Abstract

Growth response of two clones of Manihot esculenta Crantz (Cassava), TMS 30555 and TMS 30572 to Bentex T soil treatment was studied. Mycorrhizal root colonization in relation to growth parameters such as stomata size, plant water content, plant foliation, as well as height and stem circumference was examined. Bentex T, a fungicide which could be used to limit the growth of Arbuscular Mycorrhizal (AM) fungi was added to soil at the concentrations of zero 0 (control), 50, 100, 500 and 1000 µg a.i. /g soil. Growth parameters had minimal variations (p˃ 0.05) between treatments in both clones of the plant. However, clonal differences at (pË‚ 0.01) occurred in some of the growth parameters. The level of root colonization by the AM fungi affected the growth response of the plant. The untreated soil (control) with the highest AM fungi root colonization (84%) had the least plant foliation (15 and 16) and height (34.1 and 28.5 cm) for TMS 30572 and TMS 30555, respectively. The highest values obtained for stomata size (width and length) were at 50 µg/g bentex concentration; 0.040 and 0.019mm for TMS 30572 and 0.017 and 0.007 for TMS 30555, respectively. The least value obtained for the stomata size was at the zero (0) µg/g bentex concentration. Plants from soil treated with 100 µg/g bentex T concentration had the highest amount of water; 75% for TMS 30572 and 76% for TMS 30555. The untreated soil had plants with the least amount of water. Implications of Bentex T soil treatment of cassava plants was discussed in relation to mycorrhizal colonization rating and some growth parameters of the test plant.

Key words: AM fungal colonization rating, growth response, cassava, Bentex T Soil Treatment