Uyoh and Ntui

Afr. J. Hort. Sci. (2011) 4:7-12

7

EFFECT OF SEED POSITION ON SEX EXPRESSION AND SOME

AGRONOMIC FEATURES IN FLUTED PUMPKIN (TELFAIRIA

OCCIDENTALIS HOOKER FIL)

Uyoh EA and *Ntui VO Department of Genetics and Biotechnology, University of Calabar, Calabar, Nigeria

* Correspondence: gen_uyoh@yahoo.com

Abstract

Telfairia occidentalis is a vegetable crop widely cultivated in southern Nigeria for

its nutritious and palatable leaves. A field experiment was conducted to study the

effect of seed position within the pod on sex expression and some agronomic

traits of this plant. Three large pods of T. occidentalis of one local variety Edem aran were obtained from Agricultural Development Project (ADP) Calabar, Nigeria and used for the study. Seeds extracted from the head and tail were pooled together for each pod and labelled as peripheral seeds while seeds from the middle region were regarded as middle seeds. Sixteen seeds were randomly selected from each region (middle and peripheral) per pod for planting giving a total of thirty-two seeds per pod and 96 plants altogether. The

Randomized Complete Block Design (RCBD) was used in the arrangement of

treatment with 4 blocks. Data were collected on days to seedling emergence, sex

of the plant, length of vine, number of branches, number of leaves, vine diameter

and leaf area. Results obtained gave an overall sex ratio of approximately 2.5

males to 1 female. A highly significant t-test value of 4.48 confirmed that the

males were indeed more numerous than the females (P < 0.01). It was also shown

that the peripheral seeds produced more female plants (58.33%) than middle

seeds (41.67%). The vine diameter and leaf area were the only traits found to be

contingent on sex, both being significantly greater in females than in males with

X2

values of 12.86 (P < 0.05) and 26.78 (P < 0.001) respectively, at 9 weeks after

planting.

Keywords: Agronomic features, peripheral and middle seeds, sex ratios, Telfairia

occidentalis

Introduction

Fluted pumpkin (Telfairia

occidentalis Hooker fil,) belongs to the

Cucurbitaceae family of dicotyledonous

plants. It is usually cultivated for its

leaves and seeds, which constitute an

important component of the diet in many

West African countries, notably Nigeria,

Ghana, Cameroon and Sierra Leone,

(FAO, 1992). The leaves are used to

prepare various soups and porridges. The

oil rich seeds may be eaten boiled or roasted (Girgis and Turner, 1972; Oyolu,

1978). The oil from these seeds may also

be used in making soap, margarine or

cooking oil (Irvine, 1969).

T. occidentalis is dioecious,

bearing male and female flowers on

separate plants. The female bears the

fruits that carry the seeds. Thus, a farmer

who is interested in seed yield would do

much better if he or she could

predetermine the nature of seed that

would give rise to female plants. This

will enable the farmer to make

appropriate projections on the leaf and

fruit yield since leaf harvest is often

suspended following appearance of

female flowers, but may continue in the

male plants (Anyim and Akoroda, 1983).

Generally, having more female plants on

Effect of Seed Position on Sex Expression and Agronomic Features of Pumpkin

Afr. J. Hort. Sci. (2011) 4:7-12

8

the field is considered more profitable

since they also produce the seeds.

Some efforts have been made in

search of criteria for judicious selection

of seeds for cultivation of T. occidentalis

as well as ways of enhancing the

proportion of female plants in the field.

Anyim and Akoroda (1983) reported that

small seeds have a greater chance of

producing female plants than large seeds.

Akpan and Odejimi (2006) reported that

pruning increased the number of edible

shoots, percentage of pistillate flowers

and fruit set. Adeyemo and Odiaka

(2005) obtained longer vines and greater

number of leaves from heavier seeds.

Uyoh and Ikong (2004) observed that

seed weight has no significant effect on

seedling emergence, leaf area and

number of branches per plant. Little

information is available on the effect of

seed position on sex expression.

The present study, therefore,

sought to determine the effect that seed

position within the pod may have on sex

expression as well as on some agronomic

features in T. occidentalis.

Materials and Methods

Three large pods of Telfairia

occidentalis belonging to a local variety,

Edem aran, were obtained from Agricultural Development Project

(ADP), Calabar, Cross River State,

Nigeria. The major distinguishing

features of this variety are as reported by

Umoh and Sampson (1991), namely,

light green exocarp and light purple seed

coat colour.

A Randomized Complete Block

Design (RCBD) was used in the layout of

the experiment. One factor was studied in

the experiment, namely seed position, at

two levels: middle and peripheral. Each

pod was divided into three equal portions

namely: head, middle and tail. Seeds

extracted from the head and tail region

were pooled together for each pod and

labelled as peripheral seeds while seeds from the middle region were

regarded as middle seeds. The seeds were sun dried for three days before

planting. Sixteen (16) middle and 16

peripheral seeds were selected randomly

per pod, giving 32 seeds per pod and 96

seeds on the whole from the three pods-

48 peripheral and 48 middle. The seeds

were planted in a manually tilled piece of

land with 4 beds (blocks). Each block

was divided into 24 experimental units

for randomisation of 12 peripheral (4

from each of the three pods) and 12

middle seeds (4 from each pod). This

arrangement was in turn replicated in

each of the four blocks giving a total of

96 plants (24 x4) in the field. A planting

distance of 1 m either side was used.

Seeds were planted at a depth of 2 cm.

The experiment was conducted between

March and October 2007. Weeding was

done by hand fortnightly. Individual

plants were staked at five weeks after

planting.

Data on days to seedling

emergence and sex of the plants were

collected. In addition, data were also

collected at 3 week intervals on length of

vine, number of branches, number of

leaves, vine diameter and leaf area. Data

obtained were subjected to analyses of

variance using the SPSS statistical

package at 0.001% probability level with

the means separated using the least

significant difference (LSD) test.

Contingency 2 analysis was used to determine which of the traits studied was

contingent on sex. The students t-test for paired comparison was used to compare

the total number of males with the total

number of females.

Results

The mean effects of seed position

on some agronomic features in T.

occidentalis at 3, 6 and 9 weeks after

planting are given in Figure 1. At 3

weeks after planting, plants raised from

middle seeds had significantly higher

(P

Uyoh and Ntui

Afr. J. Hort. Sci. (2011) 4:7-12

9

(Fig. 1a). However, seed position had no

significant effect (P>0.05) at this stage

on vine length (Fig.1b), number of

branches (Fig. 1c), vine diameter (Fig.

1d), leaf area (Fig. 1 e), and inter-node

length (Fig. 1f) in these plants.

Fig. 1. Effect of seed position on six agronomic traits in Telfairia occidentalis at 3, 6, 9 weeks

after planting (WAP). a) Number of leaves. b)Vine length. c) Number of branches. d) Vine

diameter. e) Leaf area. f) Internode length. P Peripheral seeds, M Middle seeds

At 6 weeks after planting, plants

from peripheral seeds had a significantly

higher (P

Effect of Seed Position on Sex Expression and Agronomic Features of Pumpkin

Afr. J. Hort. Sci. (2011) 4:7-12

10

1b, 1d, 1e and 1f). At 9 weeks after

planting, plants from peripheral seeds

produced significantly greater mean

number of leaves (P

Uyoh and Ntui

Afr. J. Hort. Sci. (2011) 4:7-12

11

non significant contingency 2 results at 6 and 9 weeks after planting in most of

the traits studied (except vine diameter

and leaf area, Table 1) may be an

indication that the significant differences

obtained in such traits were not sex-

related.

Table 1. Contingency 2 results on the relationship between sex and seven agronomic features in T. occidentalis at 6 and 9 weeks after planting.

Seedling

emergence

Vine

length

No of

leaves

Vine

diameter

Internode

length

Leaf

area

No of

branches

CalX2

(5)

at 6 wks

NS

0.196

NS

0.03

NS

4.32

NS

2.64

NS

6.2

NS

8.7

NS

7.4

at 9 wks

-

NS

0.82

NS

2.01

***

12.86

NS

4.7

***

26.75

NS

4.84 *** = Highly significant difference (P < 0.001)

NS = Not significant (P > 0.05)

Varying ratios of male to female

plants have been given by several

authors. Akoroda (1990) gave a 1: 1

ratio; Ibe and Ezedinma (1979) gave a

ratio of 0.39 males to 1 female; while

Atiri and Varma (1983) gave 0.76 males

to 1 female. The values evidently vary a

great deal. Akoroda (1990) suggests that

these ratios differ probably among

maternal siblings from each fruit. In the

present study, male plants were clearly

more abundant in the field than females

giving an overall ratio of 59 males: 24

females: 13 non- flowering or

approximately 2.5 males to 1 female. The

predominance of male plants in the field

was further confirmed by the highly

significant t-test value of 4.41 obtained in

favour of male plants (Fig. 2). This

result, however, disagrees with previous

reports by Ibe and Ezedinma (1979) and

Atiri and Varma (1983) who had more

females than males in their respective

studies. Such disagreements only help to

confirm the variable nature of sex

expression among these plants.

The present study also showed

that of the total number of female plants

obtained, 58.33% were from peripheral

seeds while 41. 67% were from middle

seeds. This may seem to suggest that

peripheral seeds have a greater tendency

of producing female plants than middle

seeds. However, considering the great

variation in sex ratio reported by various

workers on this crop, such suggestions

should be made with caution as the

tendency of peripheral or middle seeds to

produce more female or male plants

could also vary.

Vine diameter and leaf area were

the only traits found to be contingent on

sex. Both were significantly greater in

females than in males with X2

(5) values of

12.86 (p

Effect of Seed Position on Sex Expression and Agronomic Features of Pumpkin

Afr. J. Hort. Sci. (2011) 4:7-12

12

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