Genetic diversity in tropical wheat germplasm and selection via multitrait index

Abstract

AbstractGenetic diversity studies and analysis of the selection gain of wheat (Triticum aestivum L.) genotypes released over the decades allow the planning of strategies and support decision‐making for crossing in wheat breeding. We investigated genetic diversity in tropical wheat germplasm, discussed the main trends in breeding programs and selected potential parents. Therefore, a trial with 90 commercial cultivars released in Brazil between 1800–2000 and 2001–2019 was conducted during the 2020 winter crop in Viçosa, MG, Brazil. The following traits were evaluated: spike height and plant height, heading date, spike weight, grain mass per spike, 100‐grain mass, number of spikelets per spike, number of grains per spike, hectoliter weight, and grain yield. The data were subjected to restricted maximum likelihood or best linear unbiased prediction analysis and used to calculate the standardized average Euclidean distance and then unweighted pair group method with arithmetic mean clusters were generated from the genotypic distance matrix. The selection of the genotypes with the best performance in each phase was accomplished using the multitrait genotype‐ideotype distance index (MGIDI). High genetic diversity was observed between the genotypes evaluated. Multitrait index revealed selection gain in the desired direction in the two phases. The present study will support the efficient use of the genetic variability present in tropical wheat germplasm. Three genotypes were selected by MGIDI in the first phase, while in the second phase 12 were selected. Two groups of dissimilar and potential genotypes were proposed to compose a partial diallel.