Extending the rapeseed gene pool with resynthesized Brassica napus II: Heterosis

Abstract

Hybrid breeding relies on the combination of parents from two differing heterotic groups. However, the genetic diversity in adapted oilseed rape breeding material is rather limited. Therefore, the use of resynthesized Brassica napus as a distant gene pool was investigated. Hybrids were derived from crosses between 44 resynthesized lines with a diverse genetic background and two male sterile winter oilseed rape tester lines. The hybrids were evaluated together with their parents and check cultivars in 2 years and five locations in Germany. Yield, plant height, seed oil, and protein content were monitored, and genetic distances were estimated with molecular markers (127 polymorphic RFLP fragments). Resynthesized lines varied in yield between 40.9 dt/ha and 21.5 dt/ha, or between 85.1 and 44.6% of check cultivar yields. Relative to check cultivars, hybrids varied from 91.6 to 116.6% in yield and from 94.5 to 103.3% in seed oil content. Mid-parent heterosis varied from −3.5 to 47.2% for yield. The genetic distance of parental lines was not significantly correlated with heterosis or hybrid yield. Although resynthesized lines do not meet the elite rapeseed standards, they are a valuable source for hybrid breeding due to their large distance from present breeding material and their high heterosis when combined with European winter oilseed rape.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-011-1765-7) contains supplementary material, which is available to authorized users.

Patterns of Heterosis in Three Distinct Inbred Populations of Spring Brassica napus Canola

“…The low seed yield in the IN inbred population was apparently attributable to introduction of several unfavorable alleles from B. oleracea, and this is not very uncommon for the inbred lines derived from interspecific crosses. For example, Girke et al (2012) found that resynthesized B. napus lines, on average, showed poor performance for seed yield; however, this type of materials can show good potential for high seed yield in hybrids. Among the three populations, the WS inbred population and its hybrid population yielded higher than the other two populations.…”

“…Several studies have demonstrated the value of utilizing allelic diversity of the allied Brassica species for increased heterosis in B. napus (Qian et al, 2005;Li et al, 2006;Zou et al, 2010;Girke et al, 2011Girke et al, , 2012Jesske et al, 2013;Li et al, 2014). For example, Zou et al (2010) observed a high level of heterosis in test hybrids while using germplasm diversified with the A genome of B. rapa and the C genome of B. carinata.…”

“…For example, Zou et al (2010) observed a high level of heterosis in test hybrids while using germplasm diversified with the A genome of B. rapa and the C genome of B. carinata. A number of researchers have also utilized genetic diversity of resynthesized B. napus (from B. rapa × B. oleracea interspecific cross) for the improvement of openpollinated or hybrid winter B. napus cultivars (Gehringer et al, 2007;Radoev et al, 2008;Girke et al, 2011Girke et al, , 2012Jesske et al, 2013). Udall et al (2006) detected two QTL, where the allele from a resynthesized B. napus increased seed yield of spring B. napus.…”

“…Thus, most of the studies conducted to date to evaluate different gene pools of Brassica for the improvement of spring or winter or semi-winter B. napus were focused on either the use of spring B. napus for spring type hybrid (Grant and Beversdorf, 1985;Brandle and McVetty, 1990;Engqvist and Becker, 1991;Diers et al, 1996;Cuthbert et al, 2009), or the use of winter or semi-winter B. napus for spring type hybrid (Butruille et al, 1999;Udall et al, 2004;Quijada et al, 2004Quijada et al, , 2006Qian et al, 2007;Kramer et al, 2009), or the use of winter or semi-winter B. napus for winter type hybrid (Lefort-Buson et al, 1987;Qian et al, 2009), or the use of the allied species for winter or semiwinter (Gehringer et al, 2007;Radoev et al, 2008;Zou et al, 2010;Fu et al, 2012;Girke et al, 2012;Li et al, 2014) or spring Seyis et al, 2006) type of hybrid. However, so far, no study has been conducted to compare the value of different gene pools for increasing the level of heterosis and seed yield in spring B. napus hybrid canola.…”

Combining Ability Analysis and Genetic-Effects Studies for Some Important Quality Characters in Brassica napus L.

“…Turi et al (2010) found significant results of GCA (0.68) for genotype NUM120 and SCA (-1.41) for cross NUM113 x NUM105. Ahmad et al (2012), Girke et al (2012), Nasim and Farhatullah (2013) and Noor-Ul-Abideen et al (2013) assessed the significant effects of GCA and SCA for protein contents.…”