Two separate experiments were conducted at the sereenhouse of the Unilorin Sugar Research Institute (USRI) IIorin, to investigate the optimum concentration of a weak acid solution required for the presciption of cut sugarcane stalks during hybridization. In the first experiment. stalks of two (2) sugarcane varieties (LS 1-047 and LS1057) which were at the flowering. phase were immersed in three (3) eonecntrations(Blank, O.004M nnd 0.006M respectively) of sulphurous acid (H2SO]) solution. In the second experiment, stalks of three (3) varieties viz: LSI-047, LSI-057 and C06806 at the vegetative phase and those of LSI-047, LSI-050, LSI-054, LSI-057, B6609 and'C06806 at the Dowering phase were also immersed in four (4) concentrations (i.e. Blank, 0.0021\1, 0.004M and O.OO(,M respectively) of sulphurie acid (H2S04) solution. Our results showed a rapid decline in the physiologienl activities of the sugarcanc stalks regardlcss of the concentration and/or the source of the weak acid used as preservative solution. Flowering sequence was also disrupted in the flowering stalks since none of the varieties could proceed to tile next ,phase, indicating that the stock solutions were toxic to the test varieties. However, rooting and side shoot emergence (beginning from the riftll and ,cvcnth day rcspeetively) were observcd ill the sugareanc stalks at both the vegetative and Oowerillg ph,lsl's or diiTercnl eoneelllralion of the weak 1-1250 •. indicating Ih,1I the: i'nrlJ'ulal ions 'frolll 112SO., were less tOXIC {O ti,l'. l''" 1-::. d"'11 {I")';l' or the 1-1)50. where the test varie{les nl:ilhl:r r()o(ed nor produce sid\' ,hm)l. i\ILllllllgh 1110 (2) or the: \'arie:lIl'S (L,SI-O'17 ,md 1..'()ll~()I,) ,'ppe"rl'" III PUSs,'ss greater {,lkral":C: k.\cl I·.' Ii;.: .!,!!"<',.:l'>I, 1:';11' lil<.'> exoLic judging by their overall performance.

1. Bioscience R..,SG2rch· Communications
Vol. 13, NO.5, October 3',. 2001
Printed in Nigeria
BRC 2000006/13505
0795-807212'X;; 1·1200 .•.0.00
~ 2001 Klobex Aeade:mc Publishers
Evaluation of Different Formulations of Weak Acid
Solution as Preservative Medium for Sugarcane Stalks
I I" 1
G. Olaoye , O.B. Bello and F.A."'A?ekola-
IDcpnrtment of Crop Production, University of lIorin, P.M.B. 1515, florin
)Department of Chemistrv. University of Ilorin, P.M.B. 1515, !lorin.
(Receivl:d .;QflUary 21, i.aOO)
ABSTRACT: Two separate experiments were conducted at thc sereenhouse of the Unilorin Sugar Resenreh Institute
(USRI) IIorin, to investigate the optimum concentration of a weak acid solution required fo'r the prescf'aLion of cut
sugarcane stalks during hybridizntion. In the first experiment. stalks of two (2) sugarcane varieties (LS 1-047 and LS1-
057) which were at the flowering. phase were immersed in three (3) eonecntrations(Blank, O.004M nnd 0.006M
respectively) of sulphurous acid (H2SO]) solution. In the second experiment, stalks of three (3) varieties viz: LSI-047,
LSI-057 and C06806 at the vegetative phase and those of LSI-047, LSI-050, LSI-054, LSI-057, B6609 and'C06806 at
the Dowering phase were also immersed in four (4) concentrations (i.e. Blank, 0.00211, 0.004M and O.OO(,M
respectively) of sulphurie acid (H2S04) solution.
Our results showed a rapid decline in the physiologienl activities of the sugarcanc stalks regardlcss of the
concentration and/or the source of the weak acid used as preservative solution. Flowering sequence was also disrupted
in the flowering stalks since none of the varieties could proceed to tile next ,phase, indicating that the stock solutions
were toxic to the test varieties. However, rooting and side shoot emergence (beginning from the riftll and ,cvcnth day
rcspeetively) were observcd ill the sugareanc stalks at both the vegetative and Oowerillg ph,lsl's or diiTercnl
eoneelllralion of the weak 1-1250 •. indicating Ih,1I the: i'nrlJ'ulal ions 'frolll 112SO., were less tOXIC {O ti,l'. l''" 1-::. d"'11 {I")';l'
or the 1-1)50. where the test varie{les nl:ilhl:r r()o(ed nor produce sid' ,hm)l.
iILllllllgh 1110 (2) or the: 'arie:lIl'S (L,SI-O'17 ,md 1..'()ll~()I,) ,'ppe"rl'" III PUSs,'ss greater {,lkral":C: k.cl I·.' Ii;.: .!,!!"<',.:l'!
forllllliatiolls of the H)50., the locals (LSI) ilppC'lIl'.lI 10 POSS'5S g,cillcr llk'rilllel' capaeit~, 10 tilt, Silld, ,·;,.,I;'!I,>I, 1:';11' lil<.'
exoLic judging by their overall performallce.
Introduction
The most convenient hybridization method ill sugarcane (Sac;cahrum ojjicnarum L.) involves the use of
weak sulphurous acid (H2SO}) solution which serves as preservative medium for cut flowering stalks
during crossing and fuzz (seeds) rupening. When used in conjuction with the breeding laniern (specially
constructed rectangular enclosures made up of cloth materials and supported by metal wires), the technique
501

2. ... ~.._~---...__ .. -......•.. _-" ..••..-
permist the sugarcane breeder to set up planned crosses between male sterile clones (as females) and male
fertile clones (as males) without fear of contamination from wind-borne pollen.
In most sugarcane breeding stations where the H2S03 solution is used as a preservative medium (lor
example, Hawaii and Florida, U.SA.), the active ingredient which is the liquefied sulphur dioxide (S02) is
manufactured industrially and supplied to the breeding stations· upon request (Miller, personal
communication). Since this facility is presently unavailable in ~igeria, our present hybridization
programme has been limited mostly to collection of fuzz from (i) open pollinated- anows (flowers) of
female clones of planned crosses or (ii) the recently proposed modified polycross method of sandwiching
female clones between identified male clones whose flowering period could be synchronized (Olaoye,
]996). The necessity to maintain sufficient isolation distance from the nearest sugarcane field (so as to
ensure the absence of contamination from unwanted pollen) limits the number of such crosses that can be
established at a time. Our experience with marcotting method has also shown that it is only feasible with
freely flowering varieties. This is because with sparsely flowcring clones, many of the marcatteu stalks
may not flower thus limiting the number of crosses that could' be made. Furthermore, it has been
established that the ratio of the female to malt: clones in our germplasm is very low (Olaoye, unpublished
data). It therefore follows that in order to fully utilize the genetic potentials of our germ plasm accessions, it
is necessary to explore the possibility of locally producing the required preservative solution The
advantage of such formulation include opportunity to (i) ulilize thl: superior clones in series of crosses III
maximize genetic variability for characters of interest and also crcate new ones; (ii) gain inllmll:lliol1 on
the mode of inheritance of certain qualitative and quantitative characters, including resistance to prevalent
disease and insect pests, in order to determine lhe type of breeding system to employ in improving the
overall productivity of the crop and (iii) set up cro~ses aimed at either correcting certain genetic defects or
upgrade other characteristics presently lacking in the existing commercial varieties.
Apart from the success with H2SO] reported in the literature (Warner, 1953), there hus been no other
report of any formulation for maintaining sugarcane stalks in a physiologically active state for the purposes
of hybridization. This study was therefore designed to investigate the effect of different formulations of
weak acid solution (including H2SO.1) on the survival and physiological activities of sugarcane stalks aimed
at developing an appropriate medium for maintaining flowering stalks in a viable state during hybridization
programme.
Materials and Methods
"'rhoratory preparatio/l (~ld{fferentjiJf'll1u/atiolls of the weak acid sO/lItioIlS: Analytical procedure ji),. the
production of H}S(),:
About fifty grams (SOg) of zinc (Zn) metal was placed in a conical ·flask connected via the uelivery
tubes to two other conical flasks connected in series into which 200ml of distilled water were added.
Approximately, IaOrnl of dilute tetra-oxo-sulphate VI acid (20% or'the H2S04) was introduced into the
reactor which contains excess amount of zinc metal. This generated a stream of sulphur IV oxide (S02) gas
which was then absorbed into the other two conical flasks containing distilled water until the reaction was
completed. The process was repeated several times to generate sufficient quantity of the solution required
for the study.
Determillatiofl of the molarity of H 2S0; alld the ti{ratiofl procedure:
Ten milliliters (10ml) of the H2SO] was added to the conical flask using 10mi pipette. The
concentration of the stock solution (i.e. HJS03) was determined by simple titration against 0.05M Na2C03
and using phenophtalein as indicator.
Determination of the molarity of H ."!SO, solutioll:
After the molarity of the dil. H2S04 solution has been determined as described forH2SO], IOml of
H2S04 was added into the conical flask using lOrnl pipette. A drop of phenophtalein as indicator was
502

3. dispensed, then O.05M of Na2CO} was gradually introduced into the j~ask until the solution turned pink
Thereafter, the volume of Na2CO} at the point of change was determined ancLrecrn:ded. A range of
concentrations of H2S04 (O.002M, O.004M and O_006M respectively) were thus prepared for the experiment
by dilution using doubly distilled water.
Experimcma/ procedure:
Two separate-experiments were conducted at the screenhouse of the Unilorin Sugar Research Illstitute
(USR1). The experimental materials included stalks of sugarcane varieties at two distinct growth phases
(i..e. vegetative and flowering respectively) The varieties used w~re part of the flowering types among the
48 sugarcane germplasm accessions being maintained at the USRI research farm. For each experiment,
stalks of the clones were prepared in the morning by cutting them··above the ground level and the cut end of
each stalk were immediately wrapped with polythene sheet. This; was done to prevent air from enlering
into the capillary vessels. The stalks were then transported to the :screenhouse where the experimem was
set up. Preparatory to the set up of the experiment, dried leaves and leaf sheaths were removed from the
stalks. Similarly, dry tips of each leaf was cut with the aid of a small scissors. The polythene sheets were
then removed and a smooth cut end made (where necessary) folloWCi;dby inserting the cut end infO jars.
containing the stock solutions. For each experiment, doubly distilled water (i.e. blank) served as the
control.
Experiment I:
The materials used comprised of flowering stalks of two (2) varieties viz: LSI-047 and LSI-054
respectively which were at the initiation phase of flowering. The two ,clones were selected for the study
since at the time of setting up the experiment, they were the only male and female clQnes with sutticient
.flowering stalks. The cut end of each stalk was inserted into jars containing SOOml each of the
.. concentrations of H2SO] (blank, 0.004 and O.006M respectively) and each treatment was replicated twice.
The stalks were then held in erect position with the aid of stick bars. The level of the solution was
monitored regularly and made constant by replenishing the stock with the equal amount that was necessary.
Data co/lee/iol/:
The general physiological conditions of the sugarcane stalks in each solution was monirored daily and
the following indices were used to assess the performance of the clones
(i) the 'stay green' assessmenl (i.e. visual appearance);
(ii) the rate at which leaves withered (an assessment of loss of physiological. activity in the
. a/reeted leaves) and
(iii) progressive development of the flowering phases.
Experiment II
The general outline of the materials and methods are essentially similar to that of experiment { except
that 0) a different source of dilute acid (H2S04) was used and (ii) additional v~ieties at both the
vegetative and flowering phases were used.
For the vegetative phase, sugarcane stalks of similar age (based on the number of internodes/stalk) were
selected from vars. LST-047, LSI-050 and C06806 and prepared as described for experiment r. With
respect to the flower.ing phase, additional varieties (vi;,:: LSJ-047-LSJ~054 and B6609) were included to
make a total of five varieties for this phase. The materials were assessed in fourdifferent concentrations of
the dil. H2S04 (biank, 0.002M; O.004M and 0.006M respectively) and set up as described in experiment 1
The level of each stock solution was also maintained similarly as for experiment [ and the same set of data
collected on all the varieties.
503

4. Results
. .
Generally, there wa~ a gradual decreasc in thc lelcl of the stock solutions (except in lhe COllillll)
beginning from two days after the commencement of the experiments and this 'is an indiclltion that probahiy
the preservative medium has activation and catalytic effects on the stored nutrients and other metabolites in
the cane staJks.
fxperimef// I
Slay green assessment (visual appearallce):
Beginning /Tom two days after the commencement of this study, decline in physiological activities were
observed in both varieties as their leaves began to wither. The withering began from the older leaves which
progressively turned form the normal green colour to brown and drying /Tom the tip of each leaf
Leaf reten/ioll capaCity:
The result of the leaf retention capacity of the two varieties (Fig:" 1) reveaJed a rapid decline in the
number of leaves as they withered and died prematurely especially in Jne' control and 'in O.006M H2SO.1
respectively. However, var. LSI-047 exhibited a greater tolerance capacity than var, LSl-054 especially at
the lower concentration (0.004M) ofH1SO" as the two inner leaves survived up"tilJthe J5th day in this
medium.
Progressive developmef/t (~fflowerif/X phase:
In sugarcane, four distinct phases of flowering IS recognizable and the sequence is as follows: .
initiation~ flaggin'g -Hipping ---~arrow emergence. Although the two varieties were at the initiation
when the experiment was set up, neither of the two could proceed to the next phase even at the lower
concentration of O.004M (H2SOJ) and this may be due to disruption in the hormonal system of the plants
resulting from toxicity ofthe solution.
Experimef/t II
SJay green assessment:
13eginning from two days aller the commencement of this study, decline in physiological activities were
observed in both varieties as their leaves began to wiLher. The withering began from the older leaves which
progressively turned /Tom the normal green colour to brown and drying from the tip of each leaf.
Leaf reJcnJiofl capacity:
The result of the leaf retention capacity of the two varieties (Fig.~ 1) revealed a rapid decline in the
number of leaves as they withered and died prematurely especially in the control and in O.006M H2SO]
respectively. However, var. LSr-047 exhibited a greater tolerance capacity tlianvar. CSr-054 especially at
the lower concentration (O.004M) of H1SOj as the two inner leaves [survived up till. the] 5th day in this
medium. i'
Progressive development of flowering phase:
In sugarcane, four distinct phases cf flowering is recognizable and tbe sequence is as follows:
initiation ~ flagging ~ tipping ~ arrow emergence. Although the two varieties were at the initiation
phase when the experiment was set up, neither of the two could proceed to the next phase even at the lower
concentration of O.004M (H2SOj) and this may be due to disruption in the hormonal system of the plants
resulting from toxicity of the solution. .
504

5. G----€> LSI-054 CONTROL
I I C06808 CONTROL
[]---El LSI-054(0.0021:f)
~ C06808!(0.002M)
1!.----A LSI-054(0.006M)
.---JE C06808(0.006M)
9 11 13 15 17 19
Days
Fi~. 2a Leaf retenlion capacity ~ithe flowering stalks of two sugar
cane "aiieties immersed illdifferent concentrations of
preservative medium H,So.·
8
Ul Q);>(";jQ)....:I 6l:: Q)Q)~CO'-H00-;L
19171513
o 0 LSI-054 CO}JTROL
I I LSI-047 CO}JTROL
o D LSI-054(0.004M}
o <> LSI-047 (0.004M)
.A A LSI-054(O.006M)
W W LSI-047(O.006M)
53 11
Days
Fig. I Leafretenlion capacity of the !lowering stalks of two sugar
cane varieties immersed in ditTerent concentrations of
preservative l11ediuOl H:SOJ
o
Z
10
Ul
Q)
;>
~ 6
>-l
~
Q)
~
bJ)4
'-H
o
U1
aU1
.~.,..

6. F..xperimellf II
Slay green m:'essmellf:
Generally, canes at the vegetative phase were more tolerant to the different concentrations or the dil.
H2S04 as well as the control than those at the flowering phase. This high level of tolerance exhibited by
the young canes may be due to higher accumulation of growth factors in the young canes than in the
flowering ones or that there is less demand for these essential nutrients during the vegetative phase.
However, the trend in the decline in physiological activity as indicated by withering and subsequent death
of leaves was similar to what was observed in experiment 1 regardless of the age of the canes.
Leqlrelelllioll cupacity:
Leaf retention capability of the young canes in the different concentrations of H2S04 and in the control
are presented in Table J. For this parameter, attention was focused only on the four innermost leaves !IS
these were the youngest and most physiologically active. All the test varieties responded similarly in the
control and the only remarkable difference' in varietal response at!,his stage was at a concentration of
0.002M H2S04 where var. LSI-047 appeared to be more tolerant than'the others. For example, while the
two innermost leaves remained alive until the experiment was terminated (51 days), those of vars. LS.I-050
and C06806 were alive for only 35 and 41 days respectively. The response of the cane stalks to the other
two concentrations did not differ much even though the varieties' changed ranking in their leaf retention
capability (Table I).
Table I:Leaf retention capacity of young (vegetative phase)sugarcane stalksimmersedIndifferent
Variety
NooCdays for which leaf remained physiologicafly active
o.
O.OOM0.002M0.004M0.006M 35+514549355140453020253515152020 35355050353545503030404020204040 35355045354145452040'40 405253020
506

7. The rate in loss of physiological activity was taster at the flowering phase that at the vegetative phase
regardless of the concentration of the preservative medium (Fig. 2) Both vars. LSJ-054 ancl (06806
showed differential response to O.002M and O.006M res~ectively with the former exhibiting higher
tolerance capacity at O.006M H2S04 while the latter exhibited similar response to both concentrations (Fig.
2a). Val'. 136609 on the other hand was intolerant of either cqncentration (Fig. 2b). Comparison among the
four varieties in their tolerance to O.006M lhSO~ (Fig. 3) revealed that vars. LSI-050 and LS1-054 both
exhibited greater tolerance level than the other two varieties as they survived longer than the other two
varieties (app. 8 days).
Similar to what was observed in experiment r, none of the test varieties could proceed to the next
flowering phase (i.e. the flag stage) irrespective of the concentration of the preserval ivc mediull1 used
However, there were initiation of rooting as well as emergence of side shoot both at the vegetative and
flowering phases (Plates 1. 2 and 3). At the vegetative phase, rooting occurred in var. LSI-047 beginning
from the fifth day in both the lowest and highest concentrations (Plate I) but not in the intermediate
concentration while emergence of side shoots were observed beginning from the 7Ul day at the Slh node in
this medium. While neither rooling nor side shoot emergence occurred in-var. C06806, var. LSJ-OSD rooted
only in the highe'1>tconcentration. The root~ de1elopeO. and progre:>:>i1elyhardeneO after 32 lia)':> and later
died. The two side shoots produced by var. LSf-047 (Phase r) measured 15 and- 25cm respectively and
were alive until the experiment was terminated.
At the flowering phase, rooting and emergence of side shoots occurred in two of the test varieties (LSl-
050 and C06806) immersed in the medium containing 0.002M H2S04 (Plates 2 and 3). Root initiation was
observed also as from the fifth day in the two varieties and this was followed by emergence of side shoots
as from the 7111 day beginning from the sixth node. Root proliferation was faster and higher in var. LSI-050
than in var. C06806 (plate 2). By the lih day, three mare. node~ llZ:. 71h, gU, and 9"1 (arrowed> lat.er
produced side shoots (Plate 3) which developed capidly than the older shoots suggesting apical d(lmirJ8.flcc
in nutr·lent sourc·lIlg. Follow·lIlg root initiation and side shoot emergence, tile solut"ton .1Ilthe jars reduced at
a faster rate in these varieties compared to others which neither rooted nor produce side shoots. This is
probably due to increased metabolic activities in the stalks. Drying of the side shoots was observed from
52 days after the experiment was set up.
Discussion
The primary objective of this study was to formulate an appropriate preservative medium which could
keep cut surgarcane stalks in a viable state during the period of hybridization and fuzz ripening. This
period is expected to last up to three weeks. The results obtained in this study revealed that test varieties
survived in the formulations from H2S04 for more than the expected-period. In other words, even at the
same molarity, formulations tram H2SO, served as better preservative media than formulations of H2S03.
For example, cane stalks at both the vegetative and flowering phases responded better by (i) being
physiologically active for a longer period and (ii) producing roots and side shoots in the different
concentrations of the dilute H2S04• while they could only survive for between 5 and 9 days in those of
H2S03 and without root initiation nor side shoot emergence (Figs. 2 and 3, Plates 1;2 and 3)
In sugarcane, development of side shoots is a common feat~re in flowering varieties especially after the
death of the main stalk following fuzz ripening. Thus the occurrence of side shoots in these varieties
indicated that the stalks were still physiologically active despite the initial withering of the leaves.
However, while the initiation of rooting and/or emergence of side shoot suggests stability of the ·stalks· in
the preservative solution after the initial shock, it was apparent that the disruption in the physiological
activities had terminated the flowering process. Consequently and upon recovery from the initial shock, the
hormones responsible for rooting and side shoots in the respective primordial wer;;- probably activated
resulting in rooting and side shoots observed. This implies that the two events (flowering versus
rooting/side shoot emergence) are independent of the otherknd are probably controlled by different
hormones. The ability of H2S04 to act as a rooting hormone has also b~n reported by Jones a.nd Hatfield
(1976).
507

8. G------€) L51:050
I I L51-054
~B6609
~C06806
2
8
5 ,7 9 11 13 15 17 ' 19
Days
Fig, 3 Leaf retention capacity of the !lowering stalks of four sugar
cane varieties immersed in 0.006M H,SO,
10
C
<lJ
<lJ
I-
bll
4-
o
o
Z
VJ
<lJ
>
cj
<lJ
..J
G-----E) L51-054 CONTROL
I I C06808 CONTROL
[}--{l LSI-054(0.002M)
~ C06808 (O,002M)
A-------A LSI-054(O.006M)
3 5 11 13 15 17 19
Days
fig, 3 Leaf retention capacity of the flowering stalks of four sugar
cane varieties immersed in 0.006M H,SO.
10
8
~ 6
>
::
:J
J.-l
..::
:J
:J
I-
~
'--<
o
0'2
ZU'1
o(Xl

9. 2 3 4 5 6
Pi,di:: I. Phc)tograph showing the extent of root formation in young stalk~ of two
sllgcrCl.1ne varieties immersed in three different COllcelltrations of the preservative
nlcdiul1i. Note that var. LS-047 failed to root in imcrmcdia1c conccntnitioLJ bell rooted in
10ver "IlI(J higher com;entralions.
(I) f..S-050, 0.0021/1 H2S04; (2) LS-047, O.OOLM H2SO.; (J) LS-OSO, O.004M H2S04;
(4) LS-047, O.004M H2S04; (5) LS-050, 0.006''1 H2S0-1; *6) LS-047:0.006M H2S04,
508

10. Fig. 2: Photograph showing the extent of root proliferation in the following stalks of
var. CO-6806 and LS-050 immersed in a.a02M H2S04 after the death gy,een
leaves. The dark colouration in roots of LS-050 showed that the roots were already old.
510

11. !", ,'.",
Fig. 3: Photograph showing the emergence of side shoots in flowering stalks of vars.
CO-6806 and LS immersed in O.002M H2S04 after death of the green leaves.
511

12. The local (LSI-) varieties appeared to have a higher tolerance level than the exotics This is
exemplified by the high sensitivity ofvar. B6609 as compared to var LSI-050 (Fig 2b) and the extent of
root proliferation in var LSI-050 relative to that of var. C06806 (Plate 1). Similar differences in
tolerance to preservative solutions have been reported by earlier workers For example, Bourne (1929)
noted that the Florida first nobilizations of"Chunee" variety kept better in the solution than the noble
canes while Warner (1953) also reported that some of the Barbados varieties could not tolerate the
conditions in solution as well as most of the locally bred varieties
Our results especially for the H2S03 is contrary to the success previously reported in Hawaii
(Warner. 1953) However. Stevenson (1965) noted that in spite of its property to maintain growth,
flowering and seed setting in cut canes, H2S03 is well known to be toxic to cane tissues when in
concentrations above the minimum required by the plants and that its function is not really well
understood. This tends to suggest the need to find means of regulating the absorption of the acid
solutiOn Walker (1960) and Stevenson (1965) have suggested certain modifications when using
sulphurous acid as preservative medium to cut canes These include coating leaf-sheaths of cut canes
with latex emuision to prevent stalks from absorbing quantities of the acid solution more than the
minimum required and cutting the surface of the stalk at least once at the time of renewal of the
SQlution. Therefore, it may be necessary to conduct further studies, aimed at regulating the absorption
of the stock solution from these formulations or lower their concentrations (for example, ofthe order of
ID") as a means of eliminating their toxic effects Alternatively, the bc:'.<lviour of new substances such
as Na2S03, CH3COOH which (may eliminate the toxic effect ofH+) could be investigated.
References
Bourne (1929) The evolution of a philosophy of sugarcane breeding in Hawaii. Hawaiian Planters
Rec.54.N03.pp. 139-162.
Hem/, DJ. (ed.) (1987). Sugarcane improvement through breeding. Amsterdam, New York. Elsene/,
USA.
Jones, 0.0 and S.G.S. Hart field (1976). Root initiation inApple Shoots cultured in vitro with Auxj ns
and Phenolic compounds. Jour. HoL Sc. 51: 495 - 499.
Olaoye. G. (1996). Genetic variability between and within progenies of sugarcane cross developed by
modified
polycross method at the seedling selection stage. Proc 14,bAnnual Conf. HO RTSON: 231-237
Stevenson. G.c. (1965). Genetics and Breeding of sugarcane. 272pp.
Walker. D.I T. (1960). Useful information from variety trials. Proc. B w.,T. Sugar Tech. Meeting, pp.
312-318.
Warner. IN (1953). The evolution of a philosophy on sugarcane breeding in Hawaii. Hawaiian
Planters Rec. 54. No.
3.pp.139-152.
512