Propagation and evaluation of effectiveness of commiphora Swynnertonii (burtt.) And synadenium glaucescens (pax.) Against Tomato fusarium wil
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Date
2020
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Publisher
Sokoine University of Agriculture
Abstract
Introduction
Over-exploitation and habitat destruction have become a major limitation to production,
marketing and usage of botanical pesticides. In Tanzania, Commiphora swynnertonii and
Synadenium glaucescens have been reported to be disappearing very fast. There is a need to develop a technique that will ensure sustainable availability of these plants. The current
study, therefore aimed at enhancing mass propagation and fungicidal effectiveness of C.
swynnertonii and S. glaucescens against tomato fusarium wilt. Specifically, the study
sought to: (1) To evaluate propagation potential of C. swynnertonii and S. glaucescens,
(2) To determine field establishment of C. swynnertonii and S. glaucescens and (3) To
determine effectiveness of C. swynnertonii and S. glaucescens in managing tomato
fusarium wilt disease. The second, third and fourth chapter in the dissertation comprise
manuscripts in the form of publishable papers which cover the first, second and third
specific objectives.
Methods
With respect to specific objective 1, screen house and field experiments were carried at
Sokoine University of Agriculture. Morogoro, Tanzania. In the screen house, two separate
trials were conducted. The first trial evaluated the influence of pre-sowing seed treatments
on germination. The second trial evaluated the influence of cutting types and growth
regulators on rooting and sprouting of stem cuttings. Pre-sowing seed treatments involved
soaking seeds in water at room temperature (25°C), hot water (60°C), Gibberellin (GA3)
solution and Potassium nitrate (KNO3) at different concentrations. The experiment was set
in a randomized complete block design (RCBD) with four replications. On the evaluation
of the influence of cutting types and growth regulators, there were nine treatment
combinations comprising of three types of cuttings (softwood, semi-hardwood and
hardwood), two rooting hormones (Indole-3-Acetic Acid (IAA) and Naphthalene Acetic
Acid (NAA)) and control. The experiment was set in a 3 x 3 factorial in RCBD with four
replications. Survived plantlets from screen house were planted in the field as per specific
objective 2.
Laboratory and screen house experiments were carried as per specific objective 3. In the
laboratory experiment, there were sixteen treatment combinations comprising of four
crude plant extracts obtained from resin of C. swynnertonii, latex, fresh and dry leaves of
S. glaucescens and four extract concentrations (0.01 g/ml, 0.05 g/ml, 0.1 g/ml and 0.15
g/ml). Sterile distilled water and Linkmil 72 WP (Mancozeb 64% + Metalaxyl 8%) were
used as a negative and positive control, respectively. The experiment was set in 4 x 4
factorial in a completely randomized design (CRD) with three replications. In the screen
house experiment, there were four treatments; resinous extracts of C. swynnertonii, extract
from latex and fresh leaves of S. glaucescens and dried leaves powder of S. glaucescens.
Untreated soil and soil treated with Linkmil 72 WP were used as a negative and positive
control, respectively. The experiment was set in RCBD with four replications.
Findings
The results revealed that seed germination of the two plant species was poor but was
significantly affected by seed treatments. Better germination was recorded when
C. swynnertonii and S. glaucescens seeds were treated with either KNO3 at 10 ppm or
soaked in water (25°C). Semi-hardwood cuttings of C. swynnertonii and softwood cuttings
of S. glaucescens dipped in 2 000 ppm NAA solution led to higher rooting of 52.50% and
97.50%, respectively. In the field experiment, higher survival ability was recorded when
C. swynnertonii and S. glaucescens plants were previously treated with either KNO3 at 10
ppm or GA3 at 250 ppm. Plants from hardwood cuttings of C. swynnertonii and semihardwood
cuttings of S. glaucescens previously dipped in 2 000 ppm NAA solution
survived better compared to the other treatments and control.
Laboratory experiment revealed that dry leaves extract of S. glaucescens and resinous
extracts of C. swynnertonii at 0.15 g/ml had the highest inhibitory effect against mycelia
growth of F. oxysporum f. sp. lycopersici. In the screen house experiment, the results
revealed that application of dried leaves powder of S. glaucescens exhibited the least
disease severity and showed a significant effect on plant growth.
Conclusions
Based on the findings, C. swynnertonii and S. glaucescens can be propagated successful
through stem cuttings. Cutting types and growth regulators had significantly enhance
rooting and survival ability. Semi-hardwood and softwood cuttings treated with NAA 2
000 ppm was found to be the best for mass propagation of C. swynnertonii and S.
glaucescens, respectively. Plants from hardwood and semi-hardwood cuttings previously
treated with NAA 2 000 ppm were found to be the best for field establishment of C.
swynnertonii and S. glaucescens, respectively. Dry leaves extract of S. glaucescens and
resinous extracts of C. swynnertonii at 0.15 g/ml had the highest inhibitory effect against
mycelia growth of F. oxysporum f. sp. lycopersici. The application of dried leaves powder
of S. glaucescens exhibited the least disease severity. Tomato plants treated with dried
leaves powder showed a significant stimulatory effect on plant growth.
Recommendations
The findings suggest that semi-hardwood cuttings and softwood cuttings dipped in 2 000
ppm NAA solution can be used for mass propagation of C. swynnertonii and S.
glaucescens. The dried leaves powder and extracts of S. glaucescens can be used in
management of tomato fusarium wilt disease. Further studies to determine the
mechanisms of botanicals involved in the inhibition of mycerial growth of F. oxysporum f.
sp. lycopersici is recommended. This will help to determine the mode and rates of the
application without a significant reduction in plant growth.
Description
Keywords
Commiphora Swynnertonii (burtt.), Synadenium glaucescens (pax.), Tomato fusarium wilt