Genotype × environment interaction effects on cured leaf colour distribution in Zimbabwean Virginia tobacco (Nicotianatabacum L)

Cured leaf colour is one of the most important traits in Virginia tobacco (Nicotianatabacum L) production.  Cured leaf colour is associated with the relative nicotine content of the leaf and determines the relative price of the cured leaf on the market.  There are three main Virginia tobacco cured leaf colours namely lemon, orange and mahogany. Virginia tobacco breeders in Zimbabwe aim to produce varieties that give each of the cured leaf styles to satisfy a wide range of farmer preferences.  However, it is often speculated without empirical evidence that the location, climatic conditions and hence farmer management practice influence the cured leaf colour of Virginia tobacco produced by a farmer.  A study involving twelve genotypes was conducted in eight farming locations across Zimbabwe over two seasons to determine the genotype × environment interaction effects on Virginia tobacco cured leaf colour.  Experiments in each location was laid out as a randomised complete block design (RCBD) with three replicates and data on the proportion of the cured leaf that was classified as dark (orange and mahogany) was observed.  The collected data was analysed using the AMMI Model in Genstat Version 17 it was shown that there were no significant genotype × environment interaction effects for cured Virginia tobacco leaf colour (p > 0.05). The results have also indicated that Virginia tobacco varieties with K E1 as their progenitor gave relatively high proportions of dark cured leaf styles.