Yield stability and agronomic performances of provitamin A maize (Zea mays L.) genotypes in South-East of DR Congo

Abstract Genotype assessment across various environments is a basic condition for developing stable and superior genotypes for sustainable maize production in the South-East of the DR Congo. Therefore, this research’s objectives were to identify the performance of newly developed provitamin A maize genotypes in various environments, and to recommend high-performing and stable genotypes for broader adaptation. Eight provitamin A maize genotypes, including one commercial variety, were planted at three sites during two consecutive cropping seasons (2020/2021 and 2021/2022) forming six environments. All genotypes in six environments were planted in a randomized complete block design containing three replications. Two stability analysis approaches, GGE biplot and Eberhart and Russell method are widely used to identify high yielding and stable genotypes. The combined analysis of variance revealed that G and E as well as their interaction (GEI) have significantly affected the emergence rate, cob’s insertion height, days to anthesis and silking, cob length, cob grain weight and grain yield. Average grain yield varied from 8.30 t/ha for PVAH-7L to 9.41 t/ha for PVAH-1L. The Eberhart and Russell method and the CV identified PVAH-1L, PVAH-4L, PVAH-7L and PVAH-6L as the most stable genotypes, but could not reliably identify the high yielding genotypes. On the other hand, the GGE biplot reliably and graphically showed the stable and high-yielding genotypes (PVAH-1L > PVAH-6L) as well as the low-yielding genotypes (PVAH-7 > PVAH-4L). In additional, the GGE biplot showed that L’shi21 was the best test environment for selecting high performing and stable provitamin A maize genotype. The results of this study indicate that PVAH-1L and PVAH-6L are the stable, high-yielding provitamin A maize genotypes in the South-East of the Democratic Republic of the Congo and should be disseminated in this region.