Breeding and Genetics of Sorghum for Striga Resistance: Future Perspectives

Sorghum is the most important cereal crop in the world. However, low yields of sorghum have been recorded due to a number of biotic and abiotic constraints. Among the biotic constraints, striga is becoming the major epidemic in most of sorghum growing areas, where soil fertility (nutrient deficiency) and moisture stress are limiting factors. The objective of these review was to review sorghum breeding strategies, methods and future implication for striga resistance. This review explore inter-specific variability among Striga species and intra-specific variation for aggressiveness must be taken into account when breeding for striga resistance. This review suggest to characterize crop germplasm, search for sources of resistance and tolerance in elite material, and improve currently available sources of resistance for agronomic performance. One strategy could be to use laboratory assays for individual resistance mechanisms as an initial screening of a larger number of breeding materials, followed by the more resource-demanding field screening. This would offer the possibility to identify resistance sources with multiple resistance mechanisms. Detecting resistance genes by their linkage to DNA markers makes it possible to screen for many different resistance genes simultaneously, without the need to inoculate with pathogens. The identification of individual genes or QTL for striga resistance and their transfer into adapted cultivars will also allow to evaluate whether there are “costs of striga resistance”, <i>i.e.,</i> whether resistance is associated with any yield drag. Pyramiding of resistance genes to provide durable resistance is therefore greatly facilitated. In addition to selection for host plant resistance, sorghum breeders could consider selecting cultivars for specific adaptation to integrated striga management regimes.