Genotypic responses of some cereal species to speed breeding conditions

Abstract

Traditional plant breeding techniques can only create one generation of cool-season cereals per year, whereas speed breeding may produce an average of 5-6 generations in the same year. Speed breeding experiments were conducted at the Faculty of Agriculture, Dicle University, Turkey in a polycarbonate-covered greenhouse, including artificial light sources and air conditioners, in 2020. The study was set up as a randomized block design with four replicates. Eight durum wheat, ten bread wheat, and five barley genotypes were examined in this study. The anthesis time (days), plant height (cm), spike number per plant (number), spike length (cm), spikelet number per spike, grain number per spike, grain weight per spike (g), grain yield per plant (g), biomass per plant (g), and chlorophyll content were measured in this study. The data for the examined traits were analyzed using the JMP Pro 13 statistical package. Under speed breeding conditions, the total growing degree-days for durum wheat, bread wheat, and barley from seed germination to harvesting were 1186 °C, 1221°C, and 1239 °C, respectively. Genotypes reached anthesis 45% earlier in wheat and 50% earlier in barley under speed breeding conditions, compared with control. Under speed growing conditions, the increase in the spike number per plant caused a decrease in grain yield. The highest reduction in yield was observed in durum wheat, barley, and bread wheat, respectively. Optimizing plant density to minimize tillering and increase the amount of fertilizer used at the end of tiller formation will improve the effectiveness of speed breeding. Anthesis time, grain number per spike, spike length, spikelet number, and biomass traits measured under speed breeding could be used as selection criteria in bread wheat breeding studies. The results show that the cycle number in a year can change between 4.3 and 5.3 for durum wheat, bread wheat, and barley under speed breeding conditions.