Category Archives: Wiley: Plant Breeding

Breeding of Lotus japonicus that can overcome adverse seasonal environment by coupling flowering time and abiotic stresses

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Abstract

Manipulation of floral transition may allow for a free change in the duration of plant vegetative and reproductive growth, thus rendering them to avoid adverse seasonal environmental conditions. In this report, we investigated the effect of the stress-inducible promoter RD29A on driving the rice FT ortholog Hd3a expression in Lotus japonicus ‘MG20’ in response to environmental changes. Constitutive overexpression of Hd3a (HOE) in ‘MG20’ hastened its flowering in contrast to non-transformed control (wild type; WT), which did not flower in winter hampered by long days and low temperatures. RD29A promoter had low activity under non-stress conditions and was induced by cold, drought and salinity in transgenic ‘MG20’. Transgenic plants of Hd3a driven by the RD29A promoter (RH) could flower under unfavourable weather conditions that prohibited the flowering of WT plants. In addition, RH transgenic plants exhibited thriving clumps of branching, inflorescence, and pods because of the low temperature-induced expression of Hd3a. These results demonstrate that inducible expression of florigen has the potential to tackle unfavourable weather conditions and boost plant production.

Progress and prospect of developing salt and alkali tolerant rice using hybrid rice technology in China

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Abstract

Soil salinization and alkalization are important abiotic stresses that affect crop growth and yield. Development of salt and alkali tolerant varieties is still dominated by the following conventional breeding method: The salt and alkali tolerant traits from screened germplasm are introduced into elite varieties by means of hybridization and backcrossing. In recent years, the breeding of salt and alkali tolerant rice has also made great progress. For example, the yield of Chao-You 1000, a two-line rice hybrid, has reached 12.04 t/ha growing in fields with salinity between 0.2% and 0.6%. This review is an update on the progress of salt and alkali tolerant rice germplasm screening and new salt and alkali tolerant varieties in development. By reviewing the performance of current rice hybrids in China's National Regional Variety Trials of Saline-Alkali Tolerant Rice, we proposed the technical approach of developing saline–alkali tolerant rice hybrids using the third-generation hybrid rice technology and furthermore the trend of developing salt and alkali tolerant rice hybrids.

The importance of Fusarium head blight resistance in the cereal breeding industry: Case studies from Germany and Austria

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Abstract

Fusarium head blight (FHB) resistance in wheat and triticale has a high priority in the European Union because of the strict guidelines for the major mycotoxins deoxynivalenol (DON) and zearalenone (ZON) and the admission policy of the regulatory authorities. Potentially 70% of the arable land in Germany and about 60% in Austria can be affected by Fusarium. Although epidemics occur only in some years and/or some regions, DON and ZON are detected every year in varying amounts in wheat, rye and maize. Despite a high significance of FHB resistance in breeding companies, as validated by a recent survey, breeding progress in wheat is basically absent for FHB resistance in both countries. The main reasons are the complex inheritance of FHB resistance and the high proportions of the dwarfing allele Rht-D1b in high-yielding varieties promoting susceptibility. Despite this, some varieties with high FHB resistance (score 2–3 on the 1–9 scale) have been released that account, however, only for 11% and 18% of the multiplication area in Germany and Austria, respectively. For triticale, an official testing system for FHB resistance in terms of DON content exists in Germany and Austria, but not for the other cereals. Susceptibility to maize ear rot has been described in Austria, but not in Germany. Additionally, a testing system for stalk rot resistance in both countries should be established.

Functional identification of OsMADS6 and OsMADS17 in floral organ development in rice

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Abstract

Rice floral organs are closely related to rice yield and quality, and MADS family genes play an important role in rice floral organ development. In this study, we identified functions of two MADS genes in floral organ development by bioinformatics analysis and CRISPR/Cas9 technology. Our results showed that MADS6 and MADS17 were a pair of highly homologous genes, which had highly similar sequences, motifs and expression profiles. The floral organs of mads6 and mads6/17 mutants were abnormal, whereas mads17 mutants showed no difference with wild type. Collectively, these results reveal that there are functional differentiations between conserved gene MADS6 and MADS17. Our findings provide a theoretical basis for further analysing the function of MADS family homologous genes and unravelling their molecular mechanism and regulatory network.

Identification of stable restorer lines developed through inter‐sub‐specific hybridization in rice (Oryza sativa) using multi‐trait stability index

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Abstract

Inter-sub-specific hybridization between indica and tropical japonica rice germplasm is the most efficient approach for broadening the genetic base of hybrid rice parental lines and enhancing the heterotic potential of hybrids in a tropical country like India. In the present study, 106 indica/tropical–japonica derived lines were developed through inter-sub-specific hybridization and screened using functional markers with respect to the major fertility restorer genes, Rf3 and Rf4, and the wide compatibility gene, S5n. The fertility restoration ability of newly developed restorers was validated through test cross nursery performance. The functional markers were observed to accurately predict the trait of fertility restoration. From the present study, the decreasing order of efficiency of different gene combinations on fertility restoration ability are as follows: Rf4/S5n > Rf4/Rf3/S5n > Rf4 > Rf4/Rf3 > Rf3/S5n > Rf3. Based on multi-trait stability index (MTSI) analysis, the four newly identified restorers, that is, RP6388-90, RP6382-49, RP6375-81 and RP6368-38, were selected as the top best performing genotypes with high stability for multiple traits, and these genotypes will be useful for the development of superior rice hybrids in India.

Susceptibility of UK oat (Avena sativa) varieties to infection by Fusarium species and subsequent HT‐2 and T‐2 toxin contamination

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Abstract

The aim of this study was to compare the susceptibility of oats to Fusarium langsethiae infection, as measured by combined HT-2 and T-2 mycotoxin concentration (HT2 + T2) in harvested oat grain samples. Over 10 years (2004–2013), samples from single replicates of each UK Recommended List oat trial were analyzed for HT-2 and T-2. For spring oats, there were small but statistically significant differences between varieties, whereas for winter oats, they had a broader range and higher mean of HT2 + T2 concentration compared with spring oats. For winter oats, the short-strawed varieties had consistently high HT2 + T2 levels compared with other varieties, whereas naked varieties were at the lower end of the range, and short, naked varieties had intermediate levels. A separate set of harvested oat grain samples of eight common varieties from 17 field experiments were analyzed by modified joint regression analysis. Results showed that environment had the strongest impact on HT-2 and T-2 concentrations but that the varietal susceptibility to HT-2 and T-2 contamination was highly stable across environments. This methodology can be used to calculate a Fusarium (HT2 + T2) resistance score for oats to aid grower selection of suitable varieties, as is available for Fusarium (DON) resistance for wheat varieties in many countries.