Some cultural control measures of weeds in cassava are discussed: quality of the material, planting system and density, density x plant type interaction and use of mulching. In order to study the interaction plant type x planting density, var. M Mex 59 (vigorous) and M Col 22 (nonvigorous) were planted in plots of 7500 and 15,000 plants/ha; and 3 levels of weed control were established: complete, intermediate and no control. The vigorous var.

Multiple cropping, sequential cropping, intercropping, mixed intercropping, intercropping in rows, in strips, relayed intercropping, cropping patterns, monoculture, crop rotation and land equivalent ratio are defined. The characteristics of multiple cropping and intercropping with beans are discussed; for the latter problems of competence are discussed (light, CO2, water and nutrients). Some cultural practices are recommended for cassava/bean intercropping: soil and fertilization type, water availability, propagation material, and weed, pest and disease control.

Emphasis has been placed on the screening of hybrid selections for resistance to rust, anthracnose, BCMV and Empoasca sp., yield and sensitivity to photoperiod. A total of 1464 materials (937 selections from the breeding program) were screened in the Bean Team Nursery and 700 (200 breeding selections) in the Preliminary Yield Trial. Results from the latter demonstrated major gains in yield among colored materials and a very high proportion of lines resistant to BCMV. Many lines demonstrated multiple-disease resistance.

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