Silkless1 gene in maize: development and validation of the gene-based markers for breeding silkless baby corn

The role of the silkless1 (sk1) gene in developing silkless baby corn, a distinctive trait in maize has been investigated. So far, no sk1 gene-specific marker has been available for accelerated development of silkless baby corn hybrids.

We developed sk1 gene-based markers and validated them in backcross (BC) and F₂ segregating generations, revealing a polymorphic marker corresponding to a silkless phenotype. Among all the developed markers, the MGU_sk1-1 marker (141 bp size in sk1-mutant allele) validated its association with the silkless trait. The chi square (χ²) analysis revealed that the segregation of alleles Sk1Sk1 (219): Sk1sk1 (414): sk1sk1 (188) is as per the Mendelian ratio (1:2:1) in the F₂ population. In 821 F₂ plants, we found a 3:1 phenotypic ratio among the population with silked (633) and silkless (188) plants. We studied 349 BC plants and found a 1:1 phenotypic ratio between silked and silkless plants, as well as a genotypic ratio (1:1) between heterozygotes (Sk1sk1) and homozygous recessives (sk1sk1). Additionally, double mutants (sk1sk1/ts1ts1 and sk1sk1/ts2ts2) were identified using the sk1-based marker.

This study is the first to show the practical use of sk1 gene in marker-assisted selection (MAS). This research also reports the development of novel genetic resources for innovative silkless baby corn breeding.