Genomics assisted mapping of earliness in pea (Pisum sativum L.)

Garden pea (Pisum sativum L.), is a temperate crop belonging to the Leguminosae family. Early maturing pea varieties complete their growth cycle in ∼80-90 days and fits very well within the crop rotation of rice, wheat, and maize, thereby providing an extra source of income to the farmers. Identification of genes associated with the earliness is very important for developing early maturing pea varieties.

In the present study we investigated the genetics of earliness and identified the putative genomic regions associated with the earliness in F₂ population derived from a cross between early-maturing (Matar Ageta-10) and late-maturing (Punjab-89) pea varieties using BSA-Seq approach. Genetic analysis revealed that earliness follows a monogenic recessive inheritance pattern. Two extreme phenotypic pools were constructed by identifying ten extreme early and ten extreme late plants from the F₂ population, and QTL-seq analysis was performed to obtain major genomic region of 6.5 Mb located at 418.46 Mb to 424.97 Mb on chromosome 7 and has been designated as PsE7. Further, a total of 907 SNPs were identified within this 6.5 Mb genomic region of which seven SNPs were validated through KASP markers. Among these, one marker namely PS423028253 showed association with the earliness trait at distance of 1.7 cM.

This novel genomic region along with KASP marker (PS423028253) identified in this study could be used for marker-assisted selection in pea breeding programs and will aid in the identification of the candidate genes in future studies.