Perspectives on molecular breeding of Africa's main staple food crops - cassava and yam

摘要

Root and tuber crops are grown in different parts of the world for different reasons, but in Africa, cassava (Manihot esculenta) and yam (Dioscorea sps.) are grown as a main staple food for hundreds of millions of people. Widely cultivated in severalAfrican countries, cassava and yam provide food security and income generation for millions of small-holding farmers. With respect to breeding for improved varieties, cassava and yam face similar challenges: 1) The genetics of the crops are poorly understood; 2) Due to lengthy growing season/generation time, the breeding cycle is considerably long; 3) ShyHowering or incompatibility hampers hybridization to develop breeding population; 4) High level of heterozygosity caused by allogamy; 5) Vegetative propagation results in low multiplication ratio of plant propagules; 6) Paucity of genomic resources; 7) Inadequate critical mass of researchers and lack of international collaboration; 8) Absence of research activity by the private sector; 9) High genotypeby environment interaction requires breeding for specific agroecology zones; 10) Cultivated by resource-limited small scale farmers with a resu Itant low productivity or large yield gap; 11) Limited diversity as both cassava and most yam species are not native to Africa; 12) High magnitude of postharvest losses due to bulkiness and perishability.