Two indigenous chicken breeds: naked neck (N) and local white (W) feathered chicken called Netch as sire lines and two exotic chicken breeds: Fayoumi (F) and Rhode Island Red (R) as dam lines were crossed with the objective of producing 4-way cross-bred chicken population, which will later be used as base population to produce synthetic chickens. They were tested under on-station conditions in a college farm and under on-farm conditions at several typical village farms. Mortality during brooding period was lower under on-farm than on-station conditions, which may be owing to housing of the chicks in hay box-brooder on-farm and the coccidiosis infection on-station. However, higher on-farm mortality was observed during the laying period than on-station; mainly because of predation. There was a significant difference between the two systems in recorded body weight from early age to maturity. Age at first egg was lower on-farm than on-station. Average number of eggs produced was not significantly different; although chickens on-station laid more eggs than those on-farm. Hen-housed egg production was lower on-farm than on-station owing to higher mortality in the on-farm system.

Dactylopius tomentosus is composed of biotypes adapted to different Cylindropuntia species. One biotype is an important biological control agent of C. imbricata in South Africa while another has the potential for the control of C. fulgida var. fulgida. These two weed species occur in sympatry in some areas of South Africa, so the introduction of the second biotype could result in hybridization, which, in turn, could impact on the biological control programs through altered host specificity and fitness of the hybrids. To anticipate what might happen, reciprocal crosses were made between the two biotypes, and the biological performance of the resultant hybrids was compared with that of each parental lineage on C. imbricata and C. f. var. fulgida. The biotypes interbred freely and reciprocally in the laboratory. Comparisons of crawler and adult female traits showed differences in performance that were dependent on the origin of the maternal and paternal genomes. However, when all traits were combined into a ‘fitness index’, both hybrids clearly outperformed the parental lineages. The increase in fitness shown by the hybrids over their maternal lineage was greater on the alternative host of the maternal parent than on the natural host of the maternal parent. Therefore, in areas where the two cacti occur in sympatry, hybridization between the biotypes is not expected to be detrimental to the biological control of either weed.