Vitamin A deficiency is a serious health problem in South Africa, as in several parts of the world. One strategy to combat micronutrient deficiency is through biofortification, particularly through orange‐fleshed sweetpotato [Ipomoea batatas (L.) Lam]. Previously, a shortage existed in South Africa of orange‐fleshed genotypes with a combination of high dry mass, good yield, and good taste. Local cream‐fleshed parents and orange‐fleshed US introductions were used in the local polycross program. This study aimed at testing the agronomic performance, stability, and genetic diversity of newly developed orange‐fleshed genotypes. Twelve entries, nine with orange flesh color, were evaluated at four sites for two seasons in multienvironment trials and the data was subjected to ANOVA and genotype plus genotype‐by‐environment interaction (GGE) biplot analysis. Simple‐sequence repeat (SSR) analysis of the 12 entries was done followed by hierarchical clustering. Two of the orange‐fleshed cultivars were recommended for production and plant breeders’ rights were registered for these. Cultivar Impilo produced stable, high root yield similar to the commercial control cultivar Beauregard; while the elite breeding line Purple Sunset (2001_5_2) had high yield and specific adaptability. Both displayed average dry mass and acceptable taste. The genetic analysis indicated relatedness of most new genotypes with the cream‐fleshed parents used in the polycross program. The improved cultivars offer considerable yield advantage above US introductions previously recommended for combating vitamin A deficiency.
The study was conducted to determine whether the efficiency of energy conversion into growth can be used as an indicator for the determination of the optimal gamma irradiation dosage for mutation breeding. To meet this objective, embryo growth, shoot growth, root growth, mobilization of food reserves, respiration and energy conversion were studied in gamma-irradiated wheat Triticum monococcum L. cultivar Einkorn kernels. Kernels were exposed to 50, 150, 250 and 350 Gy and germinated. Kernels were collected 12 h after onset of imbibition and then every 12 h until 168 h. Irradiated seed demonstrated retardation in all parameters, which increased as the gamma irradiation dosage increased. For the most, dosage and time, as well as dosage by time interaction were highly significant. Root growth appeared to be the most sensitive to gamma irradiation, followed by shoot growth, mobilization of food reserves and efficiency of energy conversion. Full recovery of the efficiency of energy conversion took place at 50 Gy, with an increase in inefficiency with an increase in dosage. The point where full recovery of efficiency of energy conversion into growth gives way to incomplete recovery (100 Gy) is in line with the suggested dosages for practical mutation breeding in Triticum monococcum L. by the FAO/IAEA and is therefore an ideal indicator for predicting the dosage that will be optimal for plant mutation breeding.
Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.