A New Approach for Evaluating Maize Transgressive Segregants and Their Three-Way Cross Potential in the S4 Convergent Breeding Population

Abstract

The development of transgressive segregant (TS) selection on convergent breeding populations of S4 maize is a concept that is rarely applied. Gene construction that focuses on the action of dominant genes and inbreeding depression are obstacles to this development. However, the development of TS is necessary to accelerate maize pipelines. Therefore, the objectives of this study were (1) to develop the concept of transgressive segregant selection and (2) to select S4 TS maize to be developed as hybrid cross parents. This study was also designed with an augmented design consisting of 6 blocks. The factors focused on maize genotypes were divided into two groups: unrepeated maize genotypes, 32 TS lines, and maize hybrid genotypes repeated in each block, namely, JH 37, NASA 29, BISI 18, and SINHAS 1. The combination of ratio analysis, path analysis, best linear unbiased prediction, relative fitness, and selection indices is a fair approach for assessing the genetic potential of the S4 TS. The selection index formed was 0.53 ear weight + 0.24 seed yield percentage + yield, which works on the fitness of BLUPs. The index selection resulted in 11 S4 transgressive segregant lines being further evaluated for their hybrid potential, with the TS line CB2.23.1 being the best. In addition, the three-way cross-hybrid evaluation results also recommended SG 3.35.12 × JH37 and CB 2.23.1 × JH37 as potential hybrid lines. However, these segregants are expected to focus on identifying and combining power and combinations of diallel crosses in the future.