Effects of irrigation frequency and water table depths on root growth and yield of tomato in a tropical soil
Abstract The effects of irrigation frequency and water table depths on tomato ( Lycopersicon esculentum , Mill, cv. Ife 1) root growth and fruit yield on a tropical soil were investigated. Tomato was grown at two water table depths (deep > 100 cm, and shallow Root length density, rooting depth, and fruit yield were generally higher at the deep than at the shallow water table location. At the deep water table location, the one-week irrigation frequency gave significantly higher root length density and fruit yield than the other irrigation frequencies. At the shallow water table location the two-week irrigation frequency gave higher fruit yield than the one- and three-week irrigation frequencies. There was a significant positive correlation between root length density and fruit yield.
Portable apparatus for separating roots from soil cores
One of the most widely used methods of root study involves obtaining soil cores and washing the roots contained free of soil (Wellbank & Williams, 1968; Ellis & Barnes, 1971; Kolesnikov, 1971; Schuurman & Geodewaagen, 1971; Bohm, Maduakor & Taylor, 1977). However, the process of root washing is time consuming and laborious. Some of the washing assemblies elsewhere (Peyev, 1952; Schuurman & Goedewaagen, 1971; Wellbank et al. 1974) have not gained popularity with researchers in developing countries because of the high costs involved or the sophisticated facilities needed. There is therefore a need for a low-cost root washing apparatus which can be fabricated with locally available materials. This note reports the development of such an apparatus.
Genetics of the phenotypic evolution in sheep: a molecular look at diversity-driving genes
Background After domestication, the evolution of phenotypically-varied sheep breeds has generated rich biodiversity. This wide phenotypic variation arises as a result of hidden genomic changes that range from a single nucleotide to several thousands of nucleotides. Thus, it is of interest and significance to reveal and understand the genomic changes underlying the phenotypic variation of sheep breeds in order to drive selection towards economically important traits. Review Various traits contribute to the emergence of variation in sheep phenotypic characteristics, including coat color, horns, tail, wool, ears, udder, vertebrae, among others. The genes that determine most of these phenotypic traits have been investigated, which has generated knowledge regarding the genetic determinism of several agriculturally-relevant traits in sheep. In this review, we discuss the genomic knowledge that has emerged in the past few decades regarding the phenotypic traits in sheep, and our ultimate aim is to encourage its practical application in sheep breeding. In addition, in order to expand the current understanding of the sheep genome, we shed light on research gaps that require further investigation. Conclusions Although significant research efforts have been conducted in the past few decades, several aspects of the sheep genome remain unexplored. For the full utilization of the current knowledge of the sheep genome, a wide practical application is still required in order to boost sheep productive performance and contribute to the generation of improved sheep breeds. The accumulated knowledge on the sheep genome will help advance and strengthen sheep breeding programs to face future challenges in the sector, such as climate change, global human population growth, and the increasing demand for products of animal origin.