We identified a loose upper panicle mutant (lup) from a japonica-type rice variety, Hwacheongbyeo, treated by Ethyl Methane Sulfonate (EMS). The lup mutant displayed an increased distance between spikelets particularly in the first primary branches, and the number of spikelet was reduced. In addition, aborted spikelets in the tip of first primary branches were observed. Besides these morphological changes in the panicle, the lup mutant also displayed overall reduction in culm length, panicle length, grain weight, and tiller number. On the contrary, the chlorophyll content was relatively high in lup mutant in comparison to wild-type plants, and displayed a "stay-green" phenotype even after physiological maturity. Genetic analysis (using F2 population of lup/M.23) revealed that a single recessive gene is involved in the above-mentioned morphological changes in the lup mutant. A candidate genomic region was fine-mapped at an interval of 1.04 Mb flanked by two molecular markers, 18170 and D0052, on the long arm of chromosome 8. In this region, we found a total of 348 mutation points using a slightly modified MutMap method. Based on these results, we expect the candidate genomic region containing a putative LUP gene will provide an important clue in developmental regulation of spikelets and panicle in rice.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Rice varieties developed through the inter-specific crosses between Asian (Oryza sativa L.) and African cultivated rice (O. glaberrima Steud.) have contributed to yield enhancement of African rice. However, the genetic diversity and genetic structure of the African varieties have rarely been reported. In this study, we characterized 40 rice varieties including rice released in Africa based on eleven yield related agronomic traits and 96 single nucleotide polymorphism (SNP) markers. They were grouped into three categories based on the cluster analysis using agronomic traits. Meanwhile, they were grouped into two distinct clusters, indica-and japonica-type, based on the genetic distance using 96 SNP markers. CG14, which belongs to O. glaberrima, was found to be an admixture type between indica and japonica. The number of secondary branches (SBs) was the only agronomic trait which was significantly different between two groups. The results of this study provide basic agronomic and genomic information of cultivated and tested rice varieties for Africa, that would be helpful for further rice varietal improvement in Africa.

Application of synthetic compounds seed dressing enhancing yield and yield components of crops but it is becoming very expensive for resource poor farmers beside this; these also have a negative effect on the natural environment. Thus, the current field and laboratory experiment was conducted during the 2018 main cropping season for testing the potential of locally available plant extracts; garlic (Allium sativum), ginger (Zingiber officinale), neem seed (Azadracta indica), varnonia leaf (Vernonia amygdalina) and crouton leaf (Crouton macrostachya) as seed priming materials on malt barley. Three levels of each priming material (5%, 10% and 15 % concentration) were prepared and full sized malt barley seeds were soaked for 12hrs in these priming materials. Seed dressing chemical (Dynamic 400 FS), distilled water soaked seeds, and dry seeds were used as a control for the field experiment. Primed seeds with all concentrations of botanicals, including distilled water and dynamic dressing chemical had a significant enhancing effect on agronomic parameters of malt barley under both laboratory and field conditions except for the effect of ginger extract priming which negatively affected the agronomic parameters as compared to dry planted (untreated) seeds. However, there was clear variation among botanical extracts and this is depending on their concentration and types of used botanicals. Among the tested botanicals, all three levels of garlic extracts have a significant enhancing effect on all agronomic parameters and this was followed by the neem. From the result of this study, seed priming with naturally available plant materials were found to improve yield and yield components of malt barley where for this particular experiment, all levels of garlic performed best as compared to other priming materials.