Breeding maize (Zea mays) for Striga resistance: Past, current and prospects in sub‐saharan africa

Abstract

Striga hermonthica, causes up to 100% yield loss in maize production in Sub-Saharan Africa. Developing Striga-resistant maize cultivars could be a major component of integrated Striga management strategies. This paper presents a comprehensive overview of maize breeding activities related to Striga resistance and its management.Scientific surveys have revealed that conventional breeding strategies have been used more than molecular breeding strategies in maize improvement for Striga resistance. Striga resistance genes are still under study in the International Institute for Tropical Agriculture (IITA) maize breeding programme. There is also a need to discover QTL and molecular markers associated with such genes to improve Striga resistance in maize. Marker Assistance Breeding is expected to increase maize breeding efficiency with complex traits such as resistance towards Striga because of the complex nature of the host-parasite relationship and its intersection with other environmental factors. Conventional alongside molecular tools and technical controls are promising methods to effectively assess Striga in Sub-Saharan Africa.

Harnessing plant resistance against Striga spp. parasitism in major cereal crops for enhanced crop production and food security in Sub-Saharan Africa: a review

“…fewer roots in the upper 15-20 cm soil depth) (Fig. 4) (Dayou et al, 2021;Mutinda et al, 2018;Yacoubou et al, 2021). Overall, genomic selection via omics and system biology, can models all markers in a framework that doesn't only identify marker-trait associations but incorporates all markers' effects to predict yield (Table 1).…”

“…the developed germplasm is then subjected to rigorous multi-environments' selection process in order to identify well adapted Striga resistant genotypes with different associated genes. Different approaches such as single seed descent, recurrent selection, half-sib, full-sib and S1 family selection methods all with hybrid breeding have proven successful in the development of Striga resistant germplasm (Afolayan et al, 2019;Ronald et al, 2016;Shayanowako et al, 2018;Yacoubou et al, 2021).…”

“…Numerous studies indicated that under highly infested fields (Fig. 1) Striga parasitism can destroy the crop resulting in 100% yield loss (Nyakurwa et al, 2018;Pfunye et al, 2021;Yacoubou et al, 2021). Almost half century ago (1940s), Striga research began and since, many research national and international institutions gave more interest in conducting research activities on all aspects related to Striga management including agronomy, metabolomics, physiology, genomics and crop improvement.…”

Prospects of genetics and breeding for low-phosphate tolerance: an integrated approach from soil to cell

“…Strigolactones are hormones involved in regulating the growth of primary and lateral roots; upregulation of strigolactone synthesis and root-exudation under Pi-limiting conditions have been shown to favor AMF symbiosis (Mayzlish-Gati et al 2012 ; Sun et al 2014 ; Santoro et al 2020 ). However, high levels of strigolactones can also promote the germination of weeds, for example Striga , which threatens crop productivity (Khosla and Nelson 2016 ; Yacoubou et al 2021 ). Therefore, by fine-tuning strigolactone levels, through generating CRISPR/Cas9 allelic variants, one would be able to improve crop fitness by modulating root traits and AMF symbiosis in benefit of low-Pi tolerance while avoiding weeds germination.…”

Prospects of Genetics and Breeding for Low Phosphate Tolerance: an Integrated Approach from Soil to Cell

“…Importantly, the network is centered in PHR family transcription factors, widely known to control P starvation adaptive responses in plants (Figure 4a), and is enriched in Pi starvation, N growth of primary and lateral roots; upregulation of strigolactone synthesis and rootexudation under Pi limiting conditions have been shown to favor AMF symbiosis (Mayzlish-Gati et al 2012; Sun et al 2014; Santoro et al 2020). However, high levels of strigolactones can also promote the germination of weeds, for example Striga, which are very well known to threaten crop productivity specially in African elds(Khosla and Nelson 2016;Yacoubou et al 2021). Therefore, by ne-tuning strigolactone levels, for instance by generating CRISPR/Cas allelic variants, one would be able to improve crop tness by modulating root traits and AMF symbiosis in bene t of low-Pi tolerance while avoiding Striga germination.…”