found for each character. Vigor was not correlated with seeds per head, but was correlated with the other characters. The more vigorous plants also exhibited less stand reduction. Data from the two evaluation years were correlated suggesting that materials selected on an annual basis performed similarly to those grown in a 2-yr stand. Although recurrent selection was effective for improving all traits, the rate of change, particularly for seeds per head, was limited. Many more cycles of such selection would be required to change zigzag clover into a useful forage species. It was suggested that the phenotypic recurrent selection program should be continued on an annual basis, but modified if possible to select against the vernalization requirement for flowering which may be associated with poor seedling growth and low aftermath vigor.Key words: Trifolium medium, recurrent selection, vigor, persistance, heads and seeds per plant

Modified Half‐Sib and Phenotypic Recurrent Selection for Resistance to Powdery Mildew in Winter Wheat

Crop Science ◽  
1989 ◽  
Vol 29 (6) ◽  
pp. 1351-1357 ◽  
Author(s):  
A. H. Abdalla ◽  
W. R. Coffman ◽  
M. E. Sorrells ◽  
G. C. Bergstrom
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Recurrent Selection ◽  
Phenotypic Recurrent Selection ◽  
Selection For
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