Inheritance of Striga hermonthica adaptive traits in an early‐maturing white maize inbred line containing resistance genes from Zea diploperennis

Abstract

Striga hermonthica can cause as high as 100% yield loss in maize depending on soil fertility level, type of genotype, severity of infestation and climatic conditions. Understanding the mode of inheritance of Striga resistance in maize is crucial for introgression of resistance genes into tropical germplasm and deployment of resistant varieties. This study examined the mode of inheritance of resistance to Striga in early‐maturing inbred line, TZdEI 352 containing resistance genes from Zea diploperennis. Six generations, P1, P2, F1, F2, BC1P1 and BC1P2 derived from a cross between resistant line, TZdEI 352 and susceptible line, TZdEI 425 were screened under artificial Striga infestation at Mokwa and Abuja, Nigeria, 2015. Additive‐dominance model was adequate in describing observed variations in the number of emerged Striga plants among the population; hence, digenic epistatic model was adopted for Striga damage. Dominance effects were higher than the additive effects for the number of emerged Striga plants at both locations signifying that non‐additive gene action conditioned inheritance of Striga resistance. Inbred TZdEI 352 could serve as invaluable parent for hybrid development in Striga endemic agro‐ecologies of sub‐Saharan Africa.

Combining ability of extra‐early biofortified maize inbreds underStrigainfestation and low soil nitrogen

“…Different reports on gene action controlling Striga resistance and tolerance, grain yield, low N tolerance, and other traits of maize lines are available. Additive genetic effect was reported to be more important than nonadditive effect in modulating Striga resistance (Amegbor et al., 2017; Gethi & Smith, 2004), whereas nonadditive gene action played greater role in genetic control of Striga resistance trait (Akaogu et al., 2019; Kim, 1994). Also, dissimilar reports are available on the genetic effect controlling maize grain yield in low‐N environments.…”

Gains in Genetic Enhancement of Early Maturing Maize Hybrids Developed during Three Breeding Periods under Striga-Infested and Striga-Free Environments

“…Its prominence has increased in SSA owing to its use as a cheap energy source in both human and livestock diets. The high insolation, cold night, and minimal occurrence of pest and diseases that characterize the savanna agroecology of SSA make it an ideal environment for maize production [1]. The early maturing maize varieties that are often available in July during the food deficit period, when other food reserves have been exhausted due to the extended hunger period, have helped to alleviate starvation in the savannas of SSA [2].…”

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

“…Striga parasitism is a limiting factor to maize ( Zea mays L.) cropping in the savannah zones of Sub‐Saharan Africa (SSA) which constitutes the maize belt of the sub‐region (Runo & Kuria, 2018). About 75% of cultivated land with maize in SSA is endemic to S. hermonthica (Akaogu et al., 2019). Maize yield losses under severe Striga infestation can be as high as 100% (Figure 1) and are economically estimated to $7 billion in the SSA alone (Spallek et al., 2013).…”

“…In contrast, other studies reported that the impact of non‐additive genes is more important than the effect of additive genes in the control of the inheritance of host plant damage, while the effect of additive genes is more important in the control of the number of emerged Striga plants (Gethi & Smith, 2004; Badu‐Apraku et al., 2007; and Yallou et al., 2009). A recent study reported that the dominant effects surpass the additive effects for the number of emerged Striga plants and inheritance of Striga resistance in maize may be conditioned by non‐additive gene action (Akaogu et al., 2019). Additionally, the involvement of epistatic effects in the inheritance of Striga resistance aa in maize has been reported (Adetimirin et al., 2001; Akaogu et al., 2019).…”

“…A recent study reported that the dominant effects surpass the additive effects for the number of emerged Striga plants and inheritance of Striga resistance in maize may be conditioned by non‐additive gene action (Akaogu et al., 2019). Additionally, the involvement of epistatic effects in the inheritance of Striga resistance aa in maize has been reported (Adetimirin et al., 2001; Akaogu et al., 2019). Unlike maize, the progress in the identification of genes for marker‐assisted selection in other crops such as sorghum and rice is substantial.…”