Seedling growth under osmotic stress and agronomic traits in Bulgarian semi-dwarf wheat: comparison of genotypes with Rht8 and/or Rht-B1 genes

Abstract

Early-season drought is an adverse environmental factor affecting seedling emergence and crop establishment in winter wheat grown in continental climates. The different semi-dwarfing (Rht, reduced height) genes exert various effects on seedling growth, plant height and productivity. The occurrence of the major Rht genes in 69 Bulgarian bread wheat cultivars was postulated by molecular markers. Cultivars carrying Rht-D1b+Rht8 (1) (43) were identified. The three latter groups were compared in respect to germination and seedling growth in response to polyethylene glycol-induced osmotic stress, plant height and main yield components. Cultivars carrying only Rht8 produced longer roots, coleoptiles and shoots, and had smaller root-to-shoot length ratio in non-stress and in osmotic stress conditions compared with those carrying Rht-B1b/d or Rht-B1b/d+Rht8. The same cultivars produced shorter culms, shorter spikes with fewer spikelets, reduced number and mass of grain in the main spike, and reduced 50-grain mass. The Rht genic effects were confirmed on Rht near-isogenic lines. The preferential semi-dwarfing allele selection aiming to combine the advantages of Rht8 and Rht-B1b/d alleles in specific eco-climatic conditions and to improve breeding efficiency in wheat is discussed.

Wheat Seedling Emergence from Deep Planting Depths and Its Relationship with Coleoptile Length

“…These results are in accordance with the earlier reports [38]. Coleoptile length and plant height are polygenic traits and many QTLs have been reported that influence traits [26], [28], [39]–[41].…”

Relationships between leaf morpho‐anatomy, water status and cell membrane stability in leaves of wheat seedlings subjected to severe soil drought

“…The modern semi‐dwarf varieties have been released at the Bulgarian main breeding centres—the Dobrudja Agricultural Institute, the Institute of Plant Genetic Resources, and the former Institute of Genetics, Sofia. The modern varieties carry the height reducing gene Rht8 (the 192 bp‐allele at locus Xgwm261 ) (Katya and Pobeda), Rht8 + Rht‐B1b/d (Rusalka, Enola and Lada), or the 174 bp‐allele at locus Xgwm261 (Lozen 6) (Ganeva et al., ; Landjeva, Karceva, Korzun, & Ganeva, ).…”

Changes in Water Status, Membrane Stability and Antioxidant Capacity of Wheat Seedlings Carrying Different Rht‐B1 Dwarfing Alleles under Drought Stress

“…The distribution of Rht‐B1b is restricted mostly to cooler regions, although a recent trend of its spread to regions with frequent periods of early season drought, such as the countries in Southeastern Europe and Ukraine, was reported (Landjeva et al. ).…”

“…It is currently widely adopted worldwide (Hedden 2003), whereas the latter allele is not commercially exploited although in certain environments, it might contribute to pre-harvest sprouting resistance (Flintham and Gale 1982). The distribution of Rht-B1b is restricted mostly to cooler regions, although a recent trend of its spread to regions with frequent periods of early season drought, such as the countries in Southeastern Europe and Ukraine, was reported (Landjeva et al 2011).…”