Assessing the breeding potential of newly developed inbred lines derived from India and Brazil germplasms in Southwest China

Abstract

Introducing exotic maize germplasm can i) enrich the current genetic pool in Southwest China and ii) settle the severe situation of narrowing genetic diversity. To pave the path of the utilization of exotic germplasms from Brazil and India, 33 newly developed lines and six testers were genotyped with 32 simple sequence repeats (SSRs) for classifying heterotic groups. Ten out of those new lines were crossed to six testers according to the North Carolina II mating design, resulting in 60 single-cross hybrids. The 60 hybrids along with the commercial hybrid “Guinongyu889” were evaluated for 12 agronomic traits in two environments. The average polymorphism information content for the 32 SSRs was 0.73 and the average genetic similarity 0.52. The genetic analysis grouped the lines into six heterotic groups that are basically in line with information obtained from pedigree and specific combining
ability effects-based groups. The lines 1862 and 363 had high general combining ability, and the hybrids 1862 × 223, Mo17 × 149, and 1862 × 363 exhibited the highest grain yield per plant; therefore, they could be used for the further commercial agronomic test. The high-yielding combinations suggested two promising heterotic patterns “Reid × PB (tem-tropical I)” and “Reid × Tropical”, and exotic germplasms from India and Brazil could be utilized directly without bridging into elite germplasms in Southwest China. According to heterotic groups classified in the  present study, bridging these exotic materials into elite base breeding populations is recommended for subsequent long-term breeding programs