Evaluation of Montana winter wheat varieties under speed vernalization and developing a protocol to assess stem solidness of winter wheat varieties in the greenhouse

Abstract

Cereal crops such as winter wheat (Triticum aestivum) represent a critical component of Montana's agricultural economy; however, the production of a single generation can require up to six months in greenhouse. This dissertation investigates the effect of speed vernalization with speed breeding in selected widely grown cultivars and winter hardy breeding lines. Speed vernalization utilizes extended photoperiod and higher temperature settings to reduce the vernalization time in winter cereals. The first study in chapter two evaluates the agronomic performance for hard red winter wheat cultivars in two speed vernalization conditions, 4 weeks and 6 weeks under 22hr day/ 2 hr night photoperiod at 10 °C and one normal vernalization condition for 6 weeks under 12 hr photoperiod at 4 °C. All plants are transferred to speed breeding growth room following vernalization which has a 22hr/2hr photoperiod at 23 °C/18 °C temperature for day and night respectively. Our study highlights that most varieties/breeding lines produced heads and had sufficient grain production and grain weight under shorter vernalization periods. The shortest crop cycle of 117 days was observed under 6 weeks of vernalization, though tiller numbers, grain numbers and grain weight were higher under 4 weeks of vernalization. Experiment Observations from this study indicate that most cultivars examined are capable of successful advancement using the described protocols. The third chapter implements a screening approach aimed at determining stem solidness-categorizing breeding lines as hollow, semi-solid, or solid-to support future breeding efforts This study assesses the effectiveness of a rapid screening method for stem solidness in hard red winter wheat breeding lines grown in greenhouse environments at Montana State University. By employing conventional vernalization, 8 weeks at 4 °C with fluorescent lighting, followed by speed breeding consisting of a 22/2-hour photoperiod, 22 °C and adjusted LED lighting meant to stimulate growth. This approach accelerates generation turnover relative to fluorescent-light growth systems while enabling reliable identification of lines with desirable stem solidness traits for Montana's diverse environmental conditions. Collectively, these studies address previously unexplored attributes of hard red winter wheat cultivars under speed vernalization and speed breeding regimes and contributes to the development of a greenhouse-based screening protocol to enhance selection efficiency in cereal breeding programs.