Combinative breeding for large seeds in soybean

 Technological qualities of the seeds, including their mass, play an important role in the purposeful use of soybean for food production. The purpose of this study is to determine the potential of specific crosses and recombinant lines in the combinative breeding of high yielding large-seeded soybean varieties. During the period of 2018-2019 the F3 and F4 hybride generations of crosses with participation of the ultra-early mature and large-seeded cultivar Romantica were studied. Data were used to evaluate: presence and extent of positive transgressive forms by absolute seed mass in F3 family crosses; genotypic diversity and additive variance at specific crosses; the effectiveness of selection of the trait large seed in F3. According to the results, transgressive selection can be successfully used to reach the goal large seeds in soybean. The efficiency of selection of transgressive forms in F3 generation is high. The genetic potential to combine a high specific mass of seeds with a high yield of seeds per plant has been established for the Romantica cross with the Bulgarian standard variety Srebrina. Recombinant lines suitable for intensive selection for the trait lage seed were obtained from the ‘Romantica’ x ‘Oria’ combination. The ‘Saikai 20’ x ‘Romantica’ cross possess a very high degree of transgressive segregations.