TITLE:
Temporal and Spatial Factors Affecting the Nature of Genotype x Environment Interaction in Sugarcane (Saccharum officinarum L.) under Ethiopian Agro-Climatic Conditions: An Integrated Approach
AUTHORS:
Mebrahtom Ftwi, Firew Mekbib, Eyasu Abraha
KEYWORDS:
AMMI Bi-Plots, Environmental Covariates, Genotypes, MET, PCA Bi-Plots, Test Environments
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.7,
June
29,
2017
ABSTRACT: Analytical
approaches are important for identification the causes of Genotype x environment
interaction (GEI) in multi-environment trials (MET). The objectives of this
investigation were to explore the nature and causes of the GEI in sugarcane
under Ethiopian agro ecological conditions. Data of Cane yield, recoverable
sucrose% and sugar yield obtained from 13 test environments were subjected to
Additive Main and Multiplicative Interaction (AMMI2) for empirical study. For
environmental characterization, mean values of twenty seven temporal and
spatial factors were subjected to Principal Component Analysis (PCA). Moreover,
to identify the environmental factors affecting the patterns of GEI and its
components, mean values of these factors were correlated with environment AMMI2
IPCA scores of the yield traits studied. Results of the present study indicated
that the GEI accounted for larger variation than the genotypic effects which
suggested its importance and complexity. The PCA bi-plot successfully
identified the environmental factors that most discriminated the test
environments (crop years and locations). The correlation analysis between the
environmental factors and environmental AMMI2 IPCA scores adequately identified
the environmental factors affecting GEI and its components. Soil organic
matter% and soil clay%, pan evaporation at establishment, relative humidity at
growth stage and harvesting month were the major factors that substantially
affect the GEI interaction patterns in cane yield while maximum relative
humidity recorded during the growing season, all temperature regimes recorded
during the entire growing season and at different crop stages were the major
factors that affect GEI in recoverable sucrose%. Moreover, the pattern of GEI
in sugar yield was significantly affected by harvest age, percent of clay in
soil, altitude, relative humidity at harvest and pan evaporation at
establishment. For efficient environmental selection and networks, genotype
evaluations and formulation of appropriate sugarcane breeding strategy, f METs
should adopt the inclusion of these environmental factors identified as major
factors influencing the patterns of GEI. Moreover, more information will be
generated if other physiological and soil moisture stress indices are included
in future GEI studies in sugarcane.