RESUMEN
Knowledge of drought tolerance in potato is limited and very little is known about stress memory in this crop. In the present study, long-term stress memory was tested on tuber yield and drought tolerance related traits in three potato varieties (Unica, Désirée and Sarnav) with contrasted yields under water restriction. Seed tubers produced by plants grown under non-restricted (non-primed tubers) and restricted (primed tubers) water conditions were sown and exposed to similar watering treatments. Tuber yield and leaf greenness of plants from primed and non-primed seeds as well as tuber carbon isotope discrimination (Δ(13)C) and antioxidant activity (AA) responses to watering treatments were compared. Higher tuber yield, both under non-restricted and restricted water regimes, was produced by primed Sarnav plants. The decrease of tuber yield and Δ(13)C with water restriction was lower in primed Unica plants. Long-term stress memory consequently appears to be highly genotype-dependent in potato. Its expression in plants originated from primed tubers and facing water restriction seems to be positively associated to the degree of inherent capability of the cultivar to yield under water restriction. However, other effects of priming appear to be genotype-independent as priming enhanced the tuber AA in response to water restriction in the three varieties.
Asunto(s)
Adaptación Fisiológica , Sequías , Solanum tuberosum/fisiología , Antioxidantes/metabolismo , Isótopos de Carbono , Deshidratación , Genotipo , Humedad , Hojas de la Planta/fisiología , Semillas/fisiología , Solanum tuberosum/genética , Luz Solar , TemperaturaRESUMEN
Relationships between flag leaf carbon isotope discrimination (Delta), water status parameters, residual transpiration (RT) and stomatal density (SD) were examined on a collection of 144 durum wheat accessions. Associations between Delta, grain yield (GY) and harvest index (HI) were also studied. The field trial was conducted under Mediterranean conditions. The crop cycle was characterised by a period of drought from February until maturity. A broad range of values we obtained for Delta (16.5-19.9 per thousand) and other physiological traits. Flag leaf Delta was positively and significantly correlated with both HI and GY. Delta was better correlated with HI than with GY, which suggests that higher Delta values indicate higher efficiency of carbon partitioning to the kernel, leading to higher GY. Delta was found positively related with RT and negatively related with SD. This relationship may indicate a possible SD component of RT due to the association between conductance and SD. Strong positive correlations were found between Delta and water status parameters, suggesting that Delta may provide a good indication of plant water status in durum wheat under rainfed Mediterranean conditions.
RESUMEN
For durum wheat, we promote the use of carbon isotope discrimination (delta) as an indirect selection criterion for transpiration efficiency and grain yield (GY), and we identify the most effective organ for characterising delta genotypic variation. A field experiment was conducted in the South of France on 144 accessions, with a drought period occurring from February to June. Harvest index (HI), GY and delta (delta L, flag leaf; delta A, awn, delta G grain) were measured. Significant positive genetic correlations were noted between delta and both GY and HI. A larger genotypic variation and a higher broad-sense heritability were noted for delta G compared to delta L and delta A. delta G correlated better with GY and HI than delta L and delta A, showing that delta G could provide a better assessment of genotypic behaviours under drought during grain filling. Moreover, the indirect selection based on delta G (even when evaluated with one replicate) appeared more efficient than the direct selection for grain yield. This result emphasised the potential value of grain carbon isotope discrimination as a criterion for grain yield improvement under stressed Mediterranean conditions.
Asunto(s)
Triticum/crecimiento & desarrollo , Isótopos de Carbono , Clima , Francia , Genotipo , Triticum/genéticaRESUMEN
The diversity of high molecular weight (HMW) glutenin subunits of 502 varieties of durum wheat (Triticum durum) from 23 countries was studied using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Twenty-nine types of patterns were observed with 18 mobility bands. A total of 18 alleles were identified by comparing the mobilities of their subunits to those previously found in hexaploid wheat (T. aestivum) and in Triticum turgidum var. dicoccum. Five new alleles were detected: two on the Glu A1 and three on the Glu B1 locus. Comparison of the frequency of alleles in the three species T. aestivum, T. dicoccum and T. durum was investigated. Significant differences exist between each of these species on the basis of the frequency distributions of their three and four common alleles at the Glu A1 and Glu B1 locus, respectively. The Glu B1c allele occuring very frequently in hexaploid wheats was not found in the two tetraploid species. More than 83% of the T. durum analysed were found to have the Glu A1c (null) allele.