**2. Determination of yield stability of rain-fed sorghum and GGE biplot analysis of multi-environment trials**

### **2.1 Materials and methods**

Drought, yield and biotic stress traits are quantitatively inherited and highly environmentally interactive and require multi-environment testing to accurately characterize them. Therefore integrating the yield and stability of genotypes tested in very unpredictable environments is an important breeding strategy to identify superior sorghum genotypes for the rain-fed areas of Uganda. It helps to determine the existence of different mega-environments for maximizing genetic gains. This was achieved by testing 20 elite genotypes identified in study 1, in four locations via GGE (genotype + genotype-by-environment) biplot analysis. Data from two seasons (2019b–2020b) of rain-fed sorghum were used in this study. The materials consist of elite germplasm; landraces, advanced breeding lines and popular cultivars within crop improvement programs and introductions which contribute to variation and differentiation. **Table 4** is a representative sample of all the diversity in the large collection and would facilitate the enhanced use of sorghum germplasm in the breeding programs for major economic and production traits. They were selected together with farmers as having the best attributes for food and niche markets. The information on genotype-environment interaction was a useful supplement for classifying genotypes. The nature of genotype-environment interaction helps in the development suitable procedures for selection and the nature of stability for vital characters. Meanwhile, multivariate analysis was used to offer a more complete examination of data by looking at all possible independent variables and their relationships to one another. Finally, levels of similarity were computed as percentages among genotypes for key variables useful for planning crosses.

*DOI: http://dx.doi.org/10.5772/intechopen.112322 Accelerating Breeding for Drought Tolerance in Sorghum (*Sorghum bicolor*): An Integrated…*


**Table 4.**

*Genetic materials.*
