Molecular marker assisted broadening of the Central European heterotic groups in rye with Eastern European germplasm

Abstract

Broadening the genetic base of heterotic pools is a key to ensure continued genetic gains in hybrid breeding and extend hybrid cultivation to new areas. In the present study, two Central European heterotic pools (Carsten and Petkus) and five Eastern European open-pollinated varieties (OPVs, Pop-1 to Pop-5) were studied with the objectives to (1) investigate the genetic diversity in OPVs and the heterotic pools using molecular and field data, (2) evaluate the molecular diversity among OPVs, (3) examine the combining ability for grain yield of the OPVs when crossed with testers in field trials, and (4) develop a strategy for targeted introgression of OPV germplasm into the heterotic pools. In total, 610 S(0) plants, 347 from OPVs and 263 from heterotic pools, were developed. Clones of the S(0) plants of OPVs were crossed with two testers belonging to each heterotic pool, while clones of heterotic pools were crossed with only the opposite tester. Testcrosses were evaluated for grain yield in multi-location trials. In addition, 589 S(0) plants were fingerprinted with 30 SSR markers. The data revealed that the Carsten pool has a narrow genetic base and should be the primary target for broadening the established heterotic pattern. Mean and genetic variance suggested that Pop-2 and Pop-4 are good candidates for introgression in Petkus pool and Pop-5 in Carsten pool. Nevertheless, introgression of Pop-5 in Carsten could reduce the genetic diversity between heterotic pools. Therefore, we suggest that either selected plants of Pop-5 should be introgressed or more Eastern European germplasm should be fingerprinted and field evaluated to identify promising germplasm for broadening the established heterotic pattern.

Genetic Distinctiveness of Rye In situ Accessions from Portugal Unveils a New Hotspot of Unexplored Genetic Resources

“…In most crops, landraces usually display higher genetic diversity than breeding cultivars, due to the genetic bottleneck and selective effect associated to its improvement (Meyer and Purugganan, 2013). In fact, the narrowing of the genetic pool of modern crop varieties has become an increasing concern also for rye breeders (Fischer et al, 2010). “Petkus” was one of the leading cultivars in the twentieth century from which many of the open pollinated varieties (OPVs) were selected or include “Petkus” in their ancestry (Hepting, 1978; Miedaner, 1997; Fischer et al, 2010).…”

“…In fact, the narrowing of the genetic pool of modern crop varieties has become an increasing concern also for rye breeders (Fischer et al, 2010). “Petkus” was one of the leading cultivars in the twentieth century from which many of the open pollinated varieties (OPVs) were selected or include “Petkus” in their ancestry (Hepting, 1978; Miedaner, 1997; Fischer et al, 2010). The two genetic pools “Carsten” and “Petkus” were previously identified as the most promising heterotic pattern (Hepting, 1978), and from then onwards, hybrid rye breeding, a breeding system used for cross-fertilized crops, was and still is based on the “Petkus” × “Carsten” heterotic pattern (Geiger and Miedaner, 2009).…”

“…The two genetic pools “Carsten” and “Petkus” were previously identified as the most promising heterotic pattern (Hepting, 1978), and from then onwards, hybrid rye breeding, a breeding system used for cross-fertilized crops, was and still is based on the “Petkus” × “Carsten” heterotic pattern (Geiger and Miedaner, 2009). Recent evidences point out for a genetic narrowing of “Carsten” pool (Fischer et al, 2010). Also, considering that the steadily improved “Petkus” was the parental ancestor of many OPVs, the probability of finding genetically diverse populations from “Petkus” pool is significantly reduced.…”

Heterotic groups of tropical indica rice germplasm

“…Recognition and determination of heterotic groups and patterns are fundamentally important for breeding hybrid crops as indicated in many studies for maize (Melchinger and Gumber 1998;Menkir et al 2003Menkir et al , 2004Reif et al 2003;Akinwalea et al 2014;Suwarno et al 2014), rye (Fischer et al 2010a), sunflower (Reif et al 2013), sorghum (Menz et al 2004), triticale (Fischer et al 2010b) and rice (Sun et al 2000;Wang and Lu 2006;Xie et al 2014).…”

Gene Pool Subdivision of East African Sweetpotato Parental Material

“…Mutually heterotic gene pools can be developed in sweetpotato, as has been shown for two South American OFSP breeding populations, and simple sequence repeat (SSR) markers were very useful in this context (Federico Diaz, personal communication, 2014; results partially described in Grüneberg et al, 2015). Molecular markers have been demonstrated to be a useful tool to group parental material into gene pools for HEBS in many crops: maize (Zea mays L.; Messmer et al, 1992;Reif et al, 2005), rye (Secale cereale L. ;Fischer et al, 2010), winter triticale (´ Trticosecale Wittm. ; Tams et al, 2004), oilseed rape (Brassica napus L.; Becker et al, 1995), faba bean (Vicia faba L.; Link et al, 1995), rice (Oryza sativa L.; Xiao et al, 1996) and sorghum [Sorghum bicolor (L.) Moench; Bhosale et al, 2011].…”