Advances in the implementation of Megathyrsus breeding program Selecting an appropriate apomictic tester: Multi environment analysis

The optimization of livestock systems in developing countries has been associated with the replacement of native pastures with exotic species from Africa and their genetic improvement. Megathyrsus maximus has high productive potential and has the capacity to contribute to climate change mitigation by means of biological carbon fixation and biological inhibition nitrification. To start M. maximus breeding scheme is necessary to identify an appropriate apomictic “tester”. This report summarizes the first step in multi-trait and multi-environment diallel analysis conducted with the aim to identify an appropriate apomictic tester to implement the breeding scheme of Mm. A selected population of hybrids obtained from cross of 9 male genotypes and 24 female genotypes was subjected to field evaluation in three environments (Llanos, Palmira, and Quilichao). In this report, we present only the multi-environment analysis conducted on plant height using factor analytic mixed models. In all environments, plant height showed low variability values (CV% < 0.17) and high broad sense heritability values (h2) except for llanos4, quili3, and quili4. The high magnitude of the phenotypic variation was composed of high genotypic variation and low environmental variation. The analysis of variance showed significant differences in the genotype – environment interaction. The factor analytic analysis biplot revealed that two factors explain 56.1% of the genetic variance and that 83% of the environments were clustered in the first factor indicating that Llanos differed strongly from Palmira and Quilichao. It is noteworthy that some hybrids expressed a better performance than genotypes used as checks.