Influence of Raspberry bushy dwarf virus on pollination of red raspberry (Rubus idaeus L.) cultivars

L. Sproģe and S. Strautiņa*

Institute of Horticulture (Latvia University of Life Sciences and Technologies), Graudu iela 1, LV-3701 Dobele, Latvia

Abstract:

Raspberry bushy dwarf virus (RBDV) is one of the major pollen-borne pathogens of the genus Rubus that causes drastic reduction of yield and degradation of berry quality. The aim of the study was to evaluate the quality of raspberry pollen and the effect of RBDV on pollination process. The research was carried out at the Institute of Horticulture. Within two years, 2017 and 2018, the pollen viability and pollen germination capacity of nine raspberry cultivars were analysed. The cross-pollination was done and the pollination quality of 31 crossing combinations was evaluated. The study found that although the pollen viability of cultivars infected with RBDV was higher than that of uninfected cultivars, there were no statistically significant differences. The viral contamination of the mother plant played a more important role in the pollination process. Pollination was better on uninfected mother plants and pollen germinated was faster than on infected plants. However, when the virus-infected cultivars were pollinated with infected pollen, the virus had an effect on the growth rate of pollen tubes, that decreased and the pollen tubes did not reach the ovary.

Key words:

Morpho-physiological traits associated with terminal drought- stress tolerance in triticale and wheat

M. Lonbani and A. Arzani*

*Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan 84156 83111, Iran; e-mail: a_arzani@cc.iut.ac.ir

Abstract:

The objectives of this study were to evaluate the genotypic effects on tolerance to terminal drought stress in triticale and to compare it with that of durum and bread wheat under drought stress and normal field conditions using morpho-physiological traits. Five triticale ('Zoro', 'Moreno', 'Lasko', 'Prego' and 'Alamos 83'), one bread wheat ('Roshan') and one durum wheat ('Osta-Gata') cultivars were used. A randomized complete block design with three replications was used in each of the drought stress and well-watered (non-stress) experiments. Morpho-physiological traits including chlorophyll content, relative water content (RWC), excised leaf water retention (ELWR), rate of water loss (RWL), initial water content (IWC), leaf area, leaf angle, number of stomata, pollen viability, dry weight of awn and awn length were evaluated. Results of combined analyses of variances indicated the highly significant differences among genotypes for all traits and significant genotype × environmental interaction for all traits with the exception of leaf width, number of stomata and awn length. Overall performance of triticale cultivars was superior to wheat cultivars under both environmental conditions. Among triticale genotypes, 'Lasko' and 'Moreno' cultivars were the most drought tolerant and 'Prego' cultivar was the most sensitive genotype to water stress. Under drought stress conditions ELWR showed significant and negative correlation with grain yield, while their correlation was significant and positive under non-stress conditions. This relationship indicates that ELWR had an important impact on grain yield under both water stress and non-stress conditions.

Key words:

drought stress, morpho-physiological traits, pollen viability, tolerance, triticale