Physiological and pollen-based screening of shrub roses for hot and drought environments

• Published in: Scientia horticulturae 2021-05, Vol.282, p.110062, Article 110062
• Main Authors: Bheemanahalli, Raju, Gajanayake, Bandara, Lokhande, Suresh, Singh, Kulvir, Seepaul, Ramdeo, Collins, Pam, Reddy, K. Raja
• Format: Article
• Language: English
• Subjects: Drought; Gas exchange; Heat stress; Pigments; Pollen germination; Rose
• ISSN: 0304-4238; 1879-1018
• DOI: 10.1016/j.scienta.2021.110062

•Significant variability in physiological, biophysical, and pollen germination traits were determined.•Pollen germination and pollen tube length of roses were reduced by high-temperature stress.•A weak correlation between the pollen viability and tube length was observed under high-temperature stress.•Cultivars sharing heat- and drought-adaptive traits are identified using cluster analysis. Rose plants growing under natural conditions are exposed to unfavorable environmental conditions such as high temperature and drought, particularly around the blooming stage. This can reduce the reproductive potential and aesthetic value of commercial rose cultivars, which are often more sensitive to harsh conditions. Plants adjust to adverse environments by regulating several morpho-physiological and biochemical processes, which are the key to tolerance mechanisms. Thus, to examine genetic potential of 22 roses, we characterized 18 traits: gas exchange, leaf biophysical, pigments, and pollen germination characteristics using field-grown roses at the blooming stage. A broad genetic variability (P < 0.001) in all measured traits suggests that roses comprise heat- and drought-adaptive traits. A weak correlation between the pollen viability or germination and the pollen tube length at 38 °C signifying the complexity of reproductive processes. However, three rose cultivars, Moje Hammarberg, Carefree Spirit, and Lavender Meidiland had better pollen germination-related traits (25 %) along with high photosynthetic capacity (24 %) and pigment traits (22 %) compared with sensitive cultivars. The generated phenotypic data, along with reliable phenotyping methods and identified candidate cultivars, would help develop roses with enhanced resilience to stress for dry and hotter climates.