Long juvenility trait: A vehicle for commercial utilization of soybean (Glycine max) in lower latitudes

Abstract

Soybean, a short‐day plant, has its origin in higher latitudes of China, and its commercial cultivation remained confined to areas >22°N till 1970s due to precocious flowering accompanied with reduced biomass in lower latitudes. This review summarizes the effect of short days on soybean phenology, discovery of a novel long juvenile (LJ) trait, its role in breaking the latitudinal boundary for soybean production, identification of genes and impact of LJ trait on world soybean production. E6, J and E9 major genes governing the trait have been characterized and cloned. LJ varieties are late in flowering and maturity and successful in long rainfall regime of Brazil. Availability of vast vacant fallows of Cerrado has been another factor for utilization of this trait in Brazil. Recent advances for developing short‐duration LJ varieties, for limited rainfall areas and its suitability to existing cropping systems by combining it with photoinsensitivity, have been reviewed. Based on the available data from lower latitudes of Brazil, the contribution of the LJ trait is estimated to 23.7% of the total world production.

Genetic Enhancement of Soybean (Glycine Max L.) Germplasm for Adaptability and Productivity

“…Soybean evolved as a short-day plant, and its cultivation had confinement to around 22 °N until the 1970s due to precocious flowering (Gupta et al, 2021). Flowering time regulation comes from photo-thermal responsive genes, the environment (daylength), and their interactions.…”

“…The discovery of long juvenile (LJ) traits has expanded the latitude boundaries for soybean cultivation. The LJ traits help increase plant biomass under a short day (Tripathi et al, 2021). Genes E6, J, and E9 are the chief genes causing the expression of long juvenile traits, such as late flowering and maturity, in varieties grown under a short-day length.…”

“…The E6 gene has a suppressive effect over E1. Another study linked LJ traits with a SNP variation in FT2a loci (Tripathi et al, 2021). Cultivars with LJ traits contributed to expanding soybean cultivation in Brazil.…”

Marker-Assisted Selection for Early Maturing E Loci in Soybean Yielded Prospective Breeding Lines for High Latitudes of Northern Kazakhstan

“…The history of major genes controlling time to flowering and maturity concludes with the J gene for long juvenility (LJ) trait and delay in flowering [27]. Such LJ soybean genotypes are extremely successful in lower latitude countries such as Brazil and account for 23.7% of world soybean seed production [28]. 'Loss of function' mutations in soybean genotypes with recessive alleles j showed later flowering and maturing, which is an important trait for regions with tropical and subtropical climates [29,30].…”