Molecular markers-based DNA fingerprinting coupled with morphological diversity analysis for prediction of heterotic grouping in sunflower (Helianthus annuus L.)

Cultivated sunflower holds a very narrow genetic base and the efficient utilization of available genetic diversity is very important for a successful breeding program. In the present study, 109 sunflower genotypes were assessed for diversity paneling through a combined approach of morphological and molecular markers analysis. Morphological parameters including days to flower initiation, days to flower completion, plant height, stem curvature, number of leaves per plant, leaf area, head diameter, hundred seed weight, and seed yield per plant were studied. Simple sequence repeats (40 DNA markers) were deployed for diversity profiling. Data were analyzed by both univariate and multivariate statistics. SD and coefficient of variation confirm the presence of significant amounts of genetic variation for all the morphological parameters. Cluster Analysis and Principal Component Analysis further confirm the presence of distinct grouping patterns in the studied material. Cluster analysis of both morphological and molecular analysis revealed that restorer lines tend to group separately from A, B, and open-pollinated lines. Further grouping, at the sub-cluster level, revealed six distinct sub-clusters in each of the two major clusters. In total, 12 genotypes, 6 CMS lines (CMS-HAP-12, CMS-HAP-54, CMS-HAP-56, CMS-HAP-99, CMS-HAP-111, and CMS-HAP-112) and 6 restorer lines (RHP-38, RHP-41, RHP-53, RHP-68, RHP-69, and RHP-71) could be used as potential parents for hybrid development. As genotypes of similar genetic backgrounds tend to group closer, it is deduced that one genotype with the highest seed yield per plant could be used for further hybrid breeding programs in sunflowers.

Molecular characterization and validation of sunflower (Helianthus annuus L.) hybrids through SSR markers

Genetic purity is a prerequisite for exploiting the potential of hybrids in cross-pollinated crops, such as sunflower. In this regard DNA-based study was conducted using 110 simple sequence repeat (SSR) markers to check the genetic purity of 23 parents and their 60 hybrids in sunflower. The polymorphism was shown in 92 markers with value 83.63%. The SSR markers ORS-453 and CO-306 showed the highest PIC values of 0.76 and 0.74, respectively. The primer ORS-453 amplified allele size of 310 base pairs (bp) for female parent L6 and 320 bp for L11, while for male parents, T1 and T2 had allele size 350 bp and 340 bp, respectively. The hybrids from these parents showed a similar size of alleles with parents, including hybrids L6×T1 (310 bp and 350 bp), L6×T2 (310 bp and 340 bp), and L11×T2 (320 bp and 340 bp). Similarly, the primer CO-306 amplified allele size 350 bp and 330 bp for female parents L6 and L11, respectively, while, allele size 300 bp and 310 bp for male parents T1 and T2, respectively. The hybrids’ allele size was like the parents viz., L6×T1 (350 bp and 300 bp), L6×T2 (350 bp and 310 bp), and L11×T2 (330 bp and 310 bp). All 60 hybrids and their 23 parents were grouped into three main clusters (A, B and C) based upon DARWIN v.6.0 and STRUCTURE v.2.3 Bayesian analyses using genotypic data. Further, each main cluster was divided into two sub-divisions. Each sub-division showed the relatedness of parents and their hybrids, thus authenticating the genetic purity of hybrids. In conclusion, this study provides useful for accurate and effective identification of hybrids, which will help to improve seed genetic purity testing globally.