Yield response of hybrid and line wheat cultivars to varying site and growing conditions and delayed sowing time

Abstract

In plant breeding, heterosis is also used as an effective genetic strategy to increase yield and stress resistance in self-pollinated crops such as wheat. For the cultivation of hybrid wheat, not only its yield superiority over line varieties is important, but also the knowledge of the reaction to different site, growth and sowing conditions. However, there is little data on the yield performance of hybrid wheat compared to line varieties under different site conditions and at different sowing times. The main objectives of this study were therefore (1) to characterize the effects of different soil and growing conditions on the grain yield of hybrid wheat in comparison with line varieties, (2) to determine the yield stability of hybrid wheat in comparison with line varieties and (3) to clarify the response of hybrid wheat to later sowing in comparison with line varieties. The present study was conducted from 2012 to 2019 at three trial sites in Giessen, Gross-Gerau and Rauischholzhausen, each of which had very different soil properties. As a result of the trials, it was found that on average over the years, the hybrid varieties achieved an additional yield of around 8 % (Giessen) and 6 % (Rauischholzhausen) compared to the line varieties. In contrast, the hybrid varieties on the sandy soil in Gross-Gerau only achieved an average additional yield of 2 %. The lower the amount of precipitation during the growing period at the Giessen site, the greater the yield superiority of the hybrid varieties over the line varieties, which is interpreted as an indication of better drought tolerance of the hybrid varieties at this site. However, this correlation was not observed in Gross-Gerau. In terms of yield stability, line varieties showed an advantage over hybrids, but yields were lower. The sowing delay of the wheat was better tolerated by the varieties at the Giessen site than on the sandy soil in Gross-Gerau. Furthermore, no reliable interaction between sowing delay and variety type (hybrid vs. line varieties) was observed. It is concluded that there is a large variation within the wheat assortment in terms of yield potential, yield stability and sowing time reaction of the varieties. This also applies to hybrid varieties, which react inconsistently to changes in growing conditions and whose yield superiority over line varieties is not always sufficient for economically efficient cultivation.