Thesis (M.Sc. Agriculture (Horticulture)) -- University of Limpopo, 2019 / Cucurbitacin-containing phytonematicides and a variety of unidentified soil microbes
in suppressive soils (Biomuti) had been consistent in suppression of population
densities of root-knot (Meloidogyne spp.) nematodes on various crops. However,
information on suppressive effects of cucurbitacin-containing phytonematicides and
Biomuti on citrus growth and suppression of the citrus nematode (Tylenchulus
semipenetrans) had not been documented. The objective of this study therefore, was
to determine the interactive effects of Nemarioc-AL and Nemafric-BL
phytonematicides and Biomuti on growth and nutrient elements in leaf tissues of
Poncirus trifoliata rootstock seedlings under greenhouse and field conditions. Uniform
six-month-old citrus rootstock seedlings [Du Roi Nursery (Portion 21, Junction Farm,
Letsitele)] were transplanted in 4 L plastic bags filled with growing mixture comprising
steam-pasteurised (300°C for 1 h) loam and compost (cattle manure, chicken manure,
sawdust, grass, woodchips and effective microorganisms) at 4:1 (v/v) ratio and placed
on greenhouse benches. A 2 × 2 × 2 factorial experiment with the first, second and
third factors being Nemarioc-AL phytonematicide (A) and Nemafric-BL
phytonematicide (B) and Biomuti (M), were arranged in randomized complete block
design, with 10 blocks. The treatment combinations were A0B0M0, A1B0M0, A0B1M0,
A0B0M1, A1B1M0, A1B0M1, A0B1M1 and A1B1M1, with 1 and 0 signifying with and without
the indicated factor. Treatments were applied at 3% dilution for each product as
substitute to irrigation at a 17-day application interval. Under greenhouse conditions,
seedlings were irrigated every other day with 300 ml chlorine-free tap water. Under
field conditions, the study was executed using similar procedures to those in the
greenhouse trial, except that the citrus seedlings were transplanted directly into the
soil of a prepared field and seedlings were irrigated using drip irrigation for 2 h every
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other day. At 64 days after transplanting, plant growth variables were measured and
foliar nutrient elements were quantified using the Inductively Coupled Plasma Optical
Emission Spectrometry (ICPE-9000). Data were subjected to analysis of variance
using SAS software. Significant second and first order interactions were further
expressed using the three-way and two-way tables, respectively. At 64 days after the
treatments, under greenhouse conditions Nemarioc-AL × Nemafric-BL × Biomuti
interaction was not significant (P ≤ 0.05) on plant variables of seedling rootstocks in
both experiments. In contrast, the Nemarioc-AL × Biomuti interaction was highly
significant (P ≤ 0.01) on stem diameter, contributing 52% in TTV of the variable in
Experiment 1 (Table 3.1), whereas in Experiment 2 the interaction was highly
significant on dry shoot mass, contributing 33% in TTV of the variable (Table 3.2).
Relative to untreated control, the two-way matrix showed that the Nemarioc-AL ×
Biomuti interaction, Nemarioc-AL phytonematicide and Biomuti each increased stem
diameter by 1%, 12% and 5%, respectively (Table 3.3). Relative to untreated control,
the two-way matrix table showed that Nemarioc-AL × Biomuti interaction increased
dry shoot mass by 10%, whereas Nemarioc-AL phytonematicide and Biomuti each
increased dry shoot mass by 23% and 17%, respectively (Table 3.4). Nemarioc-AL ×
Nemafric-BL × Biomuti interaction was not significant (P ≤ 0.05) for all plant growth
variables in both experiments. However, Nemarioc-AL × Nemafric-BL interaction was
significant for leaf number and stem diameter contributing 45% and 29% in TTV of the
respective variables in Experiment 2 (Table 4.1). Relative to untreated control, two
way matrix table showed that the Nemarioc-AL × Nemafric-BL interaction and
Nemafric-BL phytonematicides each increased stem diameter by 8% and 11%
respectively, whereas Nemarioc-AL phytonematicides reduced stem diameter by 2%
(Table 4.2). Also using two-way matrix table showed that Nemarioc-AL and Nemafric
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BL phytonematicides each increased leaf number by 1% and 7% respectively,
whereas the Nemarioc-AL × Nemafric-BL interaction increased leaf number by 6%
(Table 4.2). Nemafric-BL × Biomuti interaction was significant for stem diameter
contributing 29% in TTV of the respective variable in Experiment 2 (Table 4.1). Using
two-way matrix table showed that Nemafric-BL × Biomuti interaction and Nemafric-BL
phytonematicide each increased stem diameter by 7%, whereas Biomuti alone
reduced stem diameter by 6% (Table 4.3). Under greenhouse conditions, the second
order Nemarioc-AL × Nemafric-BL × Biomuti interaction was highly significant for foliar
Mg, contributing 5% in TTV of the variable in Experiment 1 (Table 3.4). Relative to
untreated control, the three-way matrix table showed that the three factors, Nemafric
BL phytonematicide and Biomuti each reduced Mg by 33%, 35% and 53%,
respectively, whereas Nemarioc-AL phytonematicide increased Mg by 12% (Table
3.5). Nemarioc-AL × Biomuti interaction was highly significant for foliar Mg, contributing
9% in TTV of the variable in Experiment 1 (Table 3.4). Relative to untreated control,
the two-way matrix table showed that the Nemarioc-AL × Biomuti interaction and
Nemafric-BL phytonematicide reduced Mg by 42% and 12%, respectively, whereas
Nemarioc-AL phytonematicide alone increased Mg by 14% (Table 3.6). Nemarioc-AL
× Biomuti interaction was highly significant for foliar Ca and Mg, contributing 59 and
4% in TTV of the respective variables in Experiment 1 (Table 3.4). Also using two-way
matrix table showed that Nemarioc-AL phytonematicide and Biomuti separately
reduced Ca by 12% and 22% respectively, whereas the Nemarioc-AL × Biomuti
interaction increased Ca by 1% (Table 3.7). Relative to untreated control, the
Nemarioc-AL × Biomuti interaction, Nemarioc-AL phytonematicide and Biomuti
reduced foliar Mg by 26%, 21% and 33%, respectively (Table 3.7). Nemafric-BL ×
Biomuti interaction was highly significant for foliar Mg and P, contributing 50 and 21%
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in Experiment 1, whereas in Experiment 2 the interaction was significant for foliar Ca
and Mg, contributing 41% and 38% in TTV of the respective variables (Table 3.4).
Relative to untreated control, the two-way matrix table showed that Nemafric-BL
phytonematicide and Biomuti individually reduced Mg by 60% and 51%, respectively,
whereas the Nemafric-BL × Biomuti interaction reduced Mg by 38% (Table 3.8). Also,
in the two-way matrix table the Nemafric-BL × Biomuti interaction and Nemafric-BL
phytonematicide each reduced Mg by 13% and 2%, respectively, whereas Biomuti
alone increased P by 17% (Table 3.8). Relative to untreated control, Nemafric-BL
phytonematicide and Biomuti reduced Ca by 29% and 18%, respectively, whereas
Nemafric-BL × Biomuti interaction reduced Ca by 14% (Table 3.9). Using two-way
matrix table showed that Nemafric-BL phytonematicide and Biomuti separately
reduced Mg by 21%, whereas the Nemafric-BL × Biomuti interaction reduced Mg by
16% (Table 3.9). Interaction of Nemarioc-AL × Nemafric-BL × Biomuti had no
significant effect on K, Na and Zn in both experiments. Under field conditions, the
second order Nemarioc-AL × Nemafric-BL × Biomuti interaction was not significant for
all the nutrient elements in Experiment 1. Nemarioc-AL × Biomuti was significant for
Ca, K and highly significant for Mg and P, contributing 31, 8, 23 and 19% in TTV of
the respective variables in Experiment 1 (Table 4.4). Relative to untreated control,
two-way matrix table showed that Nemarioc-AL phytonematicide and Biomuti each
increased Ca by 15% and 26% repectiviely, whereas the Nemarioc-AL × Biomuti
increased Ca by 17% (Table 4.5). Interaction of Nemarioc-AL × Biomuti, Nemarioc-AL
phytonematicide and Biomuti each reduced Mg by 48%, 70% and 37% (Table 4.5).
Also using two-way matrix table showed that Nemarioc-AL phytonematicide and
Biomuti each increased P by 4% and 5% respectively, whereas the Nemarioc-AL ×
Biomuti interaction increased P by 50% (Table 4.5). Realative to untreated control,
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Biomuti and Nemarioc-AL phytonematicide each reduced K by 10% and 5%
respectively, whereas the Nemarioc-AL × Nemafric-BL interaction reduced K by 38%
(Table 4.7). Nemafric-BL × Biomuti interaction was highly significant for Mg and Zn,
contributing 11% and 29% in TTV of the respective variables in Experiment 1 (Table
4.4). Relative to untreated control, two-way matrix table showed that Nemarioc-AL
phytonematicide and Biomuti separately increased Mg by 1% and 19% respectiviely,
whereas the Nemafric-BL × Biomuti interaction reduced Mg by 43% (Table 4.6).
Nemafric-BL × Biomuti interaction, Nemafric-BL phytonematicide and Biomuti each
reduced Zn by 35%, 31% and 64% (Table 4.6). Using three-way matrix table showed
that the Nemarioc-AL × Nemafric-BL × Biomuti, Nemarioc-AL × Nemafric-BL,
Nemarioc-AL × Biomuti and Nemafric-BL × Biomuti interactions each increased Ca by
44%, 18%,10% and 24% (Table 4.8). Further the matrix showed that Nemarioc-AL,
Nemafric-BL phytonematicides and Biomuti each increased Ca by 25%, 31% and 23%
(Table 4.8). Under both greenhouse and field conditions, although second and first
order interactions were not consistent of various variables, results demonstrated that
the three products interacted significantly for various products. In conclusion, the study
suggested that these innovative products could be used in combination with Biomuti
to stimulate plant growth but had antagonistic effects on accumulation of nutrient
elements in P. trifoliata rootstock seedlings, suggesting that the products should be
applied separately. / Agricultural Research Council-Universities Collaboration Centre and the National Research
Foundation (NRF)
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ul/oai:ulspace.ul.ac.za:10386/2944 |
| Date | January 2019 |
| Creators | Mokoele, Tlou |
| Contributors | Mashela, P. W. |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | xxiv, 120 leaves |
| Relation | Adobe Acrobat Reader |
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