Agronomic evaluation and molecular cytogenetic characterization of Triticum aestivum x Thinopyrum spp. derivative breeding lines presenting perennial growth habit

Authors: MORGAN, ROBIN - Washington State University; Danilova, Tatiana; NEWELL, MATHEW - Nsw Department Of Primary Industries; Cai, Xiwen; JONES, STEPHEN - Washington State University

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/3/2023
Publication Date: 9/9/2023
Citation: Morgan, R., Danilova, T.V., Newell, M., Cai, X., Jones, S. 2023. Agronomic evaluation and molecular cytogenetic characterization of Triticum aestivum x Thinopyrum spp. derivative breeding lines presenting perennial growth habit. Plants. 12(18). Article 3217. https://doi.org/10.3390/plants12183217.
DOI: https://doi.org/10.3390/plants12183217

Interpretive Summary: Perennial wheat has been considered a specialty cereal crop that preserves soils from water- and wind-caused erosion and produces grain for special uses. Perennial wheat can be grown for grain in the marginal farmlands protecting vulnerable soils from erosion, while generating revenue for the growers from grain production. Wheat has many wild perennial relatives that are usable to perennialize annual wheats through breeding. Three perennial wheat lines were developed from cross-pollinations between domesticated wheat and its wild perennial relatives tall and intermediate wheatgrasses. The perennial wheat lines contained the genes for perennial growth habit from the perennial grass parents and regrew after harvest. These three perennial wheat lines regrew and produced grain in a two-year field experiment in the northwest corner of Washington state. The grain yields of the perennial wheat lines were generally lower than their annual wheat parents. Vigorous regrowth was observed after the initial harvest in the first growing season. The regrowth was reduced in the second growing season due to adverse environmental conditions. This study demonstrated that tall and intermediate wheatgrasses can be used to perennialize annual wheat, but post-harvest environmental conditions have significant effects on regrowth. Developing perennial wheat with resistance/tolerance to stressful conditions would increase its regrowth vigor and improve its productivity, which would make perennial wheat viable solution for marginal lands.

Technical Abstract: The transition from annual to perennial growth habit can contribute to increased sustainability and diversification of staple cropping systems like those based on annual wheat. Amphiploids between Triticum aestivum and Thinopyrum spp. can present wheat-like morphology and post sexual cycle regrowth. The complex and unpredictable nature of the chromosomal rearrangements typical of inter-generic hybrids can hamper progress in the development of this new crop. By using fluorescence in situ hybridization we described the genomic constitution of three perennial wheat breeding lines that regrew and completed a second-year of production in field conditions in Washington state (USA). Two breeding lines presented a stable 56 chromosome partial amphiploids however their chromosome composition differed significantly. The third breeding line presented an unstable karyotype with chromosome number ranging from 53 to 58 across eight individuals. Agronomic performance of the perennial breeding lines was evaluated for two growing seasons from 2020 to 2022. The grain yields of the perennial lines were lower than the grain production of the annual wheat control line in the first season. The perennial lines displayed vigorous regrowth after the initial harvest, however, worsening environmental conditions in the second season of growth hampered subsequent growth and grain yield. This information facilitates the breeding work necessary to improve key traits, by grouping agronomically valuable individuals according to their genomic constitution.