Hybrid purity assessment in Eucalyptus F1 hybrids using microsatellite markers

Abstract

The worldwide expansion of hybrid breeding and clonal forestry is to meet the demands of paper pulp and bioenergy. Although India was one of the pioneers in hybrid production of eucalypts only recently the hybrid clonal forestry is gaining momentum. Inter-specific hybrids are being produced to exploit the hybrid vigor of F1 individuals. Quality control genotyping for hybrid purity and parentage confirmation at the early stage is one of the essential criteria for clonal propagation and field trails for the assessment of growth performance. Eucalyptus being a obligatory outcrossed species with potential to self pollination, possibilities of pollen contamination are high. Hence, in the present study, Eucalyptus camaldulensis × E. tereticornis inter-specific hybrids were genotyped using 25 fluorescent labeled microsatellite markers available in public domain. Multiplex loading of PCR products was performed successfully for most of the microsatellite loci. Hybrid purity index was calculated and parentage was confirmed. Hybrid purity values ranged from 85 to 100 % showed the efficiency of controlled pollination techniques. A subset of six fully informative simple sequence repeats was identified for routine quality control genotyping for these hybrids. Detection of non-essential genotypes observed among the hybrid seedlings proved the significance of hybrid purity tests and the false hybrids were removed at the seedling stage. The hybrids with proven hybridity will be used for generation of genetic linkage, discovery of quantitative trait loci and the individuals with high productivity can enter into mass clonal multiplication.

Fingerprinting and genetic purity assessment of F1 barley hybrids and their salt-tolerant parental lines using nSSR molecular markers

“…Hybrid purity tests is crucial in crop hybridization as the genetic purity of the F 1 seeds during the cross between the parental lines could be affected by foreign or self pollen (Subashini et al 2014). Non-essential genotypes called false hybrids should be removed at an early step of the amelioration strategy (Subashini et al 2014).…”

“…Hybrid purity tests is crucial in crop hybridization as the genetic purity of the F 1 seeds during the cross between the parental lines could be affected by foreign or self pollen (Subashini et al 2014). Non-essential genotypes called false hybrids should be removed at an early step of the amelioration strategy (Subashini et al 2014). Hybrid purity tests are also required where true hybrids are needed to develop genetic linkage maps, QTL research and marker assisted selection (Subashini et al 2014).…”

“…These SSR molecular markers have proved their utility in F 1 hybrid purity assessment for others cereal crops such as pearl millet (Kumar et al 2015) and rice (Bora et al 2016). Furthermore, SSR fingerprinting method was applied with success for other economic plant species like eucalyptus (Subashini et al 2014), pigeonpea (Bohra et al 2017) and melon (Ju-Fen et al 2008). However, for barley species, rare is documented about the use of molecular markers for hybrid purity testing.…”

Studying the Disease Resistance and Morphological Variations in Cassava

“…Such hybrids were essential to map genes controlling various economically important traits. Molecular markers based hybrid purity tests have been used in many crop species such as rice (Yashitola et al, 2002;Sundaram et al, 2008;Tamilkumar et al, 2009, Bora et al, 2016), maize (Asif et al, 2006Salgado et al, 2006), cotton (Selvakumar et al, 2010) and safflower (Naresh et al, 2009), Eucalyptus (Subashini et al, 2014).…”

Genetic diversity and hybridization in the two species Inga ingoides and Inga edulis: potential applications for agroforestry in the Peruvian Amazon

“…Our study revealed a high genetic diversity in both species, but care should be taken in avoiding related trees, particularly in the case of I. ingoides. We advise that future studies on hybridization and introgression in both species should be done together with flooding tolerance ability and legume and yield in hybrids testing, and wild hybrids could be procured by making use of today's available approaches, e.g., with tools developed specially for this genus by Dexter et al (2010), which include both morphological and molecular approaches, and by Subashini et al (2014) and Larcombe et al (2014) in Eucalyptus. Also, vegetative propagation could be used to propagate hybrids, since Inga species can be propagated easily from semi-ripe branch cuttings, and, for example, I. edulis is considered an easy-to-root species (Pennington 1998).…”