Agronomic Performance and Breeding Potential of Selected Inbred Lines for Improvement of Protein Quality of Adapted Ugandan Maize Germplasm

The use of exotic Quality Maize (QPM) donors to broaden the germplasm base used by breeders is important. This study evaluated the potential QPM inbred donors from CIMMYT for improvement of the protein quality of adapted maize lines in Uganda. Experimental plots were planted at Namulonge Agricultural and Animal Research Institute (NAARI) which is a known hot spot for several foliar diseases. Six QPM and six non QPM inbreds were planted in a Randomized Complete Block Design (RCBD) design with 3 replicates in 5-m rows. The twelve parental materials were crossed in a 6 X 6 half diallel mating design with QPM donors as males. Incidence and severity of major diseases were scored 4 times during the season while key agronomic descriptors were recorded. The field evaluation revealed that CML159 and CML144 are very susceptible to Maize streak virus (MSVD) and Turcicum leaf blight (TLB), two of the major foliar diseases in Uganda. CML173, the earliest maturing donor with the best plant aspects had moderate resistance to the major foliar diseases. CML176 with the exception of high MSV severity had moderate resistance to other diseases, good plant aspects, high protein quality and quantity. CML181 is MSVD resistant, moderately resistance to other diseases but had the lowest tryptophan level. CML182 was very susceptible to MSVD, TLB and had a poor plant aspect. Significant genotype sum of squares were divided into general (GCA) and specific (SCA) combining ability. Results indicated that existence of genetic divergence for all the diseases analyzed, where additive effects were predominant. QPM donors CML176 and CML173 were superior in terms GCA for the major foliar diseases, plant aspects and protein quality and quantity. We, therefore, recommend these lines for inclusion in Ugandan QPM breeding programs.

Keywords
Combining ability, Diallel cross, Gray leaf spot, Rust, Maize streak virus, Turcicum leaf blight, Uganda, Quality protein maize