Coconut Research Institute Repository

Nainanayake, A.D.

Use of chlorophyll fluorescence parameters to assess drought tolerance of coconut varieties

Asanka, J.R.K.

Marrikkar, J.M.N.

Gasification Technology for production of good quality edible copra and charcoal

Fernando, L.C.P.

An electronic device to detect red weevil infestations

Kumara, P.M.U.S.

Perera, S.A.C.N.

Fernandopulle, M.N.D.

The Evaluation of Morphological Differences between Green 
Dwarf x Sri Lankan Tall and Yellow Dwarf x Sri Lankan Tall Hybrids 
P.M.U .S. KUMARA S.A.C.N. PERERA 1 and M.N.D. FERNANDOPULLE 2 
'Department of Plantation Management, Faculty of Agriculture and Plantation Management, 
Wayamba University of Sri Lanka, Makandura, Gonawila (NWP). 
2Genetics and Plant Breeding Division, Coconut Research Institute of Sri Lanka, Lunuwila. 
A B S T R A C T 
The recommended coconut cultivar CRIC6S was developed by crossing Sri Lankan Dwarf forms, Green and 
Yellow, with Sri Lankan Tall. Although recommended under the same cultivar name certain morphological 
differences have been observed between these two hybrids. The current study was conducted to evaluate and 
compare stem, leaf, crown and fruit morphology and the yielding ability of the two hybrids. A total number of 80 
palms representing 40 palms each from two hybrids were selected to collect the morphological data. Primary data for 
stem and leaf morphology, nut setting percentage and fruit morphology were scored while secondary data for nut 
yield and fruit components were obtained to evaluate the differences between the two hybrids. Statistically significant 
differences were observed for stem morphology, number of leaflets and certain fruit component parameters in the 
detailed analysis with primary data. Furthermore, the analysis of secondary data revealed annual nut yield 
differences and also differences in fruit components between the two hybrids. In conclusion the study revealed that 
the hybrid Green Dwarf x Sri Lankan Tall to be the better nut producer and the hybrid Yellow Dwarf x Sri Lankan 
Tall to produce larger nuts in general. 
KEYWORDS: Fruit component, Morphology, Nut setting, Nut yield 
I N T R O D U C T I O N 
Coconut (Cocos nucifera L.) belongs to the 
family Arecaceae and is one of the major plantation 
crops in the tropics. Different communities in this 
region have used coconut for food, health and 
general well being. They referred to coconut as the 
"tree of life" and every part of coconut palm is used 
for different purposes. Sri Lanka is the 4 t h largest 
coconut producing country in the world having 
approximately 440,000ha of land (Liyanage, 1999) 
under coconut cultivation. Coconut industry has a 
great impact in the economy of Sri Lanka 
accounting for about 1.7 percent of Gross Domestic 
Product (GDP) and 2.5 percent of foreign exchange 
earnings (Anon, 2006). It is a main source of food 
in addition to bringing foreign exchange earnings 
for national economy. It also provides a large 
number of employment opportunities both in the 
plantation sector and the coconut industry. The 
national coconut production in Sri Lanka in 2006 is 
2866 million nuts, while the current productivity is 
6486 nuts/ha/yr (Anon, 2006) which can be 
increased up to 10,000 nuts/ha/yr by adapting 
proper agronomic practices with the use of 
improved planting material. 
Although, there is a considerable productivity, 
coconut industry in Sri Lanka is faced with many 
challenges today due to shortage of land, high cost 
of inputs, low productivity due to nutrition 
depletion, recurrent droughts, newly emerging pest 
and diseases, shortage of skilled labourers etc. 
Strengthening of breeding programme is one of the 
priority areas of increasing productivity by 
developing varieties to give high yields with more 
tolerance to biotic and abiotic stresses. 
Coconut Research Institute of Sri Lanka 
(CRISL) has been involved in the development of 
improved coconut hybrids mainly for higher yield 
and precocity. Accordingly, CRISL has 
recommended the cultivars CRIC60 (Sri Lankan 
Tall [SLT] x SLT), CRIC65 (Sri Lankan Dwarf 
[Green and Yellow] * SLT), CRISL98 (SLT * San 
Ramon), and one estate selection Moorock 
(Everard, 2004) for planting in order to increase the 
productivity of coconut in Sri Lanka. 
Among the above cultivars CRIC65 is 
produced by crossing Sri Lankan dwarf forms, 
green dwarf (GD) and yellow dwarf (YD) with 
SLT palms. The hybrid CRIC65 is early flowering 
(3-4 years) with average production potential of 
110 nuts/palm/year under rain-fed conditions with 
good management. Average production of copra is 
about 210g/nut. It also has a proven ability to 
produce higher toddy yields (1250ml/palm/day) 
(Liyanage et al., 1990) with 15%-18% sugar due to 
the higher number of inflorescences available for 
tapping in the hybrid. This is recommended for 
planting in better environments preferably with 
irrigation during drought and in home gardens. In 
general improved cultivars are capable of 
producing 30-40% higher yields than indigenous 
populations of the ordinary tall cultivars. 
However, some differences have been 
observed between GD*SLT hybrid and YDxSLT 
hybrid such as yielding patterns of two hybrids, 
tolerance to Aceria mite. Although, there are some 
136 
MORPHOLOGICAL DIFFERENCES BETWEEN C O C O N U T HYBRIDS 
differences between two hybrids both these are 
commonly referred to and recommended as 
CRIC65. 
The current study was conducted with the 
objective of determining morphological traits with 
respect to stem, leaf and fruit characters which 
differ between the two hybrids (GD * SLT and YD 
x SLT) within the cultivar CRIC65. 
METE RIALS AND METHODS 
The study was conducted at the Genetics and 
Plant Breeding Division of the Coconut Research 
Institute, Lunuwila, Sri Lanka during the period of 
March to September in the year 2007. 
Morphological data given below were collected 
following the descriptors for coconut outlined by 
International Plant Genetic Resource Institute 
(IPGRI). 
Leaf, stem and crown morphology 
A total of 70 palm representing 35 palms each 
from the two hybrids (GD * SLT), (YD * SLT) 
was selected from the cultivar evaluation 
experimental site at Bandirippuwa estate, Lunuwila 
for obtaining leaf, stem and crown morphology. All 
the selected palms were of the same age and were 
under similar management practices. 
The stem morphology traits girth at 20cm 
above soil level, girth at 1.5m height and stem 
height; leaf morphology traits petiole length (from 
base of petiole to the most proximal leaflet), petiole 
width, rachis length (from the base of petiole to the 
tip), number of leaflets, average width of 4 leaflets, 
and average length of 4 leaflets (at insertion of first 
leaflets) were scored. 
A total of 80 palms including the above 70 
palms were selected for counting the setting 
percentage of female flowers into fruits (i.e. From 
female flower to fruit). 
Study of fruit components 
The same 70 palms used for recording stem 
and leaf morphology were used for obtaining 
detailed fruit component data. The fruit and nut 
traits, weight of fresh nut, weight of split nut, 
weight of nut, weight of kernel, dry weight, fruit 
polar circumference, fruit equatorial circumference, 
fruit polar length, fruit equatorial length, nut polar 
length, nut equatorial length, endosperm thickness 
and shell thickness were scored in one nut 
representing each palm following the IPGRI 
coconut descriptors. 
Study of secondary yield and fruit component data 
Annual nut yield of 80 palms each form the 
two hybrids GD x SLT and YD x SLT grown in the 
same field during 1996 to 2004 was obtained for 
the period 1996-2004 from the records maintained 
at the Genetics and Plant Breeding Division of 
CRISL. Furthermore, fruit components fresh nut 
weight, husked nut weight, split nut weight and 
kernel weight of 120 nuts from each hybrid in each 
year covering the period from 1997 to 2000 were 
also obtained for analysis. 
Data analysis 
The data were analyzed by performing analysis 
of variance among variables using statistical 
software package MINITAB. 
RESULTS AND DISCUSSION 
The means and the standard deviations of 
selected important traits are given in Table 0 1 . 
Stem and leaf measurement 
The girth of stem at 20cm and 1.5m from the 
ground level and stem height were significantly 
different between GD * SLT and YD x SLT. 
Furthermore, a significant difference between two 
hybrids was also observed for number of leaflets. 
The GD x SLT is smaller than YD x SLT with 
respect to stem girth. Moreover, YDxSLT palms 
are taller than GD * SLT palms as indicated by the 
means. 
The analysis of nut setting percentage did not 
reveal any statistically significant difference 
between the two hybrids. 
Table 1. Means and the standard deviations (in 
parenthesis) of morphological traits measured 
Trait GDxSLT YDxSLT 
Primary data 
•Girth at 20cm 113.6(9.3) 126.5(21.3) 
•Girth at 1.5m 77.1 (6.5) 85.3 (10.2) 
•Stem height 640.1 (115..5) 831.3 (207 3) 
•Number of leaflets 206.8 (10.4) 216.3(10.7) 
Fresh weight 1114.5 (468.4) 1335.8(386.8) 
•Split nut weight 754.8(301.8) 884.5 (171.4) 
•Nut weight 372.5(113.3) 453.8 (96.0) 
•Kernel weight 245.1 (75.4) 292.6 (73 4) 
Secondary data 
Fresh fruit weight (1997) 1224.9 (310.4) 1294.2 (350.4) 
•Fresh fruit weight (1998) 1300.1 (306.0) 1403.8 (371.5) 
•Fresh fruit weight (1999) 1303.6 (370.8) 1339.5 (355.0) 
•Husked nut weight (1997) 657.7(161.2) 707.9(186.9) 
Husked nut weight (1999) 719.8 (183.1) 744.5 (162.9) 
Husked nut weight (2000) 750.6(183.1) 781.6(218.2 
•Split nut weight (1997) 469.8(124.0) 508.7 (112.0) 
•Split nut weight (2000) 552.5 (121.5) 597.6 (1713) 
Kernel weight (1997) 321.6(68.7) 336.8 (93.9) 
Annual nut yield (1998) 53.65(31.61) 60.73 (34.01) 
Annual nut yield (1999) 102.5 (S5.8) 88.8 (46.0) 
•Annual nut yield (2001) 89.9 (30.5) 76.2 (36.4) 
•Annual nut yield (2002) 43.5 (20.9) 35.6(14.7) 
*Traits which showed statistically significant difference 
at p>0.05 
137 
KUMARA, PERERA AND FERNANDOPULLE 
Detailed fruit component analysis 
Kernel weight is the most important 
component in relation to copra production. The 
analysis of kernel weight of the two hybrids 
revealed statistically significant differences 
between the two hybrids. In addition, there was a 
significant difference in nut weight and split nut 
weight between the two hybrids. Furthermore, 
fresh nut weight also was revealed to be different at 
the probability level of P = 0.051. These results 
indicate that nuts of the two hybrids are different in 
their capacity for copra production. GD x SLT 
hybrid produce nuts with less fresh weight, split nut 
weight and less kernel content compared to YD x 
SLT (Table 1). 
Analysis of secondary fruit component data 
The analysis of annual fruit component study 
from 1997 to 2000 revealed statistically significant 
differences between the two hybrids. Fruit 
components, fresh fruit weight in 1998 and 1999, 
husked nut weight in 1997 and split nut weight in 
1997 and 2000 were significantly different between 
the two hybrids. Accordingly, YDxSLT shows 
higher values than GDxSLT for fresh nut weight 
(Figure 1), husked weight and split weight during 
all years (apart from one year for husked nut 
weight) considered for the analysis. These 
parameters are the m ost important fruit components 
in relation to copra production. Consequently, the 
results indicated the overall superiority of Y D X S L T 
over GD x SLT in per nut copra production. 
Figure 1. Fresh fruit weight difference between 
GDxSLT and YDxSLT 
Secondary nut yield data 
The analysis of variance for annual nut yield 
per palm in the years 2001 and 2002 revealed 
statistically significant differences between the two 
hybrids. Accordingly, GDxSLT hybrid produced 
the highest nut yield in most years considered for 
the analysis (Figure 2). 
• ODxSLT 
• YDXSLT 
(99f. 1997 I99S 1999 2000 200] 2002 2003 2004 
Figure 2. Nut yield difference between GDxSLT 
and YDxSLT 
CONCLUSIONS 
The two hybrids show clear morphological 
differences with respect to stem girth, stem height 
and number of leaflets. In addition these two 
hybrids differ in their capacity for nuts and copra 
production during certain years. The hybrid GD x 
SLT produces more nuts in certain years while the 
hybrid YD x SLT produces nuts with higher 
weights. The two hybrids seem to differ in their 
response to varying environmental conditions with 
respect to nut and copra production. The study 
revealed the hybrid GDxSLT to be the better nut 
producer and the hybrid YDxSLT to produce larger 
nuts in general. 
A C K N O W L E D G E M E N T S 
The authors wish to thank Dr. Lalith Perera 
(Head), Mr. G. K. Ekanayake, Miss. Auchithya 
Dissanayaka and the field staff of the Genetics and 
Plant Breeding Division of the Coconut Research 
Institute of Sri Lanka. Thanks are also due to all 
staff members in Wayamba University of Sri Lanka 
for helping in many ways. 
REFERENECES 
Anon. (2006). Annual report, Central Bank of Sri 
Lanka. 
Everard, J. M. D. T. (2004). "From Ceylon Latin 
Square to coconut genome frame work." A 
Renewable Resource: Proceedings of the 
international conference of the Coconut 
Research Institute of Sri Lanka, Lunuwila, Sri 
Lanka. 11-18. 
Liyanage, D. V., M. R. T. Wickramaratne, and C. 
Jayasekera. (1990). Coconut varieties Sri 
Lanka. Cocos Journal Sri Lanka. 2-25. 
Liyanage, D. V. (1999). "Varieties and forms of 
coconut palms grown in Sri Lanka." Ceylon 
Coconut Quarterly. 91-101. 
138 


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