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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Sokoine University of Agriculture


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



Germination stimulants, Striga asiatica (L) kuntze, Leguminous crop species, Siriga control, Cultural control methods, Tanzania