Investigation of variable storage conditions for cultivated northern wild rice and their effects on seed viability and dormancy

Abstract

<jats:title>Abstract</jats:title><jats:p>Cultivated northern wild rice (NWR; <jats:italic>Zizania palustris</jats:italic> L.) has been bred and studied since the 1950s. One challenge facing researchers is the lack of storage options, due to the seed's unorthodox behaviour. This study evaluated varying storage temperature and moisture conditions for the maintenance of seed viability and dormancy breaking in Minnesota-grown NWR. First, seeds were placed in non-submerged, freezing storage (NSFS) for 12–26 weeks, then in submerged, cold storage (SCS) for 2 weeks. The addition of SCS increased germination (%G) relative to NSFS alone (&lt;0.1% NSFS, 15% NSFS and SCS), indicating that NSFS does not kill seeds but also does not break seed dormancy. Next, the required length of SCS was evaluated by placing seeds in NSFS for 12 weeks and then in SCS for 2–14 weeks. A longer SCS period increased %G from 3 to 79%, at 2 and 14 weeks of SCS, respectively. Lastly, seeds were placed in NSFS, followed by SCS, at varying intervals over a 29-week period. Across lines, germination increased from 20 to 76% between 4 and 7 weeks of SCS, respectively, then plateaued. The results of this study indicate that NSFS could be used to store NWR seeds, but at least 7 weeks in SCS is required to overcome dormancy. Additionally, while NSFS did not break seed dormancy, physiological changes related to stratification processes were occurring in non-submerged, freezing conditions. Results also suggest that the genotypic variation in NWR could be utilized for selection to improve germination and storage viability.</jats:p>

Dormancy Breaking Treatments in Northern Wild Rice (Zizania palustris L.) Seed Suggest a Physiological Source of Dormancy

“…However, because this study only covered about 9 months post-harvest, it was likely too short to demonstrate the drop in viability that is commonly recorded for NWR (Kovach and Bradford, 1992a;Berjak and Pammenter, 2008;McGilp et al, 2020). Additionally, the D50 for K2EF-C16 was shorter than that of Itasca-C12.…”

“…Unique breeding challenges exist for NWR due to the seeds' intermediate recalcitrance and the presence of seed dormancy. Previous studies have evaluated these traits in order to improve the understanding of NWR seed physiology and thereby increase breeding efficiency (Cardwell et al, 1978;Oelke and Albrecht, 1978;Albrecht et al, 1979;Kovach and Bradford, 1992a;McGilp et al, 2020).…”

Whole Genome Assembly and Annotation of Northern Wild Rice,Zizania palustrisL., Supports a Whole Genome Duplication in theZizaniaGenus

“…In 2018, leaf tissue from Itasca-C12 was collected from a single S2 plant for sequencing. Self-pollinated seed from the individual plant was harvested and stored in water at 3°C in the dark (Oelke and Albrecht, 1978; Oelke and Porter, 2016; McGilp et al ., 2020). Given that NWR seed is recalcitrant and ex-situ seed storage is not currently feasible for this species, seed has not been deposited to a seed bank and is maintained in the UMN NWR breeding, genetics, and conservation program.…”

“…In particular, NWR harbors several unique characteristics that pose challenges to both conservation and breeding schemes. The species’ seeds, for example, are intermediately recalcitrant or desiccation intolerant, which limits seed viability in ex-situ storage to 1-2 years (Probert and Longley, 1989; McGilp et al ., 2020). As such, NWR seed cannot be stored in seed banks or repositories unless maintained on an annual basis.…”

Physical seed dormancy in Abrus precatorious (Ratti): a scientific validation of indigenous technique

“…Where, the seeds were referred as Ratti, a traditional Indian unit of mass measurement (Shrivastava, 2017). Generally, seed weight changes or fluctuate with change in environmental conditions (temperature, relative humidity), storage-period and storage-conditions (McGilp et al, 2020). Further, seeds weight generally decline with the progression of storage/ageing due to metabolic breakdown of stored food, microbial degradation, pest infestation, and also due to bear-and-tear .…”