Advanced backcross QTL mapping of resistance to Fusarium head blight and plant morphological traits in a Triticum macha × T. aestivum population

While many reports on genetic analysis of Fusarium head blight (FHB) resistance in bread wheat have been published during the past decade, only limited information is available on FHB resistance derived from wheat relatives. In this contribution, we report on the genetic analysis of FHB resistance derived from Triticum macha (Georgian spelt wheat). As the origin of T. macha is in the Caucasian region, it is supposed that its FHB resistance differs from other well-investigated resistance sources. To introduce valuable alleles from the landrace T. macha into a modern genetic background, we adopted an advanced backcross QTL mapping scheme. A backcross-derived recombinant-inbred line population of 321 BC2F3 lines was developed from a cross of T. macha with the Austrian winter wheat cultivar Furore. The population was evaluated for Fusarium resistance in seven field experiments during four seasons using artificial inoculations. A total of 300 lines of the population were genetically fingerprinted using SSR and AFLP markers. The resulting linkage map covered 33 linkage groups with 560 markers. Five novel FHB-resistance QTL, all descending from T. macha, were found on four chromosomes (2A, 2B, 5A, 5B). Several QTL for morphological and developmental traits were mapped in the same population, which partly overlapped with FHB-resistance QTL. Only the 2BL FHB-resistance QTL co-located with a plant height QTL. The largest-effect FHB-resistance QTL in this population mapped at the spelt-type locus on chromosome 5A and was associated with the wild-type allele q, but it is unclear whether q has a pleiotropic effect on FHB resistance or is closely linked to a nearby resistance QTL

On the origin of subcompactoids in Triticum vulgare

33 Pags., Tabls. Figs.[ES] En el presente trabajo se estudia el comportamiento del cromosoma C en la meiosis de los trigos espeltoides heterocigóticos de la serie B. Se dedica una atención especial a la distribución de los cromatidios del univalente en la segunda telofase meiótica y a la formación de micronúcleos en las tétradas. .Peer reviewe

Chapter 6: Role and challenges of the private seed sector in developing and disseminating climate-smart crop varieties in Eastern and Southern Africa

To address climate change (CC) in eastern and southern Africa (ESA) will require accelerated development and dissemination of crop varieties with climate-smart (CS) traits over the coming decades. However, investment in crop improvement and rates of variety turnover are currently extremely low in the region. Smallholder farmers, who generate the bulk of agricultural output in ESA, continue to cultivate old crop varieties that lack CS traits such as drought tolerance and resistance to new and emerging pests and diseases. The emergence of the private seed sector in ESA provides a unique opportunity to complement established public crop improvement programmes, and accelerate development and dissemination of CS crop varieties through scalable, certified seed systems. This chapter will discuss; the growth of the private seed sector since the seed industry in ESA was deregulated, the importance of public-private partnerships in driving genetic gains for CS traits, and the importance of developing a favourable regional regulatory environment that incentivises the private sector to rapidly scale out CS crop varieties (and withdraw obsolete varieties).67-7