Evaluation of midland maize (Zea mays l.) varieties in selected districts of southern Ethiopia

This study was aimed at selecting maize varieties that perform better in midlandmaize production areas. Seven improvedmidlandmaize varietieswere tested in Basketo Special district (Motikesa and Sasa Kebeles) and Darashe district, southern Ethiopia. The experimentwas doneusing a randomized complete block designwith three replications. Seeds were sown on a plot size of 15m(3m × 5m) having four rows with a spacing of 75 cm between rows and 25 cm between plants. Combined analysis of variance was conducted after testing the uniformity of error variance. There were significant differences (p < 0.05) between varieties for grain yield and other studied traits over locations. Mean separation for grain yield over locations indicated that varieties BH 547 (6851 kg/ha) and BH-546 (6638 kg/ha) gave better grain yield as compared to others. These two varieties gave 41.6% and 39.7% yield advantages over the national (4000 kg/ ha) maize average productivity, respectively. Generally, the result revealed that the existence of variation for the characters studied in midland maize varieties, and so, testing of the varieties has paramount importance before large-scale production. Subjects: Agriculture & Environmental Sciences; Botany; Plant & Animal Ecology; Soil Sciences


Introduction
Maize (Zea mays L.) is one of the most important cereal crops in Ethiopia. It is an important field crop in terms of area coverage, production and utilization. It ranks second in area coverage and first in total production (Central Statistical Agency [CSA], 2018). It is grown for its food and feed values and one of the most important staples and cash crops and the main sources of calories (Wedajo et al., 2015).
ABOUT THE AUTHOR Tariku Simion is research staff of crop research department at Arba Minch Agricultural Research Center, Southern Agricultural Research Institute, Ethiopia. He has undertaken applied research to enhance crop productivity and production. Tariku Simion has designed and conducted many experimental studies on field crops. He appreciates crop production under dynamic climate changes and encourages farmers to exploit the integrated potential of cultural practices to manage climate change and sustain productivity. He is involved in many national projects focusing on crop improvement and climate smart crop production systems, along with different teams.

PUBLIC INTEREST STATEMENT
Updating the farming communities with emerging and better yielding varieties can improve productivity. Varieties should be evaluated and confirmed for their adaptation before disseminating to a large community, which is a usual practice that has been conducted in the research culture. This is due to many environmental factors varying from region to region challenging crop adaptation. In this study, therefore, released varieties from other regions have been evaluated for their adaptation. And, better performing varieties were found and recommended for demonstration.
In southern Ethiopia, maize is the first crop both in productivity and in production (CSA, 2018). It is the most extensively cultivated food crops and the main source of calories in western, southern and eastern parts of Ethiopia (Mosisa, Wonde, Berhanu, Legesse, & Alpha, 2001). Gamo, Gofa and Segen area people zones are among major maize producers in southern Ethiopia. The productivity of existing varieties is below potential. The low yield in this area is mainly not only lack of improved varieties but also attributed to improper use of technology packages. Testing of different released varieties in Ethiopia for their environmental reaction is crucial to avoid risks of various environmental factors (biological, physical and chemical). Hence, it is important to test maize varieties for their adaptation that were released for midland areas of Ethiopia to enhance production and productivity. Therefore, this study was initiated with the objective of selecting better performing maize variety/ies for yield in midland areas of southern Ethiopia.

Materials and methods
An experiment was conducted during 2018 cropping season comprising seven midland maize varieties in four testing locations of southern Ethiopia. The experiment was laid down in a randomized complete block design with three replications. The plot size of 222.5 m 2 (4.5 m × 5 m) having six rows with interrow spacing of 75-cm and 25-cm spacing between plant was used. Fertilizers (NPS 100 kg/ha at planting and 100 kg/ha urea (1/3 kg/ha at planting and 2/3 kg/ha at knee stage)) were applied after weeding. Data were collected for plant height (taken at maturity) and ear height on the basis of five sample plants randomly taken from four central rows, and grain yield was taken from four central plot bases. Data were subjected to Genstat software for analysis of variance (ANOVA) for individual and combined locations. Mean separation was conducted by using the least significant difference.

Results and discussion
Combined ANOVA for locations, varieties and varieties by location interaction revealed significant difference (p < 0.05) for the parameters studied (Table 1). This indicated that the presence of significant variations among varieties and the varieties had inconsistent performance over the tested locations. Workie, Habtamu, and Yigzaw (2013) in maize and Yayis, Agdew, and Yasin (2014) in field pea and Simion et al. (2018) in cowpea also reported the significant effect of locations, varieties, and locations by varieties on yield and some other yield-related traits.
Mean performance of varieties for grain yield for each location is presented in Table 3, 4, 5 and 6. The varieties had over locations mean grain yield of 6271 kg/ha ( Table 2). The highest over locations mean grain yield obtained were BH547 (6851kg/ha) and BH546 (6638kg/ha). These varieties had an yield advantage of 41.6% and 39.7% for BH 547 and BH 546, respectively, over the national maize average productivity (4000 kg ha −1 ). Moreover, performances of varieties were not consistent across locations. Inconsistent performances of varieties for studied traits across locations were due to physical, chemical and biological factors (Tariku et al., 2018) Among varieties, SBRH, BH660, BH547 and BH546 had better grain yield at Walayite location with a yield advantage of 50.1%, 50.0% and 48.6% and 47% over the national maize average productivity (4000 kg/ha, CSA 2018) (Table 3) in the given order. Among tested varieties at Motikesa, BH543, BH546, BH547 and BH661 yielded better in the given order with a yield advantage of 52.6%, 49.9% and 48.8% over the national (4000 kg/ha, Central Statistical Agency (CSA), 2018) maize average productivity (Table 4).   Among varieties tested at Sasa, BH661 had better grain yield with a yield advantage of 38.9% over the national maize average productivity (4000 kg/ha, Central Statistical Agency (CSA), 2018) ( Table 5). Average yield performances of varieties were low mainly due to low moisture stress and incidence of fall armyworms during the experimental season.
Among varieties tested at Belta, all except BH660 showed better performance for yield with a yield advantage of up to 30.7% over the national maize average productivity (Central Statistical Agency (CSA), 2018). Average yield performances of varieties in this study area were low mainly due to low moisture stress and incidence of fall armyworms during the experimental season.

Conclusion and recommendation
Maize is an important field crop in terms of area coverage, production and utilization in the study area. The combined analysis of variance revealed a significant difference (p < 0.05) for location, variety and variety by location interaction. The present study indicated the existence of variability among varieties studied in terms of their reaction with locations to yield and yield-related traits. The mean separation for grain yield over locations indicated that varieties BH 547 (6851 kg/ha) and BH-546 (6638 kg/ha) were superior varieties compared to others. Based on the average national maize productivity, these superior varieties had 41.6% and 39.7% yield advantages over the national maize average productivity. Therefore, to increase maize production in the study area, these two varieties are recommended and need to be demonstrated with their improved production packages in many farming fields with a larger plot size.