manihot esculenta production producción 60 starch crops 54 marketing 45 economics 40 development 37 statistical data 29 productivity 27 trade 23 mercadeo 22 cultivation systems 21 prices 20 root productivity 20 cassava products 19 costs 19 datos estadísticos 19 processed products 19 uses 19 cultivars 18 consumption 17 cultivation 16 productividad de raices 16 breeding 15 fitomejoramiento 15 processing 15 research 15 variedades 15 feeds and feeding 14 usos 13