Combining ability patterns among West African pearl millet landraces and prospects for pearl millet hybrid breeding

Abstract

a b s t r a c tPearl millet (Pennisetum glaucum (L.) R. Br.) is an important hybrid crop in India. However, to date limited pearl millet hybrid development has been undertaken in West Africa (WA), which is the center of pearl millet origin and diversity and where this crop is most important outside India. Using a diverse set of WA pearl millet germplasm, objectives of this study were to determine the superiority of population hybrids over open-pollinated varieties for agro-morphological and agronomic traits in WA pearl millet germplasm; and (ii) to derive strategies for pearl millet hybrid breeding in WA, based on quantitativegenetic parameters, combining ability and heterotic patterns among geographically close versus distant pearl millet populations. A 10 × 10 factorial mating design was performed with four parental OPVs from each of five WA countries. The 100 population hybrids and their parents were tested for 14 traits at six locations in one year, thereby using contrasting locations to indirectly sample the rainfall variability inherent to WA pearl millet production environments. Grain yield showed an average panmictic midparent heterosis (PMpH) of 16.7%, ranging from −26 to 73%. The mean grain yield of hybrids based on inter-country crosses did not differ significantly from intra-country crosses. Geographic distance between parents was positively correlated with hybrid grain yield (r = 0.31), but not with PMpH . Some crosses between accessions from Niger/Nigeria and Senegal were outstanding. Predictability of population hybrid performance for grain yield was moderate based on midparent values (r = 0.43) and slightly better based on general combining ability (GCA) (r = 0.56). Overall, pearl millet hybrid breeding in WA seems very promising, but there do not seem to be clear "natural" heterotic groups among WA pearl millet landraces. Such heterotic groups as the basis of sustainable hybrid breeding need rather to be created systematically, by building on existing combining ability patterns and aiming to maximize combining ability between the groups.

Identification of Combining Ability Patterns for Pearl Millet Hybrid Breeding in West Africa

“…Several studies support a general superiority of pearl millet population hybrids derived from WA OPVs over established cultivars in the Sudano‐Sahelian target zone. Pucher et al (2016) reported a PMPH and PBPH for grain yield up to 73 and 69% with averages of 17 and 4%, respectively, when studying 20 WA pearl millet OPVs and their 100 offspring derived from a 10 × 10 factorial at six locations in WA in 1 yr. Ouendeba et al (1993) used a diallel mating scheme to evaluate combining ability of five improved Sahelian landraces at two locations over 2 yr in Niger. For grain yield, they found a PBPH up to 81% with an average of 44%.…”

Characterization of West and Central African accessions from a pearl millet reference collection for agro-morphological traits and Striga resistance

“…It increased from 5.2 kg/ha/yr (1950)(1951)(1952)(1953)(1954)(1955)(1956)(1957)(1958)(1959)(1960)(1961)(1962)(1963)(1964)(1965) to 24.0 kg/ha/yr (1996-2012) (Yadav and Rai, 2013). Genetic initial combining ability studies among WCA pearl millets were conducted in pearl millet, but without finding clear patterns (Pucher et al, 2016). However, promising hybrids developed from Nigerien and Senegalese varieties were found.…”

A unified strategy for West African pearl millet hybrid and heterotic group development

“…Although the average panmictic better-parent heterosis ranged from 4-18%, the best hybrids yielded up to 62% more than their superior parent. The importance of good parental per se performance to create high-yielding population hybrids was shown in all of these studies (Dutta, 2019;Ouendeba et al, 1993;Presterl & Weltzien, 2003;Pucher et al, 2016;Sattler et al, 2019).…”

“…Finding the appropriate hybrid type for WA is a major question in variety development. Heterosis effects are sufficiently large to develop profitable OPV‐derived population and topcross hybrids (Sattler et al., ), whereas the heterogeneity is expected to assure higher yield stability in contrast with homogeneous single‐cross hybrids (Bidinger et al., ; Mahalakshmi et al., ; Ouendeba et al., , 2005; Presterl & Weltzien, ; Pucher et al., ; Sattler et al., ). These studies support the conclusion that pearl millet topcross or population hybrid development are the most promising approach in WA for increasing yields without putting smallholder farmers at risk.…”

“…Although Indian research is focusing on single-cross hybrids, WA efforts focused more on population hybrids. A factorial with a broad genetic base with sub-Saharan African varieties (Sattler et al, 2019), a diallel with seven Sahelian OPVs or landrace accessions (Dutta, 2019), a factorial with 20 WA varieties (Pucher, Sy, Sanogo, Angarawai, & Zangre, 2016), and a diallel with 17 WA OPVs (Sattler et al, 2019) all displayed a superiority of yield and yield stability of hybrids compared with their parental OPVs. Although the average panmictic better-parent heterosis ranged from 4-18%, the best hybrids yielded up to 62% more than their superior parent.…”