A six‐parent diallel cross, including reciprocals, of grain sorghum [Sorghum bicalor (L.) Moench] was analyzed for grain yield, percent protein, and protein yield. Highly significant differences were observed among parents and F1 hybrids for each trait. Reciprocal differences were not significant, but a partial failure of assumptions for the Jinks‐Hayman analysis was noted for all traits.Differences among the parents indicated an additive component of genetic variation for all traits. The estimates for non‐additive components suggested that dominance was important for all traits. The degree of dominance was estimated to be in the overdominance range, particularly for the yield traits. Dominance was in the direction of higher yields and lower percent protein. The positive and negative alleles were estimated to be equally frequent for yield; or percent protein, the negative alleles were estimated to be more frequent. These results suggest that improvement of percent protein requires selection for recessive alleles that have a low frequency; improvement of yield requires a method to cope with overdominance.Highly significant GCA and SCA effects were observed for all traits. A comparison of their relative magnitudes indicated SCA effects were much more important than GCA. Specified comparisons among the parents were made for GCA and among the parents and hybrids for SCA.

Studies on the effects of hydrogels on soil amendments, moisture conservation and growth of Cajanus cajan in arid and semi-arid lands were carried out. Seedlings of C. cajan were established both in the nursery and in the field with and without hydrogels. In the field, three replications were used with three levels of hydrogels concentration (7 g, 11 g, and 15 g). Control seedlings were established in soils without hydrogels. In the nursery, root collar diameters and heights were measured every two weeks up to eight weeks. Seedlings established without hydrogels in the nursery were transplanted into field soils with none, 7 g, 11 g and 15 g of hydrogels. Root collar diameters and heights were again measured every month for three months. In addition, soil was collected randomly once every month from the base of each seedling and analyzed for soil moisture using standard laboratory procedures. All data were subjected to analysis of variance. The results show that growth in both the height and root collar diameter of the species was significantly different at the three levels of hydrogels. This suggests that use of hydrogels retards plant growth in nursery soils but improves growth in the field. Hydrogels increased soil moisture volume from 8.3% to 10% in H 15g level of hydrogels under C. cajan after transplanting. It was concluded that hydrogels do not contribute to growth of seedlings in the nursery but they do so after transplanting. Hydrogels increase soil moisture in the soil, so they are recommended for use in semi-arid lands to boost the survival and growth of seedlings.

Slope failures can endanger human life and cause infrastructural destruction and socioeconomic loss. Geoscientists have strived to develop constitutive models and real-time slope monitoring models and systems to abate these processes. Most research studies have proposed models which describe the dynamics of wedge-shaped soil masses which do not mimic real field conditions. In this study, failure dynamics of spherical-cap-shaped soil masses on an inclined slope section undergoing purely translational displacement are described using empirical models derived from inertial forces in action for varying hydrological conditions. Validation of model results was done through experimental tests carried out on a laboratory flume. Empirical models representing rainfall intensity, soil water content, porewater pressure, factor of safety, and displacement were derived. More pertinently, the empirical model for the factor of safety is derived considering the moist unit weight of the soil as opposed to earlier models which focused on saturated conditions only. Model and experimental results indicate close concurrence, especially for the factor of safety with root mean square error of 0.0385 and r 2 of 0.6381. Since the models are physics based, they can be applied on a variety of rainfall-induced shallow landslides on relatively steep slopes.

Hydrological factors such as volumetric water content (VWC) and pore-water content (PWC) have been cited widely as significant factors that trigger slope failures especially shallow landslides and debris flows. Over the years, researchers have studied these processes using a range of physically-based models which in many occasions are either too complex incorporating very many parameters or fail to mimic real field conditions. The principal objective of this study was to derive and incorporate a set of physically-based equations that describe the dependence of slope failures at laboratory scale on VWC into a factor of safety expression herein referred to as the hydro-dynamical landslide model. The model was validated by a series of physical tests on soil samples in the laboratory using the Chepflume. Results showed a close agreement between computational and experimental data, confirming the hypothesis that cohesion, internal friction angle and pore-water pressure are modulated by VWC especially for slopes with sandy-loam soils. More so, rapid change of soil water content was observed to accelerate build-up of negative pore-water pressures (PWP) which triggers slope failure. Apart from giving a simplified expression for the factor of safety, the proposed model circumvents the difficulties associated with tedious procedures employed in the measurement of cohesive stress by limiting the tests to only three sets of parameters i.e. VWC, PWP and displacement.