Influence of Timing of Herbicide Application on Winter Canola Performance
Canola (Brassica napus L.) is an important source of vegetable oil for humans and canola cake is a nutritious feed for animals. However, weeds are one of the major constraints in canola production in the southeastern regions of the United States causing loss upto 50 percent in yield. Control of weeds in spring canola has been reported but research on weed control in winter canola has not been well documented. Therefore, research experiments were conducted from 2005 to 2007 to evaluate the effects of herbicide application timings on canola performance. Results showed that pre-emergence timing of trifluralin @ 1 kg ai ha resulted 496 kg ha , 411 kg ha , 502 kg ha higher canola yield as compared to control in 2005, 1 1 1 1 2006 and 2007, respectively. Pre-emergence application timing of trifluralin gave 79% less weed biomass than control plots. Increasing weed density and weed biomass significantly reduced the canola yield whereas increasing plant height increased the canola yield significantly. This study revealed that herbicide application timing significantly reduced weed biomass and increased canola yield.
Non-Chemical Weed Control in Winter Canola (Brassica napus L.)
Cultural practices, management techniques and product quality are important factors which can influence the field heath and food security. Application of low input agriculture strategies, like as organic farming will result to high quality and safe products. In order to reduce herbicide use and enhancing quantity and quality of canola seed (cultivar Hyola308) a field experiment was conducted at Varamin, Iran, on 2007- 2008 growing season. Seven experimental treatments consisted of Chemical weed control using Trifluralin (2.5 l.ha -1 ) + sethoxydim (1.0 l.ha -1 ), integrated reduced dose of the same herbicides to between rows cultivation, twice cultivation, integrated pre-irrigation (25 days before sowing) to cultivation at stem elongation stage, black plastic mulch, weed-free and uncontrolled weed were arranged in randomized complete blocks with four replications. Results indicated that canola grain yield, yield components, oil percent were significantly decreased due to weed interference. The highest crop height, leaf area index, grain and oil yield obtained from black plastic mulch treatment. This non-chemical treatment has also significantly reduced weed density and dry matter. However there was no significant difference between plastic mulch and integrated control treatments (pre-irrigation + cultivation). Since mulching practices in trade canola fields is so difficult and relatively expensive, simple integrated (agronomic and mechanical) weed control treatment including irrigation the field 25 days before planting with the aim of removing emerged winter weeds via seedbed preparation practices + cultivation at stem elongation stage could be recommended.
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.