Treatment with indolebutyric acid (IBA) significantly increased the number of roots produced by vine cuttings of ten Dioscorea rotundata cultivars. Some cultivars could be propagated by layering, especially with IBA treatment, but layering does not appear to be feasible for use on farms.

We aimed to evaluate nutrient intake, performance and rumen fermentation of sheep fed cassava leaf silage (CLS). Sixteen growing Java thin-tailed male sheep (body weight (BW) 20.4 ± 1.9 kg) were fed one of the following dietary treatments: T0 (100 % forage); T1 (100 % chopped forage); T2 (80 % chopped forage + 20 % concentrate); and T3 (80 % chopped forage + 20 % CLS). Nutrient intake, production performance and rumen fermentation characteristics were measured. There was no significant effect on the consumption of dry matter, whereas there was a significant effect (P < 0.05) on the consumption of crude protein, fat, crude fibre and total digestible nutrients. Concentrate or CLS at a 20 % level could increase BW and feed efficiency. No significant difference was observed in total bacteria; however, concentrate could increase total protozoa (P < 0.05). Total volatile fatty acids were higher in T2 than in T3, but ammonia concentration was higher in T3 than in T2. In conclusion, feeding 20 % cassava leaf silage greatly improved sheep performance, approaching that achieved by feeding concentrate.

Rain-fed upland rice (Oryza sativa L.) is one of the important crops in Sub-Saharan Africa (SSA) accounting for over 40% of the area under rice cultivation. In SSA, upland rice is primarily established by dry direct seeding (DS), which saves time and labour, although DS is associated with poor seedling emergence and establishment. It is thought that coleoptile and mesocotyl elongation in rice seedlings enhance emergence in deep sowing. A screen house study was conducted from May to December 2011 at Tokyo University of Agriculture in Japan to determine the effect of coleoptile and or mesocotyl elongation on seedling emergence in deep sowing. Six upland rice genotypes which vary in coleoptile + mesocotyl lengths, and another ten genotypes varying only in mesocotyl lengths were selected and evaluated for seedling emergence at 2, 4, 6 and 8 cm sowing depths. The experiment was laid out in a split-plot design based on randomised complete blocks. Seedling emergence was significantly reduced by sowing depth. Across the genotypes, seedling emergence was not associated with coleoptile + mesocotyl length. And although coleoptile and mesocotyl lengths both increased with sowing depth, seedling emergence in deep sowing was affected largely by mesocotyl elongation rather than coleoptile elongation. We found that only those genotypes that significantly elongated their mesocotyls like Nutsurikui and Plu-go were able to emerge from deep sowing. Our results therefore suggest that seedling emergence in dry direct seeded upland rice can be improved by planting genotypes with long mesocotyls.

The bacterial community of water yam ( Dioscorea alata L.) cv. A-19 is vital because it may promote plant growth without the need for fertilization. However, the influence of fertilization practices on the composition and proportion of the bacterial community of water yam cv. A-19 has not yet been extensively examined. Therefore, we herein investigated the diversity and composition of the bacterial community of water yam cv. A-19 cultivated with and without chemical fertilization using amplicon community profiling based on 16S rRNA gene sequences. No significant difference was detected in the growth of plants cultivated with or without chemical fertilization. Alpha diversity indices were significantly dependent on each compartment, and a decrease was observed in indices from the belowground (rhizosphere and root) to aboveground compartments (stem and leaf). The bacterial composition of each compartment was clustered into three groups: bulk soil, rhizosphere and root, and stem and leaf. Chemical fertilization did not significantly influence the diversity or composition of the water yam cv. A-19 bacterial community. It remained robust in plants cultivated with chemical fertilization. The amplicon community profiling of bacterial communities also revealed the dominance of two bacterial clades, the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade and Burkholderia-Caballeronia-Paraburkholderia clade, with and without chemical fertilization. This is the first study to characterize the bacterial community of water yam cv. A-19 cultivated with and without chemical fertilization.

Symptoms of nutritional deficiencies in D. alata and D. rotundata were observed when yam plants were grown in nutrient solutions from which any of the following had been omitted: N, P, K, Ca, Mg, Zn, Fe, B, Mn, Cu and Mo. The symptoms of deficiency of major elements were visible on plants of both species. The omission of Fe, B and Mo produced characteristic symptoms on the leaves of D. rotundata, but D. alata showed symptoms only in response to Fe deficiency. The omission of minor elements led to poor growth of the leaves, stems and roots. Nutrient deficiencies in yam plants could be diagnosed by visual symptoms in the field.