Screening Maize (Zea mays L.) Germplasm for Non-Parasitic Weed Tolerance in a Tropical Rainforest Agroecology

VK Job¹*, M.A.B. Fakorede¹, A Oluwaranti¹, B Badu-Apraku² and A Menkir^2
1Department of Crop Production and Protection, Obafemi Awolowo University, Ile-Ife, Nigeria
²International Institute of Tropical Agriculture, P.M.B. 5320, Ibadan, Nigeria
*Corresponding Author: VK Job, Department of Crop Production and Protection, Obafemi Awolowo University, Ile-Ife, Nigeria.

Published: March 02, 2023

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Abstract  

The high economic and environmental costs of weed management have led to interest in studying the genetics of non-parasitic weed stress tolerance in maize (Zea mays L.). The objectives of this study were to determine genotypic effects of weed infestation on maize, identify plant traits conditioning weed-stress tolerance, and identify maize varieties that are weed-stress tolerant for further improvement. One hundred open-pollinated maize varieties were planted in five environments in the early and late seasons of 2018 using a 10 x 10 lattice design with three replications. Data were collected on emergence, vegetative, and flowering traits as well as grain yield and its components. Analysis of variance showed that under uncontrolled weed stress, there were significant (p≤0.01) varietal (G), environmental (E), and G × E effects for emergence, vegetative vigor, flowering, grain yield, and yield component traits. There was significant positive correlation between clean weeding and zero weeding for number of leaves, tasseling-silking interval, number of ears/plot, and grain yield. Broad sense heritability estimates were 73.8% for emergence percentage, 67.75% for emergence index, and 59.48% for days to tasseling. Rank summation index (RSI) identified ten varieties as promising for weed-stress tolerance, including TZEE-W POP STR 108 BC2, (2 X TZE COMP. 3 DT/WHITE DT STR SYN) C2, TZEE-W POP STR C5, ACR.06 TZL COMP. 3 C4, EVDT-W 99 STR and five others. It was concluded that genotypic variation for non-parasitic weed stress tolerance exists in the available maize germplasm in Nigeria, is highly heritable, and promising varieties have been identified for further improvement.

Keywords: maize; weed stress; non-parasitic weed; tolerance