Phenotypic and biochemical screening of sorghum genotypes for growth and rice weevil resistance in Tanzania
Mwenda, Emmanuel Thomas
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The current study characterised sorghum genotypes based on their growth morphological variations; identified phenotypic and biochemical traits, and screened them for resistance to rice weevil (Sitophilus oryzae). A total of 117 sorghum genotypes were characterised using 10 qualitative and 10 quantitative growth morphological traits using sorghum descriptors. After preliminary yield screening, only 98 sorghum genotypes were used for the study. Data were subjected to one-way analysis of variance using GenStat version 15. Multivariate analysis and Pearson correlation was done using Mintab statistical software version 14. The study revealed significant levels of variability among sorghum genotypes (p<0.001) in terms of growth morphological traits, kernel phenotypic traits, biochemical and susceptibility to rice weevil. Positive and significant correlation was observed between grain yield and yield related parameters. Days to 50% flowering showed highly positive and significant association with plant height, number of leaves, and days to maturity. Genotypes IESH23022, IESV91104DL and IESV92172 were the best candidates for source of earliness and yield traits. Nine genotypes namely PATO, IESV92041SH, ATX623 x AIGD34533, UDO, Mbangala white, IESV74 DL, IESV92172, ICSA15 x R8602, and P9504A x ICSR172 recorded lower F1 progeny emergence, susceptibility index, median development period, kernel damage, and weight loss indicating that the genotypes were resistant to rice weevil. Kernel hardness indicated strong significant correlation with susceptibility parameters (p<0.001). Therefore, lines with adequate kernel strength are recommended for breeding against devastating storage pest, the rice weevil in Tanzania.