Inheritance of Striga hermonthica adaptive traits in an earlymaturing white maize inbred line containing resistance genes from Zea diploperennis

Striga hermonthica can cause as high as 100% yield loss in maize depending on soil fertility level, type of genotype, severity of infestation and climatic conditions. Understanding the mode of inheritance of Striga resistance in maize is crucial for introgression of resistance genes into tropical germplasm and deployment of resistant varieties. This study examined the mode of inheritance of resistance to Striga in early‐maturing inbred line, TZdEI 352 containing resistance genes from Zea diploperennis. Six generations, P1, P2, F1, F2, BC1P1 and BC1P2 derived from a cross between resistant line, TZdEI 352 and susceptible line, TZdEI 425 were screened under artificial Striga infestation at Mokwa and Abuja, Nigeria, 2015. Additive‐dominance model was adequate in describing observed variations in the number of emerged Striga plants among the population; hence, digenic epistatic model was adopted for Striga damage. Dominance effects were higher than the additive effects for the number of emerged Striga plants at both locations signifying that non‐additive gene action conditioned inheritance of Striga resistance. Inbred TZdEI 352 could serve as invaluable parent for hybrid development in Striga endemic agro‐ecologies of sub‐Saharan Africa

Phase Competition in Ln0.5a0.5mno3 Perovskites

Single crystals of the systems Pr0.5(Ca1-xSrx)0.5MnO3, (Pr1-yYy)0.5(Ca1-xSrx)0.5MnO3, and Sm0.5Sr0.5MnO3 were grown to provide a series of samples with fixed ratio Mn(III)/Mn(IV)=1 having geometric tolerance factors that span the transition from localized to itinerant electronic behavior of the MnO3 array. A unique ferromagnetic phase appears at the critical tolerance factor tc= 0.975 that separates charge ordering and localized-electron behavior for t<tc from itinerant or molecular-orbital behavior for t>tc. This ferromagnetic phase, which has to be distinguished from the ferromagnetic metallic phase stabilized at tolerance factors t>tc, separates two distinguishable Type-CE antiferromagnetic phases that are metamagnetic. Measurements of the transport properties under hydrostatic pressure were carried out on a compositions t a little below tc in order to compare the effects of chemical vs. hydrostatic pressure on the phases that compete with one another near t=tc.Comment: 10 pages. To be publised in Phys. Rev.

Journal of Ecology and the Natural Environment Full Length Research Paper Molecular diversity of arbuscular mycorrhizal fungi (AMF) in Lake Victoria Basin of Kenya

Arbuscular mycorrhizal fungi (AMF) play a key role in land reclamation, sustaining soil fertility and cycling of nutrients, which in turn increases plant vigour and productivity. AMF differ in both structural characteristics and global distribution, which is strongly correlated with the respective functional role. This study investigated the molecular diversity of arbuscular mycorrhizal fungi (AMF) in selected representative farmlands across Lake Victoria Basin and wheat farms in Njoro District of Kenya. Native AMF genera were identified by morphological techniques and their molecular diversity assessed by random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) techniques and genetic distance analysis. In all five field sites, three AMF genera were identified with varying relative abundances, namely, Glomus (50%), Scutellospora (30%) and Gigaspora (16%). Lambwe fields had the highest spore densities (13 spores per gram dry weight) and evenness (0.84) while Kibos and Njoro had least spore count (4- ditto) and evenness (0.32), respectively. The AMF population from Njoro wheat farms had highest heterozygosity (He = 0.257) and hence was the most genetically diverse compared to other populations. Key words: Glomus spp., Gigaspora spp., Scutellospora spp., molecular diversity