Agronomic performance and genetic diversity of the root crop yam bean (Pachyrhizus spp.) under West African conditions [Elektronische Ressource] / by Ahissou Séraphin Zanklan

Agronomic performance and genetic diversity of the root crop yam
bean (Pachyrhizus spp.) under West African conditions







Doctoral Dissertation

Submitted for the degree of Doctor of Agricultural Sciences
of the Faculty of Agricultural Sciences
Georg-August University Göttingen
Germany



by

Ahissou Séraphin Zanklan
from Porto-Novo, Benin





Göttingen, July 2003




















D7

st1 examiner: Prof. Dr. Heiko C. Becker

nd2 examiner: Prof. Dr. Elke Pawelzik

Date of oral examination: 17 July 2003





























To my parents, brothers and sisters

Table of contents

List of Abbreviations...................................................................................iii
List of Figures..........................................iv
List of Tables...............................................................................................v
1. Introduction and literature review...........................................................1
1.1. Background and objectives......................................................1
1.2. The genus Pachyrhizus............................................................4
1.2.1. Botanical description, taxonomy and ecogeographic
requirements.............................................................................4
1.2.2. Agronomy and breeding...........................................................9
1.2.3. Chemical Composition and Nutritional Value...........................14
1.2.4. Biological Nitrogen Fixation......................................................16
2. Evaluation of the root legume yam bean (Pachyrhizus spp.) under West
African Conditions...................................................................................18
2.1. Introduction.............................................18
2.2. Materials and Methods..............................................................19
2.3. Results......................................................................................25
2.4. Discussion.................................................................................44
2.5. Summary.................................................48
3. Genetic diversity in yam bean (Pachyrhizus spp.) revealed by multivariate
analyses of morphological and agronomic traits......................................49
3.1. Introduction................................................................................49
3.2. Materials and Methods..............................................................51
3.2.1. Plant material..........................................51
3.2.2. Field experiments .....................................................................51
3.2.3. Statistical analysis.....................................................................56
3.3. Results...........................................................57
3.4. Discussion.................................................................................64
3.5. Summary.................................................67

i
4. Genetic diversity in yam bean (Pachyrhizus spp.) germplasm revealed by
Near Infrared Reflectance Spectroscopy.................................................68
4.1. Introduction................................................................................68
4.2. Materials and Methods...............................................................69
4.3. Results.......................................................................................72
4.4. Discussion..................................................................................76
4.5. Summary..................................................77
5. Conclusion.................................................................................................79
6. Summary / Zusammenfassung / Résumé.................................................80
7. References..............................................................90
Appendix...................................................................................................111
Aknowledgements........................................................121
Curriculum vitae........................................................................................123
ii
List of Abbreviations

AC Andean yam bean (P. ahipa) accession
CC Chuin Cultivar group of the Amazonian yam bean (P. tuberosus)
EC Mexican yam bean (P. erosus) accession
G Genotype
ha Hectar
INRAB Institut National des Recherches Agricoles au Bénin
L Location
NIA Experimental station at Niaouli (Benin)
NIRS Near Infrared Reflectance Spectroscopy
PC Principal component
PCA Principal Component Analysis
R Replication
SON Experimental station of “Centre Songhai“ in Porto-Novo (Benin)
t Ton
TC Amazonian yam bean (P. tuberosus) accession




iii
List of Figures

-1Figure 2.1. Means of tuber fresh matter yield with and without pruning (t ha )
-1Figure 2.2. Means of tuber dry matter yield with and without pruning (t ha )
Figure 3.1. Plot of the first and second component scores for the 34
accessions of yam bean, Pachyrhizus spp.
Figure 3.2. Plot of the first and third component scores for the 34 accessions
of yam bean, Pachyrhizus spp.
Figure 3.3. Cluster analysis on basis of 71 agronomic and morphological traits
from a two locations field trial in Benin / West Africa
Figure 4.1. Plot of the first and second component scores for the spectral data
from 34 accessions of yam bean ( Pachyrhizus spp.)
Figure 4.2. Cluster analysis on basis of Near Infrared Reflectance
Spectroscopy (NIRS) spectra of seeds from a two locations field
trial in Benin / West Africa


iv
List of Tables

Table 1.1. Key to Pachyrhizus species 2. Literature overview of yield performance in Pachyrhizus spp.
Table 2.1. List and passport data of accessions tested 2. Description of experimental sites
Table 2.3. Agronomical characters evaluated, code and procedure of
measurement
Table 2.4. Effect of pruning on 12 agronomical characters for the Amazonian
Yam Bean (P. tuberosus), the Mexican Yam Bean (P. erosus) and
the Andean Yam Bean (P. ahipa) obtained from an analysis of
variance
Table 2.5. Means of agronomical traits after pruning of reproductive parts
measured at two locations in Benin West Africa.
Table 2.6. Means of agronomial traits without pruning of reproductive parts in Benin West Africa.
Table 2.7. Variance analysis for tuber fresh matter yield in Andean Yam Bean
(P. ahipa), Mexican Yam Bean (P. erosus) and Amazonian Yam
Bean (P. tuberosus)
Table 2.8. Variance analysis for tuber dry matter yield in Andean Yam Bean
(P. ahipa), Mexican Yam Bean (P. erosus) and Amazonian Yam
Bean (P. tuberosus)
Table 2.9. Variance components of agronomical traits estimated from
treatment pruning of reproductive parts.
Table 2.10. Variance components of agronomical traits estimated from
treatment no pruning of reproductive parts.
Table 2.11. Means of traits of individual accessions within treatment pruned
Table 2.12. Correlation coefficients of tuber fresh matter yield and of tuber dry
matter yield with important yield components (Treatment with
pruning)
v
Table 2.13. Correlation coefficients of tuber fresh matter yield and of tuber dry
matter yield with important yield components (Treatment without
pruning)
Table 3.1. Morpho-agronomic characters evaluated, code and procedure of
measurement
Table 3.2. Results of Principal Component Analysis, Eigenvalues of the
Correlation Matrix
Table 3.3. Pearson Correlation Coefficients for principal components
Table 4.1. Results of Principal Component Analysis from the spectral data,
Eigenvalues of the Correlation Matrix

Appendix

Table A 1. Field plan at Centre Songhai, Porto-Novo, for the treatment without
and with pruning
Table A 2. Field plan at Niaouli for the treatment without and with pruning
Table A.3 Coefficients of Correlation of different traits in P. ahipa without
pruning of reproductive parts
Table A.4. Coefficients of Correlation of different traits in P. erosus without
pruning of reproductive parts
Table A.5. Coefficients of Correlation of different traits in P. tuberosus without
pruning of reproductive parts
Table A.6. Coefficients of Correlation of different traits in P. ahipa with pruning
of reproductive parts
Table A.7. Coefficients of Correlation of different traits in P. erosus with
pruning of reproductive parts
Table A.8. Coefficients of Correlation of different traits in P. tuberosus with
pruning of reproductive parts


vi
1. Introduction and literature review

1.1 Background and objectives

Many thousand plant species have bee