In situ embryo rescue for generation of wide intra‐ and interspecific hybrids of Panicum virgatum L.

Abstract

SummaryWide crosses have been used for decades as a method for transferring novel genetic material and traits in plant breeding. Historically, many products of wide crosses require tedious and inefficient surgical embryo rescue prior to embryo abortion to recover single plantlets. We have utilized transgenic switchgrass (Panicum virgatum L. cv Alamo) as a pollen donor in conjunction with antibiotic or herbicide selection for recovery of intra‐and interspecific F1 crosses by using developing ovules from the female parent and selecting for embryogenic cultures derived from the in situ immature embryo. Using this approach, several intravarietial crosses were generated between transgenic Alamo and the switchgrass varieties Kanlow, Blackwell and Cave‐in‐Rock as well as an interspecific cross with Atlantic coastal panicgrass. This procedure selected F1 embryogenic callus produced from the developing embryo contained within isolated immature ovules. Several clonal plants were successfully regenerated from each cross. Southern blot, PCR, phenotypic analyses and genomic analysis confirmed F1 hybrids. Using genotyping‐by‐sequencing shows the hybridization of the recovered plants by determining the ratio of transgressive markers to total compared markers between parents and their potential offspring. The ratio of transgressive markers to total compared markers was significantly lower between parents and their predicted offspring than between parents and offspring unrelated to them. This approach provides the possibility to move useful transgenes into varieties that are recalcitrant to direct transformation which can be optionally segregated thus useful to create new hybrids, as well as recovery of wide crosses that are either difficult or impossible using traditional techniques.

Endosperm of Angiosperms and Genomic Imprinting

“…Numerous experiments on distant hybridization convincingly demonstrated the dependence of embryogenesis on the development of the endosperm. In cases of hybrid endosperm disturbance or its absence, the development of a viable hybrid embryo stops at certain stages and can only be continued if the embryo is isolated and placed on a nutrient medium in vitro (embryo rescue techniques) [ 10 , 62 , 63 , 64 , 65 , 66 ]. Navashin’s views [ 67 ] on the essence and role of double fertilization formed the basis for further ideas about the biological role of the endosperm in the formation of seeds and fruits.…”

In vitro induction of auto-allotetraploid in a newly developed wild rice line from Oryza alta Swallen

“…In fruits, embryo rescue technique was successfully used to produce interspecific hybrids (Prunus persica crossed with P. armeniaca and P. salicina) (Liu et al 2006). Several intra-varietal crosses were generated between transgenic Alamo and the switch grass varieties through in situ immature embryo rescue (Kausch et al 2016). Wei et al (2018) concluded that the use of interspecific hybridization can enrich the genetic background of cultivars with ideal agronomic traits.…”

Increasing Rice Yield through Targeting Genetic Potentials by Rice Types

“…Whereas, embryo rescue, another potential tissue culture technique, can successfully grow the plants achieved from intervarietal, interspecific and intergeneric, or more distantly related crosses and bring novel genetic material and traits in breeding programs. These crosses could otherwise generate abortive embryos (Kausch et al, 2016). Traits having limited or no natural variation eg.…”