Transgressive Variations for Spike Characteristics in a Recombinant Inbred Lines Spring Wheat Population.

Wheat spikes host the main crop product: the grains. Studies have been conducted on some spikes’ characteristics such as form, dimensions, awns, number of spikelets, and others traits. However, a need to further elucidate the variations and relationships between spikes traits is required. In the present research, a population of 163 RILs segregating for several spike traits was studied. The RIL population was developed from a cross between the elite line WCB414 and a line with supernumerary spikelets (SS), WCB617. The study included the RILs, parents, and seven checks and was grown at Carrington and Prosper, ND, during 2009, 2010 and 2011. A total of 20 spike-related traits were evaluated. The results showed significant variations among the RILs for most traits including SS, spike length and density, kernels per spikelet and per node, awns lengths, presence of pubescences and clavate shape. The RILs with SS had short awns, large spike, and a high number of nodes per rachis and immature spikelets on the spike bottom. In these lines, the number of kernels per spikelet was low, but the number of kernels per node was high. Clavate spikes showed a reduced length but high density of nodes per rachis. In many RILs, the presence of pubescence, clavate shape and SS showed different expression within and across locations. This shows the influence of the environment on these traits. This study is a first step in a long term research project in order to understand the genetics of spike-related traits, and their associations with agronomic and quality traits.