Genetic Improvement of Agronomic Traits of Winter Wheat Cultivars Released in France from 1946 to 1992

Abstract

In a context where agricultural practices in Europe are likely to go toward extensive systems with lower inputs, it is important to determine the genetic improvement of winter wheat (Triticum aestivum L.) not only in high‐input agricultural systems but also in low‐input systems. This study assesses the improvement in agronomic traits of winter wheat cultivars cultivated in France during the second half of the 20th century at four agronomic treatments: two levels of fungicide were combined with two levels of nitrogen fertilizer. Fourteen cultivars introduced between 1946 and 1992 were grown for two years (1994 and 1995) at five locations. Selection played a major role in the increase in winter wheat yield after 1946. The contribution of selection to this increase depended on the agronomic treatment and varied from one third to one half. Reduction of height was the most important factor. New cultivars with shorter straw expressed higher harvest index values and more consistent higher yields since they were less susceptible to lodging. The ability to produce more kernels from a given total above‐ground biomass was the second factor. The number of kernels per unit area had increased over time without alteration of the weight of the kernels. The negative relationship between 1000‐kernel weight and kernel number/m2 was therefore shifted and new cultivars were thus able to fill more kernels than older entries. Modern cultivars used N more efficiently than their predecessors. The future challenge will be to obtain, in low‐input systems, the same genetic gains as in high‐input systems.

Changes in durum wheat root and aerial biomass caused by the introduction of the Rht-B1b dwarfing allele and their effects on yield formation

“…The greater variability of aerial and root biomass found within semi-dwarf cultivars when compared with tall ones supports the statement that genetic variability was not reduced in modern Mediterranean durum wheat cultivars as a consequence of the breeding activities conducted during the 20th century . The significant differences observed in the greenhouse between cultivars carrying the Rht-B1a (tall) and Rht-B1b (semi-dwarf) allele for aerial and root biomass indicated that the dwarfing allele not only reduced above-ground biomass, as widely reported by previous studies (Brancourt-Hulmel et al 2003;Royo et al 2007;Álvaro et al 2008a), but also caused a decrease in total root biomass and in each root section. Moreover, the reduction caused by the dwarfing allele in root biomass (ca.…”

Meeting Cereal Demand While Protecting Natural Resources and Improving Environmental Quality

“…A number of field studies have compared yield trends of an historical time-series of wheat varieties (31,32,33). Although these studies suffer from the same confounding factors as comparable studies with rice, the wheat evaluations were more rigorous because yield gains were quantified with and without fungicide protection against diseases and at different levels of N fertilization.…”

Eficiência de uso de nitrogênio em cultivares de trigo pioneiras e modernas

“…As acurácias seletivas dos caracteres avaliados oscilaram entre 0,87 e 0,98, e indicaram boa precisão experimental (Resende & Duarte, 2007 Cormier et al (2013). Esse resultado deve-se ao aumento significativo (p≤0,01) no índice de colheita de N (Figura 2), ao longo dos anos e em todas as doses de N avaliadas (Brancourt-Hulmel et al, 2003). Os valores de ICN estiveram entre 50 e 80%, variação semelhante à observada por Barraclough et al (2010) e Gaju et al (2011).…”

“…Com doses baixas, a EAN explica a maior parte da resposta observada em EUN (Ortiz-Monasterio et al, 1997;Foulkes et al, 1998;Le Gouis et al, 2000), enquanto que, em doses altas, destaca-se a importância da EUtN (Brancourt-Hulmel et al, 2003). Entretanto, não há consenso entre os diferentes estudos, pois tanto a EAN quanto a EUtN podem contribuir para o incremento da EUN (Barraclough et al, 2010;Le Gouis et al, 2010;Gaju et al, 2011).…”