Genetic Diversification and Selection Strategies for Improving Sorghum Grain Yield Under Phosphorous-Deficient Conditions in West Africa

Abstract

Sorghum, a major crop for income generation and food security in West and Central Africa, is predominantly grown in low-input farming systems with serious soil phosphorus (P) deficiencies. This study (a) estimates genetic parameters needed to design selection protocols that optimize genetic gains for yield under low-phosphorus conditions and (b) examines the utility of introgressed backcross nested association mapping (BCNAM) populations for diversifying Malian breeding materials. A total of 1083 BC1F5 progenies derived from an elite hybrid restorer “Lata-3” and 13 diverse donor accessions were evaluated for yield and agronomic traits under contrasting soil P conditions in Mali in 2013. A subset of 298 progenies were further tested under low-P (LP) and high-P (HP) conditions in 2014 and 2015. Significant genetic variation for grain yield was observed under LP and HP conditions. Selection for grain yield under LP conditions was feasible and more efficient than the indirect selection under HP in all three years of testing. Several of the BCNAM populations exhibited yields under LP conditions that were superior to the elite restorer line used as a recurrent parent. The BCNAM approach appears promising for diversifying the male parent pool with introgression of diverse materials using both adapted Malian breed and unadapted landrace material from distant geographic origins as donors.

Transforming a traditional commons-based seed system through collaborative networks of farmer seed-cooperatives and public breeding programs: the case of sorghum in Mali

“…The large and changing portfolio of varieties co-created and in seed production by the sorghum network (Table 3) provides a direct indicator. The network's emphasis on local (Guinea-race) germplasm for breeding new varieties (Weltzien et al 2006;Diallo et al 2019), rather than the earlier focus on exotic germplasm (Yapi et al 2000), is expected to favor adaptation to widely prevalent threats such as grain mold (Weltzien et al 2018), poor soil conditions (Leiser et al 2012), and the complex of stresses associated with rainfall variability (Clerget et al 2008).…”

Characterization of adaptation mechanisms in sorghum using a multireference back-cross nested association mapping design and envirotyping

“…5a ). In each environment, the genotypes were laid out as an alpha-lattice design ( Kempton 1984 ) with 2 replications ( Diallo et al . 2019 ).…”

Characterization of adaptation mechanisms in sorghum using a multi-reference back-cross nested association mapping design and envirotyping

“…The Lata3 population was entirely phenotyped in 2013 in three environments defined by two levels of phosphorus fertilization (Low-P and high-P) at the Samanko station and standard conditions at Kolombada station (Figure 5A). In each environment, the genotypes were laid out as an alpha-lattice design (Kempton, 1984) with two replications (Diallo et al, 2019).…”

“…Kenin-Keni was derived from a directed recurrent selection population involving local parents of different botanical types (Leroy et al, 2014). Lata3 was selected from a random mating population of Guinea parents (Diallo et al, 2019). The recurrent parents were chosen for their productivity, their adaptation to soil and climate, as well as their resistance to major biotic and abiotic stresses.…”

“…In each environment, the genotypes were laid out as an alpha-lattice design (Kempton, 1984) with two replications (Diallo et al, 2019).…”