Assessment of germination stimulants from non-host leguminous crops for control of striga asiatica (L) kuntze in semi - arid areas of Tanzania.
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Date
2005
Authors
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Journal ISSN
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Publisher
Sokoine University of Agriculture
Abstract
Striga axiatica is one of'the most destructive parasitic need species in the Semi Arid
Zone of Tanzania.
In an effort to come out with an appropriate and sustainable
method of controlling the weed species, two laboratory/screen house and one field
experiments were conducted to identify leguminous crop species/cultivars that are
suitable for use as trap crops in the control of.S’rr/qr? asiatica. Effectiveness of root
exudates of 56 cultivars from six leguminous species on germination of .S’, axiatica
seeds were assessed in vitro using Petri Dish (PD) technique. A split plot design
replicated four times was used
The second laboratory- experiment, aimed at
eyaluating the effect of seed coat colour and different plant parts of selected
leguminous species/cultiyars on stimulating germination of the parasitic yveed seeds
was done
used
A Completely Randomised Design (CRD) with four replications yvas
Both experiments were repeated three times
In addition, a 2-years field
experiment was conducted to eyaluate the efficacy in situ of the species/ cultivars
identified in vitro A Completely Randomised Block Design (CRBD) was used and
the experiment w as replicated four times. Results indicated that effectiveness of root
exudates depends on Strtga seed population, and cultivars within species differed in
their capacity to stimulate germmation of .S’ axiatica seeds. Pigeon pea cultivars
ICEAP 00020 and ICEAP 00040; groundnut ex-Bukene; cowpeas white black eyed;
bambara groundnut cultivars Nyandani spotted cream and Red ex- Makutupora were
found to stimulate significantly (P < 0.001) higher germination percentages of 5.
axiatica seeds compared to the other tested cultivars within their respective species.
hence were selected for further evaluation in field. Seed exudates from black seededii
bambara groundnut stimulated 66.8% germination of .S’, asiatica seeds, which was
significantly (P < 0 001) higher compared to percent germination induced by the
positive control (41 3%)
Germination of Striga seeds exposed to exudates from
dill'erent plant pans (roots, shoots and seeds) of bambara groundnuts, cowpeas and
groundnut ranged from 15% to 63 4%. which was significantly higher compared to
percent germination induced b\ the negative control (2 4%). Rotating legume trap
crops with sorghum resulted into 38 - 48% reduction of.S'/r/gfl seeds in the soil as
well as reduction of Stnga infestation bv 50% compared to continuous sorghum
cropping anti weed free fallow - sorghum rotation. Yields of sorghum grow n after
legumes ranged between 0.75 - 2 28 tons/ha. while yields from sorghum after weed-
free fallow and sorghum continuous cropping were 0.53 tons/ha and 0.61 tons/ha
respective!}
Except for cowpeas, all other legume - sorghum rotations resulted into
significant!} (P < 0 001) higher yields compared with the weed free fallow and
continuous sorghum cropping
It is concluded that crop rotation with pigeon pea
cultivars ICEAP 00020 and ICEAP 00040; groundnut ex-Bukene. and bambara
groundnut cultivars Nyandam spotted cream and red ex- Makutupora can serve as
elTective trap crops which would reduce .S' asiatica seed bank and infestations. By
inference, rotating sorghum with any of these legumes would boost yields, thereby
sparing farmers limited resources, which would have otherwise been spent for other expensive Striffa control measures
Description
Keywords
Germination stimulants, Striga asiatica (L) kuntze, Leguminous crop species, Siriga control, Cultural control methods, Tanzania