Differences between phenotypic selection methods in two botanical varieties of Panicum coloratum L. (Kleingrass) to increase forage production under saline-hypoxic conditions

Abstract

Changes in climatic conditions increased abiotic stresses such as salinity and temporary waterlogging in previously productive environments. Livestock production has been forced to adapt to these conditions. Subtropical forage grasses, moderately tolerant to abiotic stresses, have been introduced to increase the productivity under unfavourable conditions common in these environments. We evaluated and compared variability, correlation and genetic gain per cycle in two botanical varieties of Panicum coloratum (makarikariense and coloratum) under saline-hypoxic conditions using individual and progeny test selection methods. Narrow-sense heritabilities were moderate for some characters while it was quite high in some of the traits considered. High genetic correlations between traits suggested the possibility of selecting secondary traits to increase biomass production under stress. Varieties differed in their most efficient method to perform selection, possibly as result of their different genetic structure. Individual phenotypic selection was more efficient in coloratum variety, whereas selection by progeny test was competent in var. makarikariense. To increase aerial biomass, indirect selection of genotypes with higher tiller number was more efficient than direct selection when using IPS in var. makarikariense. Breeding progress in tolerance to salinity–waterlogging stress may be achievable either by direct or indirect selection on traits and/or combination of characters in an index.