Aims: To study the phenotypic diversity of 25 forage and 45 grain sorghum genotypes for dual purpose as food and feed and to identify traits that might contribute to genetic improvement. Study Design: A 7 × 10 alpha lattice design was used with two replications at two sites.

Sorghum is an important food and feed source in mixed crop-livestock production systems where its dual usage is a preferred option, especially among the resource poor small-scale farmers. Attempts to improve fodder quality traits in maize have been at the expense of grain traits and vice versa, but other studies demonstrated that it was possible to select for high stem biomass without compromising the improvement of grain yields in sorghum. As a follow up to this effort, this study was undertaken to estimate the combining ability of grain and forage sorghum genotypes and determine heterosis for several traits as a criteria for improving dual purpose sorghum cultivars. Four grain and four forage sorghum cultivars were crossed to generate 23 crosses following the half diallel mating design scheme at Makerere University Agricultural Research institute Kabanyolo (MUARIK) in 2013. The crosses were evaluated at three locations in Uganda during two rainy seasons of 2014. Data were taken and analysed on leaf area, leaf-stem ratio, plant height, seed weight, grain yield, and biomass. Results indicated that the gene action for the traits under observation was controlled by both additive and non additive genetic effects. Majority of the parental lines had significant GCA estimates for all traits except line 20 for grain yield, lines 22 and 34 for plant height, line 35 for leaf-stem ratio, and line 22 for days to flowering. Significant (P ≤ 0.05) SCA estimates were prominent in most of the individual parental combinations for all traits except leaf area and leaf-stem ratio indicating the role of dominance gene action. Bakers ratio and heritability coefficients were  52% for biomass, flowering duration and plant height indicating that genetic gains can be achieved by conventional breeding for the three traits. Heterosis in grain yield and biomass over both the mid and better parents was shown by more than half of the crosses studied. This study suggested that both inter and intra allelic interactions were involved in the expression of the traits.

Sorghum (Sorghum bicolor L. Moench) production in sub-Saharan Africa is seriously constrained by both biotic and abiotic stresses. Among the biotic stresses is witchweed (Striga spp.), a noxious parasitic weed causing major damage in cereal crops, such as sorghum. However, resistance through reduced germination stimulant production or altered germination stimulant composition provides a sustainable and most effective way for managing the parasitic weeds. Laboratory and glasshouse experiments were conducted using seven (7) sorghum genotypes to evaluate their resistance or tolerance the witch weed (Striga asiatica L. Kuntze). The first experiment was a laboratory agar gel assay arranged in a completely randomized design with six (6) replications to evaluate the effects of the seven (7) sorghum genotypes on the production of strigolactones by determining the percentage germination and the furthest germination distance of the Striga seeds. The second experiment was a seven (7) (sorghum genotypes)∗two (2) (Striga treatments) factorial glasshouse experiment conducted to evaluate the effects of Striga on sorghum growth, physiological and yield components of sorghum, Striga syndrome rating, and number of Striga per plant. The genotypes showed a significant (p<0.05) difference in germination percentage and furthest germination of Striga seeds in the agar gel assay. Genotypes SV4, Mahube, and ICSV 111 IN showed the least germination percentage and lowest germination distance, implying that these varieties either produced low strigolactones or altered their composition. In contrast, Kuyuma, Wahi, SV2, and Macia caused high Striga seed germinations and high furthest germination distances, suggesting that these sorghum genotypes were susceptible to Striga infection. The sorghum × Striga × time interactions were significant (p<0.05) on sorghum height. It was found that the heights of sorghum genotypes ICSV 111 IN and Mahube were not altered by Striga infection, but the heights of Kuyuma, Macia, SV2, SV4, and Wahi were reduced by Striga infection. The interaction of sorghum∗Striga effects was significant (p<0.05) on chlorophyll fluorescence. Striga infection did not alter the chlorophyll content of ICSV 111 IN and SV4. The sorghum∗Striga interaction effects were significant (p<0.05) on head index, leaf biomass, leaf index, root biomass, root index, plant biomass, and root : shoot ratio. Assessing Striga tolerance based on sorghum heights, chlorophyll content, and root : shoot ratio parameters, it could be concluded that the sorghum genotypes Mahube, ICSV 111 IN, and SV4 tolerated Striga infection, whereas Kuyuma and SV2 could be susceptible.

Late blight is caused by Phytopthora infestans (Mont.) de Bary which establishes quickly in Solanum esculentum L. (tomato); as a result, it makes the pathogen one of the most devastating plant diseases across the world. The control of late blight is difficult because P. infestans has advanced and complex enzymes and effecter molecules coded by avirulence genes. As such, a study was carried out at the University of Zimbabwe, Department of Plant Production Sciences and Technologies, between August 2018 and May 2019 to evaluate the efficacy of Moringa oleifera Lour. (moringa), Eucalyptus nigra R.T. Baker (gumtree), and Lantana camara L. (sensu lato) (lantana) extracts as biofungicides on late blight development on S. esculentum. The effect of acetone, ethyl acetate, and water extracts of M. oleifera, E. nigra, and L. camara on percent inhibition and radial growth were evaluated in the laboratory. In addition, the efficacy of different extract concentrations of M. oleifera, E. nigra, and L. camara L. on defence enzymes, disease incidence, disease severity, and yield parameters of S. esculentum were assessed in the in vivo experiment. Increasing concentration of the botanical extracts significantly ( p ≤ 0.05 ) reduced radial growth and increased percent inhibition of P. infestans. In addition, increasing botanical extract concentration significantly ( p ≤ 0.05 ) increased peroxidase (PОD), phenylalanine ammonia lyse (PAL), and polyphenol oxidase (PPO) activity. Disease incidence and severity were significantly ( p ≤ 0.05 ) reduced as the concentration of the botanical extracts increased. Similarly, marketable and total yield significantly ( p ≤ 0.05 ) increased with increase in the botanical extract concentration. Gas chromatography mass spectrometry (GCMS) revealed the presence of furfural, 5-methyl-4- (trifluoromethyl) pyrido, dodecanamide, cyclopentasiloxane, and decamethyl. From the research, it can be concluded that M. oleifera ethyl acetate, E. nigra ethyl acetate, and L. camara water extracts contain antifungal compounds and can be used as biofungicides in late blight management.

Food feed crops play a cardinal role in mixed crop-livestock production systems yet views of farmers on their usage are limited. Farmers' perceptions in predominant sorghum growing areas of Zambia were solicited on socio-economic factors affecting sorghum production, awareness and willingness to adopt dual-purpose sorghum cultivars for food and feed. Preferred traits of a "model" dual-purpose cultivar were identified. The aim of the study was to generate information that would support the genetic improvement of dual-purpose sorghum. Questionnaires were used to generate this information. Results showed that less than 50% of sorghum growing SSFs had limited knowledge on the use of sorghum to produce feed silage; however, there was full awareness among the LSFs. Among other traits, farmers' "ideal" variety should combine high grain yield potential (100 %) with high biomass (100 % of LSFs and 80 % of SSFs) and high stem sugar content (100 % of LSF and 70 % of SSFs). All the SSFs and 20 % of the LSFs indicated that adequate production could be hampered by low grain yield, poor access to improved seed and unavailability of farmers'-preferred cultivars.