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BREEDI NG FOR IMPROVED NUTRIT I VE VALUE
OF PHALARI S TUBEROSA HERBAGE
A thesis prese�ted i n fulfilment of the re qui!ements
for the Ph .D. degree at Ma�sey University
ROBERT JOHN SC OTT C LEHENTS
1 970
General I nt roducti on Literature Review
TABLE OF CONTENTS
Experiment 1 : Variation .in herbage digestibili�y and nitrogen content among species and strains of Phalaris
Experiment 2: The inherita nce of herbage digestibility and nitrogen content in an Algerian ecotype of Phalaris tuberosa
Experiment 3: Selecti on for high and low n itrogen content i n an advanced Phalaris tuberosa
breeding populat i on
Experiment 4 : Fi eld studies on spaced plants of Phalaris tuberosa selecti on lines genetically different i n nitrogen content
Experiment 5: A comparison of the y i eld a nd
nutritive value of herbage from swards of Phalaris tuberosa lines previously selected for high and low herbage nitrogen concentra t i on
Experiments 6-8: An examinat i on of the seedling vi gour, nitrogen economy a nd apparent photosynthet ic rate of Ph alaris tuberosa lines previ ously selected for high o r low herbage nitrogen concentration
Experiment 9: The relati onshi p between seed weight a nd
Page
1 2
1 9
63
87
1 09
herbage nitrogen concentration in Phalaris tuberosa 1 33
General Discussion and Conclusions 1 49
Summary 1 59
Acknowledgements 1 63
References 1 64
Appendices
LI S T OF FI GURES
Figure 1 . - Regress ion of %N on heading date , for a t o t al o f 39 s t rains of 6 annual and 5 pe rennial P halaris spe c ies a nd 4 categories o f inte rspe c i fi c hybrids
Figure 2. - IVDO M ( heading) plotted agai nst IVDOM ( mature ) for
39
P . tube rosa fami lie sFigure 3. - Respons e t o select ion for h igh and low
32
percentage n it r ogen in whole tillers a t heading 55
Figure 4 . - Changes in percentage nit rogen and associated
charac ters p e r cycle of selec t ion 57
Figure 5 . - E ffe c t of freque ncy of de folia tion on the botanical c omposi tion o f swards of high , low and control N selec t i on lines
Figure 6. - D i f fe rences in seasonal Phalaris yie lds between lines previously selec t e d for high , low or random %N i n whole tillers at heading
Figure 7. - Dail� maximum and minimum glasshouse
temperatures ( weekly av erages ) during experiments 6 and 7
Figure 8.·� C orrelations be tween indiv idual seed weigh t and photosynthetic area per s e � d in different organs and comb i na tions of· organs
' . .
Figure A1 •. - Regression of leaf area on l�ngth x ·b re�dth measurements
' '
97
1 19
1 41
A1 8
