Search

Maize cultivars with resistance to Striga spp. and compatible to Fusarium oxysporum f.sp. strigae (FOS) are an economical, sustainable and environmentally Striga control option. This study's objective was to determine the type and magnitude of gene action controlling grain yield and yield‐related components, Striga resistance, FOS compatibility and to select promising maize genotypes for an integrated Striga management approach. Ninety‐nine experimental hybrids, generated by a North Carolina mating design II, were evaluated with and without FOS treatment at three Striga‐infested sites in western Tanzania. The general (GCA), and specific combining ability (SCA) effects were significant (P <.05) for all the assessed traits with and without FOS except, Striga damage ratings eight (SDR8), and 10 (SDR10) weeks after planting with FOS treatment. FOS‐treated progenies had fewer emerged Striga plants than untreated controls. Parental genotypes such as SITUKA M1, TZA4010, TZA4016, TZA4203, JL01, JL05, JL13 and JL17 showed negative GCA effects for all Striga parameters and positive GCA effects for grain yield. The new progenies and selected parents are recommended for Striga resistance breeding. [ABSTRACT FROM AUTHOR]

Striga spp. severely affect maize yields in Tanzania causing yield losses varying from 20% to 100%. The use of Striga resistant varieties is an economical and environmentally friendly option that can be easily adopted by smallholder farmers. Uptake of newly developed varieties would be high if the breeding process is inclusive and consultative to farmer preferred traits and preferences. The aim of this study was to identify farmers' maize production constraints, current Striga control options, trait preference and perceptions among smallholder farmers in western Tanzania. Surveys were conducted in four districts, namely Igunga, Shinyanga rural, Urambo and Uyui during the 2017/2018 cropping season. Data were collected from 324 farmers using a semi-structured questionnaire (166), focus group discussions (158) and field observations. The major maize production constraints reported by farmers were; drought (97.2%), Striga infestation (93.1%), insect pests in field (90.1%) and in stores (72.7%). The main Striga control options described by farmers across the studied districts were: hoe weeding, uprooting, manure application and crop rotation in descending order. Only 59% of the farmers used the seed of improved maize varieties of either hybrids or open-pollinated varieties (OPV) which are Striga susceptible and the remaining used home saved seed. A breeding programme aiming at improving maize varieties for Striga resistance, including farmers' preferred traits, should be designed and executed to control Striga infestations thus improving maize production, productivity and profitability in western Tanzania. [ABSTRACT FROM AUTHOR]

Striga species cause significant yield loss in maize varying from 20 to 100%. The aim of the present study was to screen and identify maize genotypes with partial resistance to S. hermonthica (Sh) and S. asiatica (Sa) and compatible with Fusarium oxysporum f. sp. strigae (FOS), a biocontrol agent. Fifty-six maize genotypes were evaluated for resistance to Sh and Sa, and FOS compatibility. Results showed that FOS treatment significantly (p < 0.001) enhanced Striga management compared to the untreated control under both Sh and Sa infestations. The mean grain yield was reduced by 19.13% in FOS-untreated genotypes compared with a loss of 13.94% in the same genotypes treated with FOS under Sh infestation. Likewise, under Sa infestation, FOS-treated genotypes had a mean grain yield reduction of 18% while untreated genotypes had a mean loss of 21.4% compared to the control treatment. Overall, based on Striga emergence count, Striga host damage rating, grain yield and FOS compatibility, under Sh and Sa infestations, 23 maize genotypes carrying farmer preferred traits were identified. The genotypes are useful genetic materials in the development of Striga-resistant cultivars in Tanzania and related agro-ecologies. [ABSTRACT FROM AUTHOR]