Study of combining ability of forage sorghum genotypes based on biochemical composition of biomass and grain

Resumo

The article discusses the results of the evaluation of combining the ability of forage sorghum varieties in test-crosses with CMS-lines of grain sorghum A2 O-1237, A2 AGS, and A2 KVV114. The experiment included forage sorghum varieties (11), CMS-lines (3), and tester hybrids (33) of F₁ generation. The differentiation of varieties and hybrids based on sugar content in the stem juice and protein, fat, fiber, ash and NFE in biomass and grain was performed using statistical methods, and GCA and SCA parameters were calculated. The use of forage sorghum varieties in breeding programs for the improvement of the biochemical composition of grain and biomass hybrids of the F₁-generation and synthetic varieties-populations was considered. GCA and SCA variability of the content of sugars in juice of the stem detected in genotypes allows using them in breeding programs. Chayka, k-592, and k-2963 varieties are effective in breeding for the production of synthetic varieties and unsuitable for the production of hybrids with high-sugar content, since they are characterized by high GCA but relatively low variance of SCA. In breeding for heterosis by sugar content in the stem juice, most promising were L-2, L-10, and L-69 lines. Varieties k-6 and L-7 with high values of GCA effect and variances of SCA were suitable for the use in breeding of synthetics varieties and F₁ hybrids. It was demonstrated that, in breeding of sorghum varieties, the test cross method allows identifying GCA and SCA indexes of the best lines and providing a more rigorous analysis of experimental data.