ISSN: 0940-6360 (printed version)
ISSN: 1432-1890 (electronic version)
Abstract Volume 4 Issue 6 (1994) pp 241-245
M. Habte, M. N. Byappanahalli
Department of Agronomy and Soil Science, University of Hawaii, 1910 East West Road, Honolulu, HI 96822, USA
Abstract. Cassava plants were started in the greenhouse either from small cuttings (2.0 mg P/cutting) or large cuttings (20.2 mg P/cutting) in a subsurface Oxisol not inoculated or inoculated with Glomus aggregatum at target soil solution P concentrations of 0.003-0.2 mg l-1. Vesicular-arbuscular mycorrhizal (VAM) fungal colonization levels in excess of 60% were attained on cassava roots irrespective of the size of cutting material used or target soil solution P status. However, plants started from large cuttings grew faster and better than those started from smaller ones. Cassava was found to be very highly dependent on VAM fungi if grown from small cutting but only marginally dependent if grown from large cuttings. The lower dependence of cassava on VAM fungi when started from larger cuttings appears to be related to the high P reserve in these cuttings and hence the low requirement of the plants for soil P until the P reserve in the cuttings is significantly depleted.
Key words: Glomus aggregatum - Cuttings - Dependency categories - Manihot esculanta - Soil solution P
Correspondence to: M. Habte
Cassava (Manihot esculenta) is one of the most important calorie-producing crops in the tropics. It is efficient in carbohydrate production, adapted to a wide range of environments, and tolerant to drought and acid soils. The major portion of the economic product, the root, is consumed as food through varying degrees of processing. However, the market of cassava in China is small due to its poor yield in the acidic P-deficient soils where it is produced. Mycorrhiza technology can be easily transferred to cassava production by inoculating stem cuttings that are traditionally hand-transplanted into the field.
Balota, EL; Lopes, ES; Hungria, M; Dobereiner, J. 1997. Inoculation of diazotrophic bacteria and arbuscular mycorrhizal fungi on the cassava crop. Pesqui. Agropecu. Bras. 32(6): 627-639.
EL Balota; INST AGRON PARANA; CAIXA POSTAL 481; LONDRINA; PR; BRAZIL; BR-86001970 BC
The versatility of the cassava crop (Manihot esculenta Crantz) to adapt to low fertility soils, although plants require high levels of nutrients, has been related to the occurrence of arbuscular mycorrhizal fungi (AM) and diazotrophic bacteria. One experiment was then performed with micropropagated plants, to evaluate the effects of AM fungi and diazotrophic bacteria on cassava growth and nutrition. The experiment was performed in pots of 3.5 L capacity, with sandy disinfected soil as substrate. Inoculation with diazotrophic bacteria did not show any statistically significant positive effect, while the inoculation with AM fungi and co-inoculation of AM fungi and bacteria favored growth and nutritional parameters. Co-inoculation of AM fungi and Bacterium E increased shoot and root dry weight up to 50% and 105%, respectively, in relation to the bacterium alone. Synergistic effects were also observed in the nutrient content, increasing shoot and root N up to 88% and 173%, and P content up to 83% and 158%, respectively. Co-inoculation of Bacterium E with Glomus clarum also increased mycorrhizal colonization by 40% and sporulation up to 168%, in comparison to the fungi alone. These beneficial effects suggest that the stimulus could be both by the increase in plant nutrient uptake as well as by the stimulation of colonization by MA fungi.
AzconAguilar, C; Cantos, M; Troncoso, A; Barea, JM. 1997. Beneficial effect of arbuscular mycorrhizas on acclimatization of micropropagated cassava plantlets. Sci Hortic 72(1): 63-71.
JM Barea; CSIC; ESTAC EXPT ZAIDIN, DEPT MICROBIOL SUELO & SISTEMAS SIMBIOT, PROF ALBAREDA 1; GRANADA; SPAIN; E-18008 BC
Survival and development of cassava (Manihot esculenta Crantz) plantlets has been increased by modifying tissue culture protocols and by mycorrhizal inoculation. About 90% of plantlets were successfully rooted in vitro and 75% survived after the acclimatization phase, Inoculation with Glomus deserticola early in the post vitro weaning stage enhanced percent survival and improved tolerance to the transplanting stress. Shoot, root and tuber development of the micropropagated plants was increased following inoculation with different arbuscular mycorrhizal (AM) fungi. Growth responses were dependent on both the cultivar (clone) and the AM fungi involved. G. deserticola was very effective in improving growth of both clones, the effectivity of G. clarum and C. fasciculatum being dependent on the cultivar, These results emphasize the need for selection trials before appropriate plant cultivar/AM fungi combinations can be recommended.