Strategies for Selecting Early Maturing Maize Inbred Lines for Hybrid Production under Low Soil Nitrogen and Striga Infestation

Gloria B Adu,Richard Akromah,Baffour Badu-Apraku

doi:10.3390/agronomy11071309

Abstract

Development, testing and selection of superior inbred lines is crucial for the success of a hybrid program targeting Striga-infested and low soil nitrogen (low-N) environments. The practical value of inbred lines is determined by multiple traits, most of which are inter-dependent. The main objective of this study was to identify early maturing inbred lines based on multiple traits under optimal, low-N and Striga-infested environments for hybrid development and population improvement. One hundred early maturing inbred lines were evaluated under artificial Striga-infestation, low-N and optimal growing environments for two years at Kwadaso and Nyankpala in Ghana. The inbred lines exhibited high levels of genetic variability for grain yield and other agronomic traits desirable for Striga resistance and low-N tolerance. Under optimal growing conditions, days to silking (DS), ears per plot (EHARV) and days to anthesis (DA) had high direct effects on grain yield (GYLD). Days to silking and ears per plant (EPP) had the highest positive direct effects on GYLD, while DA had the highest negative direct effect on grain yield in low-N environments. Under Striga-infestation, the highest negative direct effect on GYLD was obtained with EASP. All the measured traits previously identified to have direct influence on grain yield were associated with it and could be used for indirect selection for improved grain yield under the contrasting environments. Forty-eight of the 100 inbred lines studied were identified as low-N tolerant and forty-nine as Striga resistant.

Highlights

Maize (Zea mays L.) is the third most widely planted crop in the world after rice and wheat and the second most traded cereal after wheat [1]
× environment (G × E) interaction was significant for grain yield, plant aspect, days to anthesis, days to silking and ear aspect (Table 2)
The relative performance of the inbred lines in grain yield and other agronomic traits were altered by Striga parasitism and low soil nitrogen (low-N) stresses in the present study

Summary

Introduction

Maize (Zea mays L.) is the third most widely planted crop in the world after rice and wheat and the second most traded cereal after wheat [1]. In sub-Saharan Africa (SSA), maize is an important staple crop for human consumption and provides at least. 30 percent of the food calories for more than 50% of the population. Its availability and affordability have been central to food security [3] of countries in the sub-region [4]. It is projected that if maize yield in SSA could be increased from the current 20% to 80% of the potential yield, SSA would attain self-sufficiency in 2050 [5,6]. Yield improvement in SSA is determined largely by the limited access of small-scale farmers to yield-enhancing inputs, such as improved seeds, fertilizers, machinery, and irrigation technologies [7].

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Conclusion