Influence of genotype x environment interaction on performance of selected maize ( zea mays L.) hybrids in southern highlands of Tanzania

A field experiment was conducted during the 2010/2011 cropping season in four locations of the Southern Highlands of Tanzania viz. Inyala, Mbimba, Uyole and Seatondale. The main objective of the study was to assess the response of selected maize genotypes across different growing environments for yield and adaptability and their interaction on yield and yield components whereas the specific objectives were to evaluate stability variables, interrelations and genetic parameters for traits in the studied maize hybrids. A randomized complete block design laid in a split-plot experiment with three replications at each location was used. The data collected include plant growth parameters, maize yield components and yield. The study shows that locations and weeding regimes were important for most variables, including grain yield while genotypes were important for ear height and number of kernel rows per cob. Location x weeding regimes was also important for most traits including grain yield; genotype x weeding regimes was important for number of leaves per plant while genotype x environment interaction was important for number of kernel rows per cob and days to maturity. Estimation of genetic parameters revealed high heritability coupled with high genetic advance for days to first tasselling, 50% tasselling, 50% pollen shed, first silking and ear height pointing out that these traits were under the control of additive genetic effects and that selection of these traits can be done in early generations of the breeding programme. Phenotypic Coefficient of Variation (PCV) was moderate for most traits including grain yield whereas Genetic Coefficient of Variation (GCV) was low for all traits. Path coefficient analysis singled out number of leaves per plant, plant height, days to 50% silking, 50% pollen shed and maturity as most important traits to consider during selection for grain yield improvements among the studied genotypes. It is recommended that genotype EH-2 (FH5160) can be carried further for national performance trial or possible release while UHS 5350 (EH3) and UH6303 can be used in the breeding programme.

The Green Revolution in Africa (AGRA