Grain yield and stability of tropical maize hybrids developed from elite cultivars in contrasting environments under a rainforest agro-ecology

Abstract

In the maize producing regions of Sub-Saharan Africa (SSA), compounding effects of genotype-by-environment interaction have necessitated breeding maize for outstanding performance and stability across varying environments. This study was conducted to assess the performance and stability of late-maturing cultivars and their respective hybrids evaluated under contrasting environments in the tropical rainforest region. We evaluated 108 genotypes in field trials under three different growing conditions in 2018 involving 14 open-pollinated parents and their hybrids derived from a diallel mating design. The genotypes were evaluated under field conditions using 9 × 12 alpha lattice design with three replications in six environments. The genotypes were divided into three groups, containing either the parents, hybrids or checks, for estimating the stability variance and grain yield. The difference between the lowest and highest yielding environment was 3.9 t ha−1, while the repeatability of the grain yield trials ranged from 39 to 80%. The average grain yield of the hybrids (2.33 t ha−1) was significantly higher than that of the parents (2.19 t ha−1) and the check varieties (2.03 t ha−1). The hybrids were more stable than both the parents and the checks. They also showed a higher stability against a common group of the parents and checks. The results of this study suggest that high yielding and stable population hybrids can be utilized in breeding programmes aiming to provide improved varieties for the large number of rural maize farmers in the SSA zone, who often lack access or the capacity to purchase commercial hybrids.

INTERVARIETAL CROSSES, AN ALTERNATIVE FOR INCREASING YELLOW MAIZE (Zea mays L.) PRODUCTION IN VARIABLE ENVIRONMENTS

“…These results indicate that there is wide diversity in yield components and agronomic traits, due to the effect of the environment, genotypes, their interaction and the use of divergent varieties as parents of intervarietal crosses. The use of genetic diversity allows to identify favourable alleles for genetic improvement (Barrera-Guzmán et al, 2020;González-Martínez et al, 2020); get to know alternative heterotic patterns (Carena, 2005), which can be exploited for the development of varieties with higher productive potential and wider adaptation (Eze et al, 2020;Velasco-García et al, 2019).…”

“…The yield of the intervarietal crosses was statistically equal to the controls, ranging from 5.15 to 7.09 Mg ha -1 and was equal to that of conventional hybrids, one OPV and it was superior to all parents. Different genotypes have been found to match or outperform hybrids, such as divergent population hybrids (Carena, 2005); improved OPV (Espinosa-Calderón et al, 2013); non-conventional hybrids and OPV (Martínez-Yañez et al, 2017); crosses between maize races (Velasco-García et al, 2019); population hybrids (Eze et al, 2020); experimental single hybrids (Cieza et al, 2020). Furthermore, the use of divergent parents tends to increase yield (Moll et al, 1965).…”

“…The genotype × environment interaction effect on yield stability of genotypes was different, due to the lack of adaptation to the environments evaluated. It varies by the diverse environmental conditions in which they develop; however, stable genotypes have been found as experimental single crosses 216); hybrids (Alí et al, 2017) and population hybrids (Eze et al, 2020). Results in this study indicated that 23 crosses had consistent yields and can be grown in both evaluated locations, which may be attributed to a greater genetic variability that allowed them to ameliorate the effects of the environment, without causing drastic changes in yield, since their parents are divergent.…”

Implications of genotype x environment interaction in the indication of common bean cultivars in Santa Catarina, Brazil

“…To circumvent this situation, stability and adaptability analyses are widely employed, with the objective of simplifying or extracting more information about the genotypic behavior of the genotypes to be studied and recommended (Eze et al, 2020;Freiria et al, 2020;Inabangan-Asilo et al, 2019;Munda et al, 2020;Mwiinga et al, 2020;Nascimento et al, 2020;Sarti et al, 2020). Based on this, the indication taking into account adaptability, considers the increase in grain yield, arising from the G x E interaction.…”

Yield Components and Efficiency Index of Maize Yield: Relationship to Yields in Tidal Fields

“…The performance of plant growth and yield is largely determined by the interaction among the genetic factors, environmental factors and management factors (Worku et al, 2016;Fernandez et al, 2020;Eze et al, 2020;Lilian & Charles, 2020). In terms of management factors, the effectiveness of fertilizer technology in increasing land productivity is very needed.…”